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Discussion Starter #941 (Edited)
QUOTE=ls1curt;41240834]How are you guys getting a center of gravity measurement or camshaft height? Playing with the calculator a 1" change can have a huge effect on the ic and as%. What is the optimal rake(front wheel well to rear well)? Im currently only aespecially when ifference. It's for a mid 8 sec fox.[/QUOTE]

I'd bet NOBODY nows their TRUE center of gravity height measurement. I've tried with many sets of scales and many vehicles and have never had any success getting repeatable results. The proceedure isn't that difficult, but truly locking out front end travel is hard to do and if the tires collapse at all as you raise the back of the car it skews the results.

The reality is, anybody who when through the procedure to find IC height and trusted the results without doing it several times to verify repeatability, is basing their plotting on bad information. but here's the thing: the real ACTUAL IC height isn't that important. The most important thing is using a number that could be measured for change ACCURATELY each time you make an adjustment. Once you start making test hits, you'll be basing your adjustment decisions more on what you see the car DOING than on the pure numbers. The initial measurements are important for setting a baseline.

I personally prefer using camshaft height. As long as I maintain front ride height measured at the top of the front fender lips, even if I raise and lower the back of the car an inch, the effect to cam height is minimal and pretty easy to measure accurately, especially when compared to the scale method of determining IC height.
 

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This may be a dumb question to some but here it goes.
What happens if you set a triangulated 4 link to same IS height and length to a radial tire leaf spring cars measurments and treat it like a leaf spring car?
 

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Scott, thanks for the reply. That's what I was figuring, set a baseline and adjust based on that, not aim to get a set number/percentage. The car did work surprisingly well for the first time out and minimal suspension setup.
 

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If the IC is longer, it hits tires softer but has more leverage to lift the front of the car? and if the IC is shorter, it hits the tires harder but has less leverage to lift the front? Reason I am asking is because I have Tim Lyons adjustable upper and lower torque boxes on my car and could not keep the front end down at SGMP this fall. Best I could muster was a pathetic 4.94 at 144.44 mph pedaling the car. Maybe I wasn't hitting it with enough power initially, and bringing the rest of the power in too quickly? Damn this shit is harder than the pro's make it look! lol
 

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If the IC is longer, it hits tires softer but has more leverage to lift the front of the car? and if the IC is shorter, it hits the tires harder but has less leverage to lift the front? Reason I am asking is because I have Tim Lyons adjustable upper and lower torque boxes on my car and could not keep the front end down at SGMP this fall. Best I could muster was a pathetic 4.94 at 144.44 mph pedaling the car. Maybe I wasn't hitting it with enough power initially, and bringing the rest of the power in too quickly? Damn this shit is harder than the pro's make it look! lol
Yes and yes. The other factor is longer IC leverages the car for a longer period of time and a shorter IC leverages for a shorter period of time.
 

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front lower height 9.5
rear lower height 8.625
front upper height 15.875
rear upper height im getting between 16.375 and 17 depending on how i measure using 16.625 in calculator
lower length 17.750
upper length 7.750
cam height 20"
3225lbs
1825 front
1400 rear
28" tires

baselines calculator is showing
a/s 104.42%
icl 54.77"
ich 11.32"


the easiest thing for me to do is lower the rear mounting point to the next preset hole (already .750 lower then factory) on my brackets by .750. but my spring rides on my lca so that would also lower the front upper and lower mounting heights not sure exactly how much im guessing about .250"
that would result in
as 132.91%
icl 42.39"
ich 11.16"

to me those numbers look good but the severe lower bar angle, is that some thing to worry about?
 

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front lower height 9.5
rear lower height 8.625
front upper height 15.875
rear upper height im getting between 16.375 and 17 depending on how i measure using 16.625 in calculator
lower length 17.750
upper length 7.750
cam height 20"
3225lbs
1825 front
1400 rear
28" tires

baselines calculator is showing
a/s 104.42%
icl 54.77"
ich 11.32"


the easiest thing for me to do is lower the rear mounting point to the next preset hole (already .750 lower then factory) on my brackets by .750. but my spring rides on my lca so that would also lower the front upper and lower mounting heights not sure exactly how much im guessing about .250"
that would result in
as 132.91%
icl 42.39"
ich 11.16"

to me those numbers look good but the severe lower bar angle, is that some thing to worry about?

Any one have any thoughts?
The car still hooks then spins
 

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Kevin if I were to use your General IC Calculator wouldn't that work for any 4 link as long as the measurements were precise ?
Possibly. The only thing you need to worry about is whether the bolts on the trailing arms that bolt onto the axle housing are directly on the axle centerline. Some 4-link kits have the bolts in front of the centerline which then would produce false readings.

ks
 

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04 cobra 2.9 whipple crusher 770hp, 4R70W w/Tbrake, straight axle 3.73s.

HERE's my problem and need help bc I'm chasing my tail.

Got baselines outlaw uppers w/ARB
Team Z DA LCA w/Team Z Springs
Viking DA rear shocks
Tokico drag front struts 5way adj.
Team Z kmember w/14"-175 coil overs

2061 front weight
1590 rear weight

Front LCA Bolt- 8-5/8
Rear LCA Bolt- 8-3/8"

AS 130%
IC 38"
ICHeight 8.90"

Fairly new MT Pro Radials 276/60/15

As soon as I let off the transbrake the car blows the tires off. The nose tries to left but no traction so it falls back on its face. The shocks settings that have worked previously are C12/R4-6. I did have a IC of 28" and AS of 180% which netted me 1.37-60ft times but wasn't constant. I've also went the opposite direction on shocks to 6C/12R and blows tires off. On the two step the boost is 16-17lbs.
Just would like some input on a new starting point bc I'm getting discouraged with the areas I've already tried. The Internet is confusing the crap out of me. With the short IC and high AS the car would pull wheels about 4-6" and carry out 15-20ft and run the 1.37-.40 60ft area.. I really appreciate any advice that anyone could clear up please. I can post videos if need be.
 

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Ok I have some results on my car, I was having some inconsistent 60fts on my ss fox body, it weighs 3400 with me in it. Combo is a sbf single turbo setup, glide, 3.55 gear, upr pro series, anti roll bar, Viking b324am shocks non coil over in the stock location. The two big changes in the rear I did was install the Team Z adjustable LCA brackets, and a UPR adjustable stock location spring perch with a 10/250 spring. Strange singles up front with travel limiters and 14/175 coil over springs. I have read this thread, then read it again, then again, and again....lol
I lowered the ride height on the car and moved the lower bar 1 hole down from stock, they are slightly pointing upwards, I believe my pinion angle is -2, took all the measurements and used the Baseline general calculator. This is what I came up with and after testing the car a couple of times, seems to work very well for my set up.
AS 105
ICL 48
ICH 10
Now idk if my numbers are right or wrong as I have never done this before, we checked and double checked so I'm assuming we did it correctly.
Went to the track this past Wednesday and for the first time in a long time I have not needed to touch my shock settings in the rear, I set it before hand and never touched them. I only made one adjustment to the struts, went from 3 from full tight to full tight. I also shortened the travel on the limiters. I made 4 passes and every pass I turned up the launch rpm, and boost. Both in small increments, 100 rpm and about 1lb of boost.
pass 1 - 1.31 60
pass 2 - 1.29
pass 3 - 1.28
pass 4 - 1.24
 

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04 cobra 2.9 whipple crusher 770hp, 4R70W w/Tbrake, straight axle 3.73s.

HERE's my problem and need help bc I'm chasing my tail.

Got baselines outlaw uppers w/ARB
Team Z DA LCA w/Team Z Springs
Viking DA rear shocks
Tokico drag front struts 5way adj.
Team Z kmember w/14"-175 coil overs

2061 front weight
1590 rear weight

Front LCA Bolt- 8-5/8
Rear LCA Bolt- 8-3/8"

AS 130%
IC 38"
ICHeight 8.90"

Fairly new MT Pro Radials 276/60/15

As soon as I let off the transbrake the car blows the tires off. The nose tries to left but no traction so it falls back on its face. The shocks settings that have worked previously are C12/R4-6. I did have a IC of 28" and AS of 180% which netted me 1.37-60ft times but wasn't constant. I've also went the opposite direction on shocks to 6C/12R and blows tires off. On the two step the boost is 16-17lbs.
Just would like some input on a new starting point bc I'm getting discouraged with the areas I've already tried. The Internet is confusing the crap out of me. With the short IC and high AS the car would pull wheels about 4-6" and carry out 15-20ft and run the 1.37-.40 60ft area.. I really appreciate any advice that anyone could clear up please. I can post videos if need be.
how new are the shocks? track prep differences?
 

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So for higher power automatic with radial tire people seem to find the sweet spot for AS around 120-140%. How about 500hp stick shift with slicks, does the same apply as a good starting point? If other variables stay the same, springs, shocks, marginal track etc. how much does the power, transmission and tires effect the AS value that usually works`(if any)?

I'm just thinking since real slicks should hook better, and clutch already hits the tire harder, maybe lower AS works better on these?
 
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