Author Topic: mustang suspension question (Read 434 times)

Birddogg · « **Reply #15 on:** September 20, 2006, 05:16:27 PM »

Quote

Originally posted by Iceman24

I still don't get it, why would you want to pay the extra money for a cobra with IRS and then scrap it off and buy a solid rear axle, why wouldn't you just save the $$ and buy a GT, that's the only difference between the 2, that and goofy hoods that are supposed to have a very basic ram air system but unfortunately doesn't work

Theres a lot more diffrences when you think.

First IRS Cobras were only 5K over GT. And that included more power(260 vs 320),better engine(aluminum block), 32Valves, 7000 RPM redline,13" brembo brakes,etc etc .. Weight balance of 53F/47R and IRS was about 1" wider then solid axle in GT. Plus many more. Theres a reason why most GT owners upgrade with Cobra parts and not the other way around. The only people i know that put solid axle in their cobras were hardcore drag racers.

In 2007 mustangs, diffrences are even greater and worth every penny.

bkbandit · « **Reply #16 on:** September 20, 2006, 05:19:21 PM »

Quote

Originally posted by Birddogg
Theres a lot more diffrences when you think.

In 2007 mustangs, diffrence is even greater and worth every penny.

I feel that the current 4.6 is over engineered, dual cams, only 300 horse??

DiabloTX · « **Reply #17 on:** September 20, 2006, 05:23:13 PM »

Quote

Originally posted by Birddogg
Theres a lot more diffrences when you think.

First IRS Cobras were only 5K over GT. And that included more power(260 vs 320),better engine(aluminum block), 32Valves, 7000 RPM redline,13" brembo brakes,etc etc .. Weight balance of 53F/47R and IRS was about 1" wider then solid axle in GT. Plus many more. Theres a reason why most GT owners upgrade with Cobra parts and not the other way around. The only people i know that put solid axle in their cobras were hardcore drag racers.

In 2007 mustangs, diffrences are even greater and worth every penny.

Eagl has a 98 TA that he autocrosses and espouses the virtues of the solid rear axle. Hopefully he'll come in tonight and tell ya how his car beats many IRS cars in his class.

Birddogg · « **Reply #18 on:** September 20, 2006, 05:23:30 PM »

Quote

Originally posted by bkbandit
I feel that the current 4.6 is over engineered, dual cams, only 300 horse??

GT engine makes 300HP.
Cobra engine makes around 500HP. (its basically the same engine as in Ford GT only with iron block)

Birddogg · « **Reply #19 on:** September 20, 2006, 05:34:38 PM »

Quote

Originally posted by DiabloTX
Eagl has a 98 TA that he autocrosses and espouses the virtues of the solid rear axle. Hopefully he'll come in tonight and tell ya how his car beats many IRS cars in his class.

Hey anything is possible..

I beat some grandma in a Porcshe on the parking lot.. Does that count?

DiabloTX · « **Reply #20 on:** September 20, 2006, 06:26:46 PM »

Quote

Originally posted by Birddogg
Hey anything is possible..

I beat some grandma in a Porcshe on the parking lot.. Does that count?

I bet it was a grocery loading contest, wasn't it? LOL

Birddogg · « **Reply #21 on:** September 20, 2006, 07:06:17 PM »

Quote

Originally posted by DiabloTX
I bet it was a grocery loading contest, wasn't it? LOL

LOL:rofl

Mark Luper · « **Reply #22 on:** September 20, 2006, 07:18:46 PM »

Gun,

I beleive the shocks are shot. If it were a spring the car would set lower at that point.

I own a '06 stang with a solid rear. Main difference between IRS and Live axle is the Live Axle will upset the car on a rough corner where the IRS will generaly be more stable in that situation.

bkbandit · « **Reply #23 on:** September 20, 2006, 07:30:09 PM »

Quote

Originally posted by Birddogg
GT engine makes 300HP.
Cobra engine makes around 500HP. (its basically the same engine as in Ford GT only with iron block)

that 5.4 started out in the lighting some years back, it hasa blower more boost equals more power. I just hate that ford didnt bother to make a new engine for the gt. It either shows u how good the engine is or how lazy they are.

eagl · « **Reply #24 on:** September 21, 2006, 05:12:24 AM »

Your rear shocks might be worn out...

Mustangs often have soft rear suspension 'cause *in general* a softer suspension aids overall traction (even if it makes the car handle like crap) and mustangs have traditionally been balanced too nose-heavy, making them prone to rear wheelspin and loss of rear grip. Loosening up the rear suspension can help with overall grip at the expense of making the car handling more sloppy.

That said, the shocks should prevent it from being bouncy so your shocks might be worn out.

eagl · « **Reply #25 on:** September 21, 2006, 05:20:35 AM »

Regarding solid rear axle vs. IRS, the solid rear axle will quite often offer an advantage on the track, at the cost of trickier handling qualities. Road and Track repeatedly compared the f-body cars to the mustangs and although the new IRS mustangs handled "better" than the f-body in terms of ease of driving over bumps and uneven pavement, the f-body still soundly trounced the mustang even when the mustangs finally got a horsepower advantage.

Go to ANY SCCA autocross event, and compare the performance of stock mustangs against stock f-bodies... If you can find any stock mustangs competing that is. The f-body cars simply destroy the mustangs on the track so almost nobody races mustangs in SCCA stock classes and nobody actually wins driving them either.

The only drawback to the solid rear axle is axle hop under acceleration (controllable with suspension tweaks), axle hop under braking (controllable by skilled driving and/or suspension tweaks), and quirky handling when accelerating or cornering over uneven pavement or bumps. Even then, the solid rear axle will often come out with higher overall performance than the IRS.

Almost forgot... You can get a bulletproof solid rear capable of handling a LOT more power and torque than the stock IRS, and to my knowledge they don't sell an IRS upgrade capable of handling as much power as commonplace solid rear ends. You can spend only a couple thousand bucks and get a solid rear end that can handle well over 1000 hp. I don't know if there is an IRS swapout that can take that much power but if there is, there is no way it is nearly as cheap.

Track results do not lie... Yea everyone WISHES someone would develop an IRS that matched the last generation of solid axles in terms of overall grip and track performance, but it hasn't happened in US auto designs. Most car designers realize that the last bit of performance isn't worth the handling tradeoff so they go with a more comfortable and predictable IRS wherever feasable, but again track results show that the solid rear axle typically beats the IRS in comparable cars.

Birddogg · « **Reply #26 on:** September 21, 2006, 06:06:49 PM »

Yea, Mustangs dont compete much with Camaros and TAs in autoX because the way classes are divided makes Mustangs less competetive. Heres why:

1. 99-01 cobras dont make enough low end torque to pull em fast enough out of tight little corners of autoX courses.

2. GTs lack power compared to camaros and vettes

3. 03-04 Cobras have a supercharger and cant complete with camaros and TAs classs, so they fall into Vette class.

I think 2005/2006 Mustang GTs suits the F-class much better. (300HP, good low end power, improved suspension, etc).

Check who won the F-stock class here
http://www.scca.com/Event/Result.asp?Ref2=291

I know there are some cars with solid axle that have little problem overtaking IRS cars. But theres also alot of IRS cars that outperform solid axle. Most people who opt for solid axle in road racing do it because of cost and reliablity. Mustangs and IRS is still pretty new compared to how long the solid axle has been around.
There are race ready IRS suspensions hitting the market that are designed ground up for racing and can be bought and put in any 2005/2006 mustangs. It all looks very interesting, guess we will have to wait and see how it all goes down.