DFV-R Spec ride height not even in the ballpark
07-04-2016, 04:18 PM
#1
Thread Starter
DFV-R Spec ride height not even in the ballpark
I helped a buddy set up a car earlier today and after doing some napkin notes for ride height and spring preload I am left scratching my head.
rough preload reasoning:
-2.125" total rear shock travel so ideal would be in the middle of that or a hair less for potential aero loading conditions.
-Appox weight on the rear corners: 700lbs
-motion ratio 1.45 (again taken from the gerby thread)
-spring rate of 728lbs/in
-This comes out to needing about 8mm of preload on the spring to get the damper mid stroke while at rest.
The problem I am left with now is this cavernous wheel gap even with bottoming out the ride height adjuster at the bottom of the shock.
Has anyone devised a fix for getting the car to sit at a remotely competitive ride height? I am aware that roll center correcting ball joints will soak up a little bit of the gap but this is not even in the ballpark.
Right now we are tossing around the idea of getting the lower mount cut apart and shortened at a fab shop but I really am hoping the community has come up with something else that I just haven't thought of here.
lower mount for reference:
rough preload reasoning:
-2.125" total rear shock travel so ideal would be in the middle of that or a hair less for potential aero loading conditions.
-Appox weight on the rear corners: 700lbs
-motion ratio 1.45 (again taken from the gerby thread)
-spring rate of 728lbs/in
-This comes out to needing about 8mm of preload on the spring to get the damper mid stroke while at rest.
The problem I am left with now is this cavernous wheel gap even with bottoming out the ride height adjuster at the bottom of the shock.
Has anyone devised a fix for getting the car to sit at a remotely competitive ride height? I am aware that roll center correcting ball joints will soak up a little bit of the gap but this is not even in the ballpark.
Right now we are tossing around the idea of getting the lower mount cut apart and shortened at a fab shop but I really am hoping the community has come up with something else that I just haven't thought of here.
lower mount for reference:
07-04-2016, 05:11 PM
#2
Are you sure the rear springs are the correct length?
Creative Service Ohara makes a shorter rear lower mount if you want to buy one instead of cutting your existing one.
Creative Service Ohara makes a shorter rear lower mount if you want to buy one instead of cutting your existing one.
07-04-2016, 05:25 PM
#3
Thread Starter
I will certainly look into the lower mount.
07-04-2016, 10:06 PM
#4
Registered User
if i'm understanding correctly, i had the same problem on my bilstein pss setup. After hours of re-installs, the problem turned out to be a bad shock that wasn't compressing correctly. Any normal setup shouldn't be that far off for height.
Once we installed the replacement shock body, all was fine.
Once we installed the replacement shock body, all was fine.
07-05-2016, 10:23 AM
#5
Thread Starter
if i'm understanding correctly, i had the same problem on my bilstein pss setup. After hours of re-installs, the problem turned out to be a bad shock that wasn't compressing correctly. Any normal setup shouldn't be that far off for height.
Once we installed the replacement shock body, all was fine.
Once we installed the replacement shock body, all was fine.
07-05-2016, 11:16 AM
#7
I am on the same spring rate (13kg/mm 8" 65mm ID Swift springs - Z65-203-130) with 12mm J's roll center adjusters in rear and am able to achieve a very normal lowered ride height with the ability to go a few mm lower if needed. I have 5mm of preload on the rear springs (normal length is 203mm mine are preloaded to 198mm).
It looks like the rear quarters are also flared out? That is going to make for a bit more of a gap as well.
It looks like the rear quarters are also flared out? That is going to make for a bit more of a gap as well.
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07-05-2016, 11:23 AM
#8
I installed my Urge Speced DFV's with Swift springs this weekend. They are 16k front and 12K rear 8" long each. I used 2mm if preload and ride height floor to fender was about 26.5 front and 28 rear. I was able to adjust the lowers to achieve 26.5 and stopped there.
If you are out of adjustment I would recommend more removing preload like you would do on a standard coil over.
If you are out of adjustment I would recommend more removing preload like you would do on a standard coil over.
07-05-2016, 01:45 PM
#9
I installed my Urge Speced DFV's with Swift springs this weekend. They are 16k front and 12K rear 8" long each. I used 2mm if preload and ride height floor to fender was about 26.5 front and 28 rear. I was able to adjust the lowers to acheive 26.5 and stopped there.
If you are out of adjustment I woild recomend more apring preload like yoi woild do on a standard coil over.
If you are out of adjustment I woild recomend more apring preload like yoi woild do on a standard coil over.
07-05-2016, 04:20 PM
#10
Thread Starter
Originally Posted by dsddcd' timestamp='1467746616' post='24009605
I installed my Urge Speced DFV's with Swift springs this weekend. They are 16k front and 12K rear 8" long each. I used 2mm if preload and ride height floor to fender was about 26.5 front and 28 rear. I was able to adjust the lowers to acheive 26.5 and stopped there.
If you are out of adjustment I woild recomend more apring preload like yoi woild do on a standard coil over.
If you are out of adjustment I woild recomend more apring preload like yoi woild do on a standard coil over.
Correct. And this kit came from urge as well. The springs measured at about 204-205mm uncompressed.