Day at the Track, Good and Bad

[diambo4life]

Damn Ty, now that's the kind of knock that can hurt stock parts. So you know, it works like this:

7 counts = timing held
10 counts = 1 degree of timing retard
13 counts = 2 degrees of retard, etc, etc up to 43

Basically every 3 counts pulls 1 degree above 7 counts.

At 5 degrees of knock retard you had ~22 counts of knock. I'd upsize the injectors and fuel pump to make sure you're not starving the motor at the rail but I know the AFC can't be helping. Then again with a better 60', your car is an 11.50 waiting to happen. Damn good on pump gas if you ask me.



Low 10's for an AFR is pretty rich considering that you have methanol. I'd try at least 11-11.5:1 and see how much she picks up. I'll bet it's pretty significant since low 10's is hardly above the stock ECU's target.

That is incorrect and plain false. If you get 1 degree of knock retard, your timing advance gets pulled back ONE degree.

0.35 degrees of knock retard = 1 knock count.
5 degrees of KR = 14.3 counts of knock.
3 degrees of KR = 8.6 counts " " " " .

1 deg of KR is nothing. I personally tune mine for 2 deg of KR and I'm conservative. Most people on the Link forums like 2-3 degrees of KR.

 

[Syndicate13]

That is incorrect and plain false. If you get 1 degree of knock retard, your timing advance gets pulled back ONE degree.

0.35 degrees of knock retard = 1 knock count.
5 degrees of KR = 14.3 counts of knock.
3 degrees of KR = 8.6 counts " " " " .

1 deg of KR is nothing. I personally tune mine for 2 deg of KR and I'm conservative. Most people on the Link forums like 2-3 degrees of KR.

That's the feeling I've gotten from several of the people over at the Link forums, including Thomas. I was showing a spike of 2.5 and carrying 1.7 on that pass.

 

[andymoraitis]

If you disagree have a talk with Jeff Oberholtzer from DSM Chips. That's the information he passed on to me as to how the 2G ECU responds with respect to physical knock counts and the amount of timing being pulled.

I've seen it for myself on a log where I'll hold timing and my knock will show up as 7 counts. Continuing further, I've seen it hit 10 counts and pull one degree. The log and the knock counts correspond perfectly. You're talking about knock retard values and I'm talking about physical counts of knock.

 

[diambo4life]

It is wrong.
Wish you could read this thread. It has nothing to do with ignition timing. There's no difference between your logged "knock count" and knock retard. It's like arguing that you were not driving at 90kph but driving at 60mph. In the end, it's still the same speed expressed differently.

 

[Black95TSIawd]

Well, since not everyone on DSMtuners can view the dsmlink boards, i'm going to paste over a post by the admin on this particular subjust. I hope Tom doesnt mind and i'm sure he wont as this will clarify A LOT of minds.

Ok, I got another reply back from Todd. It really seems like that list you posted earlier was a quote someone probably took out of context from one of Todd's posts to the old digest. How that particular thing has stayed with us this long, I have no idea. I asked Todd if he had any idea where that "below 7" thing came from. His reply follows.


So it really does sound like Todd was probably trying to describe how the long term octane value gets updated, not how knock retard factors directly into ignition advance. It may have even been quoted a fews times again, further distorting the context of the original comment before it showed up on that particular page.

Who knows? The point is that it's not how the stock ECU works. Nor is it how a DSMLink ECU works. Comments like "we don't get any timing pulled until 7 counts of knock on the stock ECU" are simply false.

I really hope this finally puts this myth to rest. I've spent FAR, FAR too much time tracking this all down already.

Thomas Dorris

 

[andymoraitis]

It is wrong.
Wish you could read this thread. It has nothing to do with ignition timing. There's no difference between your logged "knock count" and knock retard. It's like arguing that you were not driving at 90kph but driving at 60mph. In the end, it's still the same speed expressed differently.

Excellent stuff. I stand completely corrected and will henceforth refer to Thomas's formula for determining knock retard values and their influence on timing.

I'll also get together with Jeff Oberholtzer and see where his info comes from since I consider him an expert on the 2G ECU. Once again, I appreciate the help.

Andy