What should I be using for rear coil springs ?

Suspension Tuning, Troubleshooting, Design and Discussion

Moderators: David Lemmond, Dave Morgan

Post Reply
Message
Author
User avatar
wikd69
Posts: 2077
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

What should I be using for rear coil springs ?

#1 Post by wikd69 » Sat Jul 18, 2009 10:28 pm

Ok, so here's a question.

My Camaro is 3845 lbs with me in it. I know, it's a porker, but it is a street car :mrgreen:

I just installed QA1's in the front with 550# springs (these are the QA1/R version, not the street version)

I currently have Alston single adjustable coilovers in the back with 135# springs.

This is a back-half 32" ladder bar car. All steel big block, TH400, lots of weight.

I've not had a chance to scale it yet, so I don't know how the weight is distributed.

My question is this: I have two sets of coils for the back, 135# and 185#. What would you recommend ? The new QA1 are essentially teakable 90/10 shocks, so there'll be a lot of weight shifting to the back of the car under throttle.

Are the 135# coils too light ? Are the 185#'s too stout ? I could get some in the middle, but I consider these two the extremes.

I know theres not a lot to go by, but I don't know what I should be stuffing under the back.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

User avatar
supernova
Posts: 2552
Joined: Sat Feb 02, 2008 7:35 pm
Location: Ft.Worth Tx

Re: What should I be using for rear coil springs ?

#2 Post by supernova » Sat Jul 18, 2009 11:09 pm

Herry,
The rule is use the lighter spring and put alot of preload on it . If you use to stiff of a spring then you don't put much preload on it. That causes it not to store enough energy to make the suspension work properly. The lighter spring will need more preload to support the back of the car and will store more useable energy.
Hey get Dave Morgan's book and that should help you out a lot. I think it's called: Door Slammers: The Chassis Book

It is always better to error on the lighter side when springing a drag car. I would stick with the lighter springs to start with and preload them.

Just my 2 cents
Attachments
dave morgan's book.jpg
dave morgan's book.jpg (13.31 KiB) Viewed 5122 times
Blackhoodmafia!!!! :mrgreen: :mrgreen:

1972 Nova SS
572 C.I. BBC

Best to date: 1/8
et: 5.28
mph: 134
new wt. 3340 lbs

User avatar
wikd69
Posts: 2077
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Re: What should I be using for rear coil springs ?

#3 Post by wikd69 » Sun Jul 19, 2009 1:04 am

supernova wrote:Herry,
The rule is use the lighter spring and put alot of preload on it . If you use to stiff of a spring then you don't put much preload on it. That causes it not to store enough energy to make the suspension work properly. The lighter spring will need more preload to support the back of the car and will store more useable energy.
Hey get Dave Morgan's book and that should help you out a lot. I think it's called: Door Slammers: The Chassis Book

It is always better to error on the lighter side when springing a drag car. I would stick with the lighter springs to start with and preload them.

Just my 2 cents
okie doke :)

I'll chase the book down too.

Thanks Chris :thumb:
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

User avatar
Bob West
Posts: 582
Joined: Sat Dec 24, 2005 1:39 pm
Location: Republic,Mo

Re: What should I be using for rear coil springs ?

#4 Post by Bob West » Sun Jul 19, 2009 2:44 am

My Camaro is 3845 lbs with me in it.
I've not had a chance to scale it yet, so I don't know how the weight is distributed.
:scratch: :scratch: :scratch: Now that I'm thoroughly confused.
72 Malibu-Nov. '08-1.329-3.995-6.280@106.94-9.988@131.62
best 60ft to date- 1.319
http://www.dragtimes.com/1972-Chevrolet ... -5251.html

User avatar
wikd69
Posts: 2077
Joined: Sat Feb 23, 2008 12:42 pm
Location: Rocklin, CA
Contact:

Re: What should I be using for rear coil springs ?

#5 Post by wikd69 » Sun Jul 19, 2009 2:54 am

Bob West wrote:
My Camaro is 3845 lbs with me in it.
I've not had a chance to scale it yet, so I don't know how the weight is distributed.
:scratch: :scratch: :scratch: Now that I'm thoroughly confused.
:smt003 :smt003

I've weighed the machine, just not corner by corner, that's what I meant...

I don't know the weight distribution front to rear, nor left and right.

I just know that with the cheeseburger munching meathead in the left seat, it weighs about 3850.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

Yellowchevelle
Posts: 129
Joined: Mon Aug 13, 2007 1:08 pm
Location: Salina, KS

Re: What should I be using for rear coil springs ?

#6 Post by Yellowchevelle » Sun Jul 19, 2009 1:17 pm

supernova wrote:Herry,
The rule is use the lighter spring and put alot of preload on it . If you use to stiff of a spring then you don't put much preload on it. That causes it not to store enough energy to make the suspension work properly. The lighter spring will need more preload to support the back of the car and will store more useable energy.
Hey get Dave Morgan's book and that should help you out a lot. I think it's called: Door Slammers: The Chassis Book

It is always better to error on the lighter side when springing a drag car. I would stick with the lighter springs to start with and preload them.

Just my 2 cents
X2 go with the lighter spring and put some preload in them

Post Reply

Who is online

Users browsing this forum: No registered users and 8 guests