Vetteslice

Hey guys what's going on. My names Mitch and I have a 2002 Corvette 6-speed. It has Headers, x-pipe, mid pipe, high flow cats with borla stinger axle back exhaust. It also has an air raid cai, ati dampener and a tune. At the load bearing dyno I was putting 372 to the ground. I've been going to the track for awhile and bone stock I was getting around a 13.1, I went again after I got my upgrades and I'm only at a 12.8, I increased my 60ft from 2.2 to a 2.1. Not really seeing a huge increase in time and was just wondering why. FYI I'm running 285/30/19 on the rear. Pretty decent tires with a good bit of life left. If you have any suggestions or comments please help me out. Thanks.

99blkfrc99

Mph? It's about right. For every .1 on the 60ft is good for about .2 on the big end. Drag radials or try lowering your tire pressure a bit.

Vetteslice

I'm at 25psi in the rear can't go much lower, and around 110mph. You think a 12.8 is all she will do? But yes I do need bigger or better tires. Rolling with the run flats right now, what would you suggest and I heard getting a short throw would increase a bit.

REDSEE5

There are many variables in 1/4 racing. Maybe when you ran a 13.1 the conditions were ideal and when you ran a 12.8 conditions were awful.

When I had my H/C LT1 Trans-Am, I would average around 12.80-12.90 run after run but on some days I would run 13.20s and other days I would run 12.40s. Keep going back and you should see improvement.

Vetteslice

Thanks I appreciate it.

99blkfrc99

Just work on that 60 ft and you'll be surprised at what you run

Gordy M

Several variables can change your ET's. What is the elevation of the drag strip, what was your trap speed with the stock configuration, was you tune based on top end HP or did you also have them also tune the intermediate tables, what is the rear camber on the car, auto or manual, etc. For example in my 2000, I was running 13.3's at 700ft elevation with with the similar 60' times because my vette alignment was set for autocrossing -2F and -1.2R camber. But my trap speeds were in the 107-108mph. With 75+ more HP you should be in the low 12's easily on street tires. also you should be running at least 315 rear tires and also your strap speeds should be in the low teens. Drag radials would make a world of difference.

ApexerER

Its all in the 60ft time...If you can lower that 2.2 to 1.8 you are looking at a 12.0 or so quarter mile time. Whether you accomplish that with better tires, better launch, better driving depends on you and your setup....My 1/4 mile times vary greatly and its all depends on the 60 ft....Good 60 ft...good time....bad 60, bad time...

Velocity_Vette

You need to get rid of those run flats. Dropping PSI on them is just like you pushing against a pull door. You'll be able to work on that 60 ft when you get a more competent tire. If you don't want to ditch the tires you have now for whatever reason at the absolute least grab a set of Good-ole-Craigslist-special C5-fit rear wheels, slap on a competent tire, and change them out when you get to the track. Most of the expectant ETs you've likely read of stock-ish or lightly modded C5s running has been with a really good tire and a good driver mod, and if your headers are LTs you're going to see them at most effectiveness at higher RPMs.

racebum

where do you live and what was the mph?

Glensgages

just curious, but what did it run over 660'?

Tusc

Lots of variables.

I'm curious though. 372 wheel with exhaust and tune basically. Seems high to me who had the same at one time and got 343 wheel after tune. I also had intake mods, but I don't count those as hp mods until they add boost. Lol.

My first c5 bone stock with a cat back wouldn't 13.0 @ 109mph. At 110 with mods, again, there must be some variable at play here. I'd guess 114 as a fair expectation for you.

Maybe video your next drag strip runs and share for education.

For reference, I'm in CT and the times I am referencing were done in NY at Lebanon Valley in September. So mid 70s to high 60s Temps and whatever elevation at lv

Chicago1

373 to the ground with basic mods? No way they definitely fudged the numbers on the dyno.

bwill03z

That's what I was thinking. What kind of dyno was this on??

Vetteslice

Jacksonville nc, and it varies from 108-112

Vetteslice

I'll try an post a video, let's see if it works.

Vetteslice

It was on a load bearing dyno they said my numbers would be less than other dynos, they were just as surprised as me with the numbers.

Vetteslice

Here's the dyno sheet

Chicago1

Well lets face it your car max is making maybe 330-350 to the ground...Maybe and your times prove it...you went 13.1 vs 12.8...Thats 3 car lengths so thats actually pretty decent for the mods. Also you can make a dyno spit any number you want for the customer..

Chicago1

Actually what was the trap speed? Hell I would probably run mid 12's in my car but pull low 130's. I cant launch for **** so your traps will tell you what your putting down