I recently swapped a turbo LQ4 into my 89 RS. When I purchased the car it had a BBC, TH400 & a rear out of a 93-97 I believe. The car drives fine (for as much as I drive it anyway) but my problems happen at the track.

In order for me to fit the 275-60 DR under the rear I had to add a small rubber spacer between the rear end and the factory rubber stop. For this reason the car doesn't transfer weight correctly. This worked okay for a while but the car is starting to make a little more power now.

I'm thinking of changing to a 26" tall tire, removing the extra spacer to see if that will help. Without rebuilding my entire suspension do you guys think I'm headed in the right direction? Please share the key to making these cars work at the track. Thanks!

 

Hey rockoosi

Do you have any other suspension mods?

ramey

 

None that I can see. It all looks stock to me and worked okay until I got in the low 11s. It hooks okay but after about 60' the tires go up in smoke. I assume this is because the car isn't squatting down over the rear tires.

 

Not sure how your track is, but ours after the 60' mark, It doesn't have near as much traction, so I start spinning also.

But, it sounds like you are heading in the right direction. Go with a smaller tire, take that spacer out, You could also put drag shocks on the front to help with lift. Get some better Lower control arms and panhard bar.

 

Hey guys. These relocation brackets are a pretty cost effective way to increase traction without major changes to the car. They help drive the rear tires into the track and really help increase traction.

http://www.umiperformance.com/catalo...roducts_id=117

I agree on the drag shock idea as well.

ramey

 

Start doing the suspension bolt ons. LCA's and brackets above mentioned make a great addition to start. Torque arm with some adjustable pinion angles helps too.

Shocks/springs is the best thing you can do. Good adjustable shocks will help get that car transfering weight to the tires and keeping traction. You dont want to squat. You want to lift and move weight to the rear to keep rear tires planted. Squatting doesnt do this.

 

I assume you mean the front shocks correct? With that being said would you stick with 275/60 DR (approx 28" tall) or go to a 26" tall tire?

 

Both shocks. Front and rear. They all have influence on how a car leaves.

Tire height depends on the gears and rpm range you need to spin by the time you hit the 1/4 mile mark or 1/8 mile if you run 1/8 mile.

generally want to cross at peak hp or slightly above, so whatever rpm that is, you need to gear to match the mph the combo will produce.

Say you have 500hp at 6500 rpm. Car will trap 120 mph with that power and at 3400lbs weight. With 26" tire you'd need 4.10's to 4.30's. 28" tire you'd need 4.56's.

taller tires require more gear to spin same rpm.

 

Got it! It is a shame that @ 3800 lbs this thing will trap at over 130 mph but me ETs are still in the low 11s because of traction.

 

i run 275/60's with stock springs and no rubber spacers. 5.5" backspacing with a stock width rear. (i could do 6.5 with these tires)
i am selling the rearend out of my car if interested. 9" housing/31sp. axles/ta mount.