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View Full Version : 1980 T/A stock 15' wheels. Subframe options?



saltfuture
07-02-2018, 10:02 AM
Howdy.
I'm looking to get a modern subframe.
I'm interested in the better handling, coilovers, rack and pinion, everything being brand new aspect.
I'm really not into modern wheels, so it's gotta be something that I can mount 15" Turbo wheels on.
If it allows for me to stretch the wheels to 10", even better.
It seems like most manufacturers offer huge brakes on their kits.

What are my options?

Schwartz Performance
07-02-2018, 12:52 PM
If you expanded your options to go full-frame, we offer a full length chassis system complete with a 9" rear end w/truetrac & gears, axles, plus all of the other items you wanted.
We can do a 12.19" 4 piston front to fit under the snowflakes even though it's not on our site.
www.gmachinechassis.com

We offer "huge" brakes on our kits as standard, because who wants to build a performance car with a Chevy Cavalier-equivalent brake system? ;)

-Dale

cornfedbill
07-02-2018, 01:19 PM
There are lots of options out there to choose from.

But why do you want to change out your subframe on a 2nd Gen T/A? To be honest, the 2nd gens have pretty good geometry, unlike the 1st gens.

I would look into good control arms with Delrin or similar bushings, some good shocks or a coil over conversion and some solid subframe mounts. The spindles can be swapped out for B-body police or wagon spindles with 12" rotors and large piston calipers, or a Kore3 or other brake kit to upgrade to excellent brakes with 12" rotors that fit in the stock wheels.

You will get much more bang for your buck if you put the money into control arms and the best shocks money can buy. In addition, if you buy a front suspension kit that bolts to your stock subframe the parts will already be proven to work together. You can even purchase a rack and pinion conversion for not too much.

I would only consider a subframe change if you are looking for extreme performance that will exceed any tire that will fit on a 15 inch wheel.

There are lots of examples of excellent performing 2nd gens with stock subframes.

That's just my opinion.

Marcus SC&C
07-02-2018, 01:58 PM
To answer the original post directly, the Chassisworks Street Machine subframe would be a perfect choice. http://scandc.com/new/node/703 It`s got great suspension geometry, it`s available with lots of options (like power rack and grease able delrin pivot ball coil overs) and the optional 11.75" 4 piston Wilwood brakes will fit into 15" wheels. Easy peasy. You may still want to consider up sizing at at least 17" wheels at some point though. This still retains a surprisingly stock look but lets you run bigger 13" brakes and buy real modern performance tires. Year One has several choices in Pontiac wheels like 17x8/17x9 snowflake wheels, Rally IIs and Honeycombs.

GregM
07-03-2018, 08:11 AM
You can even purchase a rack and pinion conversion for not too much.



Sir, what rack and pinion conversion for the 2nd GEN Firebird are you speaking of? The only one I'm familiar with is about $1800. TIA.....

79T/Aman
07-03-2018, 10:44 AM
Sir, what rack and pinion conversion for the 2nd GEN Firebird are you speaking of? The only one I'm familiar with is about $1800. TIA.....

there are no rack and pinion that properly fit, they are a wast of money on a stock frame, a good modern 600 series box works awesome, third the price and a virtual bolt in!
PTFB has proven time and again that there is really nothing wrong with the stock frame, both of the cars we sponsor have won multiple SCCA championships as well as top 3 finishes at national events while still being real street car with nothing but bolt on parts, you don't even need tubular lower A-arms, std springs, and up to 18x10.5 front wheels with 315/30-18 tires.

cornfedbill
07-03-2018, 11:52 AM
Sir, what rack and pinion conversion for the 2nd GEN Firebird are you speaking of? The only one I'm familiar with is about $1800. TIA.....

I guess the good ones are in that range or above. I'm running a quick ratio steering box from a 1988 IROC Z.

79T/Aman
07-03-2018, 01:37 PM
I guess the good ones are in that range or above. I'm running a quick ratio steering box from a 1988 IROC Z.

As I mentioned there are no good ones, unless you were to redesign the whole front A-arms and steering geometry.

BonzoHansen
07-03-2018, 07:55 PM
I'm curious, what size tire do you plan on running on a 15 by 10 wheel?

Tweak
07-03-2018, 08:18 PM
The big issue you will have is steering arm clearance. I have 7" on front, you could get 8"s on, just. Its the 15" diameter that is the problem, 17"s and larger easily clear steering arm.
154137
154138

79T/Aman
07-04-2018, 07:33 AM
FYI, the brand name of brakes does not affect the wheel size you can use, the design and size of the brakes affects the wheel size you can use, the other factor is the wheel design, those wheels look like torque thrust Ds those have about the most amount of room for brakes of any cast aluminum wheel available, just letting people known that the devil is in the details.