Coilover spring rate for DRAG RACING!!

[torchanniv03]

Just getting some ideas on what others are using.. I was thinking about running 14" 150lb in the front, but thats what my brother runs on his fox bady.. I figured our cars are a little more nose heavy so maybe 175lb? My buddy told me 150s all the way but he knows only fox body.. I want it to get away with as much weight transfer as possible, but didnt know if 150s were TOO soft.

 

[torchanniv03]

I tried to do some searching, but i found way too many numbers for road racing/everyday driving which is not what mine is being setup for.

 

[gamebred26]

i have 14-175 up front on my upr k-member no front sway bar.

 

[mikeshimek]

What are you running in the back?

 

[gamebred26]

10-175 qa1 spring.. strange strut.. upr coilover...upr upper and lower..solid rear axle. we made custom brackets to lower the coilover cause it looked like the starsky and hutch mobile at first..and we also switched to fox body strange struts.

 

[torchanniv03]

Sorry guys for not staying up on this. Im used to noone answering my threads lol.

The rear for now is stock springs with qa1 adj shocks and I just ordered wolfe's double adj uppers, adj lowers and anti-roll bar. (solid axle obviously). Front will have coilovers with strange adj struts, aje k-member, teksid aluminum block.

How do you like the 175# springs? Getting some more info last couple of days seems like 175-200 might be better..

 

[gamebred26]

i only went to the track on time last year with nitto 555rs and it was a disaster 2 passes spun till top of 3rd idling it out of the hole. so i wont go based on that.

have mt et street radials now so we will see. i def would go stiffer than a 175 though if anything softer.

 

[86merc]

Not a lot of info to go off here. But I say that I would recommend a 12" spring. I have changed several cars over to a 12" spring and they all were more stable to the 330'. Less "bounce" than the 14" springs. This was at the same spring rate. Dave at Team Z has done a lot of testing in the last two years and also says the 12" is a more controlled spring in these cars.

 

[gamebred26]

Not a lot of info to go off here. But I say that I would recommend a 12" spring. I have changed several cars over to a 12" spring and they all were more stable to the 330'. Less "bounce" than the 14" springs. This was at the same spring rate. Dave at Team Z has done a lot of testing in the last two years and also says the 12" is a more controlled spring in these cars.

front right?

 

[86merc]

front right?

That is correct.




And just for comparison I have a 3700+# Capri (with me in it) a Dart Iron Eagle block, air to water intercooler, large 88mm turbo, a/c and power steering on the front of it. It is nose heavy to say the least. haha I run a 12" 175# spring at the moment. It drives very well on the street, is not mushy and does not bottom out. This is with the Strange struts on the 4th from softest setting. I would think that may be a good place for a Termi car to start. Unless you have a lot of weight reduction up front. On 17" ROH Sypers and drag radials the car has had 1.37 short times so far (about 9 passes). I hope to put it in the 1.2x range this year. I will also be testing a 190# & 200# spring as well. Front suspension limiters will also be tested out. I like testing. :-D

 

[gamebred26]

see my car bottoms out now with the 14...its pretty low though...

 

[86merc]

I meant the strut does not bottom out or the coil spring binds due to the spring rate.

Ride height is some thing all together.

 

[mikeshimek]

That is correct.




And just for comparison I have a 3700+# Capri (with me in it) a Dart Iron Eagle block, air to water intercooler, large 88mm turbo, a/c and power steering on the front of it. It is nose heavy to say the least. haha I run a 12" 175# spring at the moment. It drives very well on the street, is not mushy and does not bottom out. This is with the Strange struts on the 4th from softest setting. I would think that may be a good place for a Termi car to start. Unless you have a lot of weight reduction up front. On 17" ROH Sypers and drag radials the car has had 1.37 short times so far (about 9 passes). I hope to put it in the 1.2x range this year. I will also be testing a 190# & 200# spring as well. Front suspension limiters will also be tested out. I like testing. :-D

What brand of springs are you using and where do you buy them? Also what rear spring rate are you using? Thanks

 

[86merc]

What brand of springs are you using and where do you buy them? Also what rear spring rate are you using? Thanks

For coil overs I usually use Afco springs. I get a deal on them. But you can get them from Summit and other retailers pretty easily. Hypercoil springs are a good choice as well.

The rear springs I run normal coil springs. I have tried the bolt on style coil overs in the rear on a couple of cars. They had clearance issues with axle rotation and caused bind. Unless you do a correct coil over conversion I recommend staying with the stock style springs. You can get rear springs cheap through Advance Auto Parts, NAPA, CarQuest and so on. Usually $50 or so on the rear OE replacements. Plus you can usually source used ones from buddies for free. haha Because they are cheap I have several I have tested with. Because I set the suspension up with anti-squat the spring rate does not seem to effect much. The control arm lifts the car more than the spring. So I pick a spring that gives me the ride height I need to get the control arm chassis and rear end mounting points where I need them. Especially in a application where I do not have any additional mounting points like on a stock car & housing. If the car is too low it is a big issue as the chassis mounting points are below the rear end mounting points. Which is bad. It seems companies have finally figured out about anti-squat brackets (I have been making them for years as have some other crafty people) and now are selling them. But not all classes allow that modification. So ride height is about the only way to move the mounting points around.

It seems 1990-93 LX with a/c springs are usually what works best. I usually use either rubber or poly spring cups to fine tune the height a little. I never cut rear springs.

If you can find a Rockwell spring chart online you can see all the different year and model specs they offer. Specs like spring rate, free height, installed height, spring wire diameter and so on. You will even see some different ones like the McLaren and Saleen cars. The Capri even uses a different spring and rate than the same year Mustang.

In a hurry and that is just a quick explination of what I have and why. :lol: A lot goes into suspension. Hopefully this will get you thinking some. And testing will yield the best results for your car. But swapping out parts can get pricey. That is for sure. But when you install a part that helps the car get a better ET it is worth it. To me at least. haha

 

[BADASS03SVT]

14" 175s on my car in the sig pic....if your stock weight or slightly lightened I would go 200. if your under 3500lbs go 175...my 2 cents

 

[mikeshimek]

For coil overs I usually use Afco springs. I get a deal on them. But you can get them from Summit and other retailers pretty easily. Hypercoil springs are a good choice as well.

The rear springs I run normal coil springs. I have tried the bolt on style coil overs in the rear on a couple of cars. They had clearance issues with axle rotation and caused bind. Unless you do a correct coil over conversion I recommend staying with the stock style springs. You can get rear springs cheap through Advance Auto Parts, NAPA, CarQuest and so on. Usually $50 or so on the rear OE replacements. Plus you can usually source used ones from buddies for free. haha Because they are cheap I have several I have tested with. Because I set the suspension up with anti-squat the spring rate does not seem to effect much. The control arm lifts the car more than the spring. So I pick a spring that gives me the ride height I need to get the control arm chassis and rear end mounting points where I need them. Especially in a application where I do not have any additional mounting points like on a stock car & housing. If the car is too low it is a big issue as the chassis mounting points are below the rear end mounting points. Which is bad. It seems companies have finally figured out about anti-squat brackets (I have been making them for years as have some other crafty people) and now are selling them. But not all classes allow that modification. So ride height is about the only way to move the mounting points around.

It seems 1990-93 LX with a/c springs are usually what works best. I usually use either rubber or poly spring cups to fine tune the height a little. I never cut rear springs.

If you can find a Rockwell spring chart online you can see all the different year and model specs they offer. Specs like spring rate, free height, installed height, spring wire diameter and so on. You will even see some different ones like the McLaren and Saleen cars. The Capri even uses a different spring and rate than the same year Mustang.

In a hurry and that is just a quick explination of what I have and why. :lol: A lot goes into suspension. Hopefully this will get you thinking some. And testing will yield the best results for your car. But swapping out parts can get pricey. That is for sure. But when you install a part that helps the car get a better ET it is worth it. To me at least. haha

14" 175s on my car in the sig pic....if your stock weight or slightly lightened I would go 200. if your under 3500lbs go 175...my 2 cents

thanks for your help guys. im just getting started in drag racing this year and want to focus my attention more on the suspension dynamics of the car rather than shoving more power at it. my previous best 60' was a 2.1 pedaling 315 555r's well past 60'.

looks like 14'' front springs with 175 spring rate are a starting point along with qa1 adjustable rear shocks. some people have posted to run stock shocks up front and stock rear springs out back. would i be looking for a faster rebound shock up front and lower spring rate in back? really appreciate the help!

 

[torchanniv03]

Yea like mike said, thanks guys! Im def a noob at suspension setup, so any and all info from different angles help alot! I know i pm'd you a while back Jake about this and that's what i am looking to start(prob finish) at, but just curious as to see other peoples setups.

As far as weight, i'm still a ways out from finishing up, but just curious as to a "guestimate" on what my car might be around. Teksid block, stock blower, aje kmember, big and littles, solid 8.8, stock anniv driver seat only for track day, possibly thinking about removing the a/c and abs system since it will be a dedicated track car with a c4... other than that, most everything else will be stock style.

 

[BADASS03SVT]

Yea like mike said, thanks guys! Im def a noob at suspension setup, so any and all info from different angles help alot! I know i pm'd you a while back Jake about this and that's what i am looking to start(prob finish) at, but just curious as to see other peoples setups.

As far as weight, i'm still a ways out from finishing up, but just curious as to a "guestimate" on what my car might be around. Teksid block, stock blower, aje kmember, big and littles, solid 8.8, stock anniv driver seat only for track day, possibly thinking about removing the a/c and abs system since it will be a dedicated track car with a c4... other than that, most everything else will be stock style.

I would say 3450 to 3550 with driver. the a/c is an easy delete....if you get one of the abs delete blocks thats easy as well as it pops right into place