But todd isnt it true if you are N/A and seeing say 19 degrees at WOT and bring it up to say 25 degrees then you will see a power increase. Because a stock grand prix runs around 25 degrees correct? I have been told that each degree of timing added until around 27 degrees is good for about 1.5-2 hp.

My timing account is strictly for boosted cars. N/A cars have much higher timing in them from the factory which is why putting a blower on an L36 takes programming (too much timing).

In our dyno tests adding timing to an N/A motor even if it can take it does nothing for power. We took Wes Blair'* GT up to 30 degrees with little noticable difference.

:? You said above that a healthy stock pcm will give 15* of timing on WOT. I am currently seeing 20-26 on the advance @ WOT. I know my pcm was flashed by my gm dealer when i took it to them a year ago. Is this possibly altitude related(7000') am I misunderstood or other?

The logical answer would be that, yes, the timing was changed in the PCM at some point. And, I would say that it is very likely related to such an altitude. 7000'? Wow, that'* up there...

OK thanks i'm still learning. Where I live is @ 6300' but the drive to work takes me slightly over 7000'

Wow that'* high.

I live at sea level and look up at majestic snow capped mountains that are at most 6000 ft high.

Something may be wrong in your scanner, I don't think there is anyway you can have timing that high with your mods. Are you sure you were at WOT while scanning it and not just in PE mode?

PE mode?
EDIT: Nevermind figured it out, PE=Power Enrichment mode.
so no my data was given after monitoring for a two weeks with the scan tool on several long drives. The aeroforce just backed it up

I've gotten the same numbers from both the Aeroforce and the cheap-o Ebay scanner I have. This concerns me because you call it "head gasket roasting territory" Ireally wouldn't want to deal with that. Is it possible when it was flashed they did something wrong? I thought that it was a file they just load to the PCM, do they actually set paramiters? like you said above the PCM learns, so if it didnt see knock wouldn't it keep advancing?
THANKS!

In the good ol' days, the general rule of thumb is 1* of timing per 1000'. So, if the PCM is programmed for 15* at sea level, then at 7000', it would need to be adjusted 7*, making the max timing for you car 22*. With your mods, your adjusted target range, acoording to Rogue'* post would be around 25-27. That may seem high for most of us, but then again, most of us are no where near 7000'.

At the same time, your fuel/air tables are alot different that what we're used to as well, and that was very likely programmed into your PCM, so that the ratio along with 22* of timing work like stock. Way up there, you're engine is getting a lot less oxygen than ours is, thus will tend to run richer if the ratio table isn't changed.

It should work the same as our stock does with leaner ratio and 15* max timing, at 1000' or less.

Granted, the range of timing that is programmed into our cars will probably work ok up to about 3000', maybe a bit more. Then, ones are likely losing performance if the chip still reads 15* of timing.

Here'* an exellent article I found that really puts it all into layman'* terms:

http://www.chevyhiperformance.com/te...tment_reading/


Anyone, feel free to correct my thinking here if I'm off a bit.

OK I took a 250mi drive yesterday and the highest timing I saw WOT was 19* avg was about 17. Apparently the PCM is slowly pulling my timing back since the drop in pulley size.