Last year in 50-60 degree temps, I ran consistant 12.5's @ 111 with a 1.725 60' with 3"tb, 20-21psi and a mail-in flash. I recently installed GSC 264/272 cams, studs, pump and Al's alky kit and am running 23-26psi (and custom tune). Yesterday in 90 degree temps, I went to the track and made 5 runs, my best was a 12.69 @ 106.8 with a 1.69 60'. Two of the runs I was sputtering all the way through 3rd gear and boost was shaking at 25psi, and I have no idea why? I know the hot weather is a killer, but that much of a killer? I don't know.

Al, or any body with knowledge, could you give me some insight? Why the sputtering? Why such crappy times? I'm kinda pissed I ran slower than last year. Thanks,

-Dave

 

You may have a leak, something definitly is not right with your car.

 

Air plays a big factor in performance of these cars. I have lost serious amounts of time on road courses when the temps get hot.

 

Temps can make a significant difference in times, however that looks like something else could be a wrong. 30 degrees wont make you lose 5mph....

 

Sounds like the time I got a P300 code in the middle of a run. What do you have your cam gears set at and are you sure the belts not of a tooth? If not, like the others said it may be a boost leak of some sort.

 

No boost leaks, boost is good. I have stock cam gears, and I don't think I am off a tooth.

 

Sputtering is not something that should come with hot air and the car is not going to run fast if its sputtering.

Can you describe this sputtering any more ? Does it do it on lower boost ?

When was the last time you changed your spark plugs?

 

My car holds boost fine but I still think it's leaking somewhere. I read on the other post that if your vaccum souce is from the manifold there could be a boost leak but the boost guage will not show it. The turbo will be less efficient, ecu pulling timing etc.

My car just does not pull like it did before. Did you notice any difference using the butt dyno?

 

I am with AL! it is probably the plugs, change them and let er-rip. the leaner you run, the more you have to change the plugs! Especially if you have the "colder" plugs, they are cheap, I change mine every 2 months, do this BEFORE a dyno also!

 

I think that the car may have been misfiring, which I think can come from excessive heat soaking. It happened only two times, which if I remember correctly, happened when I did two consecutive runs and the sputtering/misfiring occured on the second runs of the consecutive passes. It happened only in third gear both times, and the boost guage was reading a "shaky" 25psi. I had changed my plugs the day before you tuned my car (June 3- changed plugs, June 4- got tuned) and I gapped the BCR7ES's exactly what you recommended-23 or 25, I don't remember exactly. I have a felling it could be from the heat, someone told me it actually hit 100 degrees.

 

I read that post about the manifold vacuum issue even before I installed my boost guage, no problem there. Don't you have the silver EVO that I saw at Great Lakes Dragway last fall with the 18's and front mount? Is your car running better than before? As for the but dyno, mine does not work that well. I probably couldn't fell the difference between a 12.2 and a 12.9.

 

I will be there in Chicago on the 29th and 3oth if you have time please PM me and we can arrange a timne for me to look over the car.

BTW - when it gets ultra hot out the collant temps can rise significantly

The stock ecu's collant temp enrichment kicks in and richens the car up significantly - in some cases over a full point richer

Alcohol injected cars already run on the rich side

When this extra collant temp enrichment kicks in the car can easily mis-fire - especially on high boost

You did not answer my question from before - how does the car run on lower boost - say 23 psi ?

 

Al let me know if you can reflash my car back to the first flash. Not sure if there's a leak or not but ran 12.5 with the first flash on pump and 12.8 etc with the second flash. I like to see if the p0171 and p0300 codes go away as well.

Any alky kits left? If so I might go ahead with the full custom tune again? If not I'll wait until next time.


Thanks.

 

I have a 03 BBY. After the clutch installment I feel the car have never been the same. Butt dyno says it's slower but I could be paranoid Good luck with the problem and I hope it was temperature or spark plug.

 

I have several alcohol kits in stock