As we discussed on the phone and as i posted before - the bigger indication of your car's power is the huge differnce in the speed gain in the back 1/8th of the 1/4 mile

The front 1/8th is greatly effected by traction, clutch slippage, driver skill and other variables

Its clear your car is making more power

You must decide wether to add more mods such as a 3" exhuast - and high flow cat - - OR just take a few more trips to the track to refine your skill in shifting fast etc - - OR BOTH!

 

Just asking for clarification here - are you recommending 3" exhaust from turbo back with a cat-delete pipe? Or were you recommending 3" downpipe, stock cat (2.5"), and 3" cat-back exhaust?

If you've already got the 3" cat-back, and intend to keep the stock 2.5" cat, is it worth adding a 3" downpipe or is that a bad combination (meaning not enough gains for the price - without the cat-delete pipe)?

 

How about a clutch?
I lost time in the 1/8 with more power and stock clutch.
-James

 

Clutch slippage is possible, I am assuming the clutch is grabbing and if not it is noticeable.

The 3" downpipe will still make a difference with a stock cat. It's all a matter of what you are willing to run for a cat. Right now I am still running the stock cat because I don't want to drive around without it. Sooner or later I will get a high flow to replace it but I have other mods to do.

 

The clutch is still grabbing....even though I have slipped (and smelled) it several times. I am not sure how much life is left in it...but still seems to grab ok.

How does my launch look in the video?

 

The launch looked okay to me. IF it got heated on the launch it could have slipped on the 1-2 shift but usually you will see the slipping on the tach or feel it.

 

Your clutch is fine. If it would slip during that run , it would've slipped when you dropped the clutch for that is when the most load is at.

 

I really don't think the Downpipe is the issue. If anything, it would hurt the top end instead of the low end. With the 2.5 he should make power a little quicker than with the 3 inch (make less top end though). Just my opinion though... Without cams, the 2.5 should be plenty... The stock cat needs to go though (-:

 

This is not an NA engine though. The 2.5 pipe is restricting the turbos' ability to spool up. Plus there is no low end here, it's drag racing. He launched the car at 5700 RPMs and was never at a lower RPM then say 4000. That is all exhaust flow and the 2.5 is not up to the task. The more pressure drop from pre-turbo to post turbo there is, the faster the turbo can spool and the more exhuast gases that can get out of the engine. The turbo is the restrictor the exhaust needs.
I'd be willing to be that even with a 2.5 inch DP he could unbolt the exhaust at the DP and the time would significantly increase. That proof enough right there.

 

Funny you mention that...When I got my car back from having the transfer case replaced the DP was all but completely unbolted I was wondering why I could hear and smell my exhaust in the engine bay!! I should have taken it to the track then

 

hey dave when do you plan on going to the track again srry i missed your msg on srt forums i would have love to go i was bored ****less saturday. i did kick an srts *** in town from a roll hehe. Any way to stay on the topic if you can go to the track any saturday i can lend you my 3'' exaust to try out with test pipe. its perrin dp perrin test and turbo xs catback. Stop down at J.A. on sat if you have chance ill be there from 12 till 5

 

That still doesn't explain why his car is running so much better in the second 1/8th (opposed to the first 1/8th). I have a 2.5 inch downpipe and trap 111-112... With that said, I don't diagree on the fact the 3 inch will have a better top end. I am just saying that in this case, I don't think it would make that much of a difference. Something else has to be the issue here... clutch ect.

Look at the slips closely..... He lost 4mph in the 1/8 but gained 2+ mph in the 1/4. You pointed out his downpipe as the problem. That can't be possible! He lost 4mph in the 1/8 mile by INCREASING the downpipe size. He went from the stock downpipe to a 2.5 between slips.

 

Just for further reference...I finally found my other timeslip from run #2 of the night.

My first run I bogged off the line, so I won't include that

My 2nd run...shifting at redline through all gears

60' - 1.774
330 - 5.406
1/8 - 8.434
MPH - 80.17
1000 - 11.067
1/4 - 13.260
MPH - 103.21


3rd run...the timeslip posted on the first page...shifting at redline in gears 1 and 2...shifting at 6500RPMS gears 3 and 4

60' - 1.798
330 - 5.435
1/8 - 8.472
MPH - 78.78
1000 - 11.078
1/4 - 13.244
MPH = 105.94

 

That explains some of it. You were probably shifting 3->4 while crossing the 1/8 mile traps. That explains your low 1/8 trap. It looks like your car would benefit from short shifting it though as it isn't accelerating harder after 6500.

 

Ok so the 3rd run was the best this is starting to add up . I think you were shifting to late ! 3rd run you shifted 1000rpms sooner in 3rd and 4th and gained 2mph , your car power falls off on the top end b/c of the stock dp and 2.5 ext....... so try again shift @6500 in all gears !!