Hey All,
I need some help from those with more experience than me in Drag Racing. I feel like my vette is running much slower trap #s than the sum of my parts would suggest it should run. The car is an 97 coupe M6 w/ 4.10 gears and a 402. On the strip scales the car weighed in at 3300 pounds. The car dynoed at 530 rwhp/490tq. My only trip to the drag strip in the car netted me a 12.2 @ 118 with a 2.0 60ft. I understand the slow ET as I am not launching the car very hard(Blows the street tires off with anything more than ~2k rpm). Does that trap number sound right? The car runs like a raped ape on the street.

TIA

 

Yeah that does not sound right I would have guessed 120++..

 

Something doesnt add up...my car weighs 3300lbs also and it ran a 12.4 @ 112 with the same 60' of 2.0 and it only has 370rwhp if im lucky.

 

Mine has a 402, when I had the Auto in it with a SS3600 Stall, 3.73 Gears, it pulled a 11.19@120, 1.56 60ft running rich as hell. I put 3.50 Gears in mine for the T56 Swap, but I have 3.89's, and I would predict it to trap a little higher if I ran it with them..

Something is up with yours..that is a low 11's trap speed with a good hook.

I don't know what RWHP mine has, haven't had the chance to Dyno it.

 

Yeah, thats why I asked. I figured maybe the engine was hurt based on the trap. So I stuck the thing on the dyno and made 530 to the wheels. What could affect my trap like that? It really didnt feel like I was spinning the tires all the way down the track. Could the air have been really bad that day? How much of an effect can the air have?

 

If you were spinning, you would have pulled a higher trap.. was it mis-firing at all?

 

im running 12.1 @ 115 w/ 1.95 60' nearly identical with lower trap. my fast trap was 117 on a 12.44 run.
dynoed 432

 

dyno'd 500 rwhp on my 402 and best trap was 129.6 mph ...like said are there any misfires are you power shifting or granny shifting ...is your clutch slipping ?

 

What gear are you in going thru the traps? Also, are you holding the revs up all the way thru the gears? Are you short shifting? My guess would be
1. shift just before the traps
2. letting the car nose over before the next shift.
3. track conditions aren't great
4. it could be the clutch?

These are just some of the questions I have for ya.

 

Are you running with the traction control on or something? 530 HP should be trapping high 120's easy.

 

with 530hp your car should be 130mph+ in good air and in the 128 129 range in the middle of the summer.

my guess would be the driver, but I cant imagine you being so terrible that you would kill off 10+ mph. your gearing is correct, though 3.90's would suit your power level better with a 26" tires IF you were trapping what you should. I have seen bad shifting kill 4, maybe 5 mph, but not 10, so I don't think its completly you.

I would have to say that you may be getting severe false knock. When your car is stationary on the dyno it may not show up, but going down the track, shifting, spinning, maybe something is setting of the knock sensors?

Also, depending on the tune your car may be great on the dyno, and crap at the track. I have seen that as well. Don't forget that on the dyno you are only under load in 1 gear and for a short period of time, at the track you are in 4 gears, and for a longer period of time. A tune for a great dyno number, will not do well at the track. But that is a long shot, most of today's tuners know that.

 

Hmm.

1) I wasnt shifting like I hated my car, just like I disliked it.
2) Clutch doesnt appear to be slipping. It's an OZ700. Grabs plenty hard.
3) I'm running a 27" tall tire on the street, but that day at the track I had a 25.35" tall tire on the car. I was shifting into 5th as I ran through the traps.
4)I was logging the runs in HP Tuners and I didnt see any knock. The car was tuned on the street by me. I'm running stock timing. The dyno numbers I spoke of before are based on this tune.

I'm clueless at this point. I guess I will just have to take it back to the track and compare again. It's only been once with the current motor.

 

What RPM were you shifting at?

 

Near redline(6700rpm). The power is still rising through 6400rpm.

 

Scratch that tire height above. I went back and verified...its a 25.35" tall tire. I was running a set of 315/30/18 Nitto NT-01s I had laying around.

 

Sounds like you are spinning you *** off at some point in the Track..

 

datalog show, regarding this?

 

how much RPM are you losing going into 5th gear? Also, you are running a shorter tire and that doesn't help much either. If you could find a tire a little taller it would help you on the top end. That way you won't have to shift into 5th gear.

I'm sure there might be some other things going on but I'd start with that. Shifting always kills time and MPH, unless you can shift without a clutch (not recommended).

Keep us informed on your progress.

 

Yeah. I just figured out the tire height thing. That might have been a large part of the problem. They were the stickiest thing I had on hand so I ran them...thinking they were a 26-27" tall tire. Oh well. I'll give it another go with some different tires down the road.

 

You guys are trapping ALOT higher then me. Last time I ran it was 12.37 @ 107.28 with a 1.66 60'?