Spring rate vs Ride comfort vs Performance database (FD3S)
07-12-15, 12:57 PM
#101
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
Got a ride in the Tein HT with 18/18 spring rates. Holey crap those thing are rocks. were bumping all over the place. The car would struggle to do 50 mph without killing itself on the backroads. The owner is swapping to lighter springs but is undecided how much softer. says the car is getting beat up from the rates here on the CO roads. Guess those coilovers retail for like $3,500 or something.
His EFR 8374 turbo is rediculous though.
His EFR 8374 turbo is rediculous though.
07-12-15, 01:00 PM
#102
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
Hot Version Touge Challenge series uses the Gunma Cycle Sports Center track for a simulation of real mountain roads and pits tuner cars against eachother.
Cars are judged not only on fastest time, but on safety/comfort of set up for real world driving conditions with particular emphasis on suspension compliance- this course has lots of bumps.
RE Amemiya has dominated with FDs winning 3/4 series from 2004 to present. Most recently, I was blown away to see the stock turbo FD defeat the 650hp R35 GTR.
The Touge Monster FD uses DG-5 RE Amemiya Spec coilovers-
16K Front
18K Rear
This is on 255mm street tires!
Normal DG-5 FD coilover spec-
16k Front
14K Rear
Obviously, there is more than just spring rate to consider when a compliant, safe set up is being built.
https://www.youtube.com/watch?v=MCNcFCl_bUA
https://www.youtube.com/watch?v=8eFMnwerQq0
Cars are judged not only on fastest time, but on safety/comfort of set up for real world driving conditions with particular emphasis on suspension compliance- this course has lots of bumps.
RE Amemiya has dominated with FDs winning 3/4 series from 2004 to present. Most recently, I was blown away to see the stock turbo FD defeat the 650hp R35 GTR.
The Touge Monster FD uses DG-5 RE Amemiya Spec coilovers-
16K Front
18K Rear
This is on 255mm street tires!
Normal DG-5 FD coilover spec-
16k Front
14K Rear
Obviously, there is more than just spring rate to consider when a compliant, safe set up is being built.
https://www.youtube.com/watch?v=MCNcFCl_bUA
https://www.youtube.com/watch?v=8eFMnwerQq0
I rode in those 18/18 and there is no way in the world that damping is going to save those rates on the roads we drive on, no way.
07-12-15, 02:15 PM
#103
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
i do agree that 18/18 is a bit much for the street though.
07-15-15, 06:45 AM
#104
Senior Member
Race car design Book
https://books.google.com/books?id=FR...0rates&f=false
"However it is true that to maximise mechanical grip the suspension should be as soft as possible."
Read the book linked for explenation why.
https://books.google.com/books?id=FR...0rates&f=false
"However it is true that to maximise mechanical grip the suspension should be as soft as possible."
Read the book linked for explenation why.
8kg/mm springs will be in the 1.5-1.7 Hz range. That's probably about as stiff as you'd want to go for a very handling-performance-oriented *street* car on *street* tires, but it's a bit soft for track work.
My car, with 13kg/mm front and 11kg/mm rear springs is right at 2 Hz. For me, it's a good street/track compromise (i.e., too soft for the track, too stiff for the street!).
Almost every single thread/book/etc I have seen has said to run the softest springs as possible to run.
"Soft as possible" has a different context if you are talking about a race car on slicks vs. a street/track car on R-comps at the track vs. a high-performance street car on street tires being driven on the street.
I still say it is something of a myth that softer springs give greater grip. The idea springs from the fact that when you soften one end of the car you get more grip at that end, and when you stiffen one end of the car you get less grip at that end. But again, this is not directly due to the stiffness, but rather the load distribution between the outside (and inside) front and rear tires. Soften or stiffen one end of the car and overall grip remains about the same, you've just traded grip at one end for grip at the other end by redistributing the vertical loads on the tires to favor one end over the other.
There is a point of diminishing returns when going stiffer, but it is well beyond the 8kg/mm range for just about any road course.
Mechanical grip is a HUGE factor in lap times. If stiffer spring rates in the 11-18kg/mm range really gave less mechanical grip than 8kg/mm, then track cars would go slower on the stiffer-rate springs. But they typically go faster...
Last edited by ZDan; 07-15-15 at 07:09 AM.
07-15-15, 11:09 AM
#106
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
"Soft as possible" is relative. What is "soft" at the track can seem very stiff on the street. Look at pages 95 and 96 in the "Race Car Design" link, he refers to 2.05Hz frequency as a "soft car" and 4.8 Hz as a "hard car".
8kg/mm springs will be in the 1.5-1.7 Hz range. That's probably about as stiff as you'd want to go for a very handling-performance-oriented *street* car on *street* tires, but it's a bit soft for track work.
My car, with 13kg/mm front and 11kg/mm rear springs is right at 2 Hz. For me, it's a good street/track compromise (i.e., too soft for the track, too stiff for the street!).
Why not 1kg/mm? 0.1 kg/mm?
"Soft as possible" has a different context if you are talking about a race car on slicks vs. a street/track car on R-comps at the track vs. a high-performance street car on street tires being driven on the street.
I still say it is something of a myth that softer springs give greater grip. The idea springs from the fact that when you soften one end of the car you get more grip at that end, and when you stiffen one end of the car you get less grip at that end. But again, this is not directly due to the stiffness, but rather the load distribution between the outside (and inside) front and rear tires. Soften or stiffen one end of the car and overall grip remains about the same, you've just traded grip at one end for grip at the other end by redistributing the vertical loads on the tires to favor one end over the other.
There is a point of diminishing returns when going stiffer, but it is well beyond the 8kg/mm range for just about any road course.
Mechanical grip is a HUGE factor in lap times. If stiffer spring rates in the 11-18kg/mm range really gave less mechanical grip than 8kg/mm, then track cars would go slower on the stiffer-rate springs. But they typically go faster...
8kg/mm springs will be in the 1.5-1.7 Hz range. That's probably about as stiff as you'd want to go for a very handling-performance-oriented *street* car on *street* tires, but it's a bit soft for track work.
My car, with 13kg/mm front and 11kg/mm rear springs is right at 2 Hz. For me, it's a good street/track compromise (i.e., too soft for the track, too stiff for the street!).
Why not 1kg/mm? 0.1 kg/mm?
"Soft as possible" has a different context if you are talking about a race car on slicks vs. a street/track car on R-comps at the track vs. a high-performance street car on street tires being driven on the street.
I still say it is something of a myth that softer springs give greater grip. The idea springs from the fact that when you soften one end of the car you get more grip at that end, and when you stiffen one end of the car you get less grip at that end. But again, this is not directly due to the stiffness, but rather the load distribution between the outside (and inside) front and rear tires. Soften or stiffen one end of the car and overall grip remains about the same, you've just traded grip at one end for grip at the other end by redistributing the vertical loads on the tires to favor one end over the other.
There is a point of diminishing returns when going stiffer, but it is well beyond the 8kg/mm range for just about any road course.
Mechanical grip is a HUGE factor in lap times. If stiffer spring rates in the 11-18kg/mm range really gave less mechanical grip than 8kg/mm, then track cars would go slower on the stiffer-rate springs. But they typically go faster...
For my set up, minimal downforce, and the ride height I have, 8/6 springs give MORE grip and road compliance than the stock 11/11 set up. and its a big difference more especially on ok roads. 8/6 will also give me more grip on the track as I won't be bottoming out my car at the ride height of 25" front and 25.5" rear. I am running street tires which probably max grip out around 1.1-1.3G's.
stiffer springs are for aero downforce, super low ride heights, and cars who have poor suspension camber curves.
Lower ride frequencies produce more grip as they are softer and more compliant (they push the inside and outside tires back to the road with more force due to more droop travel), but when I say soft as possible, I am saying you want a suspension that gives the most suspension travel possible without bottoming the car on the track/road, and not bottoming the suspension.
Last edited by lOOkatme; 07-15-15 at 11:12 AM.
07-15-15, 01:06 PM
#107
I agree with what you are saying that you use the softest spring you can use and avoid being on the bumpstops (as it will raise the rate) for the most traction over rough surfaces and ignoring the impacts of transient response.
There is an element of driver's preference and ability here that an engineer who forgot to factor time into this calculations might not think of either (in the video he did not factor the time required to accelerate the unsprung mass into the depression or over the bump and the vehicles rate of travel versus the length of depression/bump to see if the vehicle could even use the full droop/compression travel available).
Racers think about time... a lot.
---------------------------
Preference-
Driver X might prefer having a settled chassis through the bumpiest section of the course at the expense of slower chassis response due to the lower spring rates. He doesn't mind "dancing" with the chassis to keep ahead of it in transitions.
Driver Y might prefer a faster responding chassis set up of a higher spring rates and sacrifice a settled chassis over the bumpiest section of the course. Perhaps he slows down over the bumps or perhaps he simply corrects for the chassis losing traction over the bumps. This driver want the most responsive chassis on the rest of the course for faster transitions. We say preference, but there is also some ability in the preference.
---------------------
Ability-
Driver x might be clearing the turns with 1" travel on said spring rate and have that 1" travel before the bumpstop to absorb the road irregularities.
Driver Y has higher abilities and is keeping the tire at the maximum level of traction throughout the turn and is already at 0" travel on same spring rate before hitting the bumpstop. He has no travel on the spring rate to absorb road irregularities- it will go straight to the higher spring rate of the bumpstop.
It would be better for this driver to have a higher initial spring rate to gain travel before the bumpstop.
---------------
Now, lets look at our real world examples-
Driver X (that is you) is an automotive enthusiast driving on public roads that prefers a lower 8K/6K spring rate to have a settled chassis over bumps. That is a good thing, we aren't knocking it.
Driver Y (that is Keiichi Tsuchiya) is one of Japan's best drivers with about this much racing experience-
1977 Debut in Fuji Freshman series.
1977-1984 Ran selected entries in All Japan Touring Car championship.
1984 Fuji Freshman series race (Toyota AE86)= 6 wins
1985 All Japan Touring Car championship (Toyota AE86) 1st in Class 3
1986 Corolla Sprinter Cup-2 podium places
1987 All Japan Touring Car championship (Honda Civic) -1 win
1988 Toyota Cup-1st overall
All Japan Touring Car championship (BMW E30) -3rd in Class 2
Macau Guia race (BMW M3) -4th overall
1989 All Japan F3 championship
All Japan Touring Car championship (Ford Sierra Cosworth) -1 win
1990 All Japan Touring Car championship (Ford Sierra Cosworth)
Macau Guia race (Ford Sierra Cosworth)
New Zealand Touring Car series (Toyota)
1991 All Japan F3 championship (Ralt-Mugen)-10th overall
All Japan Touring Car championship (Nissan Skyline GT-R) -5th overall
1992 All Japan Touring Car championship (Nissan Skyline GT-R)
1993 All Japan Touring Car championship (Taisan Nissan Skyline GT-R) -1 win
Japan Endurance series (Honda Prelude) -2nd Tsukuba 12 Hours
1994 All Japan GT championship (Porsche 911T) -1 win
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Porsche 911T) -1st in class, 2nd overall
Le Mans 24 Hours (Honda NSX) -18th overall
1995 All Japan GT championship (Porsche911TRSR)
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Honda NSX) -5th overall
Tokachi 12 Hours (Honda NSX) -1st overall
Le Mans 24 Hours (Honda NSX) -1st in class
1996 All Japan GT championship (Honda NSX) -13th overall
Entered NASCAR Thunder Special race at Suzuka
Le mans 24 Hours (Honda NSX) -3rd in class
1997 All Japan GT championship (Porsche 911/Dodge Viper)
Fuji InterTec race (Toyota Chaser)
Suzuka 1000 km (Lark McLaren F1 GTR) -9th overall
Entered NASCAR Thunder Special race at Suzuka
Le Mans 24 Hours (Lark McLaren F1 GTR) -qualified 10th, retired from race
1998 All Japan Touring Car championship (Toyota Chaser) -7th overall
All Japan GT championship (Toyota Supra) -8th overall
Le Mans 24 Hours (Toyota GT-One) -9th overall
NASCAR at the California Speedway.
1999 Japan Touring Car Championship (Advan Altezza Touring car).
Le Mans 24 Hours (Toyota GT-One) -2nd overall
2000 Le Mans 24 Hours (Panoz LMP-1 Roadster-S) -8th overall
2000-2003 he joined team ARTA racing an NSX once again in the All Japan GT championship.
2004-2005 studied in Australia to complete inter-2 course.
and he started and was disciplined for racing on the street- so he certainly knows that too.
Driver Y prefers 16K/18K spring rate on the same chassis with less tire. He likes the suspension set up so much he starts selling it under his own companies offerings along side the rates he had already chosen on his own for the chassis (16K/16K).
Not only that, but driver Y had driver Z (that is Manabu Orido) who also started racing on the street and is a also a current GT and Lemans championship winning driver drive the car and verify the suspension set up is all that driver Y thinks it is.
Driver Y and Z time their laps on course to verify their driving impressions.
_________________
Now, which suspension is better for me?
It depends on my preference and ability.
I would love to try the 16K/18K set up and GT wing and see if I can handle it, but the fact is I know I am somewhere in between that and the 8K/6K in terms of my preference and ability.
I would love to be doing the same thing you are and trying different spring rates to find which I like best, but I would be mindful that whatever I chose would not necessarily be the best for all drivers.
There is an element of driver's preference and ability here that an engineer who forgot to factor time into this calculations might not think of either (in the video he did not factor the time required to accelerate the unsprung mass into the depression or over the bump and the vehicles rate of travel versus the length of depression/bump to see if the vehicle could even use the full droop/compression travel available).
Racers think about time... a lot.
---------------------------
Preference-
Driver X might prefer having a settled chassis through the bumpiest section of the course at the expense of slower chassis response due to the lower spring rates. He doesn't mind "dancing" with the chassis to keep ahead of it in transitions.
Driver Y might prefer a faster responding chassis set up of a higher spring rates and sacrifice a settled chassis over the bumpiest section of the course. Perhaps he slows down over the bumps or perhaps he simply corrects for the chassis losing traction over the bumps. This driver want the most responsive chassis on the rest of the course for faster transitions. We say preference, but there is also some ability in the preference.
---------------------
Ability-
Driver x might be clearing the turns with 1" travel on said spring rate and have that 1" travel before the bumpstop to absorb the road irregularities.
Driver Y has higher abilities and is keeping the tire at the maximum level of traction throughout the turn and is already at 0" travel on same spring rate before hitting the bumpstop. He has no travel on the spring rate to absorb road irregularities- it will go straight to the higher spring rate of the bumpstop.
It would be better for this driver to have a higher initial spring rate to gain travel before the bumpstop.
---------------
Now, lets look at our real world examples-
Driver X (that is you) is an automotive enthusiast driving on public roads that prefers a lower 8K/6K spring rate to have a settled chassis over bumps. That is a good thing, we aren't knocking it.
Driver Y (that is Keiichi Tsuchiya) is one of Japan's best drivers with about this much racing experience-
1977 Debut in Fuji Freshman series.
1977-1984 Ran selected entries in All Japan Touring Car championship.
1984 Fuji Freshman series race (Toyota AE86)= 6 wins
1985 All Japan Touring Car championship (Toyota AE86) 1st in Class 3
1986 Corolla Sprinter Cup-2 podium places
1987 All Japan Touring Car championship (Honda Civic) -1 win
1988 Toyota Cup-1st overall
All Japan Touring Car championship (BMW E30) -3rd in Class 2
Macau Guia race (BMW M3) -4th overall
1989 All Japan F3 championship
All Japan Touring Car championship (Ford Sierra Cosworth) -1 win
1990 All Japan Touring Car championship (Ford Sierra Cosworth)
Macau Guia race (Ford Sierra Cosworth)
New Zealand Touring Car series (Toyota)
1991 All Japan F3 championship (Ralt-Mugen)-10th overall
All Japan Touring Car championship (Nissan Skyline GT-R) -5th overall
1992 All Japan Touring Car championship (Nissan Skyline GT-R)
1993 All Japan Touring Car championship (Taisan Nissan Skyline GT-R) -1 win
Japan Endurance series (Honda Prelude) -2nd Tsukuba 12 Hours
1994 All Japan GT championship (Porsche 911T) -1 win
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Porsche 911T) -1st in class, 2nd overall
Le Mans 24 Hours (Honda NSX) -18th overall
1995 All Japan GT championship (Porsche911TRSR)
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Honda NSX) -5th overall
Tokachi 12 Hours (Honda NSX) -1st overall
Le Mans 24 Hours (Honda NSX) -1st in class
1996 All Japan GT championship (Honda NSX) -13th overall
Entered NASCAR Thunder Special race at Suzuka
Le mans 24 Hours (Honda NSX) -3rd in class
1997 All Japan GT championship (Porsche 911/Dodge Viper)
Fuji InterTec race (Toyota Chaser)
Suzuka 1000 km (Lark McLaren F1 GTR) -9th overall
Entered NASCAR Thunder Special race at Suzuka
Le Mans 24 Hours (Lark McLaren F1 GTR) -qualified 10th, retired from race
1998 All Japan Touring Car championship (Toyota Chaser) -7th overall
All Japan GT championship (Toyota Supra) -8th overall
Le Mans 24 Hours (Toyota GT-One) -9th overall
NASCAR at the California Speedway.
1999 Japan Touring Car Championship (Advan Altezza Touring car).
Le Mans 24 Hours (Toyota GT-One) -2nd overall
2000 Le Mans 24 Hours (Panoz LMP-1 Roadster-S) -8th overall
2000-2003 he joined team ARTA racing an NSX once again in the All Japan GT championship.
2004-2005 studied in Australia to complete inter-2 course.
and he started and was disciplined for racing on the street- so he certainly knows that too.
Driver Y prefers 16K/18K spring rate on the same chassis with less tire. He likes the suspension set up so much he starts selling it under his own companies offerings along side the rates he had already chosen on his own for the chassis (16K/16K).
Not only that, but driver Y had driver Z (that is Manabu Orido) who also started racing on the street and is a also a current GT and Lemans championship winning driver drive the car and verify the suspension set up is all that driver Y thinks it is.
Driver Y and Z time their laps on course to verify their driving impressions.
_________________
Now, which suspension is better for me?
It depends on my preference and ability.
I would love to try the 16K/18K set up and GT wing and see if I can handle it, but the fact is I know I am somewhere in between that and the 8K/6K in terms of my preference and ability.
I would love to be doing the same thing you are and trying different spring rates to find which I like best, but I would be mindful that whatever I chose would not necessarily be the best for all drivers.
07-15-15, 01:35 PM
#108
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
I agree with what you are saying that you use the softest spring you can use and avoid being on the bumpstops (as it will raise the rate) for the most traction over rough surfaces and ignoring the impacts of transient response.
There is an element of driver's preference and ability here that an engineer who forgot to factor time into this calculations might not think of either (in the video he did not factor the time required to accelerate the unsprung mass into the depression or over the bump and the vehicles rate of travel versus the length of depression/bump to see if the vehicle could even use the full droop/compression travel available).
Racers think about time... a lot.
---------------------------
Preference-
Driver X might prefer having a settled chassis through the bumpiest section of the course at the expense of slower chassis response due to the lower spring rates. He doesn't mind "dancing" with the chassis to keep ahead of it in transitions.
Driver Y might prefer a faster responding chassis set up of a higher spring rates and sacrifice a settled chassis over the bumpiest section of the course. Perhaps he slows down over the bumps or perhaps he simply corrects for the chassis losing traction over the bumps. This driver want the most responsive chassis on the rest of the course for faster transitions. We say preference, but there is also some ability in the preference.
---------------------
Ability-
Driver x might be clearing the turns with 1" travel on said spring rate and have that 1" travel before the bumpstop to absorb the road irregularities.
Driver Y has higher abilities and is keeping the tire at the maximum level of traction throughout the turn and is already at 0" travel on same spring rate before hitting the bumpstop. He has no travel on the spring rate to absorb road irregularities- it will go straight to the higher spring rate of the bumpstop.
It would be better for this driver to have a higher initial spring rate to gain travel before the bumpstop.
---------------
Now, lets look at our real world examples-
Driver X (that is you) is an automotive enthusiast driving on public roads that prefers a lower 8K/6K spring rate to have a settled chassis over bumps. That is a good thing, we aren't knocking it.
Driver Y (that is Keiichi Tsuchiya) is one of Japan's best drivers with about this much racing experience-
1977 Debut in Fuji Freshman series.
1977-1984 Ran selected entries in All Japan Touring Car championship.
1984 Fuji Freshman series race (Toyota AE86)= 6 wins
1985 All Japan Touring Car championship (Toyota AE86) 1st in Class 3
1986 Corolla Sprinter Cup-2 podium places
1987 All Japan Touring Car championship (Honda Civic) -1 win
1988 Toyota Cup-1st overall
All Japan Touring Car championship (BMW E30) -3rd in Class 2
Macau Guia race (BMW M3) -4th overall
1989 All Japan F3 championship
All Japan Touring Car championship (Ford Sierra Cosworth) -1 win
1990 All Japan Touring Car championship (Ford Sierra Cosworth)
Macau Guia race (Ford Sierra Cosworth)
New Zealand Touring Car series (Toyota)
1991 All Japan F3 championship (Ralt-Mugen)-10th overall
All Japan Touring Car championship (Nissan Skyline GT-R) -5th overall
1992 All Japan Touring Car championship (Nissan Skyline GT-R)
1993 All Japan Touring Car championship (Taisan Nissan Skyline GT-R) -1 win
Japan Endurance series (Honda Prelude) -2nd Tsukuba 12 Hours
1994 All Japan GT championship (Porsche 911T) -1 win
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Porsche 911T) -1st in class, 2nd overall
Le Mans 24 Hours (Honda NSX) -18th overall
1995 All Japan GT championship (Porsche911TRSR)
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Honda NSX) -5th overall
Tokachi 12 Hours (Honda NSX) -1st overall
Le Mans 24 Hours (Honda NSX) -1st in class
1996 All Japan GT championship (Honda NSX) -13th overall
Entered NASCAR Thunder Special race at Suzuka
Le mans 24 Hours (Honda NSX) -3rd in class
1997 All Japan GT championship (Porsche 911/Dodge Viper)
Fuji InterTec race (Toyota Chaser)
Suzuka 1000 km (Lark McLaren F1 GTR) -9th overall
Entered NASCAR Thunder Special race at Suzuka
Le Mans 24 Hours (Lark McLaren F1 GTR) -qualified 10th, retired from race
1998 All Japan Touring Car championship (Toyota Chaser) -7th overall
All Japan GT championship (Toyota Supra) -8th overall
Le Mans 24 Hours (Toyota GT-One) -9th overall
NASCAR at the California Speedway.
1999 Japan Touring Car Championship (Advan Altezza Touring car).
Le Mans 24 Hours (Toyota GT-One) -2nd overall
2000 Le Mans 24 Hours (Panoz LMP-1 Roadster-S) -8th overall
2000-2003 he joined team ARTA racing an NSX once again in the All Japan GT championship.
2004-2005 studied in Australia to complete inter-2 course.
and he started and was disciplined for racing on the street- so he certainly knows that too.
Driver Y prefers 16K/18K spring rate on the same chassis with less tire. He likes the suspension set up so much he starts selling it under his own companies offerings along side the rates he had already chosen on his own for the chassis (16K/16K).
Not only that, but driver Y had driver Z (that is Manabu Orido) who also started racing on the street and is a also a current GT and Lemans championship winning driver drive the car and verify the suspension set up is all that driver Y thinks it is.
Driver Y and Z time their laps on course to verify their driving impressions.
_________________
Now, which suspension is better for me?
It depends on my preference and ability.
I would love to try the 16K/18K set up and GT wing and see if I can handle it, but the fact is I know I am somewhere in between that and the 8K/6K in terms of my preference and ability.
I would love to be doing the same thing you are and trying different spring rates to find which I like best, but I would be mindful that whatever I chose would not necessarily be the best for all drivers.
There is an element of driver's preference and ability here that an engineer who forgot to factor time into this calculations might not think of either (in the video he did not factor the time required to accelerate the unsprung mass into the depression or over the bump and the vehicles rate of travel versus the length of depression/bump to see if the vehicle could even use the full droop/compression travel available).
Racers think about time... a lot.
---------------------------
Preference-
Driver X might prefer having a settled chassis through the bumpiest section of the course at the expense of slower chassis response due to the lower spring rates. He doesn't mind "dancing" with the chassis to keep ahead of it in transitions.
Driver Y might prefer a faster responding chassis set up of a higher spring rates and sacrifice a settled chassis over the bumpiest section of the course. Perhaps he slows down over the bumps or perhaps he simply corrects for the chassis losing traction over the bumps. This driver want the most responsive chassis on the rest of the course for faster transitions. We say preference, but there is also some ability in the preference.
---------------------
Ability-
Driver x might be clearing the turns with 1" travel on said spring rate and have that 1" travel before the bumpstop to absorb the road irregularities.
Driver Y has higher abilities and is keeping the tire at the maximum level of traction throughout the turn and is already at 0" travel on same spring rate before hitting the bumpstop. He has no travel on the spring rate to absorb road irregularities- it will go straight to the higher spring rate of the bumpstop.
It would be better for this driver to have a higher initial spring rate to gain travel before the bumpstop.
---------------
Now, lets look at our real world examples-
Driver X (that is you) is an automotive enthusiast driving on public roads that prefers a lower 8K/6K spring rate to have a settled chassis over bumps. That is a good thing, we aren't knocking it.
Driver Y (that is Keiichi Tsuchiya) is one of Japan's best drivers with about this much racing experience-
1977 Debut in Fuji Freshman series.
1977-1984 Ran selected entries in All Japan Touring Car championship.
1984 Fuji Freshman series race (Toyota AE86)= 6 wins
1985 All Japan Touring Car championship (Toyota AE86) 1st in Class 3
1986 Corolla Sprinter Cup-2 podium places
1987 All Japan Touring Car championship (Honda Civic) -1 win
1988 Toyota Cup-1st overall
All Japan Touring Car championship (BMW E30) -3rd in Class 2
Macau Guia race (BMW M3) -4th overall
1989 All Japan F3 championship
All Japan Touring Car championship (Ford Sierra Cosworth) -1 win
1990 All Japan Touring Car championship (Ford Sierra Cosworth)
Macau Guia race (Ford Sierra Cosworth)
New Zealand Touring Car series (Toyota)
1991 All Japan F3 championship (Ralt-Mugen)-10th overall
All Japan Touring Car championship (Nissan Skyline GT-R) -5th overall
1992 All Japan Touring Car championship (Nissan Skyline GT-R)
1993 All Japan Touring Car championship (Taisan Nissan Skyline GT-R) -1 win
Japan Endurance series (Honda Prelude) -2nd Tsukuba 12 Hours
1994 All Japan GT championship (Porsche 911T) -1 win
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Porsche 911T) -1st in class, 2nd overall
Le Mans 24 Hours (Honda NSX) -18th overall
1995 All Japan GT championship (Porsche911TRSR)
All Japan Touring Car championship (Honda Civic)
Suzuka 1000 km (Honda NSX) -5th overall
Tokachi 12 Hours (Honda NSX) -1st overall
Le Mans 24 Hours (Honda NSX) -1st in class
1996 All Japan GT championship (Honda NSX) -13th overall
Entered NASCAR Thunder Special race at Suzuka
Le mans 24 Hours (Honda NSX) -3rd in class
1997 All Japan GT championship (Porsche 911/Dodge Viper)
Fuji InterTec race (Toyota Chaser)
Suzuka 1000 km (Lark McLaren F1 GTR) -9th overall
Entered NASCAR Thunder Special race at Suzuka
Le Mans 24 Hours (Lark McLaren F1 GTR) -qualified 10th, retired from race
1998 All Japan Touring Car championship (Toyota Chaser) -7th overall
All Japan GT championship (Toyota Supra) -8th overall
Le Mans 24 Hours (Toyota GT-One) -9th overall
NASCAR at the California Speedway.
1999 Japan Touring Car Championship (Advan Altezza Touring car).
Le Mans 24 Hours (Toyota GT-One) -2nd overall
2000 Le Mans 24 Hours (Panoz LMP-1 Roadster-S) -8th overall
2000-2003 he joined team ARTA racing an NSX once again in the All Japan GT championship.
2004-2005 studied in Australia to complete inter-2 course.
and he started and was disciplined for racing on the street- so he certainly knows that too.
Driver Y prefers 16K/18K spring rate on the same chassis with less tire. He likes the suspension set up so much he starts selling it under his own companies offerings along side the rates he had already chosen on his own for the chassis (16K/16K).
Not only that, but driver Y had driver Z (that is Manabu Orido) who also started racing on the street and is a also a current GT and Lemans championship winning driver drive the car and verify the suspension set up is all that driver Y thinks it is.
Driver Y and Z time their laps on course to verify their driving impressions.
_________________
Now, which suspension is better for me?
It depends on my preference and ability.
I would love to try the 16K/18K set up and GT wing and see if I can handle it, but the fact is I know I am somewhere in between that and the 8K/6K in terms of my preference and ability.
I would love to be doing the same thing you are and trying different spring rates to find which I like best, but I would be mindful that whatever I chose would not necessarily be the best for all drivers.
I agree with what your saying. Time does not necessairly mean grip, as you mentioned drivers preference and some drivers will drive faster with less grip, as weird as that sounds.
I do notice that the mines skyline is sprung stiffly, it did very well on the japanese tracks (looked smooth as they were filming). they brought that car over here and you can see how poor the track surface is compared to the japanese tracks, the car was very bumpy although Tsuchiya still drove it wonderfully. The car is leterally skipping all over the place, look at Tsuchiya bumping around and how fast and twitchy the inputs are. Still set the course record.
07-15-15, 02:16 PM
#109
I agree with what your saying. Time does not necessairly mean grip, as you mentioned drivers preference and some drivers will drive faster with less grip, as weird as that sounds.
I would say again you are confusing your definition of "grip" and maximum tire traction which actually happens at ~6-10degrees slip angle (past the limit of "grip").
I do agree there are a few segments where slip angle beyond maximum traction is fastest.
The timed section of the Touge Challenge does include that one downhill decreasing radius turn. Getting the car rotated there is critical to clearing the corner with minimum time lost even if it means throwing rear "grip" to the wind.
I do notice that the mines skyline is sprung stiffly, it did very well on the japanese tracks (looked smooth as they were filming). they brought that car over here and you can see how poor the track surface is compared to the japanese tracks, the car was very bumpy although Tsuchiya still drove it wonderfully. The car is leterally skipping all over the place, look at Tsuchiya bumping around and how fast and twitchy the inputs are. Still set the course record.
Yes, and when you watch the Touge Challenge segement you will continuously hear them state that a car set up to lap such and such track (most often Tsukuba for handling comparisons) will not be suitable for the Touge.
The cars appearing in the Touge Challenge are set up for that rough surface and when you watch the segment enough you really get to see good and poor suspension set ups and it is interesting to see how little spring rate is a factor between the two.
look at Tsuchiya bumping around and how fast and twitchy the inputs are. Still set the course record.
Yes, the car can responds quickly to his fast inputs.
In a car with a softer set up he would have to slow his inputs down. Did you see the car drifting? Not really, he is able to use all of the tires available traction to set a fast lap time.
If you are clearing corners without correction you aren't driving up to the limit of traction 99% of the time.
You say despite the cars set up, but he would say because of the cars set up.
I would say again you are confusing your definition of "grip" and maximum tire traction which actually happens at ~6-10degrees slip angle (past the limit of "grip").
I do agree there are a few segments where slip angle beyond maximum traction is fastest.
The timed section of the Touge Challenge does include that one downhill decreasing radius turn. Getting the car rotated there is critical to clearing the corner with minimum time lost even if it means throwing rear "grip" to the wind.
I do notice that the mines skyline is sprung stiffly, it did very well on the japanese tracks (looked smooth as they were filming). they brought that car over here and you can see how poor the track surface is compared to the japanese tracks, the car was very bumpy although Tsuchiya still drove it wonderfully. The car is leterally skipping all over the place, look at Tsuchiya bumping around and how fast and twitchy the inputs are. Still set the course record.
Yes, and when you watch the Touge Challenge segement you will continuously hear them state that a car set up to lap such and such track (most often Tsukuba for handling comparisons) will not be suitable for the Touge.
The cars appearing in the Touge Challenge are set up for that rough surface and when you watch the segment enough you really get to see good and poor suspension set ups and it is interesting to see how little spring rate is a factor between the two.
look at Tsuchiya bumping around and how fast and twitchy the inputs are. Still set the course record.
Yes, the car can responds quickly to his fast inputs.
In a car with a softer set up he would have to slow his inputs down. Did you see the car drifting? Not really, he is able to use all of the tires available traction to set a fast lap time.
If you are clearing corners without correction you aren't driving up to the limit of traction 99% of the time.
You say despite the cars set up, but he would say because of the cars set up.
07-15-15, 03:57 PM
#110
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
we have tested this, and it is not a true statement. the miata we are running now, which has no aero, good camber curves, and isn't super low, is fastest with 13/9 springs, on the tires we are using, at laguna. we tried both softer and stiffer and its slower.
as a suspension engineer, you have two jobs. the first is to get everything in its optimal spot, and everything has an optimal spot. everything works in a bell curve, although some are peaky and some are really flat. by everything, i mean everything, tire pressure, spring rate, spring rolls, camber, toe, AFR, timing; both comedic and for the engine, etc etc etc etc etc etc.
the second is to know what the car does when you need to change something. weather changes, track temps vary, etc. sometimes the car is perfect one day, and 3 months later it needs less understeer or whatever, its very very nice to know how to dial in (or out) a little of something to get the car right
another example is the FD, both in the optimal rate department, but it also illustrates the bell curve. it comes on 2k springs, but these are too low a ride frequency, and even Mazda stiffened it up. then 8/6 is even better, it drives like an animal. but 11k? it depends, the curve must be pretty flat, 14k and 18k probably depend a lot on the track and driver, i wouldn't expect a big difference in lap times
as a suspension engineer, you have two jobs. the first is to get everything in its optimal spot, and everything has an optimal spot. everything works in a bell curve, although some are peaky and some are really flat. by everything, i mean everything, tire pressure, spring rate, spring rolls, camber, toe, AFR, timing; both comedic and for the engine, etc etc etc etc etc etc.
the second is to know what the car does when you need to change something. weather changes, track temps vary, etc. sometimes the car is perfect one day, and 3 months later it needs less understeer or whatever, its very very nice to know how to dial in (or out) a little of something to get the car right
another example is the FD, both in the optimal rate department, but it also illustrates the bell curve. it comes on 2k springs, but these are too low a ride frequency, and even Mazda stiffened it up. then 8/6 is even better, it drives like an animal. but 11k? it depends, the curve must be pretty flat, 14k and 18k probably depend a lot on the track and driver, i wouldn't expect a big difference in lap times
07-15-15, 04:05 PM
#111
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
we have tested this, and it is not a true statement. the miata we are running now, which has no aero, good camber curves, and isn't super low, is fastest with 13/9 springs, on the tires we are using, at laguna. we tried both softer and stiffer and its slower.
as a suspension engineer, you have two jobs. the first is to get everything in its optimal spot, and everything has an optimal spot. everything works in a bell curve, although some are peaky and some are really flat. by everything, i mean everything, tire pressure, spring rate, spring rolls, camber, toe, AFR, timing; both comedic and for the engine, etc etc etc etc etc etc.
the second is to know what the car does when you need to change something. weather changes, track temps vary, etc. sometimes the car is perfect one day, and 3 months later it needs less understeer or whatever, its very very nice to know how to dial in (or out) a little of something to get the car right
another example is the FD, both in the optimal rate department, but it also illustrates the bell curve. it comes on 2k springs, but these are too low a ride frequency, and even Mazda stiffened it up. then 8/6 is even better, it drives like an animal. but 11k? it depends, the curve must be pretty flat, 14k and 18k probably depend a lot on the track and driver, i wouldn't expect a big difference in lap times
as a suspension engineer, you have two jobs. the first is to get everything in its optimal spot, and everything has an optimal spot. everything works in a bell curve, although some are peaky and some are really flat. by everything, i mean everything, tire pressure, spring rate, spring rolls, camber, toe, AFR, timing; both comedic and for the engine, etc etc etc etc etc etc.
the second is to know what the car does when you need to change something. weather changes, track temps vary, etc. sometimes the car is perfect one day, and 3 months later it needs less understeer or whatever, its very very nice to know how to dial in (or out) a little of something to get the car right
another example is the FD, both in the optimal rate department, but it also illustrates the bell curve. it comes on 2k springs, but these are too low a ride frequency, and even Mazda stiffened it up. then 8/6 is even better, it drives like an animal. but 11k? it depends, the curve must be pretty flat, 14k and 18k probably depend a lot on the track and driver, i wouldn't expect a big difference in lap times
grip is grip, as in skidpad. Lap times is not grip. you have MANY factors coming into play. I am not stating softer rates are faster, I am stating softer rates have more grip. which is true.
Lots of drivers think stiffer springs are faster, and if many drive stiffly sprung cars they might produce faster lap times on them. If you swapped to softer springs their driving style and preference might overdrive a softly sprung car, and even if the softer sprung car is in fact faster, the driver at this point of time cannot drive the car faster than the old one. With much practice and patience the driver relearns how to drive fast on a softer spring rate set up, and with time the driver produced faster times than the more stiffly sprung set up.
There are a lot of things that effect lap times, driver being a HUGE role in it and just because the driver perfers or is used to stiffer springs doesn't necessarily mean it is faster.
Those race car drivers drive a ton of cars with lots of aero downforce, I bet they drive faster on stiffly sprung cars, as that is what they are used to and like, and probably do drive faster on them, doesn't mean its the fastest
07-15-15, 05:18 PM
#112
Those race car drivers drive a ton of cars with lots of aero downforce, I bet they drive faster on stiffly sprung cars, as that is what they are used to and like, and probably do drive faster on them, doesn't mean its the fastest
If you ever start racing you will have the wonderful experience of having a better driver drive your car and he will be rubbing the tire on the upper fender liner around every turn and either on the gas or brakes constantly and you will get it.
A higher level of driving requires a higher level of car set up.
You think Keiichi Tsuchiya doesn't know how to set up a car to drive the fastest around a course? He graduated from being a very successful race car driver to a GT team director as his "retirement".
If you really know better do the world a favor and start racing so you can beat everyone with your superior set up abilities and driving.
This is not a dig at you, you might be an automotive god waiting to be discovered. It wouldn't be a first.
I am just telling you what I have learned from my own experiences.
If you ever start racing you will have the wonderful experience of having a better driver drive your car and he will be rubbing the tire on the upper fender liner around every turn and either on the gas or brakes constantly and you will get it.
A higher level of driving requires a higher level of car set up.
You think Keiichi Tsuchiya doesn't know how to set up a car to drive the fastest around a course? He graduated from being a very successful race car driver to a GT team director as his "retirement".
If you really know better do the world a favor and start racing so you can beat everyone with your superior set up abilities and driving.
This is not a dig at you, you might be an automotive god waiting to be discovered. It wouldn't be a first.
I am just telling you what I have learned from my own experiences.
07-15-15, 05:24 PM
#113
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
I am stating softer rates have more grip. which is true.
Last edited by j9fd3s; 07-15-15 at 05:35 PM.
07-15-15, 11:18 PM
#115
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
07-16-15, 07:24 PM
#117
Rotary Enthusiast
iTrader: (19)
Join Date: Apr 2002
Location: Colorado Springs, CO
Posts: 1,169
Likes: 0
Received 11 Likes
on
10 Posts
I obviously was playing devils advocate for a lot of the thread. Trying to continue to drive on WHY something is better or worse. For me and the roads in this area, I would think an ideal spring rate for being smooth and performance driving, and given our shock/droop, etc travel is in the 9/9, 8/8, 8/7, 9/8, 9/7 area. I am running 8/6 with some good preload just cause I have the springs already (purchased cheap before). So if you are wanted a really good ride with performance in mind I would choose a 8/8 or 8/7 spring set up. If you are going to race, for me I think 9/9 or 9/8 might be a really strong set up for stickier tires.
I found this website that gets you in the ballpark for spring rates and its about what I would agree with from my experience playing with spring rates.
I used 700 to 755 pounds corner weight with 70lbs unsprung weight and my car with me in it is probably around there(I have a lot of stuff yanked out).
I used .6 motion ratio front, .68 motion ratio rear. I used 75-80 degrees for front, 88 rear or so.
I am currently running 448lbs front with .5" preload (almost what they recommend to a T), and 336 rear with .75" preload for a 40/60 or 50/50 droop/bump.
I have 4.1" travel in the front coilover for shock travel, 3.6" travel in the rear measured.
website below.
Spring Rate Calculator « Ridetech News and Information
I found this website that gets you in the ballpark for spring rates and its about what I would agree with from my experience playing with spring rates.
I used 700 to 755 pounds corner weight with 70lbs unsprung weight and my car with me in it is probably around there(I have a lot of stuff yanked out).
I used .6 motion ratio front, .68 motion ratio rear. I used 75-80 degrees for front, 88 rear or so.
I am currently running 448lbs front with .5" preload (almost what they recommend to a T), and 336 rear with .75" preload for a 40/60 or 50/50 droop/bump.
I have 4.1" travel in the front coilover for shock travel, 3.6" travel in the rear measured.
website below.
Spring Rate Calculator « Ridetech News and Information
Last edited by lOOkatme; 07-16-15 at 07:32 PM.
07-17-15, 03:34 AM
#118
Yes, ride and spring rate are subjective on a non competition car and you use what is most comfortable.
We have to remember in 1993 the FD RX-7 R1 was praised for its stock performance and panned for its rough ride... stock.
In looking for the FD motion ratios you must have stumbled across thread from racers and seen the spring rates they use.
Such as this one-
https://www.rx7club.com/race-car-tec...ratios-591954/
Well, the national champion contenders with FDs recommended 16K/13K as a good minimum starting point for an ASP FD (2nd lowest class FD qualifies for, 1 up over stock).
And he explains why as I have been trying - any lower and you will be on the higher spring rate of the bumpstop cornering.
Softer is faster! The 16k spring is softer than a bumpstop.
You can check out typical bumpstop rates here-
EBS Eibach Bump Stops - Secondary Spring Tuning | eibach.com/america
We have to remember in 1993 the FD RX-7 R1 was praised for its stock performance and panned for its rough ride... stock.
In looking for the FD motion ratios you must have stumbled across thread from racers and seen the spring rates they use.
Such as this one-
https://www.rx7club.com/race-car-tec...ratios-591954/
Well, the national champion contenders with FDs recommended 16K/13K as a good minimum starting point for an ASP FD (2nd lowest class FD qualifies for, 1 up over stock).
And he explains why as I have been trying - any lower and you will be on the higher spring rate of the bumpstop cornering.
Softer is faster! The 16k spring is softer than a bumpstop.
You can check out typical bumpstop rates here-
EBS Eibach Bump Stops - Secondary Spring Tuning | eibach.com/america
07-17-15, 07:34 AM
#119
Senior Member
My own experience is that I went more than a second quicker around New Hampshire Motor Speedway on 11/11 than on 9/7, and that jibed with my subjective impression that I had not lost but if anything *gained* grip at critical points on the track an had improved responsiveness everywhere, quicker transitions, and reduced pitch under maximum braking and reduced roll under maximum cornering.
and its a big difference more especially on ok roads. 8/6 will also give me more grip on the track
stiffer springs are for aero downforce, super low ride heights, and cars who have poor suspension camber curves.
Lower ride frequencies produce more grip as they are softer and more compliant (they push the inside and outside tires back to the road with more force due to more droop travel),
grip is grip, as in skidpad. Lap times is not grip. you have MANY factors coming into play. I am not stating softer rates are faster, I am stating softer rates have more grip. which is true.
Also, grip isn't the only thing but it is a HUGE determining factor in lap times. Swapping from the best street tires to DOT R-comps with roughly 20% more grip can be worth 2-4 seconds a lap. If going from 8/6 to, 13/11 or 16/14 spring rates cost even small amount of grip, lap times would suffer. But they improve...
Lots of drivers think stiffer springs are faster, and if many drive stiffly sprung cars they might produce faster lap times on them. If you swapped to softer springs their driving style and preference might overdrive a softly sprung car, and even if the softer sprung car is in fact faster, the driver at this point of time cannot drive the car faster than the old one.
With much practice and patience the driver relearns how to drive fast on a softer spring rate set up, and with time the driver produced faster times than the more stiffly sprung set up.
There are a lot of things that effect lap times, driver being a HUGE role in it and just because the driver perfers or is used to stiffer springs doesn't necessarily mean it is faster.
Those race car drivers drive a ton of cars with lots of aero downforce, I bet they drive faster on stiffly sprung cars, as that is what they are used to and like, and probably do drive faster on them, doesn't mean its the fastest
Last edited by ZDan; 07-17-15 at 07:37 AM.
07-18-15, 12:18 AM
#122
And performance is measured by racing.. So this is an odd thread. And we have an armchair engineer telling all of us how to make our track cars faster because he read some stuff about some racing things on the Internet, Furthermore he will prove all of this to us by driving and testing on the street.
07-18-15, 01:30 PM
#123
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
And performance is measured by racing.. So this is an odd thread. And we have an armchair engineer telling all of us how to make our track cars faster because he read some stuff about some racing things on the Internet, Furthermore he will prove all of this to us by driving and testing on the street.
07-18-15, 06:06 PM
#125
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,796
Received 2,574 Likes
on
1,830 Posts
lol, so really a few years ago we had 3 FC's knocking about,
1. 88 GXL, ~68k miles, completely OEM, everything worked, mechanically in great shape.
2. 88 GXL sister car (they even both had ABS, same blue, everything) it was running on KYB AGX's, and 320/220lbs springs.
3. 89 GTUs it was running koni's, with 400/300 springs.
so obviously the GTUs handled best, although the GXL on AGX's was ok too.
the surprise was that the GTUs also rode the best on the street. it was able to handle bumps better, although you could tell that it was also doing it with less suspension travel.
the lesson of course is that the spring rate doesn't tell you much about ride quality. the shock however, does have everything to do with ride quality.
1. 88 GXL, ~68k miles, completely OEM, everything worked, mechanically in great shape.
2. 88 GXL sister car (they even both had ABS, same blue, everything) it was running on KYB AGX's, and 320/220lbs springs.
3. 89 GTUs it was running koni's, with 400/300 springs.
so obviously the GTUs handled best, although the GXL on AGX's was ok too.
the surprise was that the GTUs also rode the best on the street. it was able to handle bumps better, although you could tell that it was also doing it with less suspension travel.
the lesson of course is that the spring rate doesn't tell you much about ride quality. the shock however, does have everything to do with ride quality.