dizwiz24

I am just curious. If one was to record a WOT run on a scantool, what maximum spark advance would one see with the stock chip?

I have an Ed Wright custom 'hotcam' chip and I see 36 degrees max spark advance at WOT.

It shows 33 degrees at 2650 RPM at WOT, then my next reading is at 4325 RPM showing 34 degrees. My final reading says 36 degrees at 5875 RPM.

I have a frame scanner scanning in .7 second intervals. So, thats why my engine speed is ramping up so quick (im in 1st gear on a dragstrip here)

But my main question is how much spark advance does the stock chip give at WOT ?

STL94LT1

At 5800 rpms my stock 94 M6 was recording 39* advance. Currently modded, I am running 41* advance.

dizwiz24

39 degrees spark advance stock? Is this at WOT (Wide open throttle, 99% throttle angle)?

That sounds kind of high. I may be totally wrong, but that sounds like part-throttle spark advance, which in my case goes up to 41 degrees.

STL94LT1

Yes it was at WOT, 100% tps. It does seem high, but it was recorded on Datamaster.

DieL

i remember seeing 34

Timmy!

Just depends on what KPA you are at. At 35 KPA and 4,000 RPM and up the max timing advance is 44 degrees but at 90 KPA (WOT) and up (4,000 and up) the max advance is only 35 degrees.


[Modified by Timmy!, 4:09 PM 7/2/2003]

96GS#007

As Timmy! mentioned, rpm & load impact what timing you'll see when logging. Some other comments...

The timing values that are set in the tables viewed with LT1 Edit or Tunercat are NOT the timing values you see when logging. This "Phantom Advance" has been well documented/beaten to death on the LT1 Edit mailing list. At WOT in the rpm range mentioned by STL94LT1, an additional 4* is added to the base timing you see in the tables. My tables are programmed for 33* of advance at 6500rpm / WOT / 100kPa, yet I can show you log after log of 37* of advance.

In addition to the above, the phantom advance is "stepped". At lower rpms, the extra advance is 0*. In the mid-range it's 2*, and above 5000rpm or so it's 4*. One of the guys on the mailing list mapped the rpms at which this occurs, I just don't have it handy right now.

Different engines like different amounts of advance. STL94LT1 just turned 355rwhp on the dyno. I stepped my timing up closer to his and lost hp. I turned 342 with 37*. Our cars are set up very very similar. The biggest difference is that he has CNC LT1 heads and an extra .1 or .2 of compression with the Imp head gaskets. My heads are stock LT4...for now ;)

Just another reason that the aftermarket "cookie cutter" programs will get you 95% of the way there but it takes dyno tuning to capture the rest. "The rest" may only be a few hp or it may be 20+. Just depends on the setup :)

STL94LT1

Just a footnote:
Both the stock 39* advance and the modified 41* advance were recorded in the 95 MAP KPa range.

Atok

I've got a stock '95 ZF6. I took a look at one of my recent WOT recordings and the timing peaked out at 35 - 36 degrees.