Knock Sensor voltages vs. Correction Factor readings
06-20-2005, 11:59 AM
#11
what has me curious now is how some people seem to think CFs are determined by software
I always figured it would be an inherant function of ME7.1.
Figure that if the correction factors are determined by the software, that code A is set to retard timing at a higher threshold than code B. This effectively means that code A is less sensitive to detonation than code B. For example, in this situation, if code A and B each have a CF of 9, code A is running much closer to detonation than code B. Add a few degrees of timing on top of that and code A could be moving towards a dangerous level of timing advance, but the ECU wouldnt 'know' to pull timing because of the reduced sensitivity to detonation.
sounds like scary stuff to me. I'd feel a lot safer continuing to believe that correction factors are determined inherantly by ME7.1 and arent defined by the tooners out there.
Figure that if the correction factors are determined by the software, that code A is set to retard timing at a higher threshold than code B. This effectively means that code A is less sensitive to detonation than code B. For example, in this situation, if code A and B each have a CF of 9, code A is running much closer to detonation than code B. Add a few degrees of timing on top of that and code A could be moving towards a dangerous level of timing advance, but the ECU wouldnt 'know' to pull timing because of the reduced sensitivity to detonation.
sounds like scary stuff to me. I'd feel a lot safer continuing to believe that correction factors are determined inherantly by ME7.1 and arent defined by the tooners out there.
06-20-2005, 12:08 PM
#12
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ding ding ding! Why track CF's if these tuners are arbitrarily setting them?
I like my trusty KV's much better when I'm tweaking if this really is true.
*SOMEONE CONFIRM THIS PLEASE*
*SOMEONE CONFIRM THIS PLEASE*
06-20-2005, 12:16 PM
#13
yeah, its certainly enough to make you think. I have to wonder though, if KSVs only play partly
into how the ECU determines how much timing to pull. I dont think we have any real evidence that tuners are setting their own thresholds for correction factor, other than differences in KSVs when compared to correction factors. In light of this possibility though, im much more leary of cranking up timing without knowing how correction factor is really calculated.
06-20-2005, 12:20 PM
#14
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out there, somewhere...
Part of an email recieved today:
--
Hello from Amazon.com.
We wanted to let you know that there is a delay with item(s)
in the order you placed on February 28 2005 21:15 PST
--
--
1 of: Me-Motronic Engine Management: Gasoline-Engine Management : Technical Instruction, by Not Applicable
- Updated shipping estimate: July 18 - August 1
- Updated delivery estimate: July 21 - August 8
--
At this point, I'm gonna keep waiting
--
Hello from Amazon.com.
We wanted to let you know that there is a delay with item(s)
in the order you placed on February 28 2005 21:15 PST
--
--
1 of: Me-Motronic Engine Management: Gasoline-Engine Management : Technical Instruction, by Not Applicable
- Updated shipping estimate: July 18 - August 1
- Updated delivery estimate: July 21 - August 8
--
At this point, I'm gonna keep waiting
06-20-2005, 01:14 PM
#17
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Tuners can and do raise knock threshold. The Vag tooners are pretty tight lipped,
but Google around and you will find some stuff out there on people screwing with knock threshold.
My car is a great case- with no changes in hardware at all, just replacing the ECU, I get more boost, more timing and lower CFs. No matter how fat I made the fueling with APR, I just couldn't get good timing.
The thought scared me at first, but hey, If MTM does it, then it has to be okay
My car is a great case- with no changes in hardware at all, just replacing the ECU, I get more boost, more timing and lower CFs. No matter how fat I made the fueling with APR, I just couldn't get good timing.
The thought scared me at first, but hey, If MTM does it, then it has to be okay
06-20-2005, 01:19 PM
#18
Interesting. I had a case with Home Brew stage III where I simply could not..........
make my CFs go down. Knock sensor activity was fine but CFs were high (pegged at 15) - this was on the X-chip. I tried and tried to get them lower by lowering boost with an MBC, running 100 octane and pulling timing - nothing would make them come down.
I pulled the X-chip, popped in XR with NO other changes and bammmmm...the CFs went down. Wierd huh? I thought my chip was just broken but maybe there was something in that particular file?
I don't know, the car fine on both chips.
I pulled the X-chip, popped in XR with NO other changes and bammmmm...the CFs went down. Wierd huh? I thought my chip was just broken but maybe there was something in that particular file?
I don't know, the car fine on both chips.
06-20-2005, 01:39 PM
#19
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I remember that. Mike2ks4 also recently posted that he has to clear codes to get his timing back
with XR. He said it likes to hang on to those high CFs....
IIRC swapping chips was the only thing you could do to get timing back. That might be a GIAC thing.
IIRC swapping chips was the only thing you could do to get timing back. That might be a GIAC thing.