Lowered...too much?
Full Member
Joined: Dec 2007
Posts: 84
Likes: 2
From: Hartselle, AL
as you said, I'm interested in finding the best amount to cut. I know I could buy coilovers or whatever, but this is a side project that I'm not going to drop a ton of money on.
Anyways, I was thinking that half a coil would give me a little drop and some more stiffness. would that still be too much?
Anyways, I was thinking that half a coil would give me a little drop and some more stiffness. would that still be too much?
Hey man-you don't want to cut 2" from your bumpstops. You only have about 1.5" until the bolt's head is exposed and then you're riding on the bolt. That's a lot rougher ride, and very noisy when you hit a bump...
I also have two complete sets of sagging stock springs, but I live pretty far away from you...
I also have two complete sets of sagging stock springs, but I live pretty far away from you...
The ride height is dictated by the lenght of spring. The car can be lowered by a shorter spring, Shorter upper mount, lowering the lower spring mount or moving the upper mount higher (as with the RB units)
When you use all but the last option you take away from the suspension bump travel. Meaning the insert is using part of its available bump travel at a static ride height. Not so much a problem with average lowering but come in to play when heavily lowered.
By using a insert with a shorter body then the the static ride height is not using the available bump travel. Koni, Bilstien are commonly used for this. back in the day we had a off the shelf bilstien that was shorter but with the same body diameter and valved higher. Now the options have larger bodies. To use them the strut housings must be modified. The stock tube is cut off and replaced with a tube that accepts the larger diameter insert and the length needed. The lower perch is then placed where you want the coil over sleeve to sit.
The use of the RB kit involved cutting the chassis shell. There wasn't a way to go back after it was done.
Now that you have lowered the vehicle the center of gravity is lower. This is a good thing but the roll center was also migrated to low. The roll center is dictated by the relationship of the inner control arm pickup to the outer control arm pickup. Since the inner dropped by the amount the vehicle was lowered but the outer stayed put the roll center dropped and the lenght between the roll center and the center of gravity became larger. The vehicle roll about the roll axis (line between the rear roll center and the front roll center) and the center of gravity is how much it has to through around. Shortening the lenght between the roll center and the center of gravity lessens the leverage that the center of gravity has. Lessening the roll.
So simply put, How heavy the car is, How high the weight is, the leverage it has to through that weight around have allot to do with the handling. Shorter inserts are used for more bump travel. To high of a spring rate will over power a stock replacement shock insert. Cutting springs should only be done once you have an understanding of all these aspects and can calculate the desired effects.
-billy
OLDROTA
Joined: Apr 2003
Posts: 1,389
Likes: 2
From: Los Angeles
That is correct.
The ride height is dictated by the lenght of spring. The car can be lowered by a shorter spring, Shorter upper mount, lowering the lower spring mount or moving the upper mount higher (as with the RB units)
When you use all but the last option you take away from the suspension bump travel. Meaning the insert is using part of its available bump travel at a static ride height. Not so much a problem with average lowering but come in to play when heavily lowered.
By using a insert with a shorter body then the the static ride height is not using the available bump travel. Koni, Bilstien are commonly used for this. back in the day we had a off the shelf bilstien that was shorter but with the same body diameter and valved higher. Now the options have larger bodies. To use them the strut housings must be modified. The stock tube is cut off and replaced with a tube that accepts the larger diameter insert and the length needed. The lower perch is then placed where you want the coil over sleeve to sit.
The use of the RB kit involved cutting the chassis shell. There wasn't a way to go back after it was done.
Now that you have lowered the vehicle the center of gravity is lower. This is a good thing but the roll center was also migrated to low. The roll center is dictated by the relationship of the inner control arm pickup to the outer control arm pickup. Since the inner dropped by the amount the vehicle was lowered but the outer stayed put the roll center dropped and the lenght between the roll center and the center of gravity became larger. The vehicle roll about the roll axis (line between the rear roll center and the front roll center) and the center of gravity is how much it has to through around. Shortening the lenght between the roll center and the center of gravity lessens the leverage that the center of gravity has. Lessening the roll.
So simply put, How heavy the car is, How high the weight is, the leverage it has to through that weight around have allot to do with the handling. Shorter inserts are used for more bump travel. To high of a spring rate will over power a stock replacement shock insert. Cutting springs should only be done once you have an understanding of all these aspects and can calculate the desired effects.
-billy
The ride height is dictated by the lenght of spring. The car can be lowered by a shorter spring, Shorter upper mount, lowering the lower spring mount or moving the upper mount higher (as with the RB units)
When you use all but the last option you take away from the suspension bump travel. Meaning the insert is using part of its available bump travel at a static ride height. Not so much a problem with average lowering but come in to play when heavily lowered.
By using a insert with a shorter body then the the static ride height is not using the available bump travel. Koni, Bilstien are commonly used for this. back in the day we had a off the shelf bilstien that was shorter but with the same body diameter and valved higher. Now the options have larger bodies. To use them the strut housings must be modified. The stock tube is cut off and replaced with a tube that accepts the larger diameter insert and the length needed. The lower perch is then placed where you want the coil over sleeve to sit.
The use of the RB kit involved cutting the chassis shell. There wasn't a way to go back after it was done.
Now that you have lowered the vehicle the center of gravity is lower. This is a good thing but the roll center was also migrated to low. The roll center is dictated by the relationship of the inner control arm pickup to the outer control arm pickup. Since the inner dropped by the amount the vehicle was lowered but the outer stayed put the roll center dropped and the lenght between the roll center and the center of gravity became larger. The vehicle roll about the roll axis (line between the rear roll center and the front roll center) and the center of gravity is how much it has to through around. Shortening the lenght between the roll center and the center of gravity lessens the leverage that the center of gravity has. Lessening the roll.
So simply put, How heavy the car is, How high the weight is, the leverage it has to through that weight around have allot to do with the handling. Shorter inserts are used for more bump travel. To high of a spring rate will over power a stock replacement shock insert. Cutting springs should only be done once you have an understanding of all these aspects and can calculate the desired effects.
-billy
...in short...Thank you Sir. I am using Koni adjustables for an MR2 in my Rx2, so I'll probably do something similar to the 7. Not really wanting to go coilovers. No fundage.
...and you're right, the RB kit made it impossible to go back, but why would you want to anyway. It worked really well for the price, and was easliy done when welded in instead of using the million nuts and bolts it came with.
Full Member
Joined: Feb 2008
Posts: 73
Likes: 0
From: P.Nth NZ
thats my car above, the silver seven. since that photo i've got hold of some "low" King Springs (from Australia) and had them compressed to measure just a bit higher than the springs i have in that foto above. Since doing this, the ride comfort level has improved 100-fold, amazing, doesnt bottom out and bump all over the road like it used to 
haha (took some concentraion to drive before!!), front wheels dont rub on the guards.
All in all it sits really low like i've always wanted, handles awesomely, good ride and looks great!
i personally wouldnt cut springs again, do it once do it right and get the correct height/rate spring you want, you won't regret it.(took me a while to realise this thou)
DONT RAISE IT!!!!!!!!!!!!!!!
haha
haha (took some concentraion to drive before!!), front wheels dont rub on the guards.All in all it sits really low like i've always wanted, handles awesomely, good ride and looks great!
i personally wouldnt cut springs again, do it once do it right and get the correct height/rate spring you want, you won't regret it.(took me a while to realise this thou
)DONT RAISE IT!!!!!!!!!!!!!!!
haha
Last edited by Bridge it baby; Apr 28, 2008 at 05:08 PM. Reason: add pic
Full Member
Joined: Feb 2008
Posts: 73
Likes: 0
From: P.Nth NZ
yep, King Springs, for australia. For the 1st gen rx7 they offer 3 different hieghts and rates. (front and rear)
1. "Standard" - standard height but stiffer spring
2. "Low" - stiffer then OEM but lower the car 25mm (not enough for my taste)
3. "Super low" - bascally these springs are a little shorter than the OEM springs uncompressed (out of the car and strut, loose on the ground), but they are quite a soft spring rate, more for looks than for handling, lower the car 50mm.
I opted for the 'Low' version, basically because i could get them cheap at the time Then i had a spring spiealist in town compress them down to the measurments i had worked out (can't remember what they were off heart) woukd sit the car at a good, legal, level. I did have to machine the front and rear shocks down to ensure the springs remained captive with the wheels off the ground thou(legal requirement here), but i just did that at work (mechanic). After all that, its a dream to drive, handles well and looks greats
1. "Standard" - standard height but stiffer spring
2. "Low" - stiffer then OEM but lower the car 25mm (not enough for my taste
)3. "Super low" - bascally these springs are a little shorter than the OEM springs uncompressed (out of the car and strut, loose on the ground), but they are quite a soft spring rate, more for looks than for handling, lower the car 50mm.
I opted for the 'Low' version, basically because i could get them cheap at the time
Then i had a spring spiealist in town compress them down to the measurments i had worked out (can't remember what they were off heart) woukd sit the car at a good, legal, level. I did have to machine the front and rear shocks down to ensure the springs remained captive with the wheels off the ground thou(legal requirement here), but i just did that at work (mechanic). After all that, its a dream to drive, handles well and looks greats
Last edited by Bridge it baby; Apr 29, 2008 at 07:30 PM. Reason: spelling
Thread Starter
Rota-lution
Joined: Feb 2008
Posts: 229
Likes: 0
From: Reno, NV
That sounds great. Good job!
I'm going to go ful-on with my suspension from here on out. I'll be starting a suspension thread soon following the install of some GForceengineering components.
The front adjustable Koni coilovers, The Tri-link, PanHard, I'm putting Lexan windshield and back glass as well.
I also REALLY need some 4x110 wheels.
I'm going to go ful-on with my suspension from here on out. I'll be starting a suspension thread soon following the install of some GForceengineering components.
The front adjustable Koni coilovers, The Tri-link, PanHard, I'm putting Lexan windshield and back glass as well.
I also REALLY need some 4x110 wheels.
OLDROTA
Joined: Apr 2003
Posts: 1,389
Likes: 2
From: Los Angeles
yep, King Springs, for australia. For the 1st gen rx7 they offer 3 different hieghts and rates. (front and rear)
1. "Standard" - standard height but stiffer spring
2. "Low" - stiffer then OEM but lower the car 25mm (not enough for my taste)
3. "Super low" - bascally these springs are a little shorter than the OEM springs uncompressed (out of the car and strut, loose on the ground), but they are quite a soft spring rate, more for looks than for handling, lower the car 50mm.
I opted for the 'Low' version, basically because i could get them cheap at the time Then i had a spring spiealist in town compress them down to the measurments i had worked out (can't remember what they were off heart) woukd sit the car at a good, legal, level. I did have to machine the front and rear shocks down to ensure the springs remained captive with the wheels off the ground thou(legal requirement here), but i just did that at work (mechanic). After all that, its a dream to drive, handles well and looks greats
1. "Standard" - standard height but stiffer spring
2. "Low" - stiffer then OEM but lower the car 25mm (not enough for my taste
)3. "Super low" - bascally these springs are a little shorter than the OEM springs uncompressed (out of the car and strut, loose on the ground), but they are quite a soft spring rate, more for looks than for handling, lower the car 50mm.
I opted for the 'Low' version, basically because i could get them cheap at the time
Then i had a spring spiealist in town compress them down to the measurments i had worked out (can't remember what they were off heart) woukd sit the car at a good, legal, level. I did have to machine the front and rear shocks down to ensure the springs remained captive with the wheels off the ground thou(legal requirement here), but i just did that at work (mechanic). After all that, its a dream to drive, handles well and looks greats
OLDROTA
Joined: Apr 2003
Posts: 1,389
Likes: 2
From: Los Angeles
Dragging an old thread up...I was just thinking...
First off...how different are the front upper mount bolts from 1st to 2nd gen? spacing wise?
Second, would using the Racing Beat 2nd gen front lowering kit, which replaces the top mount, work on our cars to bring down the height 3/4" without losing travel.....I know the lower mounting on FC's is different to FB's, BUT....think it would work?
Third....will the FC mount work on an FB at all?
Whatcha guys think?
First off...how different are the front upper mount bolts from 1st to 2nd gen? spacing wise?
Second, would using the Racing Beat 2nd gen front lowering kit, which replaces the top mount, work on our cars to bring down the height 3/4" without losing travel.....I know the lower mounting on FC's is different to FB's, BUT....think it would work?
Third....will the FC mount work on an FB at all?
Whatcha guys think?
Thread Starter
Rota-lution
Joined: Feb 2008
Posts: 229
Likes: 0
From: Reno, NV
Couldn't you just shorten the shock tubing? Or would you have to widen it's OD as well?
I know Koni has the racing coilovers available at GForceengineering.
Could someone reproduce that?
I know Koni has the racing coilovers available at GForceengineering.
Could someone reproduce that?
First off...how different are the front upper mount bolts from 1st to 2nd gen? spacing wise?
Second, would using the Racing Beat 2nd gen front lowering kit, which replaces the top mount, work on our cars to bring down the height 3/4" without losing travel.....I know the lower mounting on FC's is different to FB's, BUT....think it would work?
Second, would using the Racing Beat 2nd gen front lowering kit, which replaces the top mount, work on our cars to bring down the height 3/4" without losing travel.....I know the lower mounting on FC's is different to FB's, BUT....think it would work?
The FC bolt pattern is slightly different. Not by much though. Enlarging the 4 holes and you could get that to bolt up.
It will not lower a first gen. It may actually raise it a bit. The stock second gen top mount was very long. They just made a shorter version.
Full Member
Joined: Feb 2008
Posts: 73
Likes: 0
From: P.Nth NZ
I was just looking thru some old posts and found this.
Since I've had my car off the road (ALOT being done), i've sorted out some coil-overs for it...
I've done a write up about them here, a NZ rotary car club
http://www.rotahavik.co.nz/viewtopic.php?f=35&t=24273
Since I've had my car off the road (ALOT being done), i've sorted out some coil-overs for it...
I've done a write up about them here, a NZ rotary car club
http://www.rotahavik.co.nz/viewtopic.php?f=35&t=24273
Full Member
Joined: Jul 2009
Posts: 106
Likes: 1
From: ashburton new zealand
i had a set of 15" simmons (check my photos) and to get the car down to our min ride hight (100mm) i used super low spring(2"drop) then cut a coil off them on rear and 1.5 coils on front to get even. then shortened rear shocks and pulled front apart and fitted a 75mm spacer into the bottom to keep springs captive. refilled shocks with 10w-40 engine oil and removed all bump stops.... i have about 1.5inch travel and a smooth ish ride and hadles well... i have now got 13" rims on it and ride height is about 65mm. have to rase it up and ill do that by fitting the factory rubber pads under the springs in front and rear.... down side is when there are 4 people in car drive shaft touches the floor every now and again at rear by diff... not much has just knocked the underseal off
Full Member
Joined: Feb 2008
Posts: 73
Likes: 0
From: P.Nth NZ
i had a set of 15" simmons (check my photos) and to get the car down to our min ride hight (100mm) i used super low spring(2"drop) then cut a coil off them on rear and 1.5 coils on front to get even. then shortened rear shocks and pulled front apart and fitted a 75mm spacer into the bottom to keep springs captive. refilled shocks with 10w-40 engine oil and removed all bump stops.... i have about 1.5inch travel and a smooth ish ride and hadles well... i have now got 13" rims on it and ride height is about 65mm. have to rase it up and ill do that by fitting the factory rubber pads under the springs in front and rear.... down side is when there are 4 people in car drive shaft touches the floor every now and again at rear by diff... not much has just knocked the underseal off
haha, love it! any pics man??
thats my car above, the silver seven. since that photo i've got hold of some "low" King Springs (from Australia) and had them compressed to measure just a bit higher than the springs i have in that foto above. Since doing this, the ride comfort level has improved 100-fold, amazing, doesnt bottom out and bump all over the road like it used to haha (took some concentraion to drive before!!), front wheels dont rub on the guards.
All in all it sits really low like i've always wanted, handles awesomely, good ride and looks great!
i personally wouldnt cut springs again, do it once do it right and get the correct height/rate spring you want, you won't regret it.(took me a while to realise this thou)
DONT RAISE IT!!!!!!!!!!!!!!! haha
haha (took some concentraion to drive before!!), front wheels dont rub on the guards.All in all it sits really low like i've always wanted, handles awesomely, good ride and looks great!
i personally wouldnt cut springs again, do it once do it right and get the correct height/rate spring you want, you won't regret it.(took me a while to realise this thou
)DONT RAISE IT!!!!!!!!!!!!!!!
haha