Opinions on these methods to lower knock and IDC's...

[dpartinvr4]

where's the log?

He did it himself, and he said he no longer has the logger.

[Chris@Rvengeperformance]

He did it himself, and he said he no longer has the logger.

lol, trust me man if you hit actual factual 100% IDC you hit fuel cut and it is like running into a brick wall.

If you don't believe me go put 360s in and try to run 16 or 17 PSI, you'll see 100% IDC.

[dpartinvr4]

lol, trust me man if you hit actual factual 100% IDC you hit fuel cut and it is like running into a brick wall.

If you don't believe me go put 360s in and try to run 16 or 17 PSI, you'll see 100% IDC.

I"ve hit cut when my boost controller line wasn't reatached, i know the brick wall feeling, but if he's getting that much knock, it maked sense that his ecu is dumping in fuel to make the ratio richer and stop the knock, which is why over 100% makes sense to me.

[Chris@Rvengeperformance]

I"ve hit cut when my boost controller line wasn't reatached, i know the brick wall feeling, but if he's getting that much knock, it maked sense that his ecu is dumping in fuel to make the ratio richer and stop the knock, which is why over 100% makes sense to me.

but the ECU will not request greater than 100% IDC. The ecu requests a certain injector pulse width in milliseconds. The pulse width can only get so high before the injector is completely static, the ecu programmers were smart enough to know this point and the ecu will only request up until that point because as you said it is pointless to request more. The injector drivers cannot request more than 100% IDC, anything that reports that is either hugely overestimating or subject to rounding or measurement error.

If you have logs showing over 100% IDC please post the pulsewidth and rpm, because in 7 years I've never seen a log like that posted where it actually calculated out to more than 100% IDC.

It has been turned into almost gospel on here that a 9b car can run 14-15PSI safely, but this isn't ALWAYS the case. Turn the boost down and see what the car does. It takes a very healthy car (no vss leaks, no oil consumption, clean cylinders, etc.etc.) to run that much boost on a stock setup safely.

Edit: let me further explain the logger thing a bit more. Even on an "accurate" idc calculator like HHH or manually calculating it you are depending on the rather slow speed of the ECU's protocol. Different values are "polled" from the ecu, so there can be some delay between say the reading of the RPM and the reading of the MS injector pulse width. What these means is they are not always EXACTLY correct.

I've never really paid much attention to IDCs anyway, as long as you do not hit fuel cut and timing advance is where you want it they really don't matter.

20 degrees of timing advance is actually a good place to be when you are pushing things on stock turbos, limited fuel, and small intercoolers.

I would reduce the boost until the knock goes away and not worry about it. You aren't going to see a huge power difference between 13 and 14 PSI on a stock setup anyway.

[dpartinvr4]

but the ECU will not request greater than 100% IDC. The ecu requests a certain injector pulse width in milliseconds. The pulse width can only get so high before the injector is completely static, the ecu programmers were smart enough to know this point and the ecu will only request up until that point because as you said it is pointless to request more. The injector drivers cannot request more than 100% IDC, anything that reports that is either hugely overestimating or subject to rounding or measurement error.

If you have logs showing over 100% IDC please post the pulsewidth and rpm, because in 7 years I've never seen a log like that posted where it actually calculated out to more than 100% IDC.

It has been turned into almost gospel on here that a 9b car can run 14-15PSI safely, but this isn't ALWAYS the case. Turn the boost down and see what the car does. It takes a very healthy car (no vss leaks, no oil consumption, clean cylinders, etc.etc.) to run that much boost on a stock setup safely.

Edit: let me further explain the logger thing a bit more. Even on an "accurate" idc calculator like HHH or manually calculating it you are depending on the rather slow speed of the ECU's protocol. Different values are "polled" from the ecu, so there can be some delay between say the reading of the RPM and the reading of the MS injector pulse width. What these means is they are not always EXACTLY correct.

I've never really paid much attention to IDCs anyway, as long as you do not hit fuel cut and timing advance is where you want it they really don't matter.

20 degrees of timing advance is actually a good place to be when you are pushing things on stock turbos, limited fuel, and small intercoolers.

I would reduce the boost until the knock goes away and not worry about it. You aren't going to see a huge power difference between 13 and 14 PSI on a stock setup anyway.

Yeah, I'm just going off what the OP gave us, we gave him the formula, and he told us they were right.....maybe he'll chime in here?

[J. Fast]

but the ECU will not request greater than 100% IDC. The ecu requests a certain injector pulse width in milliseconds. The pulse width can only get so high before the injector is completely static, the ecu programmers were smart enough to know this point and the ecu will only request up until that point because as you said it is pointless to request more. The injector drivers cannot request more than 100% IDC, anything that reports that is either hugely overestimating or subject to rounding or measurement error.

If you have logs showing over 100% IDC please post the pulsewidth and rpm, because in 7 years I've never seen a log like that posted where it actually calculated out to more than 100% IDC.

It has been turned into almost gospel on here that a 9b car can run 14-15PSI safely, but this isn't ALWAYS the case. Turn the boost down and see what the car does. It takes a very healthy car (no vss leaks, no oil consumption, clean cylinders, etc.etc.) to run that much boost on a stock setup safely.

Edit: let me further explain the logger thing a bit more. Even on an "accurate" idc calculator like HHH or manually calculating it you are depending on the rather slow speed of the ECU's protocol. Different values are "polled" from the ecu, so there can be some delay between say the reading of the RPM and the reading of the MS injector pulse width. What these means is they are not always EXACTLY correct.

I've never really paid much attention to IDCs anyway, as long as you do not hit fuel cut and timing advance is where you want it they really don't matter.

20 degrees of timing advance is actually a good place to be when you are pushing things on stock turbos, limited fuel, and small intercoolers.

I would reduce the boost until the knock goes away and not worry about it. You aren't going to see a huge power difference between 13 and 14 PSI on a stock setup anyway.

I agree with Forest, you can't exceed 100% Injector Duty Cycle. What I'm thinking is the logging software has some sort of delay in reading both Injector Pulswidth, RPM, and Timing. There's some sort of overlap that's not being accounted for. On a lighter note, maybe that's a tell tale sign of a problem and the loggers way of telling you the mechanical base timng is incorrect. The hall effect sensor is stating it's position as being set at correct base timing but it's infact an incorrect timing position so the actual fuel injection events are being calculated beyond actual engine cycles.

[O_ROD]

I completely understand that it's impossible to go over 100% IDC's theoretically. I've done the manual IDC calculation and it's still giving me 108%. Clearly I'm not calculating it correctly lol. I'll post my recent logs when I get home and maybe someone can help me out with that? In open loop, whether I run 12 or 16psi my IDC's, NB02's and Advanced timing do not fluctuate, they stay constant, and no knock. This is with a hotwired walbro and 52psi base fuel pressure.

When in open loop, I can understand that the ECU uses base maps and doesn't adjust for a rich/lean mixtures unless knock is present, at that point it just pulls timing. As long as I don't have a fuel controller I can't "trick" the ECU into thinking there's less air going in then there actually is. And as long as I have 360's, and no fuel control, my IDC's will always read high even though I'm running rich. Check out the "IDC for a several pre-selected injector sizes" on Stealth 316 - Injector Duty Cycle Calculation

I may just manually advance my timing taking this into consideration, and watch my knock closely ignoring my IDC's.

Thanks for all the info as well, very informative... I'll post my logs when I get home.

[kywhitelightning]

Why would you attempt to advance timing if you are having knock issues?

Jeff

[O_ROD]

Why would you attempt to advance timing if you are having knock issues?

Jeff

Knock is no longer seems an issue, at WOT my timing fluctuates from 16-20deg. My ECU isn't compensating for the added fuel in open loop.

[dpartinvr4]

you need a wideband to even know what your ratio is......