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Old 03-13-2004, 09:45 PM   #1
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Default Dyno Disappointment

I came really close today wishing I still had my GTP instead of the SSEi.

I guess the PCM is just to damn agressive. My previous best before headers and with a 3.4 pulley was 247whp. The best I could pull out of it today with headers and a 3.2 pulley was 245. No knock running 11 to 1 air fuel and I couldnt get ANY more power out of the car. The best I got with the 3.4 still on it was 235.5whp. I did manage to gain about 20 wheel torque at 3100rpm but no more power.

I am very disappointed. Not sure there is any point in trying to mod further until i get a pcm.



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Old 03-13-2004, 10:18 PM   #2
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Wow, that sucks. A LOSS in horsepower. At least you only lost 2 hp and still gained considerable torque.

But, I am not suprised. A DHP is your BEST FRIEND. Just ask the guys with the '04 GTP'*. There are quite a few of them running right at 13.5, but no matter how many mods they do once they hit 13.5, they don't get any faster. This is why they are BEGGING DHP to release a PCM for them. You are basically in the same boat as them, only they can program one for you. The '04 GTP guys have to wait for DHP to feel like releasing one.

Anyhow, so much for you adding 100hp over stock. That still looks like ~70hp to me. (sorry, just being an *** from your 100hp sticker topic)

Shawn
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Old 03-13-2004, 10:24 PM   #3
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Thats a very flat Torque curve you got there. It really looks like the pcm is maxing out torque and keeping you from bigger numbers? How is the car when driving, how is the 0-60 time any quicker?

That pcm upgrade is going to look like a Hero when it releases the reins
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Old 03-13-2004, 11:04 PM   #4
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next time you go, do me a favor, put some race fuel in, and drive it hard for about 60 miles before you take it there. it takes the pcm time to learn how you are running it and what fuel i can handle. for every degree of kock retard, you lose aprox 2-3 HP. and if the pcm has learned just how much timing i can allow, it will limit it when you do your runs so that it doesnt go into knock retard. when i go to the track, i add 6 gals of 112 oct race fuel and drive it to the track with it in there, that way it has learned that it can advance the timing more without knock. also, try this too. ice the SC down, take a bag of ice and lay on top of the SC about 30 mins before the run
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Old 03-13-2004, 11:07 PM   #5
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Quote:
Originally Posted by jeffrey10x2
next time you go, do me a favor, put some race fuel in, and drive it hard for about 60 miles before you take it there. it takes the pcm time to learn how you are running it and what fuel i can handle. for every degree of kock retard, you lose aprox 2-3 HP. and if the pcm has learned just how much timing i can allow, it will limit it when you do your runs so that it doesnt go into knock retard. when i go to the track, i add 6 gals of 112 oct race fuel and drive it to the track with it in there, that way it has learned that it can advance the timing more without knock. also, try this too. ice the SC down, take a bag of ice and lay on top of the SC about 30 mins before the run
I was running 100 octane, learned, and iced the sc down 20-30 min before each pull.
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Old 03-13-2004, 11:11 PM   #6
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thats still low for the HP, did you try to richen up the A/F ratio. 11:1 sounds just a little lean at WOT
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Old 03-13-2004, 11:12 PM   #7
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I didn't break it when i drove it! I Swear!!!
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Old 03-13-2004, 11:17 PM   #8
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Todd, post your AutoTap results with the 3.2 and 3.4 pulley. Might give the experts an idea if they see yer numbers.

Bout time to show em off under this topic
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Old 03-13-2004, 11:36 PM   #9
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Quote:
Originally Posted by Jim W
Todd, post your AutoTap results with the 3.2 and 3.4 pulley. Might give the experts an idea if they see yer numbers.

Bout time to show em off under this topic
Ive got the actual runs from the dynos ill put up in a bit.

Airfuel on the runs were

1) 12:1 (very lean, due to dyno boost sensor falling out and creating vaccuum loss)
2) no dyno data, computer crash
3) 10.1:1 after addition of AFC at 103 percent (very rich)
4) 10.4:1 after turning AFc to 102 percent
5) 10.5:1 after chaning 3.4 pully to 3.2
6) 11:1 after removing AFC (leaving it at MAF controlled 100 percent)

I could have leaned it out with the AFC a bit but it was getting late. We added the afc because the 12.1 scared the hell out of me (until we figured out later the boost sensor problem) so these runs probably could have been a done better if we hadnt of screwed up the first pull.

Anything in the 10'* was bogging it way down (to rich), I toyed with the thought of 11.5 to 1 but never got to doing it with the afc.
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Old 03-13-2004, 11:41 PM   #10
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Quote:
Originally Posted by PontiacDad
Thats a very flat Torque curve you got there. It really looks like the pcm is maxing out torque and keeping you from bigger numbers?
L67 torque curves are ALWAYS flat, with the stock cam especially. The engine basically makes the same torque all the time, thanks to it being a pushrod motor and because of the M90. It makes its power all the way through the powerband instead of peaking high, and dropping off quickly. It doesn't peak as high as it could, but it stays close to its peak the whole time. Thats one of the many reasons why the trannies go so easily. Peak horsepower and torque numbers don't mean anything to me, you could have 400 peak horsepower and have 200 average horsepower (very unlikely, but possibly). If that were the case, another engine making 300 peak horsepower with a flat power curve could make the same car go faster than the 400 horsepower engine, because it could have 280 average horsepower or something like that.

Shawn
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