IRS and Drag Racing?

[remtlm]

ok..i know an independant rear suspension is not ideal for drag racing..but are there anything you can add to it to help in drag racing? or what??...thanks.

[Paul Westerbeck]

Check out this thread. http://www.ffcars.com/cgi-bin/ultima...t/005255.html?

[DwHoyle]

Right out of the rule book.

2.3 REAREND

After market axles and axle-retention device mandatory on any car running 10.99 (*6.99) or quicker and any car with locked differential. Cars running 10.99 (*6.99) or quicker that weigh more than 2,000 pounds (907 kg) with independent rear suspension must have swing axle differential replaced with conventional differential housing assembly.

D

[greg schroeder]

I have a Superformance replica Cobra with IRS. I don't really launch the car, but rather start off idle for the most part. It hits some good 1.6 60ft times now and again if the drag radials stick. It's usually 1.8 if they slip a bit.

I ran a 10.91 @ 128.7 mph the other day with DA of 2100 ft. I think it would do a 10.5 if I launched and the half shafts stayed together.

I did try launching once from 3000 rpm with the Superformance supplied 28 slpline half shafts. The driver side shattered inside the differential. I replaced both complete half shafts with a set from The Drive Shaft Shop, but still haven't launched. I put in a Detroit Trutrac rear end for track and drag strip versatility.

[ January 19, 2007, 10:38 AM: Message edited by: Larry N. Johnson ]

[Larry N. Johnson]

Greg

Welcome to the Drag Racing Forum!

You have a very, very quick street car!!
Beautiful, too.


The SPF uses a Ford 8.8, so that is the same as an FFR with IRS.

Questions:
- What gear ratio is yours?
- What engine?
- Total weight?

[greg schroeder]

easy start video
10.91 @ 128.75 pass

- What gear ratio is yours?
Ford 8.8 3.73 with Detroit Truetrac, Tremec TKO 600 and the tires for drag racing are Mickey Thompson ET Street Drag radials, 325/50 15, actual height 27 inches tall.


- What engine?
Roush 427R-095 with single plane intake manifold
Switched carb to Pro-Systems 1000 cfm double pumper
switched to 2 inch primary headers
switched to Buckshot Racefab side pipes

- Total weight?
race weight should be 2550lbs with me in the car and gas.

My SPF number is 2040. Mine was one of the last ones with the Ford 8.8 3.73. I'm not sure exactly which number car they switched, but the new SPF cars come with a Dana rear end which I believe is the same type in a new Pontiac GTO.

[Larry N. Johnson]

Greg,

You made the guy in the Porsche feel bad.

Nice video!

Thanks for posting.

Larry

[greg schroeder]

You made the guy in the Porsche feel bad.

To give credit to the 996 twin turbo it's not an easy car to launch, so I get the jump on him. He's a member in our car club. The car has the Evolution Motorsports GT 640 package, 640HP. It's a really fast car, just hard to start off the line. As I recall he trapped 124 mph for that pass.