Posted this in the drag racing forum, but not many had suggestions or not alot of people read that particular forum or what... but since my car is a bolt on only car I will post it here...


Finally took my car to the track on sunday... and am very disapointed with the results.

Best time of the day was as fallows:

60' 2.24
1/8th 8.72 @ 84.35 mph
1/4th 13.32 @ 106.02 MPH

Now these would be decent times if I was stock.. but I am not, Mods are as fallows.
2000 SS
SLP LT Headers
2.5" True Duals
LID, Bellows
Ported + Descreened MAF, Ported TB
Removed all emissions equip, AIR and EGR

Car dyno'ed just over 333 at the wheels before the ported TB and ported MAF...

The car seemed to run fine on my first run, I cut the best 60' of the day on my Nitto drag radials of a 2.1 but the car still only ran a 13.4 @ 105
I know my 60' sux for drag radials, but I was unable to heat them up without a linelock and I had some wheel hop issues coming off the line, but my trap I know should have been considerably higher.
After the first 2 or three runs I had a slight misfire problem.. I could sit and hold the rpms on 3k and hear a slight popping and or thud coming from my exhaust, when I'd let off the gas car would idle extremely low and sound like it had a misfire at idle. I let the car cool down for 30 minutes and ran again, car didn't have the misfire sound but it still only ran a 13.4 @ 105 again.

I should be trapping close to 110 and running high 12's in my car with a decent launch.. but I do no know what the problem is.

Is it possible the ported MAF has my car running 5mph slower then it should be?

Also, on my good runs when I would hit 4th gear right at the end of the quarter mile my car would bog... and not accelerate at all it seemed which is probaly what hurt my trap speed the most on the decent runs....

Any help or suggestions are appreciated... plugs and wires are fine, and I had no idea there was a problem until I went to the track ...

Thanks

 

I would ditch the ported MAF , the stock one flows enough to support 400+ RWHP.You need to know the Airfuel ratio , I know that a ported MAF will tend to make a car run lean, I would start there.

 

Ever do the pcv mod? and id get rid of the maf crap too. did it feel faster before the maf and tb? either way, respectable times...

 

I ported my MAF, and painted it and my TB on the same day... I got some paint on the spring of my TB but I noticed driving around the next day it felt sluggish in the throttle... but I chalked it up to paint on the TB return cable.. making the difference.

I already have a stock MAF on its way, so I am going to throw it back on... the problem is I won't really know the difference until I can get back to the track though.



A copy of my Dyno sheet before the ported MAF and ported TB.. the car was making good power, tons of it under the curve... so with that power there I know my trap would have been a bit higher then 106.. I was thinking around 109-110. I'm afraid though that a ported MAF can't **** up my HP enough to kill 4-5 HP in the quarter mile though...

The dyno I went to did not have wideband.. so I couldn't tell you what my AF ratio was.

 

The PCV mod? Can you explain what that is? I read the instructions on install university but I didn't quite understand the purpose.. can you lose HP and such that way? And I have also noticed some oil around the blade on my TB.

 

Whoa ****.. just checked my oil and I am down a good bit.. I think I might have a much bigger problem..

Oil consumption was never a problem on my car before I switched to the 5w30 Mobil 1 Synthetic...

If I do the PCV mod what can I do to clean out all the oil from my intake and TB?

 

Times aren't bad with that 60'. Run a 10w30 oil and a catch can to help oil consumption.

 

I wasn't really worried about my times.. It was the trap speed that had me really worried... it just seems like I should be around 109-112 with near 340rwhp.

 

Just a couple of basics?

What's you elevation?
Do you know what the DA was?

Have you ever raced @ a track before?

The difference between a 13.3 car and a 12.8 car can be something as simple as learning how to drive your car at the track.

Also if you are running Nitto's and can get your 60' down to a 1.9 or so you would be looking at a very high 12 or very low 13 sec pass.

 

Low on oil isn't a good thing, but how low was it? I've heard of people running low oil to pick up a few tenths due to less windage, but it's not practical for all intents and purposes. What was the weather like at the track? What temperature was your car running right before you made your passes? Is it an M6 car? If so, stock clutch? You can test the MAF thing, it works for some people, not for others. My car did lean out with it, but the MAFT fixed that and my particular car runs faster with my set up vs. the stock MAF. FWIW - my car had detonation issues with a completely stock MAF sensor.

 

Track is about at Sea Level.. south Georgia track. Temperature was high.. 80s and was very humid...

Z06's were running mid 12's with their normal trap.. with a stock LS1 z28 automatic running consistent 13.6-7's @ 102-103

New GTO was there cutting 14.0's...

I had my codes scanned tonight.. and I have a bad passenger side front 02.. can this throw my power off enough to lose that kind of MPH? Changing out that 02 tonight.

Codes for that 02 are:
P0154 Bank2 Sensor 1
P0155 Bank2 Sensor 1

 

I thought it was a pretty repectable time

 

The time was nothing horrid.. but average I was running 13.5@ 105.. even with a 2.1 60' on one of those runs..

My trap speed just seems too damn low...

 

00' Z28 - A4. Junk 2.73's, SLP lid, all free mods, SLP D/D, cut out , !cats, SLP Y-pipe, TR55's, Thunder Racing MAF ends & MAFT, IROC rear sway bar 13.285 @ 106.16 - 2.057 60ft - 12/19/03. Recent stuff - MSD 8.5mm wires, QTEC, HPP3. Recent best - 13.301 @ 106.62, 2.123 60'. ----

For comparison.. you really have less mods then me... you have an a4 with the 2.73s and you trapped higher then my car and ran a better time.. even with an almost similar 60' time...

my car

 

I see what you mean, now I am wondering why it's lower?

 

Something is definately not right, it may be a total bitch to track it down... hopefully you'll find it quick and fix the problem. The reason I asked about it being an M6 car and the clutch question is, I have a few friends w/ M6 cars that lost some serious MPH once the clutch started to go away. Another one lost 4 MPH when he bent some pushrods. Just throwing out things to check. With your LT's and M6 - I see no reason why you shouldn't be trapping 111+. My car isn't a factory freak, it runs OK for what it has, but nothing stellar.

 

I did have a bad 02 which I replaced tonight.. as far as pushrods and such I have no major ticking in the engine bay except on start up...

My clutch grabs fine.. no major slippage.. engages pretty smooth and never slips even on 4-5 grand dumps and barks second fine with the DR's...

 

Hrmm.... not sure what it could be. The guy with bent pushrods didn't have any ticking, it was just down on power up top and wouldn't trap any higher than 101-102. A friend of mine has a 00' SS M6, free mods and a cut out. He gets 3rd gear rubber on drag radials. It's typically a 13.20 - 109 car, but has gone 12.90 something at 110 on a perfect pass.

 

With a good 60 my car would be in the 12's even with that 106 trap speed.. I am just completely lost as to WTF is wrong, and where the power loss is coming from..

The bad front 02 I replaced could have caused it?

 

How did you know that the O2 was bad? If you received a code from the front O2 after a missfire that is normal (at least I got some). When I had a bad plug wire my car would run like a$$ and it threw several O2 codes even though the problem was no spark due to the wire. You may have too much oil consumption and fouled a few plugs which intern got crap on the O2, enough to foul it up. Also like said above, I am pretty sure I fubared a few push rods b/c of miss-shift b/c 4th does not pull as hard as the day prior to the incident and has not since .