Ok, so I'm headed up to the track for the first time this season, and for the first time since breaking 500RWHP. I'll be running 110 octane of course, but my question is what'd be the best way to launch?

I'm running stock axles and am going to do my best not to break them. I'm also running 285 Nitto NT 555Rs on the back, and will be running on a prepped track. I've got the banzai racing diff brace as well. I'd like to stage @ 5k or 6k and launch fairly aggressively, but am a little afraid of getting too much axle hop. I ran it at the track last year with some rather aggressive launches and it's taken the abuse thus far, but as all 7 owners know things can break on a moments notice...

Any suggestions? Any input at all would be much appreciated. I'll be going with chromoly axles in due time, but just won't have them in by Wednesday.

 

I would be more concerned with the diff. You made no mention of any upgrade, the Torsen has a difficult time with high RPM launches. We have customers with as loww as 300rwhp that have destroyed the Torsen at the drag strip.

 

Oh really? You don't think that could be attributed to an already weakened diff? I've been to the strip lots of times since I've been making north of 370RWHP with no ill effects thus far. It's all Russian roulette though.

 

The spider gears just can't handle the abuse that a clutch pack diff can support. This is why most people upgrade when they get near 400whp. A common swap is an S4 TII diff others go with a Kaaz, Carbonetics, etc



Here are some pics of the carnage of 310whp at the drag strip. It crumbled apart in the burnout box. This is mild, we have seen much worse

 

Yikes...You're not making me feel too good about this. :P Not that it matters a whole lot, but I won't be doing any burnouts on these tires...

 

My friend split the diff. case in half as soon as he left the hole.

 

Wow, this is the first I'm hearing about all these diff problems. Dave @ KDR has never mentioned anything to me about being concerned with the diff.

I've been drag racing it for several years and have no problems to report yet. Maybe I've been extremely lucky?? Now I'm kinda afraid to run because of my diff. :P

I'm assuming I'll be fine with no burnouts and a slightly less aggressive launch. Thoughts?

 

Dont scare the guy. Go have fun. If you were not on radials I would bet you being ok. Biggest issue I have found was guys not pulling the slack out of the driveline. I ran 10.6 with stock everything and 8k launches but on MT ET streets.

 

Thanks man, that’s a little more reassuring. I figure as long as I spin a little bit and all of the initial torque doesn’t end up on the axles I’ll be ok. It’d be a much different story if I was running drag radials or slicks, that’s for sure! :P

I can't believe you were running MT ET streets and launching @ 8k w/ stock axles and a stock diff!! That takes some ***** man!

 

So sk8world, out of curiosity how much power were you making when you ran your 10.6? Trap speed?

 

7-7.5k, quick slip of the clutch. If it even thinks about hopping, which it probably will on a radial if you put too much down at once, let off. Your run is already shot anyway.

MT streets are worth a lot in broken drive line parts, if you really want a good pass, go get some and launch off the rev limiter.

 

dont be afraid to break anything.....best advise i can give you.

if anything breaks replace it with a better, stonger part. your diff seems to be the weekpoint of your drivetrain. when you have a chance buy an S4 TII LSD and swap it into your pumpkin.

i launch my car at 5500 RPM. as some have suggested above, take the slack out of the drivetrain prior to launching. if you dont have drag radials, your launch should be around 2500 RPM.

trial and error is your best freind. try different RPMs til you get the one that works best for your car. every car and track is different!!!

 

TRWeiss1 pm sent

 

pull handbrake while holding down the release button, rev **** off it, roughly 8.5k and let out a tiny amount of clutch at the same time so it feels like it wants to pull forwards a small amount or the rear suspension loads up , and in one hit drop the handbrake and just release the rest of the clutch simultaneously flooring the accelerator pedal , no rev an dumps allowed or the pic above will become a reality

 

Hahaha, thanks for the advice guys! Again, I'm not new to the track...I've run this car many times, just never with this much power, and never with tires this sticky. :P

Actually, I found that my best launch occurred when my rpms were on the upswing around 5500rpms while feathering out the clutch. I spun slightly, but didn't wheel hop at all. Of course this was on 255 Nitto 555s. Now I'm on wider R compound tires, so we'll see how that changes things.

Again, thanks all for the advice! I should be going tomorrow, so we'll see how things play out.

Lastly, as far as "if you break it replace it with something better goes", I do that. The only problem in this case is that I don't want it to break and leave me stranded, as the track is 3 hours away from my house.

 

Damn, that's rough. I don't think i would drag race if the closest track was that far away. I just counted 10 1/4 mile tracks within 3 hours of me.

 

Lucky. See, ESTA is only an hour from me, but EVERYONE runs slower there. They charge you more to run, the track isn't prepped, the 60' mark is all bumpy, etc....To put it simply, it just sucks to run there.

Unfortunately, this is the next closest track for me...

 

I was on 24-26psi so around 580-600rwhp. However that was a bad run as I had to let off most off 4th gear as the wall was calling me over. Only had 3-4 more 1/4 mile passes and always one thing or another. Best trap speed was 133.

Once I got everything figured out and started cutting 1.5's the diff didnt last long. I replaced with a TII diff and still on stock axles now cutting 1.49's.

 

Very nice. What do TII diffs usually run?

 

If you're patient you can probably find one close to you for a few hundred bucks, if that.

 

saw one on the other group rotarycarclub.com for $150 afew days back.

 

Gotcha. Thanks guys. If it comes down to it I'll have to pick one of those up!

 

Welp, I don't think I'm going to make it tonight. I was out practicing some launches last night, and something very very strange happened...

On my first launch I got some very minor wheel hop...nothing crazy. I ran it up through 3rd gear, then slowed down. However, when I changed gears after that I could feel vibrations in the clutch pedal when it was to the floor. It almost felt like it did before my clutch fork broke.

I pulled back into my neighborhood and made it to a stop sign. When I went to take off I felt more vibrations in the clutch pedal, and heard a whirring noise that's really hard to describe...almost felt like my pilot bearing was on its way out. I also felt some grinding in the shifter, then out of nowhere everything just clicked and the car took off. The grinding went away, the whirring noise went away, and the clutch pedal vibrations stopped...

I was like no ****ing way, if this thing's breaking it's breaking here, NOT 3 hours from home. I proceeded to stop, start, stop, start, stop, start....no problem. Everything returned to normal as if nothing happened. So, I went back out to see if I could make it happen again. I did 5 hard launches, and the car was totally fine. However, I think it's worth noting that I didn't encounter any wheel hop during those launches...

So what I'm thinking is that I'm right on that threshold of breaking something IF I get wheelhop. Dave has even told me, "you'll be fine as long as you're spinning, but if you bunny hop it's all over." (Just like you guys have said as well)

I just don't know what I'd do if I broke 3 hours from home...I really don't even want to think about what that tow bill would be like. That all being said, I think I'm sitting this one out. I *may* go up to ESTA to race on Sunday, only because it's closer if something were to happen...or I may not even track it until I get axles and a stronger diff.

Really sucks since I was very much looking forward to going today, but I just can't chance it. I feel like I've pushed my luck already, seeing as how I've dragged/launched it many times with 450RWHP.

 

rev it to red and pop dat clutch!!





DANGER!
do not attempt

 

^ HAHAHAHAHAHAHA, that had me rolling man.

I'm all for that if you'll pay for my new axles and/or rear diff!

:P