MikeGyver

iTrader: (5)

Oh, ok, at the shifts.
Check the screen shot where he's cruising at 63mph- 52 degrees advance. Yes, all of the screenshots show total advance. There is no other kind of advance on a computer controlled ignition. I think that you're right about W'ed 496 needing more advance, but not as much as you think. I think that you should research more on what kind of timing all the pressurized LS-series engined guys are using. Check over at LS1tech.com

kbracing96

iTrader: (26)

Vernon, Here is a screen shot of a stock 8.1 timing table.



This is the base high octane timing table for a 2002 8.1, there are other table that will contribute to this, mostly retarding for IAT, ECT temps, KR and stuff like this. If everything is up to snuff, these will be the timing values you will get. There is not initial + advance like in the old days, this is it. You can add some to this in stock form, but trust me, for boosted motor, you just can't run the boosted WOT timing like the old SB and BB, you will brake pistons. Ask Tierod on here, he has broken 8.1 pistons a couple of times. These gen III motor will not take the timing like the old school motors will. They are a WHOLE different ball game. They will detonate and the hypereutectic (sp) piston break ring-lands off like there nothing. You can not believe me if you like, but do some searching on here and LS1Tech, and you will find what I'm talking about is all true.

Whippled 496

iTrader: (4)

We actually zero'ed out the BK table because of this. Also, in previous runs when i mashed the pedal, it would auto drop to the low octane table (About 7.5*-8.5*) and slowly come up from there. It wouldnt do it everytime, but it would only need to detect about 1* of KR to make it drop down. 1* of KR (whether it was false or not) is all it would take to cause it to revert to the low octane table. Since 1* was the most it ever saw, he said it would be safe to copy the high octane table to the low, so thats what he did. Not sure if thats a great idea or not considering i could run into some bad gas or something and it would run like ****......but it doesnt drop anymore (obviously). I think if i remember correctly, i want to maximize my timing with as little boost as possible with a S/C setup. In other words, its better to run 15* of timing with 5psi than it is to run 13* with 7psi. I think turbo's are reverse. What i am trying to do is get consistancy with my setup. I would like to run the most timing i can safely. He should be sending me the complete log files today or tomorrow and i will put them up on my site and link to them. Maybe with some of the smarter heads here i can get some suggestions. Its running great, but i know its got more in it. Maybe if someone has the time, i can send them the tune and they can look at it for me.

Manic Mechanic

iTrader: (3)

https://www.performancetrucks.net/fo...d.php?t=370323

Also I've discussed Tie-Rod's engine troubles with him in the past, and he never said timing was the issue. He had other reasons.

Vernon

kbracing96

iTrader: (26)

I'm not sure what your trying to get at here Vernon. I've read that thread and it pretty much all NA small block discussion. Where is the supercharged gen III big block info? Apples to Oranges.

Whippled 496

iTrader: (4)

The only way im gonna really get to the bottom of this, is to get EFILive and do some testing. Talking with a few guys, its looks like that i may be running a little to much timing, even at 13* or 14*. I am going to have to do some logging and testing to see where i am. Unfortunately, there are not that many guys out there who log and tune blown 496's, i wish there were. I have downloaded the EFILive software and been messing with the program for about a week or so. 02, DEW, and Justin have been helping me out understanding a few things. Its really gonna come down to just having to do some real world testing and logging i think. It just doesnt look like the 496 likes timing as much as the small blocks do, especially under boost.

Here are 2 tunes and a few logs that came from those tunes. The newer tune and the newer logs are what im running now.....the first tune had some KR in it as seen in those logs. Justin has been helping me with another tune to use when i get setup here in a few weeks that will hopefully work a little better and give me a nice starting point to work off of. Im not posting that tune. Take a look and tell me if you see anything that looks obviously crazy. the tune i have now is the 002 tune...

www.pasadenatownhall.com/496tune.zip

On a side note...does anyone have a STOCK 8.1L tune from a 2003 that i can use to compare with?

hog

Not sure if it makes a difference or not, but the Vortec HP3-High Tech Crate engine, the 1 that is rated at 525+hp at 5200 rpm and 560+ lb/ft of torque @ 4000 rpm uses a GEN VII (GEN 7) iron truck block which uses PORTED iron cylinder heads from GM where the truck 8.1 uses non-ported iron heads in the trucks.
Could this change the timing needs of an engine as well.

The HP3 8100 crate engine uses a 9.1:1 compression ratio what does the truck engine use? The HP3 crate engine also uses hypereutectic pistons as well.

Maybe while GM was porting the crate engine heads, they performed some machining to the combustion chamber as well???

Irregardless the WOT timing needs of a NA 8.1 are going to be far different from the WOT timing needs of a blown 8.1 engine.


In the Silverado Coolside 2 pickup AWD concept reg cab shortboxtruck. GM installed a NA 8.1 truck block with the GMPP performance ZZ502(8.2L) cylinder heads on it. It made well over 500 hp and over 600 lb/ft torque.
Structurally there isnt much difference between the old 454/502 and the newer 8.1(496) engine. I have heard that the 8.1 engine is just an overgrown 454 with the coil on plug ignition a more effecient intake manifold.

Irregardless, I find the 8.1 engine very interesting, and I have been following this Whippled 8.1 D-max cooler project very closely. Keep up tye good work man.

I have also heard that the mothballed GM V-10 engine project has been given new light. Cube for cube a V10 will make more power than a V8, with less emissions.

IMO This is unfortunate because the V10 sounds like CRAP compared to the beloved V8 engine. Oh well, I dont care, as long as it is a combustion engine and not an electric.

peace
Hog

Whippled 496

iTrader: (4)

I have no idea about that one. Someone with more tuning experience than me will have to answer that.

Same thing, 9.1:1 comp ratio and hypereutectic pistons are what is in my engine.

I agree, i was just curious to see what the stock timing table looked like for a NA 2003 8.1L. The 2002 8.1L timing table that was posted differs from the 2003's i believe, but i am not positive about that.

Thanks...and I'm trying...LOL

kbracing96

iTrader: (26)

I have one from a 02

Whippled 496

iTrader: (4)

Okay cool. I heard there were some tuning changes between the 02's and 03's....but shoot it to me if you get a chance....it will give me some practice either way.

Gable74@hotmail.com