Alright, last Friday when I went to the track, no one was able to get any traction. I was hoping that I would finally be able to run a 14, but wasn't able to. I was able to run a 2.8 sec 60' and 15.3 at 94 mph. This is my fastest mph by far, but I was running much slower due to no traction. I have 2.73 rear gears and deflated the pressure from 30 psi to 15 psi. But before Friday I had run at the 30psi and been able to pull a 2.2 60'. I'm just curious what could cause my car to all of a sudden just not hook. I was racing my dad at the time and he told me I am doing one wheel burn out when I started racing...but even with an open differential I would think I would be able to pull better than a 2.8. Oh yah, the track temperature was 40 degrees. Could it be to my tires being cold? I really need this problem to be solved, and the only thing I can really think is that I burnt out my limited slip differential. Any advice on what the problem is, or what to modify in my suspension would be helpful. This car is my daily driver, but occasional drag car. Also, what should a L98 run stock? Any advice would be appreciated

 

Ouch!!! - sounds to me like your limited slip is fried. make sure you pull up straight to do your burn out. If you pull in around a corner, the diff will unlock. - I went 1.9's on all stock suspension, a cold air and exhaust w/ my L98. How are you launching the car? - Are you leaving against the brakes, or just nailing it from idle? If you are leaving against the brakes, how many r's? Your mph is up because of wheel spin. It takes time to build up mph. If you hook up and get there, your mph drops. -

 

What kind of tires are you running? If you are running regular street radials, then 15 psi is too low. I don't even run my Nitto Drag radials that low. I'd put it back at 30 psi and work on how you launch. For occasional trips to the track, I recommend getting another set of wheels and real tires like ET Streets. Suspension mods mean nothing without good tires

 

Your running posi with 2.73's?!?!? Are you even sure you have a limited slip dif? Get some bigger gears like 3.42 or 3.73's and verify that you have a good working posi unit. That should help.

 

Hey everyone thanks. Well, when I bought the car back a few years ago, the person who had it before me had the differential replaced. He kept the stock gears, and it's a limited slip differential. Anyway, before I dropped it to 15 psi, I tried 30 and it didn't change my time in anyway...still 2.8's. Also, is it true you run more mph when you have wheelspin? I've never heard of that before. I may save up for some E.T streets...but tires alone wouldn't cause that bad of a 60' time. I have less than 5k miles on my tires, and have only done very occasional burnouts. I guess 90k miles on a differential could burn it out though. Oh, is limited slip the same as posi? I was thinkin about pickin up an SLP differential, and some 3.43 gears...but if my differential is a posi, then that would be a waste. Oh and by the way, I"m not looking for a sub 2 second 60' just somewhere near the 2 mark, would be good. Thanks

Matt

 

Oh by the way, I tried launching both ways, various tire pressures, and everytime I would lose traction. The track was horrible. I would spin through first, shift into second, then get traction, shift back into first, spin again, and then spin through second, and then finally in third gear gain traction. It was increadibly hard to do while tryin to go straight down the track. Oh, and if your posi is fried...can it just stop working? Well, I guess what I'm trying to ask is coudl I get stuck somewhere and have to get my car towed. Alright, sorry, but I know little about rear ends and I need help.

 

It is enirely possible that your dif is fried and you getting peg leg traction. Posi = Limited Slip. They are one in the same. I still cant imagine anybody putting posi on a 2.73 rear, but it is possilbe. If its fried all that measn is that the clutches in the unit are toast. Depending on the unit you can rebuild it. Eaton and Auburns are rebuildable but the SLP unit is not. And yes the SLP $99 zexel torsen unit is a posi unit. Not the best but for the price it gets the job done. And the job done well.

 

yeah i hear lowering the psi in street tires is a no no...
spinning one tire isnt going to help either..

 

Well, now that you mention it, is that SLP unit able to hold that much power. I plan on putting on AFR heads and an LT4 hotcam, and that should put me near 400lbs of torque. Would the SLP unit stand up to that much power, or should I go with the eaton posi?

 

Spend the $$$ and get the eaton unit. Its more of a long term investment. Everytme the SLP unit breaks it will need to be replaced, and i doubt that they will sell the $99.00 posi unit forever. Get the eaton and if it starts to crap out on you all it needs is a rebuild.