s|s mustang rear suspension question

SLOCOUPE · Sep 14, 2009

I see a lot of these cars gettin it done with basic boltons. I used to have a complete upr rear setup and a sbf. Car had been 1.30
60'. I swapped to some baseline uppers to move instant center. Had suspension plotted
And has been downhill since. New tires several suspension adjustments and still 60' is terrible
Car has gone 5.56 with a 1.36 60'. Should 60 better. Thinking of going back to my old uppers.
Am I crazy. how fast have you been with basic boltons.

Racecraft Inc. · Sep 15, 2009

Sounds like your car doesn't like your new instant center. Put the car back the to the way it was and try something else to improve
your 60 foot.

Mark Wilkinson
http://www.racecraft.com

SLOCOUPE · Sep 16, 2009

I agree. I think I will do that and see what happens.

Badboss351 · Sep 16, 2009

You need to go with me to Rockingham, and see what it does!!

XJHEAD · Sep 17, 2009

I put on the same uppers. I have adj. spring perches in the lowers. I had to change my rear ride height to get the 60's to improve. I am still playing around with it to get it to improve. 3400 lbs. 1.31 60'

SLOCOUPE · Sep 17, 2009

I figured I could make it work but I dont have coilovers or adj perches.

Just curious, what was the 60 before and after?

feetfirst · Sep 17, 2009

Where was IC before you changed it?? Where is it now??
You said you plotted IC, so you should have some numbers........??

It IS all about IC for sure.......shocks etc are just a final tuning tool........

I have been 1.26 60 ft with lakewoods/poly bushings.....

But I only run 6.0's.......you should easily be in the low 1.2's 60 ft...

4digitHP · Sep 17, 2009

i have to kinda disagree with this statement.. depends alot on the power he is making. granted most of the time the 60 should be alot lower being a half second faster, BUT if he has tons of power sometimes 60 is sacrifices a little to even get going. we have a stock susp mustang with an f3 and get out 60 regularly with slower cars, but we have to leave a little easier.. be nice to hook it all on the hit and not flip over or blow them off. lol

with the smaller blower. on 28s and stock 4cyl springs, and non adj upper and lowers is has been 1.26. we are just now playing with the front end limiters and tuneup to get it there with lots more power..

Blk88GT · Sep 17, 2009

Where/how can I plot my suspension? I need to figure out what's going on back there, my car doesn't hook for SHIT and I have all good parts. Any help/guidance would be very much appreciated. I took the day off work tomorrow to get it sorted out before the track on the weekend.

Best 60ft so far is a dismal 1.54. I can't even leave off the brake without blowing the tires off

SLOCOUPE · Sep 17, 2009

I agree with this feetfirst but there are plenty of guys that 60 better than I do with just stock mounting locations. With my MPH I should run mid to low 40's . I have instant center numbers I'll have to look. Kevin plotted it for me. I'll post back when I find them.

SLOCOUPE · Sep 17, 2009

I have three graphs. And I remember having to raise the rear to get the number Kevin wanted.

The final is IC length 32.3
IC Height 9.0
Anti squat 143.5

SLOCOUPE · Sep 17, 2009

But they could be IC Lenght 53.7
Height 10.3
Anti squat 99.3

I'd have to get the car out the trailer and remeasure to be sure

feetfirst · Sep 17, 2009

I hope this is the one......the other one above with 32" - 140% AS would be way to violent, as the 140% would try to separate the body from the tire to quickly....especially with a 32" IC......ladderbar territory....

I know if it were my ride, I would try from 45-55" IC, with a 105-110% AS....you want an AS just above 100% just to get some downforce on the tire as its moving out......

maxamus · Sep 17, 2009

I have UPR lowers
Metco double adjustable uppers
UPR Antiroll bar.
And S & W S-Box. with the bars in the stock location.
1.28 60ft and 5.75 to the 1/8th

SLOCOUPE · Sep 17, 2009

I am going to get the car out of the trailer and verify the measurements.

Your avitar, is that stock suspension.

SLOCOUPE · Sep 17, 2009

got car out and measured.

47.793 Length
10.0 Height
106 Anti squat

feetfirst · Sep 18, 2009

My avatar is pretty much exact measurements you have^^^ for IC etc....and in fact last Sunday it went up that high first pass, so i limited the front end the rest of the day, which kept it down to about 18" of lift.

I now run full UPR suspension with stock rear coil springs, and see no difference in how the car launches from my old southsides. It does have better stability in the top end.

Instant Center (IC) and Anti Squat (AS) can be measured here... http://inductionmotorsports.com/im/

fastlx · Sep 17, 2009

Sorry to hyjack...

This is all chineese to me ?

How do we mesure IC ; AS Height etc... ? from my garage floor ??

feetfirst · Sep 18, 2009

fastlx said:
Sorry to hyjack...

This is all chineese to me ?

How do we mesure IC ; AS Height etc... ? from my garage floor ??

All you need to measure is,

1 - from floor to lower rear control arm rear bolt center
2 - from floor to lower rear control arm front bolt center
3 - from floor to upper rear control arm front bolt center
4 - from floor to upper rear control arm rear bolt center
5 - measure length of lower control arm from bolt centers
6 - measure length of upper control arm from bolt centers

MEASURE the control arm lengths 90 degrees to axle, not with the angle of the arm as this will give a longer measurement, giving an incorrect IC/AS measurement.

Then plot these measurements into the calculator....

Happy plotting...

SLOCOUPE · Sep 18, 2009

How much travel in the front and whats it consist of. Tryong to figure out whats going on with my car. What are you using for uppers in the rear?

feetfirst · Sep 18, 2009

They are strange struts 10 way's, 5" of travel, set full loose, and limited 2".....130's for springs...1650 lbs on the nose

What springs are in the front? What is the front weight of the car?
This is where it can be different in settings, depending on weight bias etc, spring rates...

SLOCOUPE · Sep 18, 2009

I my need to look at my convertor. Next time at the track I will get video and my ignition trace. Maybe I can get some help with that.

SLOCOUPE · Sep 18, 2009

Same as yours. Strange 10 ways, full loose, 14/130 springs, rod end lowers. and my nose weight is at the shop but from what I remember its not much different from yours. I have 5 inches of usable travel and its limited to @3 inches.

What you running for motor?

feetfirst · Sep 18, 2009

Dont laugh..........its a 9.5-1 pump gas 501 CI BB ford with a C4, 8.8 with 3.27 gears....

SLOCOUPE · Sep 18, 2009

Not laughing just trying to get an idea on the nose weight as compared to mine.

About to give up on this thing.

You never did say what you had for uppers on the rear.

feetfirst · Sep 18, 2009

UPR pro series double adjustables.

Have you checked for binding in the rear? Antiroll bar?

SLOCOUPE · Sep 18, 2009

no binding and I do have antroll bar.

SLOCOUPE · Sep 18, 2009

Anybody know the affects of raising the front as far as the instant center is concerned. I know I will loose travel. Now I have 27 in at the rear from floor to top of fender and I have 25 3/8 in the front.
If I level it up that may help with transfer. I know it will put more weight on the rear tires. Are you foxbody guys running level or with some rake?

n2oracer · Sep 19, 2009

Have you ran the car somewhere other than Ware Shoals? Have you tried the HOH since you changed the suspension?

Flamedhatch · Sep 19, 2009

I think thats his biggest problem. Just my opinion, and we all know about them......

SLOCOUPE · Sep 19, 2009

I plann n taking it somewhere this week. Prob HOH Thursday

n2oracer · Sep 19, 2009

If you decide to go, shoot me a PM and I'll try to make plans to go.

SLOCOUPE · Sep 19, 2009

Who is this?

n2oracer · Sep 19, 2009

My name is Josh. We've never met. I just like to put a face with the names from the bullet.

s|s mustang rear suspension question

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