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Discussion Starter #1
was curious what you guys would recommend for my car for front coil over springs. 86gt. it currently has 12 inch 150 pound springs. the car is stock block 302 heads cam and intake with an S trim. made 464rwhp. tremec tko 600 trans. has interior but all the heating stuff was removed. all the bumper and door supports were removed. aluminum rad(just mention because less weight on the nose) rear mounted battery. tubular k member/A arms. lakewood 90/10s and 50/50s. manual rack. no PS..AC or smog stuff. wasnt sure if they are too soft of a spring for a car with a blower adding weight to the front. this is my first foray into coil overs so please forgive any dumb questions. lol. weight transfer is the main concern over street driveability. (although it will be on the street some)
 

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A few ways of doing it. One way would be to use a 14" 100-125 lb spring. The thinking is this: that light of a spring needs to be compressed more to get your ride height the same. By compressing the spring more, (thus the 14" length) you are storing more energy and thus help raise the nose of the car when launching the car thereby transfering weight better.
 

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Discussion Starter #4
How do the 12-150's look on there now? How much gap between the coils? That spring should be in the ballpark for your setup
i'm not sure i'll look when i get home and get back to you. theres a decent amount of room. i wasnt worried about coil bind. is there a ballpark distance there should be between the coils? i would just do some hole shots and get some real world data but i still need to get my torque boxes situated before i feel comfortable doing that. lol.
 

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I would say that spring sounds good for your current setup.
 

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I use a 14" 130 with iron heads and a turbo.
Have a manual rack and only run an alt.
The ride height is around 3/4 gap fender to tire.
Almost dead hooks with 17" Nt05r on the street.
I think the 150 isn't to light for you.
 

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Discussion Starter #7
I use a 14" 130 with iron heads and a turbo.
Have a manual rack and only run an alt.
The ride height is around 3/4 gap fender to tire.
Almost dead hooks with 17" Nt05r on the street.
I think the 150 isn't to light for you.
cool. i have 12" ones on there now. i guess i'll just keep these on and see how they were once i get my torque boxes all welded up. i might order a pair of 14" 150lb just to have on hand to play around with.
 

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As stated above the 12-150 is in the ball park. To dated Ive tested the 12-150 and 14-150 with no real difference on my car. The 14 rubs the adjuster. Be careful with ride height when using the 12" spring. If I put the ride height low the 12" is loose in the spring pocket at full droop so make sure you check that. This has not been an issue with the 14" spring no matter how low I set the ride height.

Im currently testing a 14-130 spring and so far the nose pops up much quicker. My RT have improved because it yanks the wheels up out of the beams. I dont have enough data to say if ET is better.
 

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Also, would like to add to this. A pic from under the front suspension would really be helpful. In the past on my '86GT, I was trying to get the ride height where I liked it. Just about even with top of tires. Then I would check under the front suspension. I wanted to have the correct Bump Steer which had both the Lower Control Arms and the Tie Rods parrarell even to each other. My final opinion was trying to get the correct weight springs to accomplish correct Bump Steer and desired ride height. For example: what if you have a 150lbs. Spring @ 14" and your Tie Rods don't align parrarell for Bump Steer? How would you accomplish your correct goal then?
 

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Discussion Starter #12
As stated above the 12-150 is in the ball park. To dated Ive tested the 12-150 and 14-150 with no real difference on my car. The 14 rubs the adjuster. Be careful with ride height when using the 12" spring. If I put the ride height low the 12" is loose in the spring pocket at full droop so make sure you check that. This has not been an issue with the 14" spring no matter how low I set the ride height.

Im currently testing a 14-130 spring and so far the nose pops up much quicker. My RT have improved because it yanks the wheels up out of the beams. I dont have enough data to say if ET is better.
looks like you're also running a blower in your signature. so 150s worked well? i'm just gonna keep them in for now. i have the ride height set a little higher currently. theres a little gap between the tire of the tire and the fender. and to racerxmdd..i have a bumpsteer kit so that wont be a problem but thanks. =) i keep forgetting to get a picture up. i will soon. busy at work then went to the yellow bullet nationals this weekend which was awesome.
 

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looks like you're also running a blower in your signature. so 150s worked well? i'm just gonna keep them in for now. i have the ride height set a little higher currently. theres a little gap between the tire of the tire and the fender. and to racerxmdd..i have a bumpsteer kit so that wont be a problem but thanks. =) i keep forgetting to get a picture up. i will soon. busy at work then went to the yellow bullet nationals this weekend which was awesome.
The car presently does not have a supercharger.
 

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I got it close, but then the project snow balled to where it is now! Lol Here is a pic when the k-member was dropped w/ front suspension:

 

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A few ways of doing it. One way would be to use a 14" 100-125 lb spring. The thinking is this: that light of a spring needs to be compressed more to get your ride height the same. By compressing the spring more, (thus the 14" length) you are storing more energy and thus help raise the nose of the car when launching the car thereby transfering weight better.
that spring will be more prone to bounce coming back down which will unload the tire as well. Unless you're running a really good front strut. But in this situation, I doubt the OP is running a quality dbl adj front strut.

One thing to remember, the more power you make, the firmer spring you run.. you're controlling the down, not the up! Wheelies are easy... and expensive!! lol
 

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that spring will be more prone to bounce coming back down which will unload the tire as well. Unless you're running a really good front strut. But in this situation, I doubt the OP is running a quality dbl adj front strut.

One thing to remember, the more power you make, the firmer spring you run.. you're controlling the down, not the up! Wheelies are easy... and expensive!! lol
I guess if you are pulling wheelies, big ones, you have a point. My car pulls high 1.2's 60 foot and runs low 5's in the 1/8 and low 8's in the 1/4 and barely pulls the front end off of the ground with only a 26 X 8.5 tire @ 3150 lbs. I have single adjustable front struts. A lot has to do with how the rest of the car is set up. But I get your point. A lot of people do not have their chassis set up right so they chase one issue or another.
 

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I guess if you are pulling wheelies, big ones, you have a point. My car pulls high 1.2's 60 foot and runs low 5's in the 1/8 and low 8's in the 1/4 and barely pulls the front end off of the ground with only a 26 X 8.5 tire @ 3150 lbs. I have single adjustable front struts. A lot has to do with how the rest of the car is set up. But I get your point. A lot of people do not have their chassis set up right so they chase one issue or another.
Are you using a transbrake? Even on that 26, I would think you would be able to dip into the teens in the 60'. That's with the single adj fronts. But you'd need to get some good rear shocks.

Granted, I don't know the surface you're racing on.. but you have the power to get there.
 

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Are you using a transbrake? Even on that 26, I would think you would be able to dip into the teens in the 60'. That's with the single adj fronts. But you'd need to get some good rear shocks.

Granted, I don't know the surface you're racing on.. but you have the power to get there.
Yes, using a transbrake. Still playing with the launch control. Leaving on the brake @ 2,500 rpm is 14 psi of boost. Converter flashes to about 6,200 rpm. At that point, I am at over 18 psi. This happens in a fraction of a second. So trying to control power on launch on that small tire is a challenge. Going to put a wastegate on the supercharger and use a boost controller to control boost on launch and thus power. Right now, the only thing I can do is pull timing and ramp it is over the first 60' to get it to go. It is a lot of fun though. I do utilize AFCO double adjustable shocks on the rear.
 

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Yes, using a transbrake. Still playing with the launch control. Leaving on the brake @ 2,500 rpm is 14 psi of boost. Converter flashes to about 6,200 rpm. At that point, I am at over 18 psi. This happens in a fraction of a second. So trying to control power on launch on that small tire is a challenge. Going to put a wastegate on the supercharger and use a boost controller to control boost on launch and thus power. Right now, the only thing I can do is pull timing and ramp it is over the first 60' to get it to go. It is a lot of fun though. I do utilize AFCO double adjustable shocks on the rear.
Right on.. and if you're having fun that's all that matters.

This is taking away from the OP's question.. but looking at you sig. You've been 8.60's and 5.30's.. Is this with the same combo? I ask because the numbers don't line up. You may be experiencing some issues up top. With a 5.30 hlaf track, barring anything unforeseen, taking it out the back "should" net 8.30's. This has nothing to do with a 60'... You have the pieces.. and it's showing it can do the work. just sayin'
 
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