SSnakekiller

iTrader: (8)

HPT->Spark Control->Knock Sensors

How many of you guys have played around with knock sensor sensitivity reduction???

I believe on any N/A or forged internals tune, reducing the sensitivity is probably acceptable. Has anyone played with these settings, and if so, how did you go about determining what levels to use?

I just tuned an 04 Z06 with LG LT's and was only able to pick up a few HP with tuning (knock sensors are very sensitive with stock settings). Once I got a nice 13:1 AFR, timing tuning was a bitch....anything over 22* advance was retarded

I know these cars are good for 27-28* all day long, so I reduced the AFR to 12.5-12.6 and bumped up the advance to about 26-28 ramped from 2500rpm. At the same time, I adjusted the knock sensitivity down slightly to make knock sensing a bit LESS sensitive, but not much.

This made all the difference in the world and the car ran strong...final numbers were 16RWHP gain with ~12.5AFR and 27-28* max advance. After the headers and tuning the car picked up a whole 27RWHP

This is also with all the retard tables left STOCK.

Before tuning the car would not even chirp the nittos. After tuning, it spun like hell

Again, if anyone has played with these settings, please report your results.

MeentSS02

iTrader: (11)

How much is a "bit" less? I've only messed with my burst knock settings because they were WAY too sensitive...my timing was all over the place (hardly any of it correlating to the table I have).

MeentSS02

iTrader: (11)

Oh, and I'm wanting your settings because I have the same problem with my bolt-ons only SS...anything over about 22 degrees, and it starts complaining. I'd like to go out this weekend and get this nailed down.

SSnakekiller

iTrader: (8)

Just scale it a little at a time. As long as your fuel is there, most likely it is not going to hurt anything. Everything under "knock sensor level", especially tip in RPM. The stock values should be around 10-15. and they run up to about 64. I only scaled mine up from 13.0 to 16 or 17.0 and it elimited the retard. I would definitely suggest NOT editing this value over 26 or 27, unless you are tuning a forged motor and just looking to squeeze out a couple extra degrees....

Either way, always listen for pinging. This is only necessary to squeeze out that extra little bit of power at the compromise of safety. How much you scale the knock sensor level upward is how much you are compromising safety.

But again, only scaling it up maybe 10% while maintaining a safe AFR under 12.9, you should have nothing to worry about.

MeentSS02

iTrader: (11)

I might give that a shot to see what I can come up with...my fueling is already definitely there. I'm running a couple things that could be causing false knock, so I think I'll have to look into this.

MeentSS02

iTrader: (11)

Blast from the past...I can now get 25-26* of timing at WOT with no issues after desensitizing the sensors 10%, and a little more (like 20%) in the WOT areas. I think my poly tranny mount and B&M shifter wer causing most of my KR, as the shifter buzzes like a **** when going WOT at higher speeds.

SSnakekiller

iTrader: (8)

Nice glad to see it worked...but did it really take 20% to get there? Be careful, that seems like a lot...

What was your power gain before and after using this method?

What was your max timing before desensitizing? Also, a lot of people think that maximizing the amount of advance is the goal... IT IS NOT. Sometimes a motor will be happier at a certain spot running 24-25* instead of 26-28. Usually these cars can take 28* and like it, but again, you have to make sure that the extra timing is necessary. If you are making 350hp at 26* and making 350hp at 28*, then obviously 28* is not necessary.

Also, I suggest to anyone that uses the above desensitizing method to be careful...do not try it unless you know what you are doing.
Again, if this is on a non-forged motor, you are MOST LIKELY going to be okay if it is an N/A car. If this is a power-adder car (Nitrous/FI) with stock internals, I would suggest avoiding this method altogether or only make very small adjustments.

MeentSS02

iTrader: (11)

I'll have to go back and do the math to make sure...no before/after numbers though. The timing before was 19-20 degrees max, and I'm at around 25-ish (I think I see about 25.5 at some points).

I need to dig back into my tune...I still feel I am safe, and think the parts I am running were causing me problems.

It would be a good idea to have somewhat more of a grasp on this concept, but people swapping an LS1 to an LS2 have this type of issue since the knock sensors are in the side of the block, and need a different calibration.

If it blows, it blows, but I don't see that happening if it hasn't done it yet. I've actually gotten knock a couple places (high load, low RPM) even with these settings, so I know the sensors are still working.

ThaLS1KidII

iTrader: (7)

Can you adjust these parameters in Edit?

SSnakekiller

iTrader: (8)

It is possible, but I know there are features in HPT that you will not find in edit and these COULD be one of them...I dont know though.
I traded in my edit a couple yrs ago or whenever HPT came out. My opinion is that HPT is far more powerful than edit.

ThaLS1KidII

iTrader: (7)

Yea I know that everything else is better, but I can't afford anything else right now.

SSnakekiller

iTrader: (8)

Didnt mean to bust ur ballz just trying to inform people that are so die hard edit fans that HPT is better. Edit is fine, it is a great tool nevertheless, but it has shortcomings thats all. Just look through all things related to KNOCK in edit..I still have edit stored on my laptop, i will try to check it out later when I get home to see if i can find anthing related...it is an old version though. And remember, I think HPT still takes trade ins for edit. Ask them about it. When I traded mine I had edit and Autotap which was something like $300 credit toward the purchase.

ThaLS1KidII

iTrader: (7)

Oh I know, no busting taken. I will definately upgrade one of these days.

Dragman

[QUOTE=SSnakekiller The stock values should be around 10-15. and they run up to about 64. I only scaled mine up from 13.0 to 16 or 17.0 and it elimited the retard. I would definitely suggest NOT editing this value over 26 or 27,
But again, only scaling it up maybe 10% while maintaining a safe AFR under 12.9, you should have nothing to worry about.[/QUOTE]

where in HPT are u doing this??

SSnakekiller

iTrader: (8)

Engine->Spark Control->Knock Sensors

Make sure you understand what you are doing before you mess with that stuff

MeentSS02

iTrader: (11)

Or just go ***** nilly through there like me and adjust whatever you like

Dragman

does my Y body C5 have that? Might have found it! Thanks

SSnakekiller

iTrader: (8)

Yes it does

jimmyblue

iTrader: (11)

Does anyone have a pinging car, that could tell us what
their threshold knock detect level is? Anyone mapped out
no-knock, "silent knock", "can of marbles" levels? I'm
wondering just how much latitude there is, between
oversensitivity, tolerance and loss of protection.

I guess maybe you could dial it down on a conservatively
fueled/sparked car, find the "noise floor" and then offset it
up by some amount. But, what the difference between
baseline mechanical clatter and actual knock impulses is,
is the real question. Probably very variable I expect?