Before putting on sticky tires I do plan to upgrade the IRS attachment parts as has been mentioned. I'll probably upgrade the 1/2 shafts too, just for peace of mind. I suppose the diff will need to be replaced with something like a Torsen at some point too. I don't plan to upgrade the power for at least 3 years...need to pay off the car first.
You can get away with GT350 axles for now to save a bunch of money since adding power is years away. Either Steeda, BMR, and UPR have complete kits to stop wheel hop. Get a hold of beefcake for tire and wheel combos as he has them in stock because I just bought some drag wheels and tires from him. Next is suspension mods probably UPR, I tried the others and my go to is Team Z but that is for solid axle cars not IRS, I'm already working with Lund on a 93 tune, not going E85 unless it is from a pale because the pump stuff is crap and to inconsistent. As far as the friction discs just run it until they fail, depending on which torsen you are talking to the road course ones don't handle drag launches at all and will break.
Have a look here to see just how bad wheel hop is on the S550 platform.
I’ve installed the following suspension and drivetrain related parts on my Bullittt to help it perform the best that it can on the street and strip:
- Steeda differential bracket (hardcore part which required completely removing the entire IRS assembly from the car)
- Steeda subframe braces
- Steeda subframe bushing support kit
- Steeda subframe alignment kit
- Steeda differential bushing kit (black bushings) with through bolt kit
- Steeda Billet aluminum vertical links (with delrin bushings)
- Steeda RLCA spherical bearings (PITA mod, but I’m sure glad I did it!)
- Steeda adjustable camber links
- Steeda adjustable toe links
- BMR camber lockout kit
- Steeda adjustable motor mounts
- Steeda driveshaft safety loop
- Boomba Racing race transmission crossmember bracket
- Ford Performance half shafts
I think this is as far as I can go with suspension mods, as my car is a magneride car and I’m not willing to get away from that, nor do I wish to lower it and risk scraping a very expensive set of LTHs.
Sticky tires and an alignment, Suspension is an often overlooked component in drag racing "mostly stock" cars. reduce deflection in the rear, get the alignment right, good set of tires, and you'll go A-B consistently
At your power level, I wouldn't worry about suspension just yet. I still have yet to do any upgrades to the suspension(other than the sportline lowering springs already on it when I bought it)and I'm running high 10's n/a. First thing you need is a good tire(drag radial imo is best for auto and a bias ply for manual). In most cases, this will solve any wheel hop issues and yield you the consistent 60' times you're looking for. Later down the road, you will probably need the previously mentioned suspension mods. Lighter weight is also your friend. Less weight is easier on parts. This is just my opinion of course based on 34+ years of racing.
The first thing I did was take the car out to the track showroom stock to get a feel for it. I have some old 17x9s with 26" tall MT ET Street bias ply tires and they do the job at the track for eliminating wheel hop.
If you hook, you usually won't wheel hop. I did add BMR cradle lockouts and braces and a 4-wheel alignment found the front end was pretty far off from perfect out of the factory.
I have always been of the opinion that you mod to use the power you have before trying to add more so I'm still on stock tune.
IRS Braces, front skinnies (17x4.5 wheel with MT Sportsman), the bias ply DR on back, and no front seat (needed room for wheels, tires, tools, and jack), I've run 11.55 down to 11.32 at 121.5-122.98 MPH in the 1/4 (DA and seat time was the difference). Best 60' is 1.79.