tip in knock with turbo

[jamesm]

Originally Posted by Td-d

Yeah, I've diassembled a couple of earlier PZEV models (mostly 2005 Legacy and Outback models) - they were a pain in the arse to trawl through, as large chunks of code are substantially different from non-PZEV models (not least of all the 5 O2 sensors!).

But we digress from the OP, apologies James

no need... this is what i come here for

[DougW]

You might try holding the bypass valve open with a restrictor until after 1-2psi to slow the load ramp up to give the fuel time to catch up with the air. Sometimes there is a hardware solution to a software problem.
DougW

[ft_sjo]

Originally Posted by DougW

You might try holding the bypass valve open with a restrictor until after 1-2psi to slow the load ramp up to give the fuel time to catch up with the air. Sometimes there is a hardware solution to a software problem.
DougW

I know a man who has tried this. I will compare in the morning.

[s2d4]

@jamesm

did you end up finding anything that has helped?

The following is my log which I believe it demonstrates the issue at hand pretty well?
http://datazap.me/u/s2d4/ofh-stock-i...zoom=3784-4790

[steve99]

Originally Posted by s2d4

@jamesm

did you end up finding anything that has helped?

The following is my log which I believe it demonstrates the issue at hand pretty well?
http://datazap.me/u/s2d4/ofh-stock-i...zoom=3784-4790

Hi Sd24,

are you boosted ?? if your N/A I might have something

My N/A log for 1.5 oft tune was pretty much the same.

Have been doing a bit of adjustment to timing in 1800 - 3000 where it occurs. pulled 0.35 degrees from a few cells on the 1800 - 3000 rpm load ranges 0.7 to 1.1. currently doing some more logging but got rid of 90% already. just needs a bit more work.

Happy to send you a ROM if your G series or I can send changes only about 10 cells so far.

It still does it on United 100 octane which I am currently running.

[jamesm]

Originally Posted by s2d4

@jamesm

did you end up finding anything that has helped?

The following is my log which I believe it demonstrates the issue at hand pretty well?
http://datazap.me/u/s2d4/ofh-stock-i...zoom=3784-4790

Yeah that's about it, looks similar to what I see sometimes.

I've tried lots of things, not many of which helped lol. I've never been able to get it to go away completely. Pulling a little bit of timing (0.35-0.7 deg) in the places you see it most (for my car it's mainly 0.6-0.8 load, 2k-3k rpm) works to an extent sometimes. Oddly tip in enrichment doesn't seem to effect it much. Custom maps applying timing corrections seemed to help as well.

But really no, I haven't figured it out yet. It still happens just much less often.

[s2d4]

Originally Posted by steve99

Hi Sd24,

are you boosted ?? if your N/A I might have something

My N/A log for 1.5 oft tune was pretty much the same.

Have been doing a bit of adjustment to timing in 1800 - 3000 where it occurs. pulled 0.35 degrees from a few cells on the 1800 - 3000 rpm load ranges 0.7 to 1.1. currently doing some more logging but got rid of 90% already. just needs a bit more work.

Happy to send you a ROM if your G series or I can send changes only about 10 cells so far.

It still does it on United 100 octane which I am currently running.

On N/A.
I've pulled some timing in the offending areas for the more steady state fbkc events. However, when load goes from ~0.2 to ~1.2, pulling timing for that entire range doesn't seem like the best solution since there aren't any knock events doing pulls.

[s2d4]

Originally Posted by jamesm

Yeah that's about it, looks similar to what I see sometimes.

I've tried lots of things, not many of which helped lol. I've never been able to get it to go away completely. Pulling a little bit of timing (0.35-0.7 deg) in the places you see it most (for my car it's mainly 0.6-0.8 load, 2k-3k rpm) works to an extent sometimes. Oddly tip in enrichment doesn't seem to effect it much. Custom maps applying timing corrections seemed to help as well.

But really no, I haven't figured it out yet. It still happens just much less often.

Thanks for the clarification.
Yeah I was doing my best to get repeated occurrences and it succeeded at that albeit annoying at best.
I'll try pulling timing as per suggestion and try 100 octane fuel to see if different fuel may help.

btw, thanks for the maf scaling info you posted before, the yikes spreadsheet works like a charm.
Although I don't seem to have PI/DI scaling issue, haven't found how you are doing this exactly?

[jamesm]

Originally Posted by s2d4

Thanks for the clarification.
Yeah I was doing my best to get repeated occurrences and it succeeded at that albeit annoying at best.
I'll try pulling timing as per suggestion and try 100 octane fuel to see if different fuel may help.

btw, thanks for the maf scaling info you posted before, the yikes spreadsheet works like a charm.
Although I don't seem to have PI/DI scaling issue, haven't found how you are doing this exactly?

You don't have to worry about balancing port and di unless you change the port injectors. Normally whenever you're doing that you're also changing the maf (FI install), so it's a bit time consuming to get everything set up such that the port and di both individually have very low fueling error, and you avoid issues where switching between them causes drivability problems, like stumbles and stalling when coming to a stop.

One particularly bad case is when you first start the car and you're idling on ports, it builds up a huge fuel trim, then later when it's warm you come to a stop and it switches to direct which has a completely different fueling error (and thus required trim) and the car stalls. It'll also play hell with your closed loop maf scaling attempts if you don't account for the two systems independently first.

Assuming the maf and port injectors have both been changed, my 'easy way' solution is to make a good educated guess on the global maf correction, turn off the port injection and collect closed loop fueling error charts, then scale the maf such that trims are minimal. Then I enable only the ports and first dial in latency (ensuring a flat fueling error line), the adjust the scaler to apply the global correction that brings the error as close as possible to zero.

Then I set the injection control back to normal, collect more fueling error logs and fine tune out any new error that was introduced when you recombined them in the maf (usually <2% corrections at this point).

[Kodename47]

FYI, I just had to adjust for about 3% difference between PI and DI on the stock setup, on a well scaled MAF the fuelling error on DI was -3% in comparison to the PI. I used the method @jamesm described above.

[regal]

I've been in contact with a lot of tuners, my main goal is eliminating the stock tip-in knock. Two top tuners claim they have nearly eliminated the problem.


The odd thing is almost all I've talked to say it is easier to get rid of with FI, because your allowable retard windows are bigger. IOW's you can retard ignition (on several tables) and not lose huge amounts of power. That might be a hint to your predicament.

[s2d4]

Originally Posted by regal

IOW's you can retard ignition (on several tables) and not lose huge amounts of power. That might be a hint to your predicament.

Are you talking to me?
Care to be more specific?
I am N/A, are you saying the solution is going FI?
If so, are you saying innovate due to it's behaviour of low down boost (more air for combustion)? so I can just pull timing down low which will be compensated?

[wparsons]

Originally Posted by jamesm

mine happens the instant you tip into the throttle. if i open the throttle ever so slightly and ease into it before stabbing the throttle to the floor it doesn't knock, and never at any point other than after that initial tip in if it does. it always at least begins while the manifold is still under vacuum.

i'll try to find a log that illustrates it clearly and post it.

I don't have any logs, but I've heard tip in knock on the stock tune on heel toe downshifts many times. Zero load on the engine, just a blip while in neutral and you can hear it ping.

I'm also finding that city driving (or getting stuck in traffic) kills my IAM in a hurry, but beating on it doesn't effect it.

[steve99]

Originally Posted by wparsons

I'm also finding that city driving (or getting stuck in traffic) kills my IAM in a hurry, but beating on it doesn't effect it.

Pretty well exactly what I see here, at first thought it was our fuel but I am now running 100 RON (maybe 94 AKI) and it still does it but much less.

all seems to be in 1500-3000 under load. attempting to dial it out with timing , but will see how it goes. If @jamesm had troubles I doubt I will have success