Negative knock

[rainmaker]

What is negative knock value? Is additional timing being added with a negative reading? Anyone with FI running 100 octane unleaded, how much timing are you seeing?

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[beefcake]

its adding timing, - is always good, positive is what you don't want

 

[BLKONBLK2015]

^^^ What he said.... ^^^

 

[rainmaker]

FI guys running 93 Octane - how much timing?
FI guys running 100 Octane - " " doesn't seem like anyone is running straight 100, just mixing
FI guys running E85 - how much timing advance with the corn? 20+ ?

I know there are other variables (amount of boost, temps, fuel quality, etc) - just looking for a general idea

 

[z06psi]

I am seeing up to 14-16 degrees advance on 92.

 

[Kryckter]

I am seeing up to 14-16 degrees advance on 92.

On low boost (7lbs) I can get about 14-15 on 91 at high elevation. On high boost (10/11lbs) I can only get by with 13-14 on 91...

Im starting my E85 tune now so we shall see how much I can get now

 

[Tyler2386]

16-18 degrees on 93 at WOT

 

[Process]

Seeing about 23* at 17psi on E85.

 

[z06psi]

Lol

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[Kryckter]

Seeing about 23* at 17psi on E85.

What kind of power?

 

[rainmaker]

With my latest tune I am seeing 19.5 - 19.75 with negative knock (pulls 1, 2, & 4). On my 3rd pull I did log some positive knock and the timing was reduced to around 15 Deg. What's weird is the first two pulls were basically back to back, then I cruised for a bit and made the 3rd pull (detected some knock) and then almost immediately made a 4th pull with 19.5 - 19.75 deg timing and negative knock. Do the knock sensors sometimes detect a false positive? Otherwise car feels really strong.

 

[Process]

What kind of power?

Most I ever did was 19psi with that timing. Saw over 900.

Now I just run a 4.385 pulley without an inlet which is rated for 15psi but sees about 16.5. I get over 830hp.


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[Justin@VMP]

FWIW, SCT is adding DMRs to a lot of the newer cars and if you log the uppercase KS value (DMR) it will show the old way, positive is adding, negative is pulling.

However, for the lowercase parameter, neg is adding, as Beef stated.

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