}BlueFire{

iTrader: (8)

Ok so I did a 13.19 @ 109 with a 2.0 60ft Last year. Now this year I was expecting to be faster due to the fact i added 1 7/8 headers, catted 2 1/2 Y pipe dumped with no catback, and a p&p TB??? Oh and i also added tex z-grip...so i don't understand how i can be slower with 5 mph less trap speed also.This year my best was a 13.46 @ 104 with a 2.0 60ft??? Why i ask!?! Can weather make that much of a difference? Temp wise it was comparable as last year except more humid. Completely lost and disappointed, need some advice and ideas thanks guys.

Navy David SS

iTrader: (13)

Temp will make a huge difference. If you ran the 13.19 at say 70* and now it is 90*... big difference.

Have you had it tuned at all since the changes? Need to get that done. You'd be surprised the difference just with a good tune -- by a good tuner on a dyno..

Yes your 60' sucks -- you said it not me. What tires? Suspension? A few more changes and 12's shouldn't be a problem.

David

Villain281H

iTrader: (5)

I agree with David, temps can be a few tenths of the time, but the MPH is a big indication that something isn't right. Going from 109 to 104 on a car with more mods means power is lost. As mentioned, the tune should be a first place to look.

Otherwise, check all the normal stuff:

spark plugs, fuel filter, full throttle engagement w/ the new TB

Derek

}BlueFire{

iTrader: (8)

I just got a tune and he couldn't get it any better over the stock 99 tune. I ran bald sumitomo srixon last year and this year 1 month old sumitomo htr4's i believe they are called. Stock suspension 133k on it.

}BlueFire{

iTrader: (8)

dynoed 338 hp and 346 torque by the way which i thought was low but others say average???

Villain281H

iTrader: (5)

I'm calling bs here. My stock tune to a modified tune found 12 rwhp and 11 rwtq on a car without headers or a catback. Since then, I've done an LS6 intake, Mac headers and an off road y-pipe and a Magnaflow muffler and found yet more power from the time on the dyno with new stuff installed to re-tuning it.

Just my $.02, what program did you/said tuner use and was it on a dyno, track, road testing???

}BlueFire{

iTrader: (8)

It was a dyno tune using hp tuners...i thought it was strange that i gained absolutely no power also. All in all we did 9 dyno pulls and took a few hours. to my knowledge he messed with fuel and timing by adding in taking it away too...Only thing i can think of is are my headers to big for my car and i'm losing power? I really don't understand two things? How from a tune i gained no power whatsoever. Two i don't understand how i lose 5 mph and the only changes were p&p throttle,headers, and y pipe. Oh and i took off the cat back so it just dumps after the y pipe.

Navy David SS

iTrader: (13)

Me personally, I would take it to another tuner. Something is not right. I suppose you could get to big of headers, but I have not seen it yet.

Another question: are you dumping right off the headers? If so, it is possible that your O2s are not reading correctly.


David

}BlueFire{

iTrader: (8)

Dumping right off the y pipe...so basically when it connects the two into one pipe it dumps...where as normally it would go into the cat back...mine is just dumped

Jakes Dad

DAMN - I thought I posted in this thread but. Something about 02 sensors not installed in the new system and perhaps no back pressure in the exhaust because of the 1-7/8" header. Are the headers long or short?

Jakes Dad

ScreaminRedZ

iTrader: (3)

I gained 0 rwhp with headers and my friend gained 1 rwhp with headers. Once tuned, both cars picked up around 12-15 rwhp. It's possible that you're down on some power. I'd start looking for a faulty component (plugs/wires, fuel filter, etc).

Also, humidity and temp will make a very big difference. Were the runs done at the same track?

}BlueFire{

iTrader: (8)

Headers are long tubes and i have brand new gm o2's...Yes runs were made at the same track. Can weather make a 5mph difference though?

Jakes Dad

So, the next thing I would confirm would be the compression in each hole, cylinder.

Jakes Dad