Good news,,,,,,,,,,,Don emailed me the tune and I installed it this afternoon. He upped the Knock threshold just a little bit more than the Stage PCMs.
Bad news,,,,,,,,,,,Unfortunately the Desired torque and wastegate tables inadvertantly were left "stock", and i just got home to recieve the fixed tune. So no real news.
I got a chance over lunch to test drive the new tune.
~20psi
92 octane
0 knock
I need to go back and monitor A/F, guage and/or pc weren't hooked up.
__________________
"Just because someone goes fast doesn't mean you should do whatever you think they did.
This path assumes they knew what they were doing, which isn't necessarily the case"..........RB Racing
so is this only for the 93 octane tune, or is it a crom update for the DSP in general? If I updated the crom, would it have any affect since I have a custom tune?
so is this only for the 93 octane tune, or is it a crom update for the DSP in general? If I updated the crom, would it have any affect since I have a custom tune?
This applies to the 93 tune only.
It will have NO effect on your custome tune. You'd have to have your tuner add this to your custome tune is he didn't already.
I ran this tune as well and only got 1/2 * of knock I shot up to 15 psi and held 15-14psi to redline . I will try to up the boost a bit on the DSP to see how she reacts.
It is really nice not seeing all that knock. Big thanks to Duster and Diablo!!!!!
So Duster, do you think that the knock sensor is less forgiving to cars with forged pistons?
Just asking because I have a built motor, and at times it seems it can be a bit harsher on the knock. I might need to re-check my torque but yeah...
1) Forged pistons are "noisy" by their nature
2) When you change pistons it changes the shape of the combustion chamber. Which drastically changes and engines potential to knock.
Those two facts completely recharacterizes when Knock occurs(RPM, MAP, ACT), what is noise and what is Knock, the Knock's Frequency(Hz),,,,ect
The stock Knock sensor and more importantly the algorithms in the PCM used to determine and filter what is REAL Knock and what is just noise, are nearly useless once you change pistons.
Here's a theoretical example to illustrate what I mean.
Lets say the stock engine is a bit "noisy" at 3750rpm but the Engineers during development know this, so they program the PCM to ignore that particular range of frequencies at that RPM. They also see that Knock is a problem for ONLY cyl 1 and cyl 4 at 5200rpm. So they make these 2 cylinders a little more sensitive to knock but leave cyl 2/3 and little LESS sensitive
Now Ricky Racer throws some 9:1 forge pistons into his "built" engine (he blew 2 stock engines). Now Ricky's engine is noisy as hell, especially cly 1&4 at 5200rpm but the PCM is thinking its knocking and is loading up LT KR and Ricky pos car is slow as shit. And post bitching about all his knock and how he can only run 5 degrees of timing.
It gets worse: at 3750rpm Ricky's engine is knocking like crazy. BUT the PCM IGNORES most of the knock (on a stock engine the Engineers could tell their engine wasn't knocking) , chamber surface temps sky rocket and Ricky is quickly on his way to engine #4.
Bottom line
1) Its real hard to trust the knock sensor once the pistons are changed
2) no "Real" tuner tunes off the knock sensor. Get it on the dyno, find the new MBT with high octane fuel and work backwards with pump gas using auxiliary knock detection equipment
Last edited by duster360 : 08-19-2009 at 08:53 AM.
So this is just like turnning the sensetivity down on the knock sensor? Custom tuners offered this to me awhile back.... Is the safe? And does this help staged pcm's?
So this is just like turnning the sensetivity down on the knock sensor? Custom tuners offered this to me awhile back.... Is the safe? And does this help staged pcm's?
I think you answered this question but I'm gonna ask again, if load the Crom file with a custom tune will it do anything for me or do I have talk to my tuner?
I think you answered this question but I'm gonna ask again, if load the Crom file with a custom tune will it do anything for me or do I have talk to my tuner?
2) When you change pistons it changes the shape of the combustion chamber. Which drastically changes and engines potential to knock.
Those two facts completely recharacterizes when Knock occurs(RPM, MAP, ACT), what is noise and what is Knock, the Knock's Frequency(Hz),,,,ect
The stock Knock sensor and more importantly the algorithms in the PCM used to determine and filter what is REAL Knock and what is just noise, are nearly useless once you change pistons.
Here's a theoretical example to illustrate what I mean.
Lets say the stock engine is a bit "noisy" at 3750rpm but the Engineers during development know this, so they program the PCM to ignore that particular range of frequencies at that RPM. They also see that Knock is a problem for ONLY cyl 1 and cyl 4 at 5200rpm. So they make these 2 cylinders a little more sensitive to knock but leave cyl 2/3 and little LESS sensitive
Now Ricky Racer throws some 9:1 forge pistons into his "built" engine (he blew 2 stock engines). Now Ricky's engine is noisy as hell, especially cly 1&4 at 5200rpm but the PCM is thinking its knocking and is loading up LT KR and Ricky pos car is slow as shit. And post bitching about all his knock and how he can only run 5 degrees of timing.
It gets worse: at 3750rpm Ricky's engine is knocking like crazy. BUT the PCM IGNORES most of the knock (on a stock engine the Engineers could tell their engine wasn't knocking) , chamber surface temps sky rocket and Ricky is quickly on his way to engine #4.
Bottom line
1) Its real hard to trust the knock sensor once the pistons are changed
2) no "Real" tuner tunes off the knock sensor. Get it on the dyno, find the new MBT with high octane fuel and work backwards with pump gas using auxiliary knock detection equipment
Thank you. That makes a lot of sense. For the record I have never blown any engine, I bought this car with a blown piston so a rebuild was my only option, and I opted for forged internals.
So sounds like i'm screwed as far as the KR sensor goes....
yeah i thought i seen you write about that question.....ok cool i'm gonna ask my tuner if he can do this if its safe which you said it was, i'm sick of running low timing to tame the knock. right now i have no knock but like i said timing is lower its *22@5k-6k with 11.1-11.4 afr's on 20psi. wanna get more power.
1) They also see that Knock is a problem for ONLY cyl 1 and cyl 4 at 5200rpm. So they make these 2 cylinders a little more sensitive to knock but leave cyl 2/3 and little LESS sensitive
I discussed this with DS in the past, after seeing the different knock thresholds between the cylinders, the only logical explanation that I could come up with, is because its due to the proximity of the sensor in relation to the cylinders.
It should take less voltage from 1 and 4 to trigger "KR" than 2 and 3, because they are further away from the sensor. Considering that the knock sensor is pretty much smack in the middle, it makes perfect sense.
Its going to hear more "noise" from 2 and 3 , simply because they are closer than 1 and 4. So, it will take less "voltage" (noise) for the computer to determine knock. Granted, there are harmonics,.. and frequencies that make it more complex than that,.. but.. that's pretty much the gist of it from what I have gathered, and discussed with others.
__________________
Stage 1 ECM (NOT stock), Diablosport Predator, 3 bar map and tip, Interceptor Scangauge, AEM wideband, 750's (no return-line), MPX BFMIC, Walbro 255, DCR top end modifier, AGP WGA, 3 in O2 housing, QTP 3in downpipe with E-cutout stock catback, Nitrous Oxide Systems 65 HP shot, motor mount inserts.
Best MPH to date on the bottle,119.04 --- Off the bottle 113.55. --- best ET 12.44. on borrowed DR's. Stock turbo, stock Mani.
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