howard coleman's FD Chassis/Setup
11-17-08, 11:23 AM
#526
Racing Spirit
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Hey Howard,
The racelogic GPS box sounds very good and expensive. I wish I have the money to buy something like that for my car. I actually find a program for my Palm Treo and uses GPS to track laptime and G-force.
http://www.schlangmann.mynetcologne....mer/index.html
I just bought a palm GPS receiver on ebay for $50 just for this purpose.
I haven't purchased the software yet but I will soon to see how well it works. Its definately nothing like what you have but it should give me all the info I need for the money.
Also for guys who has Iphone, this program will eventually work on Iphone and should be much more accurate than using just GPS receiver. Iphone has a built-in Gyro so it will give you much more accurate Lat-G's and laptime via GPS.
Just wanted to share what I find for those who are in a budget like me.
The racelogic GPS box sounds very good and expensive. I wish I have the money to buy something like that for my car. I actually find a program for my Palm Treo and uses GPS to track laptime and G-force.
http://www.schlangmann.mynetcologne....mer/index.html
I just bought a palm GPS receiver on ebay for $50 just for this purpose.
I haven't purchased the software yet but I will soon to see how well it works. Its definately nothing like what you have but it should give me all the info I need for the money.
Also for guys who has Iphone, this program will eventually work on Iphone and should be much more accurate than using just GPS receiver. Iphone has a built-in Gyro so it will give you much more accurate Lat-G's and laptime via GPS.
Just wanted to share what I find for those who are in a budget like me.
can't wait for the iphone version! awesome solution
11-17-08, 12:02 PM
#527
I too have been wondering this, for example RE-Amemiya's FD coilovers, the DG-5, run 12/10kg and I think they recommend not running a lot of bar and using it more as a tuning tool rather than a substitute for rate to counter body roll. What is the reasoning behind your recommendation to run less rate and more bar?
-Andy
-Andy
11-17-08, 05:13 PM
#529
Just trying to help - you guys might want to re-read post #1 in its entirety.
Here is a partial copy/paste of howard's comments:
Mahjik also makes a good point on aero. There was a discussion on that and spring rates a few pages back.
As jkstill mentioned, there are a few good books that also go into further details on this subject. Makes for great reading material. This site sells a few of them: http://motorbooks.com/
Here is a partial copy/paste of howard's comments:
Which brings me to subject one… lateral weight transfer. Ideally you want equal weight on your lateral tires. Too much weight causes the tire eventually to wash out, lose traction. Further, every pound transferred to the outside tire is removed from the inside tire diminishing it’s value.
There is a major point of confusion here that needs to be cleared up so you can get tuning.
There are only two items that determine total lateral weight transfer…
Center of gravity
Track width.
The typical FD weighs 2900. add 200 for the driver… 3100 pounds. Remove the unsprung weight (wheels/tires, brakes, half of the A arms, half of the shocks/springs, half of the swaybar, half of the driveshafts). Call it 350 pounds.
So… 3100 minus 350= 2750 X 15.5 (center of gravity for stock FD is 17 inches, our track car is lowered a bit) X 1.1 G’s divided by the track (stock is 57.5 minus your positive offset wheels so we use 55.5) = total lateral weight transfer in a 1.1 G turn.
That’s 844 pounds of total lateral weight transfer.
So what can you do about it? Given the ride height and track… Nothing.
But if you put stiffer springs and roll bars on the car it won’t roll as much. Do you see roll anywhere in the aforementioned equation? You can weld the suspension solid, you can bolt on 2000 psi springs and a 6 inch swaybar.
And you will still transfer 844 pounds.
But springs and roll bar stiffness can apportion (front to rear) where the 844 pounds transfer. By changing the longitudinal roll stiffness you can move more of the 844 pounds to the front or to the rear.
And that is one of the ways we can trim our chassis… understeer, oversteer. If, for instance, the chassis is balanced and we increase the rate in the rear we will transfer more of the 844 rearwards and will tend towards oversteer.
BTW, a common mistake when attempting to longitudinally balance a chassis is to work on the wrong end. Let’s say the car is oversteering (rear loose). You could stiffen the front by adding spring or bar but you would be decreasing front grip so it would balance against poor rear grip. You just lost total grip.
The correct path would be to find a way to increase rear grip.
Stiffer springs and shocks do decrease body roll and that is generally a good thing to a point. The FD, due to it’s double A arm front and rear suspension and attendant negative camber gain on bump, is not as effected by roll as most other cars. That is as the crucial outside wheel in a turn moves up into the fenderwell w body roll the suspension adds negative camber thus keeping the wheel properly cambered to the track.
That’s why the FD takes few prisoners ontrack.
Some cars need to run huge springs and bars to kill roll because their suspspension goes off camber in bump. These cars with too much spring rate are very hard to drive near the adhesion limit.
The stock FD spring rate is 263 pounds per inch in front and 195 pounds in the rear. These are my numbers from my Longacre Digital Spring Checker. Just FYI, with linear rated springs the rate increases with contraction. The second inch of the FD front spring is 526 and the third is 789…
I run 432 front and 378 rear. Expressed metrically 8 KG and 6 KG. I am delighted with this rate. If my springs vaporized I would repurchase this rate. It works on the track. It works on the street.
That said, Frank runs 566/422 or 10Kg/8Kg. I consider this rate the outer limit.
Remember, both rates transfer the same lateral load. The higher the rate the harder it is to drive at the limit.
There is a major point of confusion here that needs to be cleared up so you can get tuning.
There are only two items that determine total lateral weight transfer…
Center of gravity
Track width.
The typical FD weighs 2900. add 200 for the driver… 3100 pounds. Remove the unsprung weight (wheels/tires, brakes, half of the A arms, half of the shocks/springs, half of the swaybar, half of the driveshafts). Call it 350 pounds.
So… 3100 minus 350= 2750 X 15.5 (center of gravity for stock FD is 17 inches, our track car is lowered a bit) X 1.1 G’s divided by the track (stock is 57.5 minus your positive offset wheels so we use 55.5) = total lateral weight transfer in a 1.1 G turn.
That’s 844 pounds of total lateral weight transfer.
So what can you do about it? Given the ride height and track… Nothing.
But if you put stiffer springs and roll bars on the car it won’t roll as much. Do you see roll anywhere in the aforementioned equation? You can weld the suspension solid, you can bolt on 2000 psi springs and a 6 inch swaybar.
And you will still transfer 844 pounds.
But springs and roll bar stiffness can apportion (front to rear) where the 844 pounds transfer. By changing the longitudinal roll stiffness you can move more of the 844 pounds to the front or to the rear.
And that is one of the ways we can trim our chassis… understeer, oversteer. If, for instance, the chassis is balanced and we increase the rate in the rear we will transfer more of the 844 rearwards and will tend towards oversteer.
BTW, a common mistake when attempting to longitudinally balance a chassis is to work on the wrong end. Let’s say the car is oversteering (rear loose). You could stiffen the front by adding spring or bar but you would be decreasing front grip so it would balance against poor rear grip. You just lost total grip.
The correct path would be to find a way to increase rear grip.
Stiffer springs and shocks do decrease body roll and that is generally a good thing to a point. The FD, due to it’s double A arm front and rear suspension and attendant negative camber gain on bump, is not as effected by roll as most other cars. That is as the crucial outside wheel in a turn moves up into the fenderwell w body roll the suspension adds negative camber thus keeping the wheel properly cambered to the track.
That’s why the FD takes few prisoners ontrack.
Some cars need to run huge springs and bars to kill roll because their suspspension goes off camber in bump. These cars with too much spring rate are very hard to drive near the adhesion limit.
The stock FD spring rate is 263 pounds per inch in front and 195 pounds in the rear. These are my numbers from my Longacre Digital Spring Checker. Just FYI, with linear rated springs the rate increases with contraction. The second inch of the FD front spring is 526 and the third is 789…
I run 432 front and 378 rear. Expressed metrically 8 KG and 6 KG. I am delighted with this rate. If my springs vaporized I would repurchase this rate. It works on the track. It works on the street.
That said, Frank runs 566/422 or 10Kg/8Kg. I consider this rate the outer limit.
Remember, both rates transfer the same lateral load. The higher the rate the harder it is to drive at the limit.
Mahjik also makes a good point on aero. There was a discussion on that and spring rates a few pages back.
As jkstill mentioned, there are a few good books that also go into further details on this subject. Makes for great reading material. This site sells a few of them: http://motorbooks.com/
11-29-08, 02:18 PM
#530
Bosozoomku
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Howard, if you're still checking in to this thread, thanks so much for the advice. I ended up going with a set of Tein S.TECH springs, 7.8kg/mm front and 5.8kg/mm rear... it was the closest set to 8/6 I could find offhand.
12-05-08, 08:28 AM
#533
Racing Rotary Since 1983
Thread Starter
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just a note to all readers of this thread.
if you are new to the thread i sympathize w you re it's length but i am happy to say there is alot of meat in it so since winter is upon us, at least in the Northern Hemisphere, consider it a reading assignment.
if you haven't read the first post in it's entirety please do it now
.
further, i plan to add an index within the first post so if you are interested in, say swaybars, you'll know where to go. i also will edit the thread so various meanderings which were fine at the time but off topic will not add to the already significant length.
finally, looking forward, i am in great shape to actually get ontrack in 09. after 5 very serious years of development my car is close to where i want it.
during that time i designed, built and tuned my own twin turbosystem featuring two Garrett TO4s that make as much air as a GT42 but at only 27 psi. i plan to run them at 20 psi where they make only 21 psi of exhaust backpressure versus the typical single at 35 psi backpressure. less backpressure equals less heat which is essential for road racing. (two three inch downpipes and two Stage 5 exhaust turbines make it happen).
during my 5 year development process i have seen 6 other twin sytems, each somewhat different... some have been dynoed, all are in the scrapheap. mine made 498 rwhp at extremely conservative tune at 20 psi and has 14,000 miles on it. it is ready for the track and will not be retaining as much heat as other turbosystems.
the other item that has been a couple years in development has been my alcohol (methanol) injection system. heat kills poorly fixtured/tuned turbo'd rotaries, especially on road courses. after a 2000-8000 4th gear dyno run i would advise you not to put your hand on my UIM as it might just stick. the UIM is that cold.
Methanol is Magic. AI is essential.
previous AI (Auxiliary Injection) systems featured a nozzle and pump and injected based on pump speed. they were repeatable and the quantity of injectant was able to be ramped w boost. they work pretty well for drag racing where your foot is mostly on the floor.
they do not work well for road racing where you are constantly modulating the throttle in a corner. if you have tuned your car you know about the base fuel map. w the Apexi PFC (which i run and love) you have 400 discrete cells within the fuel map that you can tune individually to the MILLISECOND!
consider what type of tune you would have comparatively if you were to substitute the older pump and nozzle system governing most AI systems! if your car would run, it would get 4 mpg and be undriveable at moments when you are feathering the throttle as the pump wouldn't be able to mimic your desired setting in time.
consider also... if you have your max boost set at 15 psi and you reach max boost at 5000 rpm that you need a different amount of fuel at 15 psi at 7500 rpm. since the old style AI systems only key off boost you will get a constant amount of injectant regardless of rpm.
that's old school stuff. meet AI-High Def
new school is a system that is exactly the same as your current OEM fuel system. the new system uses fuel injectors not nozzles. it is tunable just like your base fuel map. you pick the cell at a particular rpm and then you pick the boost and set the delivery in that cell!!! my system (FJO) has 156 cells in which to tune.
i have added a return line and a pressure regulator which i consider to be essential. details in the Auxiliary Injection section under a thread "Forging Fearlessly into new Frontiers..."
why all this engine related commentary in the suspension thread?
because a turbo'd rotary on a road course needs to live so you can enjoy the FD's awsome track potential and you need AI to make it happen.
BTW, water may also be used as an injectant as well as a combo of water and methanol. some sanctioning bodies disallow methanol so do your homework.
the reason i did the twin turbo setup and the alcohol is i believe that the rotary when properly fixtured is capable of making 500 rwhp on a road course and living. almost everyone tracking their FD's turns down the boost to around one bar and makes 350-375 to be kind to their motors.... or perhaps slips a v8 in after melting a few poorly fixtured/tuned rotaries.
there's no need to go thru all the transplant stuff, although i have no problem w it... there is a need to properly build/fixture/tune your rotary. it does include AI.
i pulled my motor last week. it has been in my car for four years since i built it. 14,000 miles, 498 rwhp, over 100 2000-8000 dyno runs. when i pulled it i had 17 inches of vacuum at idle and it ran perfectly. a great time to take it apart. thanks to the alcohol, the rotors had almost no carbon on them, all the seals rode in carbon-free grooves and the side seals had only one thousandth of additional clearance! i will just replace all the seal springs and oil and coolant seals and reassemble.
and put it on the shelf... as i am building a new engine with some advanced design work and NRS ceramic seals.
do visit the Auxiliary Injection section. while it may not be the most active section if you search the archives you will find what you need to know.
i will be adding a new thread in the section within a week which will provide an A to Z on my specific system. i will be adding an additional post in this thread on essential instrumentation re your motor.
and a BIG "Your Welcome" to all for their kind comments
hc
if you are new to the thread i sympathize w you re it's length but i am happy to say there is alot of meat in it so since winter is upon us, at least in the Northern Hemisphere, consider it a reading assignment.
if you haven't read the first post in it's entirety please do it now
.further, i plan to add an index within the first post so if you are interested in, say swaybars, you'll know where to go. i also will edit the thread so various meanderings which were fine at the time but off topic will not add to the already significant length.
finally, looking forward, i am in great shape to actually get ontrack in 09. after 5 very serious years of development my car is close to where i want it.
during that time i designed, built and tuned my own twin turbosystem featuring two Garrett TO4s that make as much air as a GT42 but at only 27 psi. i plan to run them at 20 psi where they make only 21 psi of exhaust backpressure versus the typical single at 35 psi backpressure. less backpressure equals less heat which is essential for road racing. (two three inch downpipes and two Stage 5 exhaust turbines make it happen).
during my 5 year development process i have seen 6 other twin sytems, each somewhat different... some have been dynoed, all are in the scrapheap. mine made 498 rwhp at extremely conservative tune at 20 psi and has 14,000 miles on it. it is ready for the track and will not be retaining as much heat as other turbosystems.
the other item that has been a couple years in development has been my alcohol (methanol) injection system. heat kills poorly fixtured/tuned turbo'd rotaries, especially on road courses. after a 2000-8000 4th gear dyno run i would advise you not to put your hand on my UIM as it might just stick. the UIM is that cold.
Methanol is Magic. AI is essential.
previous AI (Auxiliary Injection) systems featured a nozzle and pump and injected based on pump speed. they were repeatable and the quantity of injectant was able to be ramped w boost. they work pretty well for drag racing where your foot is mostly on the floor.
they do not work well for road racing where you are constantly modulating the throttle in a corner. if you have tuned your car you know about the base fuel map. w the Apexi PFC (which i run and love) you have 400 discrete cells within the fuel map that you can tune individually to the MILLISECOND!
consider what type of tune you would have comparatively if you were to substitute the older pump and nozzle system governing most AI systems! if your car would run, it would get 4 mpg and be undriveable at moments when you are feathering the throttle as the pump wouldn't be able to mimic your desired setting in time.
consider also... if you have your max boost set at 15 psi and you reach max boost at 5000 rpm that you need a different amount of fuel at 15 psi at 7500 rpm. since the old style AI systems only key off boost you will get a constant amount of injectant regardless of rpm.
that's old school stuff. meet AI-High Def
new school is a system that is exactly the same as your current OEM fuel system. the new system uses fuel injectors not nozzles. it is tunable just like your base fuel map. you pick the cell at a particular rpm and then you pick the boost and set the delivery in that cell!!! my system (FJO) has 156 cells in which to tune.
i have added a return line and a pressure regulator which i consider to be essential. details in the Auxiliary Injection section under a thread "Forging Fearlessly into new Frontiers..."
why all this engine related commentary in the suspension thread?
because a turbo'd rotary on a road course needs to live so you can enjoy the FD's awsome track potential and you need AI to make it happen.
BTW, water may also be used as an injectant as well as a combo of water and methanol. some sanctioning bodies disallow methanol so do your homework.
the reason i did the twin turbo setup and the alcohol is i believe that the rotary when properly fixtured is capable of making 500 rwhp on a road course and living. almost everyone tracking their FD's turns down the boost to around one bar and makes 350-375 to be kind to their motors.... or perhaps slips a v8 in after melting a few poorly fixtured/tuned rotaries.
there's no need to go thru all the transplant stuff, although i have no problem w it... there is a need to properly build/fixture/tune your rotary. it does include AI.
i pulled my motor last week. it has been in my car for four years since i built it. 14,000 miles, 498 rwhp, over 100 2000-8000 dyno runs. when i pulled it i had 17 inches of vacuum at idle and it ran perfectly. a great time to take it apart. thanks to the alcohol, the rotors had almost no carbon on them, all the seals rode in carbon-free grooves and the side seals had only one thousandth of additional clearance! i will just replace all the seal springs and oil and coolant seals and reassemble.
and put it on the shelf... as i am building a new engine with some advanced design work and NRS ceramic seals.
do visit the Auxiliary Injection section. while it may not be the most active section if you search the archives you will find what you need to know.
i will be adding a new thread in the section within a week which will provide an A to Z on my specific system. i will be adding an additional post in this thread on essential instrumentation re your motor.
and a BIG "Your Welcome" to all for their kind comments
hc
Last edited by Howard Coleman; 12-07-08 at 06:45 PM.
12-06-08, 03:45 PM
#534
Registered User
iTrader: (4)
Join Date: Oct 2004
Location: Pacifica
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just a note to all readers of this thread.
if you are new to the thread i sympathize w you re it's length but i am happy to say there is alot of meat in it so since winter is upon us, at least in the Northern Hemisphere, consider it a reading assignment.
if you haven't read the first post in it's entirety please do it now.
further, i plan to add an index within the first post so if you are interested in, say swaybars, you'll know where to go. i also will edit the thread so various meanderings which were fine at the time but off topic will not add to the already significant length.
finally, looking forward, i am in great shape to actually get ontrack in 09. after 5 very serious years of development my car is close to where i want it.
during that time i designed, built and tuned my own twin turbosystem featuring two Garrett TO4s that make as much air as a GT42 but at only 27 psi. i plan to run them at 20 psi where they make only 21 psi of exhaust backpressure versus the typical single at 35 psi backpressure. less backpressure equals less heat which is essential for road racing. (two three inch downpipes and two Stage 5 exhaust turbines make it happen).
during my 5 year development process i have seen 6 other twin sytems, each somewhat different... some have been dynoed, all are in the scrapheap. mine made 498 rwhp at extremely conservative tune at 20 psi and has 14,000 miles on it. it is ready for the track and will not be retaining as much heat as other turbosystems.
the other item that has been a couple years in development has been my alcohol (methanol) injection system. heat kills poorly fixtured/tuned turbo'd rotaries, especially on road courses. after a 2000-8000 4th gear dyno run i would advise you not to put your hand on my UIM as it might just stick. the UIM is that cold.
Methanol is Magic. AI is essential.
previous AI (Auxiliary Injection) systems featured a nozzle and pump and injected based on pump speed. they were repeatable and the quantity of injectant was able to be ramped w boost. they work pretty well for drag racing where your foot is mostly on the floor.
they do not work well for road racing where you are constantly modulating the throttle in a corner. if you have tuned your car you know about the base fuel map. w the Apexi PFC (which i run and love) you have 400 discrete cells within the fuel map that you can tune individually to the MILLISECOND!
consider what type of tune you would have comparatively if you were to substitute the older pump and nozzle system governing most AI systems! if your car would run, it would get 4 mpg and be undriveable at moments when you are feathering the throttle as the pump wouldn't be able to mimic your desired setting in time.
consider also... if you have your max boost set at 15 psi and you reach max boost at 5000 rpm that you need a different amount of fuel at 15 psi at 7500 rpm. since the old style AI systems only key off boost you will get a constant amount of injectant regardless of rpm.
that's old school stuff.
new school is a system that is exactly the same as your current OEM fuel system. the new system uses fuel injectors not nozzles. it is tunable just like your base fuel map. you pick the cell at a particular rpm and then you pick the boost and set the delivery in that cell!!! my system (FJO) has 156 cells in which to tune.
i have added a return line and a pressure regulator which i consider to be essential. details in the Auxiliary Injection section under a thread "Forging Fearlessly into new Frontiers..."
why all this engine related commentary in the suspension thread?
because a turbo'd rotary on a road course needs to live so you can enjoy the FD's awsome track potential and you need AI to make it happen.
BTW, water may also be used as an injectant as well as a combo of water and methanol. some sanctioning bodies disallow methanol so do your homework.
the reason i did the twin turbo setup and the alcohol is i believe that the rotary when properly fixtured is capable of making 500 rwhp on a road course and living. almost everyone tracking their FD's turns down the boost to around one bar and makes 350-375 to be kind to their motors.... or perhaps slips a v8 in after melting a few poorly fixtured/tuned rotaries.
there's no need to go thru all the transplant stuff, although i have no problem w it... there is a need to properly build/fixture/tune your rotary. it does include AI.
i pulled my motor last week. it has been in my car for four years since i built it. 14,000 miles, 498 rwhp, over 100 2000-8000 dyno runs. when i pulled it i had 17 inches of vacuum at idle and it ran perfectly. a great time to take it apart. thanks to the alcohol, the rotors had almost no carbon on them, all the seals rode in carbon-free grooves and the side seals had only one thousandth of additional clearance! i will just replace all the seal springs and oil and coolant seals and reassemble.
and put it on the shelf... as i am building a new engine with some advanced design work and NRS ceramic seals.
do visit the Auxiliary Injection section. while it may not be the most active section if you search the archives you will find what you need to know.
i will be adding a new thread in the section within a week which will provide an A to Z on my specific system. i will be adding an additional post in this thread on essential instrumentation re your motor.
and a BIG "Your Welcome" to all for their kind comments
hc
if you are new to the thread i sympathize w you re it's length but i am happy to say there is alot of meat in it so since winter is upon us, at least in the Northern Hemisphere, consider it a reading assignment.
if you haven't read the first post in it's entirety please do it now
.further, i plan to add an index within the first post so if you are interested in, say swaybars, you'll know where to go. i also will edit the thread so various meanderings which were fine at the time but off topic will not add to the already significant length.
finally, looking forward, i am in great shape to actually get ontrack in 09. after 5 very serious years of development my car is close to where i want it.
during that time i designed, built and tuned my own twin turbosystem featuring two Garrett TO4s that make as much air as a GT42 but at only 27 psi. i plan to run them at 20 psi where they make only 21 psi of exhaust backpressure versus the typical single at 35 psi backpressure. less backpressure equals less heat which is essential for road racing. (two three inch downpipes and two Stage 5 exhaust turbines make it happen).
during my 5 year development process i have seen 6 other twin sytems, each somewhat different... some have been dynoed, all are in the scrapheap. mine made 498 rwhp at extremely conservative tune at 20 psi and has 14,000 miles on it. it is ready for the track and will not be retaining as much heat as other turbosystems.
the other item that has been a couple years in development has been my alcohol (methanol) injection system. heat kills poorly fixtured/tuned turbo'd rotaries, especially on road courses. after a 2000-8000 4th gear dyno run i would advise you not to put your hand on my UIM as it might just stick. the UIM is that cold.
Methanol is Magic. AI is essential.
previous AI (Auxiliary Injection) systems featured a nozzle and pump and injected based on pump speed. they were repeatable and the quantity of injectant was able to be ramped w boost. they work pretty well for drag racing where your foot is mostly on the floor.
they do not work well for road racing where you are constantly modulating the throttle in a corner. if you have tuned your car you know about the base fuel map. w the Apexi PFC (which i run and love) you have 400 discrete cells within the fuel map that you can tune individually to the MILLISECOND!
consider what type of tune you would have comparatively if you were to substitute the older pump and nozzle system governing most AI systems! if your car would run, it would get 4 mpg and be undriveable at moments when you are feathering the throttle as the pump wouldn't be able to mimic your desired setting in time.
consider also... if you have your max boost set at 15 psi and you reach max boost at 5000 rpm that you need a different amount of fuel at 15 psi at 7500 rpm. since the old style AI systems only key off boost you will get a constant amount of injectant regardless of rpm.
that's old school stuff.
new school is a system that is exactly the same as your current OEM fuel system. the new system uses fuel injectors not nozzles. it is tunable just like your base fuel map. you pick the cell at a particular rpm and then you pick the boost and set the delivery in that cell!!! my system (FJO) has 156 cells in which to tune.
i have added a return line and a pressure regulator which i consider to be essential. details in the Auxiliary Injection section under a thread "Forging Fearlessly into new Frontiers..."
why all this engine related commentary in the suspension thread?
because a turbo'd rotary on a road course needs to live so you can enjoy the FD's awsome track potential and you need AI to make it happen.
BTW, water may also be used as an injectant as well as a combo of water and methanol. some sanctioning bodies disallow methanol so do your homework.
the reason i did the twin turbo setup and the alcohol is i believe that the rotary when properly fixtured is capable of making 500 rwhp on a road course and living. almost everyone tracking their FD's turns down the boost to around one bar and makes 350-375 to be kind to their motors.... or perhaps slips a v8 in after melting a few poorly fixtured/tuned rotaries.
there's no need to go thru all the transplant stuff, although i have no problem w it... there is a need to properly build/fixture/tune your rotary. it does include AI.
i pulled my motor last week. it has been in my car for four years since i built it. 14,000 miles, 498 rwhp, over 100 2000-8000 dyno runs. when i pulled it i had 17 inches of vacuum at idle and it ran perfectly. a great time to take it apart. thanks to the alcohol, the rotors had almost no carbon on them, all the seals rode in carbon-free grooves and the side seals had only one thousandth of additional clearance! i will just replace all the seal springs and oil and coolant seals and reassemble.
and put it on the shelf... as i am building a new engine with some advanced design work and NRS ceramic seals.
do visit the Auxiliary Injection section. while it may not be the most active section if you search the archives you will find what you need to know.
i will be adding a new thread in the section within a week which will provide an A to Z on my specific system. i will be adding an additional post in this thread on essential instrumentation re your motor.
and a BIG "Your Welcome" to all for their kind comments
hc
12-14-08, 01:57 PM
#538
Time Attack FD3
Join Date: Dec 2007
Location: UK
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Howard this has been a truely imense thread and thrown my setup out the window!
I'm running what is mainly a track car, it has solid engine and diff mounts along with solid bearing toe-links and trailing arms. The chassis has been seam welded and a full custom cage welded in. All the interior is stripped out. I'm making 500hp.
Tires are Toyo R888 (for the UK time attack) and are 255x35x18F and 275x35x18R.
Now the thing is I have Feed suspension which has 18kg F+R springs I run them at half way in the damping clicks. I run the stock F+R roll bars and mounts too.
The car feels tight in the corners, but braking feels a little loose with the weight transfer to the front of the car. I suspect the spring rates are way too high! What would you recommend?
I'm running what is mainly a track car, it has solid engine and diff mounts along with solid bearing toe-links and trailing arms. The chassis has been seam welded and a full custom cage welded in. All the interior is stripped out. I'm making 500hp.
Tires are Toyo R888 (for the UK time attack) and are 255x35x18F and 275x35x18R.
Now the thing is I have Feed suspension which has 18kg F+R springs I run them at half way in the damping clicks. I run the stock F+R roll bars and mounts too.
The car feels tight in the corners, but braking feels a little loose with the weight transfer to the front of the car. I suspect the spring rates are way too high! What would you recommend?
12-14-08, 11:10 PM
#540
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we need a pdf made by howard with contents of this thread and Auxiliary Injection.......im currently prepareing to refesh two fd's and plan to make one a time attack track car other just perefect street/track car!
12-21-08, 08:49 PM
#543
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Wow great thread. I am planning on starting to track my car in 09' and this really helped me figure out exactly what I should do suspension wise in order to be competetive. Thanks Howard.
12-22-08, 08:10 AM
#544
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
re determining proper spring rate:
Bean-Bandit:
any significantly modded track car requires a procedure to determine optimum spring rates. i mentioned (pics too) this procedure earlier in this lengthy thread.
it is very expensive, actually not.
four tie wraps. wrap each shock rod w a tie wrap. just before going out push each wrap down to the bottom of the shock rod. do 3-5 laps at max speed.
measure the distance the tie wrap has been pushed up on each shock.
you want to see between 1 to 1.5 inches of travel at the shock rod. any less soften the springs, any more add spring.
hc
Bean-Bandit:
any significantly modded track car requires a procedure to determine optimum spring rates. i mentioned (pics too) this procedure earlier in this lengthy thread.
it is very expensive, actually not.
four tie wraps. wrap each shock rod w a tie wrap. just before going out push each wrap down to the bottom of the shock rod. do 3-5 laps at max speed.
measure the distance the tie wrap has been pushed up on each shock.
you want to see between 1 to 1.5 inches of travel at the shock rod. any less soften the springs, any more add spring.
hc
Last edited by Howard Coleman; 12-30-08 at 09:09 AM.
12-22-08, 08:26 AM
#545
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
"how the sumitomo's are treating you?"
a qualified "love them."
i ran them shaved to 6/32nds this year. as you can see the wear pattern was perfect w my out of the box alignment specs... see post one.
255/35/18 fr and 295/30/18 rear on 9.5 and 10.5 wheels. the car was predictable and has a very high grip level.
i bought a set of Hawk DTC 70 pads for my RacingBrake setup and bedded them in in prep for an ontrack day at BlackHawk and was completely blown away by the stopping power of the combo. interestingly the Sumitomo HTRZ IIIs never made a squeal even under lots of Gs.
i look forward to tracking them early next year and highly recommend the for someone looking for a very high performance dual purpose application.
the recommendation is qualified only in that i was unable to get them ontrack in 08.
hc
a qualified "love them."
i ran them shaved to 6/32nds this year. as you can see the wear pattern was perfect w my out of the box alignment specs... see post one.
255/35/18 fr and 295/30/18 rear on 9.5 and 10.5 wheels. the car was predictable and has a very high grip level.
i bought a set of Hawk DTC 70 pads for my RacingBrake setup and bedded them in in prep for an ontrack day at BlackHawk and was completely blown away by the stopping power of the combo. interestingly the Sumitomo HTRZ IIIs never made a squeal even under lots of Gs.
i look forward to tracking them early next year and highly recommend the for someone looking for a very high performance dual purpose application.
the recommendation is qualified only in that i was unable to get them ontrack in 08.
hc
12-22-08, 08:34 AM
#546
Racing Rotary Since 1983
Thread Starter
iTrader: (6)
please do read my thread on fixing the heat generated by a rotary FD on a roadcourse...
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/making-case-rotary-powered-fd-fix-806104/
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/making-case-rotary-powered-fd-fix-806104/
12-29-08, 02:37 PM
#548
First of all, Howard thank you for all your hard work and putting this in writing! Your information will really help me in setting up my car. I'm thinking '09 will be the year I finally move away from the stock suspension. I've been running my car mostly stock for 3 years at the track now as a true dual-purpose street car. So far all I've done is:
-Stock Seq Twins at Stock Boost
-Reliability Mods
-Safety
-Original '93 supension w/new pillowballs, toe links and trailing arms
-Falken Azenis RT615 235/40 Front on 17x8, 255/40 Rear on 17x9.5
I've read all your posts in this thread and I think I'm going to go with your recommendation of the Eibach Pro Kit springs with the Tanabe sway bars with aftermarket swaybar mount. I'm not particularly interested in a complete coilover system, so the only thing left to the equation is what shock to use. I've read people have had success with the Tokicos. Do you have any other recommendations? I'd keep the OEMs but they are going on 16 years old now and probably could stand to be replaced as I've already lost one to a bad seal and the others can't be too far behind.
i had a shock dyno for a number of years and dynoed over 30 FD shocks. surprisingly they all dynoed the same and the spread was between 3500 miles and over a 100 thousand. i dynoed each shock completely so all three (high, medium and low speed) valves were fully evaluated. i also think they match up well w the Eibachs. i would run the Eibachs first w the stock shocks and see how they work w the uprated swaybars and then if i felt i needed more shock would go w Konis. i like your program in that you are curving into your mods. FDs aren't built in a day.
and thanks for the pic. i assume you are getting ready to lap the corvette. howard//////
here's a fun picture from my last event of '08:
Thanks again for your contributions!
-Stock Seq Twins at Stock Boost
-Reliability Mods
-Safety
-Original '93 supension w/new pillowballs, toe links and trailing arms
-Falken Azenis RT615 235/40 Front on 17x8, 255/40 Rear on 17x9.5
I've read all your posts in this thread and I think I'm going to go with your recommendation of the Eibach Pro Kit springs with the Tanabe sway bars with aftermarket swaybar mount. I'm not particularly interested in a complete coilover system, so the only thing left to the equation is what shock to use. I've read people have had success with the Tokicos. Do you have any other recommendations? I'd keep the OEMs but they are going on 16 years old now and probably could stand to be replaced as I've already lost one to a bad seal and the others can't be too far behind.
i had a shock dyno for a number of years and dynoed over 30 FD shocks. surprisingly they all dynoed the same and the spread was between 3500 miles and over a 100 thousand. i dynoed each shock completely so all three (high, medium and low speed) valves were fully evaluated. i also think they match up well w the Eibachs. i would run the Eibachs first w the stock shocks and see how they work w the uprated swaybars and then if i felt i needed more shock would go w Konis. i like your program in that you are curving into your mods. FDs aren't built in a day.
and thanks for the pic. i assume you are getting ready to lap the corvette. howard//////
here's a fun picture from my last event of '08:
Thanks again for your contributions!
Last edited by Howard Coleman; 01-06-09 at 02:17 PM.
01-04-09, 06:54 PM
#549
i noticed you are running 255's and 295's on your fd howard, and that now you are in the 500whp range. but i also know you plan ahead after reading this thread and your AI thread, so i know you will more than likely acheive or come close to your goal of 630whp at 27lbs.
so my question is why not wider tires? is 295 plenty for that horsepower range(up to 600 whp)? i thought wider up front would be better as well. but i guess a good question would be, is there a point where there is too much tire for a road course? where it adds too much weight versus the extra grip the larger tire would add?
you raise an excellent question... when do you have too much rubber? i do believe there is a point where the tread width becomes so sensitive camberwise that the tire starts lateral jacking. for dual purpose i really think that 255 is about right. you just aren't going to be able to use much more width on the front. also, i really like the stock front fenders both aesthetically and aeroslim-wise and the 255s work perfectly at 25 inches ride height. the rear of course is a bit different. the rears have to hold the power as well as support the rear weight. so you run a bit more rear. i didn't want to add much to the body in the rear and the burnout flares work nicely, providing another 5/8 inch clearance. i plan to run at the 500 rwhp level ontrack... the 630 is for the Texas Mile where i hope to break 200. howard/////
so my question is why not wider tires? is 295 plenty for that horsepower range(up to 600 whp)? i thought wider up front would be better as well. but i guess a good question would be, is there a point where there is too much tire for a road course? where it adds too much weight versus the extra grip the larger tire would add?
you raise an excellent question... when do you have too much rubber? i do believe there is a point where the tread width becomes so sensitive camberwise that the tire starts lateral jacking. for dual purpose i really think that 255 is about right. you just aren't going to be able to use much more width on the front. also, i really like the stock front fenders both aesthetically and aeroslim-wise and the 255s work perfectly at 25 inches ride height. the rear of course is a bit different. the rears have to hold the power as well as support the rear weight. so you run a bit more rear. i didn't want to add much to the body in the rear and the burnout flares work nicely, providing another 5/8 inch clearance. i plan to run at the 500 rwhp level ontrack... the 630 is for the Texas Mile where i hope to break 200. howard/////
Last edited by Howard Coleman; 01-06-09 at 02:27 PM.
01-05-09, 08:17 PM
#550
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Hey Howard, I was wondering what size rims and tires you were running before you installed the wider fenders? I was thinking of using much of the information in this thread to set up my car for dual purpose track/street driving but wanted to know what you used as the ideal wheel set-up?///////when i bought my FD in 99 it had Enkei 18X8.5 fr 245s & 18X10 rear 285s Toyos. the rears just fit w a touch of rolling the fenders. i now run 18 X9.5 255 and 18 X 10.5 and consider them to be just right for my purposes. Enkei NTO3+M. howard///////
Last edited by Howard Coleman; 01-06-09 at 02:33 PM.