Thread: JoRoW's '01 GT - update 6/26/13 new track times

So what you're saying is, 3.4 pulley?

3.8"...I'd leave it. For reals.

Ported heads/blower/TB/LIM/WB Tune/headers/intake...should be able to get away with at least stock timing all across the MAP...

I'm pretty sure i can get into some good timing, I just havent gotten that far in my tune yet. If i get up to 19-20 im trying out a 3.4.

Meh, 3.8" +19-20* > 3.4" with stock-ish~ timing...IMO.

Then, less heat...translates to less parasitic loss...less chances of knock as well.

To add, knock is much more devastating on a higher compression motor than it would be on say...a low compression L67 setup. After running a pissload of timing on my setup...I'm a huge fan of a timing car over a boost car. Even though, to an extent...you will eventually need to pulley down. Smaller pulley does however sound pretty legit.

Originally Posted by matt5112

Why?

Most suggest 16-18 on pump gas on a low compression shortblock.

More compression increases cylinder pressure and reduces EGT. More timing has the same effect.

Boost also decreases the need for timing.

If you wanted accurate results you'd need dyno time, EGR sensors or better yet a pressure sensor in the combustion chamber.

Then you could find your MBT.

Why?

Because grand prix.

Shouldn't need a damn explanation.

I understand blue is a big fan of timing. It would be sick to be ownin' guys with a stock pulley. But I am still going to try both to see what I like better. If i'm lucky Ill get dyno time, but dont count on it.

If you're like everyone else...and do lots of street...stop and go driving...you'll like the pullied car better, obviously because of the larger torque figure you'll probably be making instead of the higher top end performance you'd be getting from timing.

This is probably a question for matt, but is there a peak torque timing at WOT? I know theres some kind of peak torque timing table in the tune. Also, 3.4 pulley should be here tomorrow But i have an exhaust leak from my crappy headers so i have to fix that before I can tune it. Maf still isnt even close.

Yea I wasnt going to mess with that, GM knows what theyre doing better than I do.

Got band clamps for the crossover leaks and spades LC-1 WB in the mail now. Soooo I pulled 2* WOT timing and added some fuel to the maf and threw the 3.4 pulley on for a few runs....sometimes i had no knock others i had 1-2* and one spike of 4*. 3.8 is back on now until I get this crap tuned (I planned on putting it back on anyway). I feel like a 3.4 will be a little too much until E85, but dang it sounded/felt nice.

Oh and the used 3.4 i bought came with the 3.5" Idler pulley so I dont have to change belts...But it was the same size that I had on there, looked exactly the same. Hopefully my belt on there now isnt too tight.

So before I put the 3.4 on I decided to use seafoam to find my exhaust leak. long story short i left the tee in so ive had a huge vac/boost leak for the last few days and i didnt even notice (Including when I had the 3.4 on). I think my crank position sensor is going out because my car dies in the middle of nowhere and wont start for a minute or two, but then a little while later its back to normal. So Ill have to get that fixed.

I got my band clamps in the mail today and I attempted to fix my exhaust leak, im not 100% sure if i got it yet though. The wideband is also in so Ill be having that on soon. And I got a why dont i set up the WB and just move the sensor around the outside of the pipe to see if i can find the leak? I may have to try it.

Im thinking it may have been because of the boost leak, but who knows. Ill find out soon.

Well on the stock pulley im up to 18* I think and no knock still. I tried to fix my exhaust leak. It sounds better but my LTFT are still almost always negative. Should my TB be reading less air than stock? because it is on this tune. My wideband says im at around 14.3 which I hear is what E10 is close to, but then again my wideband is downstream of the O2 sensor. I think the only real leak I have is the flex pipe and thats before the O2 sensor. Whats a good A/F ratio to run WOT? im in the high 10's and I know thats rich which is probably why I have no knock.

This thing is also turning into a money pit. I spent 600 on new tires, 25 each on 2 tie rod ends, 80 on an alignment, and when i was replacing those i noticed both the tranny and motor mount are shot. And since im going to drop the subframe when i replace those Im just going to get an alum subframe from a junkyard. Oh and I need new wheel hubs.

If anyone saw my post about my car randomly dying, well its still doing it. It runs really really lean when it happens so I assume its a fueling issue. Im going to try ZZP's fuel pump rewire and see what that does before replacing the pump. Oh but when it dies i get the battery light, so yea Idk the deal with that.

yep