Went to the track on friday(9-19) and got a new best..... The car ran great but the mph seemed to be off most of the night. It normally traps 94-96 mph through the 1/8th but on friday was mostly stuck in the 93 mph range and the 1/4mph was all over the place.

Mods: stock crank, scat 6" rods, .060 mahle pistons, AI 200cc h/c, AI street strip ported intake, 58mm TB, LT's, rebuilt 4l60e, edge 4000 converter,10-bolt w/3.73 gear, 275/50-15 M/T drag radials running 10psi.....

Has some weight reduction....removed hvac, no ps ( low mount alternator), front and rear bumper supports removed, front sway bar gone and passenger side air bag removed. Car still retains a stock looking interior, ie front and back seats, radio, carpet, all plastic, etc.

Anyways I ran six passes (all low to mid 11's) and here are my top 3.

Best pass.....
60ft---- 1.642
330ft--- 4.622
1/8th -- 7.16@93.699
1/4---- 11.28@118.033

2nd best...
60ft---- 1.696
330ft--- 4.685
1/8th -- 7.23@94.213
1/4---- 11.33@116.210

3rd best....
60ft---- 1.603
330ft--- 4.646
1/8th -- 7.20@93.093
1/4---- 11.36@114.879

I'm pretty happy with it as it gets faster everytime I go. Can't wait to see how it runs in some 40-50* temps The only thing that puzzles me is the mph.

 

Wow, that's awesome.

10PSI on the DRs? That seems dangerously low

 

Good runs! My friend that runs the MT DR has found the best traction at 10-11psi as well.

Your MPH would probably best be attributed to the weather. Heat and humidity have big effects on those numbers. Something mechanical could be causing, but no need to cross that bridge if you don't have to.

 

I think it's interesting that your 3rd try you did better in the 1/8 than your 2nd, but different story in the 1/4...

 

That 10 psi is real low, but it looks like its working for you.

Nice passes.

 

Nice runs. I also have an Edge converter and my et is good but my mph is also very low so I think it has something to do with the converter

 

Weather was similar to my last outing but that was at a different track. Previous best looked like this....

60ft--- 1.6541
330--- 4.7140
1/8th-- 7.28@95.77

I know and the third best pass had the best 60ft?

 

Maybe take a look at the transmission. Is it locking? How is the fluid? Converter ineffeicency?

 

Depending on the STR of that particular converter, it's entirely possible that the slip is normal.
For example, my SS4000 has a 2.65:1 STR which means hard launches but lots of slip up top.
A fair trade for a car that sees track time.

As for lockup, I've had the best luck with WOT lock disabled all together.
I do keep a part-throttle lockup at 62mph for street use though.
(could probably be lower now that the converter is broken-in)

 

Not locking, fluid looks and smells fine....... 2.40 STR on my converter. I do feel like the transmission doesn't shift the same everytime. Sometimes it will tag the limiter ever so slightly other times it doesn't.

 

I'd say keep an eye on the fluid and slipping. It is odd that it varies so much on the big end. Why don't you lock it? Did you happen to scan/data log the runs?

I'd like to take a look if you did.

 

Wow, your really down on mph (except #1), get some air in them tires and work on making it hook 10psi is way low for those tires.

 

I may try and lock it next time. Didn't get to log the runs due to my laptop not working properly.

Yeah the mph is down but the car is definitley et'ing (sp?) a lot harder than before. I agree with you on the air pressure...

It may be time to bite the bullet and purchase a torque arm and subframe connectors as well.

 

that kind of tire pressure is gonna hurt your mph imo