Couple Questions Regarding Bilstein Coil-Over Conversion
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
Likes: 245
From: Summerland B.C. Canada
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
Likes: 245
From: Summerland B.C. Canada
Haven't decided on who's 36mm kit I will buy, but it will be using 1 7/8" ID springs. The front's may turn out to be a lot easier than planned.
Time will tell
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
I hope it does! You are going 425 fronts right? I did some work with motion ratios and trying to calculate spring rates. I took a quick shot at the angles but if you have a desired setup in leaf rates, let me know and I might be able to help you convert.
Looking forward to seeing how it turns out, keep us posted with PNs etc.
Are you thinking LD85 mount modification for the rear?
Looking forward to seeing how it turns out, keep us posted with PNs etc.
Are you thinking LD85 mount modification for the rear?
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
Likes: 245
From: Summerland B.C. Canada
I hope it does! You are going 425 fronts right? I did some work with motion ratios and trying to calculate spring rates. I took a quick shot at the angles but if you have a desired setup in leaf rates, let me know and I might be able to help you convert.
Looking forward to seeing how it turns out, keep us posted with PNs etc.
Are you thinking LD85 mount modification for the rear?
Looking forward to seeing how it turns out, keep us posted with PNs etc.
Are you thinking LD85 mount modification for the rear?
Happy Holidays
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
Likes: 245
From: Summerland B.C. Canada
I was going with 300#, but after reading LD85's complaints and finding 350# solved it, I decided to go halfway between the two. 
I thought I would update my rear install info ,
I went from 10"-275# to 10"-350# springs and it was a huge improvement, at a 27" ride height I don't bottom out any more and the ride is not as soft and bouncy as the 275's,,
with the 275's if I set the shocks stiff the ride on my car was harsh, and if I softened up the shocks then it would bottom out on interstate dips.
I really really like it a lot the way it is now.... now on dips it does great ..
The coil over system is so sweet, you can pop in new springs for $80 a set and adjust the ride height to your desired height
I went from 10"-275# to 10"-350# springs and it was a huge improvement, at a 27" ride height I don't bottom out any more and the ride is not as soft and bouncy as the 275's,,
with the 275's if I set the shocks stiff the ride on my car was harsh, and if I softened up the shocks then it would bottom out on interstate dips.
I really really like it a lot the way it is now.... now on dips it does great ..
The coil over system is so sweet, you can pop in new springs for $80 a set and adjust the ride height to your desired height
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Race Director
Joined: Feb 1999
Posts: 12,772
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From: Indianapolis IN
I had 275's rear and they would bottom out on dips, the rear was loose and not as tight as it is now.
and when you think about the C4 with its 51%-49% weight distribution, it makes sense to me that the spring rates should be closer to the same rather than 275/rear 450/front
I love my new setup and I will probably even stiffen the rear up to 375lb, the higher spring rates in the rear made a substantial improvement in the feel of the car during cornering and exit ramps etc.
They tell you now to increase less than 10% so I went from 275 to 350 and I will probably go up to 375 or 400 next in the rear, at $40 a shock it is cheap and easy to experiment
and when you think about the C4 with its 51%-49% weight distribution, it makes sense to me that the spring rates should be closer to the same rather than 275/rear 450/front
I love my new setup and I will probably even stiffen the rear up to 375lb, the higher spring rates in the rear made a substantial improvement in the feel of the car during cornering and exit ramps etc.
They tell you now to increase less than 10% so I went from 275 to 350 and I will probably go up to 375 or 400 next in the rear, at $40 a shock it is cheap and easy to experiment
Instructor
Joined: Nov 2005
Posts: 161
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From: Pittsburgh Penna.
I also did coilovers front and rear with QA1's. I have an 85 so I had to fab up new front shock towers. After I installed the rear I went back and fabbed up new lower mounts that replaced the shock stud. This moved the coilover far enough away from the steering knuckle to eliminate conflict between the bolts on the knuckle and the coil spring.
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
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From: Summerland B.C. Canada
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Pics? Agent86, here is the thread back when I was really going to try this and I was trying to calculate spring rates based on motion ratios. Fwiw here it is... Not sure what it is worth... Haha
Http://forums.corvetteforum.com/auto...culations.html
Tried to fix the link, it works on my phone but I'll fix it later if I can.
Last edited by USAsOnlyWay; Dec 26, 2011 at 02:36 PM.
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
Likes: 245
From: Summerland B.C. Canada
Pics? Agent86, here is the thread back when I was really going to try this and I was trying to calculate spring rates based on motion ratios. Fwiw here it is... Not sure what it is worth... Haha
forums.corvetteforum.com/autocrossing-and-roadracing/2926518-motion-ratio-and-wheel-rate-calculations.html
Found this thread from DC with some info from Dick Guldstrand. Looking at his numbers, I should be go to go with 425/325.
http://www.digitalcorvettes.com/foru...ht=spring+rate
Thread Starter
Team Owner
Joined: Jan 2003
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From: Summerland B.C. Canada
Front sleeves ordered from Predator Race Products, good match for the looks of the rears.
http://www.predatorraceproducts.com/...oilover/Detail
http://www.predatorraceproducts.com/...oilover/Detail
Race Director
Joined: Feb 1999
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From: Indianapolis IN
Thread Starter
Team Owner
Joined: Jan 2003
Posts: 20,314
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From: Summerland B.C. Canada
I already ordered a full set from Eibach, so no hurry.