Tuning Advice on a 2006 Pontiac GTO

[LS2Greg]

I am new to the tuning arena and am trying to learn as much as possible. I am sure some of you will be able to offer me some good advice. I have a 2006 Pontiac GTO. It is a 6 speed and is basically stock except for a K&N drop-in filter and I might be putting on some Magnaflow mufflers in a week or so. So yeah, pretty much stock and staying that way.

Without seeing my recorded data can you give me any advice regarding some starting basics (ie: fan temp controls and %'s, VE table etc)? Also, I am getting some knock in 1st and 2nd gear after a mild tune. The factory AFR is 12.0 which is way too rich, so I adjusted it to 12.72. I am not sure why I am getting knock and have a hunch it might be bad gas. I got 91 from Valero. Could that cause KR in the 1.0-2.5 range?

Any advice would be much appreciated. I will try to upload and attach my graphs and info for a point of reference.

Thanks for your help!

Greg

[Bill@HPTuners]

just remember what is "commanded" AFR is almost always going to be different then the "actual" afr unless you've tuned the two to match.

[LS2Greg]

Bear with me here...can you please elaborate on this? What importance does that play when tuning? LOL I told you I was a newb

[Bill@HPTuners]

changing your commanded af ratio without knowing your actual afr is not only pointless but also dangerous since your only guessing & hoping everything matches up which it rarely will in stock form. Find our your actual afr & adjust the tables surrounding it to get your commanded to = your actual.

[LS2Greg]

changing your commanded af ratio without knowing your actual afr is not only pointless but also dangerous since your only guessing & hoping everything matches up which it rarely will in stock form. Find our your actual afr & adjust the tables surrounding it to get your commanded to = your actual.

That makes a TON of sense. I did not just guess what my AFR was. I ran the data logging program for about 3 hours of drive time and utilized the given info to determine what was the appropriate AFR. Then adjusted accordingly and logged some more drive time. THAT is when I noticed the KR was around 1-2.5 in 1st and 2nd gears. Any advice?

[12secSS]

Greg,

If you used the LTFT or the stock O2 sensor voltages as your reference to the fueling, you may be running dangerously. LTFT or fuel trims are only to be used for closed loop part throttle fueling corrections for your VE and/or MAF. Untrustworthy for WOT fueling, that is where the wideband is absolutely necessary.

[LS2Greg]

Greg,

If you used the LTFT or the stock O2 sensor voltages as your reference to the fueling, you may be running dangerously. LTFT or fuel trims are only to be used for closed loop part throttle fueling corrections for your VE and/or MAF. Untrustworthy for WOT fueling, that is where the wideband is absolutely necessary.

UH OH...

The thing is, from the factory the car seemed completely out of tune (MPG was significantly lower than anybody else I have spoke to about this). So I took it in and they ran diagnostics and said nothing was wrong. Bullshit! Their factory "tune" was hideously off of stoic. I was getting up to 9* of knock from their so-called "tune". So upon running my own diagnostics I recallibrated the AFR tables and am now getting 1-2.5 at most and the MPG went up 4 MPG. I THINK (emphasis on think!) that I did a substantially successful recal. Could I still be dangerously off? We did NOT use a wideband BTW.

[flea]

Here are some basic suggestions/settings if you have not already made these changes.

From personal experience (and other GTO posts) the LS2 GTO's all seem to have some minor KR ~1.5 -2 that shows up sporadically. Post some log files so we can see how often and under what conditions you are getting KR and we can better help you out.

[LS2Greg]

Here are some basic suggestions/settings if you have not already made these changes.

From personal experience (and other GTO posts) the LS2 GTO's all seem to have some minor KR ~1.5 -2 that shows up sporadically. Post some log files so we can see how often and under what conditions you are getting KR and we can better help you out.

Do you have an A4 or M6?

[LS2Greg]

Here's 1 of my logs and current tune. Any advice would be AWESOME!

[EC_Tune]

Here are the steps I take when ever tuning a new vehicle:

I would put it in SD mode first (set MAF Fail to 0) to tune the VE table.
Turn off LTFT by setting the enable temp to 283 F
Turn off decel fuel cutoff by changing *all* the parameters to disable it.
Copy the HO Spark to the LO spark for tuning purposes only. Then make sure they match all the time: when you change one, copy it to the other.
Reduce the amount of IAT spark that gets pulled by moving things over about 1-2 columns. They are pretty aggressive there.
Reduce Burst Knock Retard values by 1-2 degrees across the board.
Increase the Knock Retard Decay value by 50%

Pull timing wherever you see KR. You may want to customize the KR histogram by putting in Knock Retard in place of Timing Retard as Knock Retard is just that. Timing Retard encompases KR, burst KR, etc...
Last but not least:
Get a wideband o2 kit. (See the EIO section for suggestions)

[flea]

IAT vs spark
Zero out the 86 – 104F columns to start out with. Return everything else above this to stock for the time being.

Timing
Return the low octane table to stock values until you get a WB02 and can dial in the AFR and MAF tables

PE Table
Don’t change this table without WB02 data

Attached are my current ignition off fan settings

[Bill@HPTuners]

Oh greg, try the E40 configs I posted here http://www.hptuners.com/forum/showthread.php?t=10689 these work much better then the default config thats setup in the scanner.

[LS2Greg]

Oh greg, try the E40 configs I posted here http://www.hptuners.com/forum/showthread.php?t=10689 these work much better then the default config thats setup in the scanner.

I'll try it out this weekend and let you know the results. Thanks!

[LS2Greg]

So I didn't get a chance to try the E40 configs because I totally forgot about them. BUT, I did install some Magnaflow mufflers and X-pipe so I retuned it. Here's the problem, I don't know if it's my car is just an exception or what but it gets KR NO MATTER how we tune it. The only thing we are able to tune on my car (because we don't have a wideband on it) is the PE tables. We switched the Enrichment rate from 1 to 2 for each tune we tried and we still got KR on EVERY tune we tried. So eventually we stuck with the original tune because it seemed to give them best throttle response. BUT I will be richening up the top end above 5k RPMs because it feels like it is gasping for more fuel.

I think the best thing at this point is to wait until I get the Lingenfelter CAI installed and then get a professional dyno tune to get everything dead on. Then I can read the exact numbers the tuner sets my tables at and whenever (or if) I add more mods then I can have a starting point.

Other then what I have already tried, do you guys have any advice or opinions that might help me out? We have spent over 4 hours of logging and tuning and can't get rid of the damn KR.

THANKS!

[Cyclone Chris]

Is your knock in 4th Gear + at low RPM? If so, that's pretty common. You're basically ptting a load on the motor which will case it to knock.

[LS2Greg]

I am getting some KR (avg of 2*) mainly in 3rd+ at WOT no matter what the tune.

the only power effecting changes to my CURRENT tune is:

high octane table to low octane table
PE delay RPM enters @2200
PE table set to
1.13965 @4000
1.16016 @4250
1.16504 @4500
1.16504 @4750
1.16504 @5000
1.16504 @5250
1.16504 @5500
1.16504 @5750
1.17969 @6000
1.17969 @6250
1.17969 @6500
1.19043 @6750

this tune is barely +1 from stock in the interest of total safety

[flea]

1. Don't change the PE values without a WB. You could be too lean or rich. No way to know without WB data.
2. You can still set the PE delay RPM without the WBO2. Set this to zero.
3. Restore (at least for the time being) the low octane timing back to stock.

[PurplePiss]

If your getting knock in 3rd after going up through 1st and 2nd (i.e. drag racing) then it sounds like the cylinders are getting hot. The only thing you can do is try to richen it up across the board (12.8) and/or remove some timing.

[LS2Greg]

Sorry it took me so long to get back to everyone but I have some awesome news! A buddy came over yesterday and hooked up his WB on my Goat. Problem solved! KR is gone and good ridance. It drives SOOOOO much better, it's like night and day.

Thanks to everyone for your time, help and advice. It's much appreciated!