Acceptable KR, stock PCM, L36

**Sabrewings** · 04-11-2008

I got my Aeroforce put in today, and started some scanning. I know we strive for 0* of KR, but what is acceptable.

I have a catback, WizAired, 2.5" DP, and 180* T-stat on the stock PCM (took the ZZP out because of how my tranny was acting) for the L36. I see 0 KR most of the time, at 1/3-1/2 throttle I get maybe 0.5* KR. But, at WOT, I see as much as 10* of KR.

Acceptable for the L36?

TDCRacing · 04-11-2008

10* is by far from acceptable. When crusing or when i stab the throttle real quick i usually dont worry about any kr as long as it is not over 2*. I wouldnt know what to tell you to look for (someone else chime in) but i would say you have some sort of mechanicale problems.Lots of times you will have kr from the factory but 10* seems like a lot.

Wot I tune for 0 kr.That is the only thing acceptable to me at wot.

I belive for every * of kr that is present you lose 2.5 hp

**IndeedSS** · 04-11-2008

Geez thats a lot of KR. Can you verify with someone elses scanner that those numbers are correct? Acceptable to me is 0 although I live with less than 1.

**Sabrewings** · 04-11-2008

Originally Posted by IndeedSS

Geez thats a lot of KR. Can you verify with someone elses scanner that those numbers are correct? Acceptable to me is 0 although I live with less than 1.

It was mentioned that with my mods the stock PCM is running it lean. I'm going to monitor the LTFTs tonight and see what I get.

**Bio248** · 04-11-2008

usully stock gts knock a lot. mine used to.

**JCG's-GTP** · 04-11-2008

Not to thread jack ya.. but my ZZP PCM shifts odd too. Interesting

TDCRacing · 04-11-2008

Originally Posted by JCG's-GTP

Not to thread jack ya.. but my ZZP PCM shifts odd too. Interesting

There is a thread around here some where( I think in the overkill performance section for community vendors) asking about this or letting overkill know if he was aware of the problem...I think it turned out to be something with the line pressure being at 96 witch is to high for the 04+ models...check it out it's somewhere around here.

**Sabrewings** · 04-12-2008

Okay, good news. It's not as bad as I thought. I may have had the values set up wrong earlier and I went through the whole setup process making sure I only had the values enabled that I needed. That way I didn't have something similar that was confusing it (like Knock 1, 2, and 3. only need knock 1 for our cars).

Anyway, I went out and recorded a few WOT runs with the gauge's own record feature. During normal driving, my LTFTs are usually negative (whatever that means) and between -1 and -3. Rarely do I see them positive.

During WOT, I saw the LTFTs go immediately to 0.0 and the knock was only 1-2*. After the 1->2 shift, it spikes to 6.7* and starts dropping back to around 1-2* all the way to the 2->3 shift. This is with the stock PCM, BTW.

These seem like much more acceptable numbers to me.

Thoughts from the tuning experts?

TDCRacing · 04-12-2008

As for the ltft and stft's that is good if they lock in at zero at wot....When they are showing numbers like -3 or +3 that means the pcm is pulling or adding fuel to that particular cell (bad). You dont want to have the pcm making corrections for anything like that.but the only way to fix this is with a tuner and a mass airflow tune.

1-2 degrees...may be acceptable to some. 6.7...no where near acceptable to any.

As far as the problem with the spike in kr after the upshift.That caused by anything from torque management to false knock.But again you would need a tuner to do some tests to tell anything further.

With your 6.7* of kr cosider all of the hp gained from all of you mods gone.

**Minno** · 04-14-2008

That spike in knock is more than likely false knock. Knock does not just appear at 6, it has to climb...true knock that is. If it just spikes extremely fast from 2-6 without going 3-4-5-6 then it is false knock. I would check the transmission dipstick tube and also see if your downpipe is close to your swaybar as you may have to flip it. This may be different on an impala but I do believe it is the same setup as far as a "rolling chassis" is concerned.

TDCRacing · 04-15-2008

Originally Posted by Minno

That spike in knock is more than likely false knock. Knock does not just appear at 6, it has to climb...true knock that is. If it just spikes extremely fast from 2-6 without going 3-4-5-6 then it is false knock. I would check the transmission dipstick tube and also see if your downpipe is close to your swaybar as you may have to flip it. This may be different on an impala but I do believe it is the same setup as far as a "rolling chassis" is concerned.

I read that thread about you possibly getting that dhp tuner so if thats the case just decrease the timing in the cell that you are getting the flash kr in and see if it goes away...There are manny things that could cause false kr...the things stated above and even tranny noises

**Minno** · 04-15-2008

Yah, Lee weren't you having issues with your resonator as well? There are sooooo many possibilities in knock and the more mileage you have the more possibilities come into play haha.

**IndeedSS** · 04-15-2008

Originally Posted by Minno

Yah, Lee weren't you having issues with your resonator as well? There are sooooo many possibilities in knock and the more mileage you have the more possibilities come into play haha.

Yep Trannyman found the resonator to be too restrictive and was causing 6* of knock no matter the size pulley. He removed the resonator and removed the knock.

**Sabrewings** · 04-15-2008

Well, I have no resonator.

Today, I saw that at 40-45% throttle I was getting 0.3* then as I pushed a little harder it went to 1.5*. I am still on the stock tune, for the moment, so is this the "part throttle" KR that ZZP says their PCM gets rid of?