it aint staying at 22 degrees I can assure you of that. 22 deg BTDC at 4K would cook your exhaust valves and probably not give enough power to go any higher.
id assume our engines are seeing 40-50+ deg of advance near redline.
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05-13-2010
it aint staying at 22 degrees I can assure you of that. 22 deg BTDC at 4K would cook your exhaust valves and probably not give enough power to go any higher.
id assume our engines are seeing 40-50+ deg of advance near redline.
05-17-2010
k, did a couple wot runs on my aeroforce and came up with this:
its actually 28* timing
o2 is 890-900
KR is 2-3.5* KR on 93 octane vs the 7-8* on 87
so, looks like if i had it down to 26* of timing, i would have 0* KR on 93 octane....
05-13-2010
http://upload.wikimedia.org/wikipedi.../Timingmap.jpg
last column seems pretty consistent.
05-13-2010
Hmm maybe i'm wrong tho? I donno, i'm going on very old old information.
Matt : do you have any info on the timing curves the 3800 specifically uses?
Last edited by MrTube; 05-13-2010 at 06:27 PM.
05-13-2010
It's not a curve so much as it is a map. Matt posted one there in that link. I have a few from HP Tuners if you'd like to see them.Originally Posted by MrTube
05-13-2010
it is static at WOT, for sure 100%.
05-13-2010
My wot timing log from when I started tuning.
9.00000
10.25000
11.00000
10.50000
13.38235
13.31618
14.02326
13.79851
13.88710
13.69444
15.00000
05-14-2010
Hmmm..
CALLED IT.
05-14-2010
Wow, all these years I was looking at timing advance backwords. I always assumed under load you had more advance. It looks like you can run 40+ deg of advance but not under load.
And at the same time, I think the long mystery of why my 87 grandprix pinged BAD even on 94 octane is solved. I swapped out almost every part even the ECM at one point, it still pinged. I even swapped in different metering rods and had it rich to the point it smoked a decent amount floored, still pinged. And we're talking it pinged to the point it sounded like a diesel.
The more you opened the carb, the more it pinged. It didn't ping idling, or under light load\cruising. The ONE PART i never changed was the vacuum sensor. I bet it wasn't retarding the timing as the vacuum dropped (load increased)
Looks like I learned a lot from this thread
05-17-2010
you need to reduce your timing and you'll be good.
05-17-2010
Or run race gas ALL the time
05-17-2010
^^^^
i would if it didnt run my pockets dry
05-18-2010
I was kidding...its like nearly $9 a gallon here for unleaded 108 or whatever.
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