Mixing fuels

[Sven59]

So if I end up with say 95 octane I should see either 0.0 or 0.14 on the KR I should be good or at that point should it be 0.0 only?

[ZO6 Bryan]

Originally Posted by jon6.0

I turn off burst knock on any car of mine that gets tuned. For those that don't know, burst knock is basically a predictive thing. The ECU pulls timing based on when it thinks what you are doing might cause knock.

Didn't turn mine off completely but set it where it would rarely be seen and limited just how much can be pulled. Burst Knock is a real problem if you have done a pulley swap and upped your boost.

[ZO6 Bryan]

Originally Posted by Sven59

So if I end up with say 95 octane I should see either 0.0 or 0.14 on the KR I should be good or at that point should it be 0.0 only?

If you have 95 octane your KLF should be 0.00

[jon6.0]

Originally Posted by ZO6 Bryan

Didn't turn mine off completely but set it where it would rarely be seen and limited just how much can be pulled. Burst Knock is a real problem if you have done a pulley swap and upped your boost.

How is yours set?

[Sven59]

If it wasn't, the fuse pull should speed up the process?

[jessrayo]

Originally Posted by Sven59

Can you run that in a car that is stock? All I can get is 91 octane here. I am trying to find a way to run higher octane on a race day, I have a CAI, but I want to keep my warranty for now but still get the best performance.

Octane prevents knock. If you don't have knock you don't need more octane. If you have more octane you can get more timing advance and more power, but you have to have the octane to support the timing advance without knock. True 93 octane should never knock in a stock. Adding octane won't hurt but without advancing timing you are kind of wasting the benefits of more expensive fuel.

Originally Posted by jon6.0

It depends on your tuner if you have a low and high octane table. Some tuners copy and paste the high octane table to the low table.

I have this on my car.

Originally Posted by ZO6 Bryan

That's a good way to blow up a supercharged engine.

I disagree, the knock sensors still work if you don't have 2 tables. You just need to be more aware of the fuel you put in the car and if you periodically look at the tune and see KLF is getting higher you probably need to adjust the tune somewhere. I always have 10 gallons of 100 octane in the trunk in case I'm stuck buying low grade fuel. No fuel or knock related problems in my car with one table.

Originally Posted by jon6.0

If you aren't changing the tune then all you need is a mix of 93-94 octane to get the most out of the stock tune. Any higher octane would just be a waste of money.

Agreed.

Originally Posted by ZO6 Bryan

You really need to be able to scan the car to see if you're doing any good. There is a parameter called "Knock Learn Factor" This KLF goes from 0.00 to 1.00
0.00 means no knock learn is happening. People don't understand that the PCM doesn't switch to the low octane table. It blends the high octane table and low octane table.

0.00 all high octane table
1.00 all low octane table
0.14 is 14% low octane and 86% high octane table.

And this KLF will move around quite a bit in a car that is getting knock. Until the PCM doesn't hear any knock. Every now and then the PCM will add back some timing and if it doesn't hear any knock it will shift back to the high octane table numbers a little at a time. If you use good gas the KLF should stay at 0.00 all the time. If you get a "custom tune" and they try to get too aggressive with the timing you're shooting yourself in the foot because the PCM will shift to the low octane table. A well tuned car should keep a KLF of 0.00 all the time.

Any questions?

This is all correct but I have to say if you significantly upgrade the car and make a lot of changes to the tune, then any pulling into the stock low octane table robs a lot of power. Hell the stock high octane table would rob a ton of power on my car. Knock is bad, so is losing races because your car is pulling timing because it sensed some knock sometime in the past. KLF is good to know and a good back-up. If it is not close to 0.00 you're running bad gas or your tune is wrong. Then upgrade your gas or adjust your tune.

[ZO6 Bryan]

Originally Posted by Sven59

If it wasn't, the fuse pull should speed up the process?

Correct.

[jon6.0]

Originally Posted by Sven59

If it wasn't, the fuse pull should speed up the process?

Fuse pull will reset it to zero.

[jon6.0]

I ran my C6 with the high and low octane tables the same as well. I pretty much data logged everywhere though.

[ZO6 Bryan]

Originally Posted by jon6.0

How is yours set?

Labels 0.000 0.006 0.012 0.018 0.024 0.030 0.036 0.042 0.048
Deac In Prog 0.0 0.0 0.0 0.5 1.0 2.0 2.5 3.0 3.0
V4 Mode 0.0 0.0 0.0 0.5 1.0 2.0 2.5 3.0 3.0
V8 Mode 0.0 0.0 0.8 1.8 2.0 2.3 2.5 3.0 4.0


Max amount that can be pulled is 4 deg. In stock tune it could (and did with the pulley) pull 14 deg.

[Sven59]

This is great, I have been looking for every way to improve performance before my warranty expires and the real modding starts. Every little bit helps.

[jon6.0]

Originally Posted by ZO6 Bryan

Labels 0.000 0.006 0.012 0.018 0.024 0.030 0.036 0.042 0.048
Deac In Prog 0.0 0.0 0.0 0.5 1.0 2.0 2.5 3.0 3.0
V4 Mode 0.0 0.0 0.0 0.5 1.0 2.0 2.5 3.0 3.0
V8 Mode 0.0 0.0 0.8 1.8 2.0 2.3 2.5 3.0 4.0


Max amount that can be pulled is 4 deg. In stock tune it could (and did with the pulley) pull 14 deg.

Thanks!

[CanadianZL1#992]

Far more informative than closing my hood!!

[jon6.0]

Originally Posted by CanadianZL1#992

Far more informative than closing my hood!!

LMFAO!!!!