rear suspension rubber bumper extentions ....

[jonszr1]

i have been drag racing 2 of my zr1s for about 4 years now and the one thing that allways bothered me was it was really tough to get the car to 60ft decent .having drag raced for 30+ years i knew i could drive but why darn it couldnt i get better than a 1.78 60 ft. the car had the mph to go midd elevens anyway 117-119.87. this year i switched to the new nitto nto5r tires which hooked better that the mickeys 315x35x17s.it brought the 60 fts to under 1.9 all the time mickeys was tough to get better than 1,97. but still whats missing, a buddy said the car squatted an awful lot for him . so we made an extention for the rubber bumpers that limit rear end travel on each side .we used a piece of round stainless that we threaded all the way through and set the air gap at .60 to start . we ended having a .15 on the drivers side and 1.7 on the passenger side and what a difference 50ft time went to a best of 1.48 to a high of 1.55. we also found that we picked up a little saving on the3 gear changes .about 1.2tenths as near as we can figure my 92 which has coilovers went from a best . of 11.94 to 11.55 at my home track . the changes make the car launch better plus one doesnt have to worry about the half shafts going into the negitive angle on launch which can cause the 1/2 shafts u joints to snap . just thought to share this for those of you like like going to the strip with a manual trans car. oh ps we used washer to adjust the air gap

 

[jonszr1]

opps didnt catch a couple of errors .it should read 60 ft not 50 and air gap ending fig on passenger side .17. sorry forgot my glasses

 

[vetteoz]

plus one doesnt have to worry about the half shafts going into the negitive angle on launch which can cause the 1/2 shafts u joints to snap .

I set my extensions up to limit travel so half shafts are level on launch.I figure having max power going through the uni at any angle ( positive or negative) is bad

These DRM relocation brackets are highly recommended as they reduce squat and reduce the camber change in the tire which results in the outer 1/2 of tire not making contact on launch
Unfortunately out of stock at present I believe

Corvette Forum - View Single Post - Now back in stock, Camber and Trailing Arm brackets

 

[jonszr1]

the 82 has coilovers and is lowered about 2 in below stk so the 1/2 shafts are pretty darn close to level when the car is at rest. but that is an excellent suggestion for those whos car is stk height . you also need a friend who eats lots of doughnuts to sit on the rear bumper so you can adjust them correctly. the camber plates are a good suggestion, i dont beed those as i have heim jointed rear suspenson from gulstrand. the other important thing to not scrimp on is u joints .dennys driveshafts has a comprte deal that includes 6 ujoints (the best 799 series spiecers )and befy straps for the half shafts. i havent broke a u joint in 3 yrs since getting them . my 89 has aver a 100 runs and they are still tight. also ck your wheel bearings for slop.

 

[93Rubie]

Hmm, I'll have to keep this in mind as my stock (for now) LT1 manual trans is getting more (drag) strip action. When I decide to add more power this will come in handy. I wonder if these hurt handling any? I don't want to hurt handling because it is a sports car, has to corner at the road course.

 

[jonszr1]

i dont use them on the street the car would feel like a truck, bounce, bounceit takes about 2 minutes a side to switch them out while i am changing over to the drag radials. stk setuo has a stud coming out of the rubber attached by a nut . i just undo the nut screw on the extention and then use a short bolt to connect it to the car