The KR Battle!

[pbabyjoker]

I'm new to hp tuners and I've been trying my best to get rid of my kr. My mods are in my sig. My scans are with the 3.6 pulley. The most kr I see is 3*.
Any advice for a noob.

[BlackGS]

That KR is not all that bad. Start with a part-throttle MAF tune and try to get LTFT's closer to zero. I think you could add a little fuel without being overly rich and that will help. Do this by raising MAF values above 7000 by 1 or 2 percent, and adjust commanded afr in PE a little lower.

[Russ K]

The fuel trims are negative, why would you raise the Maf table?

Make the changes as shown so the commanded PE is 11.5 AFR.
Then use a wideband to adjust the maf table to get the actual AFR at 11.5. You most likely need to desensitize the knock sensors.

I assume your spark plugs are 2 heat range colder than stock?

Russ Kemp

[Perforator]

You most likely need to desensitize the knock sensors.

Heck, you might as well remove them. What the heck do we need them for.

[Russ K]

Heck, you might as well remove them. What the heck do we need them for.

Is your comment of any value to pbabyjoker's tune question?

Russ Kemp

[Perforator]

Why do you keep telling people to desensitize the knock sensors? Have you ever owned a 3800 V6? Just curious because they are different than the V8's.

[Russ K]

Why do you keep telling people to desensitize the knock sensors? Have you ever owned a 3800 V6? Just curious because they are different than the V8's.

I'll tell you for the last time, the knock sensors are way too sensitive on the V6 cars. The same as the I6 engines in the Trailblazers, and the 5.3 & 6.0 and 6.2 new body style trucks. The 5.3 FWD car knock sensors are also too sensitive. I believe the knock sensors are being set off from normal engine/transaxle noise, because it certainly isn't real spark knock.

I've tuned many V6 cars (NA & SC) since 2005, including several friends that own 3800 NA & SC cars. As you know, I tune the AFR with a high end wideband, and not guessing with a stock O2 sensor. I have customers that travel several hours to my shop for me to tune their vehicles because they talked to someone that had their vehicle tuned by myself. And not one of my tunes caused any engine damage.

You can believe what ever you hear or read about, but I base my methods on first hand experience, and positive customer feed back.

Russ Kemp

[BlackGS]

The fuel trims are negative, why would you raise the Maf table?

Russ Kemp

Once the part-throttle MAF tune is done, the trims will be in line, and I'll bet the upper range (over 7000) will be leaner and need about 1-2%. That in combination with PE adjustment should set it straight since he doesn't have a wideband.

[BlackGS]

I'll tell you for the last time, the knock sensors are way too sensitive on the V6 cars.

Russ Kemp

I've never seen as many chipped and shattered pistons on any other engine than our 3800. If the knock sensors are too sensitive, then why so many of these problems? Could it be that the knock is allowed to get too high (15*)? I'm not doubting that you can get good results on a well-tuned engine by desensitizing, but I'm not so sure that it should be done as a first step.

[Perforator]

I'm not doubting that you can get good results on a well-tuned engine by desensitizing, but I'm not so sure that it should be done as a first step.

Thank you!
You don't tell someone who says he is new and asking for help to desensitize their knock sensors and if you do at least tell them the risks.

[mtcrusan]

I'll tell you for the last time, the knock sensors are way too sensitive on the V6 cars. The same as the I6 engines in the Trailblazers, and the 5.3 & 6.0 and 6.2 new body style trucks. The 5.3 FWD car knock sensors are also too sensitive. I believe the knock sensors are being set off from normal engine/transaxle noise, because it certainly isn't real spark knock.

I've tuned many V6 cars (NA & SC) since 2005, including several friends that own 3800 NA & SC cars. As you know, I tune the AFR with a high end wideband, and not guessing with a stock O2 sensor. I have customers that travel several hours to my shop for me to tune their vehicles because they talked to someone that had their vehicle tuned by myself. And not one of my tunes caused any engine damage.

You can believe what ever you hear or read about, but I base my methods on first hand experience, and positive customer feed back.

Russ Kemp

I know of a vendor who sells a false knock retard kit. It is some Dynomat for the transaxle and knock sensors.

Russ, In your tuning experience is there a relationship with knock in certain areas of the histo's? <<<<< Curious question. Thanks Russ for being here to help us less knowledgable people out here.

[starks]

I've never seen as many chipped and shattered pistons on any other engine than our 3800. If the knock sensors are too sensitive, then why so many of these problems? Could it be that the knock is allowed to get too high (15*)? I'm not doubting that you can get good results on a well-tuned engine by desensitizing, but I'm not so sure that it should be done as a first step.

in my opinion thats because alot of people dont have a clue and the first thing they do is drop a 3.4 pulley on, or smaller.

[BlackGS]

in my opinion thats because alot of people dont have a clue and the first thing they do is drop a 3.4 pulley on, or smaller.

That's true, but I've seen plenty of stockers with chipped pistons as well, although a lot of people buy these used, so who knows what the previous owners did to them. However, if the knock sensors were overly sensitive, then wouldn't they go off like crazy and kill the timing when these smaller pullies were on? Then, it would seem like the PCM would set the low octane table timing, which would not only make the car run like crap, but would actually help reduce knock.

[pbabyjoker]

Thanks Black GS. I'll let you know how it turns out.

[pbabyjoker]

Finally got the time to play with the car. I found out that the car volts was at 11.3 due to a loose battery cable. Now the volts are at 14.5 at start and 13.9 at regular engine temps. The voltage increes brought my ltft to -1.6 but im still getting kr. Do I still need to do a part-throttle MAF tune? Here's the new scan.

[BlackGS]

There's a good possibility that you are running lean on that run. The O2's never get into the 900's. Have you tried adding fuel by increasing MAF values at WOT? You also are running some pretty low timing. It might be better to increase the pulley size and raise timing.

[pbabyjoker]

How do you raise your timing?

[JerryH]

I don't get the concept as a whole. First we tell them to desinsitize the knock sensors, then we tell them to zero out the spark AFR table.

In essence... we are telling them to make your engine not be able to detect knock, but then run around with max timing lowered from 16 to 11 to save your hiney because you don't want KR. Bad tuning techniques, if you ask me. It is not a smart thing to do, IMHO and then to hide this fact... you lower your overall timing. Why???

I would much rather have a setup that is overly sensitive (if it indeed *is* so, because every time we ask for tangible proof that they are "oversensitive", there is none offered, nor how they came to this info... becuase GM sure did not think they are "oversensitive" and I sure as heck am not having any issues getting rid of my KR on my car and many others without doing so) and be running around with higher than stock timing WITHOUT any KR. Besides, I would rather run around with a car that has over sensitive sensors than ones that do not properly report KR when I do have it.

I suppose it all comes down to what you want. On my car, I run anywhere from 35-47 degrees timing while cruising and 18-21.5 degrees of timing at WOT... and here is the kicker... I am doing this on 87 octane, and I have been doing this for the last 3 years!

And here is the final sword thrust into the heart of the matter. The previous argument was that "you don't have a wide band sensor, so you have no idea what your REAL A/F is". My counter was that others have been tuning with WB O2s and seen commanded numbers VERY close.

What I know now: Commanded A/F and WB A/F are *INDEED* within 0.1-0.2 on my car as measured on my calibrated Innovate LC-1 versus what the PCM is commanding.

So... I am *NOT* running around overly rich, and never was! My fueling always was as I knew, quite close, tuning by NB alone. I can now say WITH EXPERIENCE that you *can* tune a GTP very well with a NB if you know what you are doing, and you can boost timing numbers to *above* stock numbers quite easily, safely with out KR showing up and without desensitizing the knock sensors.

Don't desensitize your knock sensors becuase you do not have the knowledge to tune out KR and if you want performance and/or MPG increases, don't run around with lower than stock timing numbers! Even a 100% mechanically stock GTP can run around with increased timing SAFELY.

Where the WB comes in handy is at extended WOT runs where we see the NB overheat and start to say that the fueling is leaning out and the PCM is compensating for it, when it should not be. Even so, as a worst case scenario, you are running around a little richer (and we are talking single digit percentages!), which IMHO is a lot better than running around too lean.

One also has to understand that though there is great latitude for increasing spark timing (not decrease it!) to gain additional horsepower AND gas mileage, there is no amount of tuning that will bend the laws of physics. If you are running around on a 3.0" pulley on a GenV and don't have the PROPER supporting mods, *NO* amount of tuning will get rid of the KR for you. Under those circumstances, the last thing you should be looking at is desensitizing the sensors... because they are the only thing standing between you and an engine rebuild.

Too many people treat KR like an enemy. I see it as a friend becuase it is often saving someone from popping a piston or 6.

End of rant, thanks for listening.
(edited for typos)

[KShef]

amen!

[/thread] ...


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Butt Plug

[johnh]

What I know now: Commanded A/F and WB A/F are *INDEED* within 0.1-0.2 on my car as measured on my calibrated Innovate LC-1 versus what the PCM is commanding.

So... I am *NOT* running around overly rich, and never was! My fueling always was as I knew, quite close, tuning by NB alone. I can now say WITH EXPERIENCE that you *can* tune a GTP very well with a NB if you know what you are doing, and you can boost timing numbers to *above* stock numbers quite easily, safely with out KR showing up and without desensitizing the knock sensors.

x2!!!

My NB tuning, had me within .1 / .2 AF on the WB as well.

I have not desensitized my Knock Sensors either....and I see very little KR with 18-20* timing and ~14psi boost. I'd rather have them be over sensitive and potentially save my pistons, than try to squeeze a few more ponies out and risk piston popping.