Mike00FRC

iTrader: (1)

How the hell do I fight knock at tip-in. I'm running a P1SC and am seeing 5, 5 1/5# at 6200. At WOT, I'm getting zero knock in 3rd/4th after it pulls for a little bit.

However, when I first floor it, I see the knock spike up to around 3 degrees. It is more pronounced in the lower grears 1st/2nd.

Think I should lower timing a little in the midrange? From .6g-1.2g/cyl @ 4000 and up I have it set for 16deg; .6-1.2g/cyl @ 3200-3600 17deg; .6-1.2g/cyl 2400-2800 18 deg.

IFR with the SVO 42# injectors is set at 168%
PEvsRPM is scaled 119% (o2s are right around .92 flat... sorry, no wideband yet)
Idle LTerms- +/- 1
Part Throttle LTerms- -3 to -6
Decel LTerms- Anywhere from +3 to +15

I also lowered the values between .4 and .56g/cyl, however not as much as .6 and up.

Anyone think lowering the Throttle Position Angle at which the PCM enters WOT may take care of part-throttle knock? Tip-in?

Thanks,

Blackbird

I lowered the value of when the car thinks it's going wot because you don't have to floor it to build boost and the car won't be ready for it was my logic. I don't have any tip in KR issues.

I think if you drop the tpa at which the pcm enters wot you will cure your problem.

felton316

Have you tried changing the knock Attack vs RPM and Decay vs RPM rates?

Mike00FRC

iTrader: (1)

Blackbird,
I dropped it some, but I think I'll drop it even more. Those instances of knock always seem to occur at just enought throttle where the car wants to really move, but not enough to be put into cell 22.

I still dont think that this will take care of my tip in knock. If I punch it, not gradually open the throttle blade, thats when I see it spike, then gradually drop.

Felton,

Right now, I'm running with the stock Knock values. If I was 100% sure that everything was safe and that the knock was false, I mignt modify them, but at this point although its a pain, the knock sensors are a bit of added security for me.

Thanks,

Blackbird

you may be right but give it a try. the lower the value the faster the car goes into WOT mode.

other than that your tuning looks quite good if not conservative so I am pretty suprised your getting the kr. do you actually hear it ping for a sec or it is just registering on ATAP?

if you are crusing in 2nd or 3rd then nail it do you get the KR spike? or is it only when you start off in first and go ***** out? perhaps it's just the violence of getting on it in first causing false knock, i'm sure the car is fighting for traction etc... at that point.

felton316

If you change the the knock Attack vs RPM and Decay vs RPM rates. It wont get rid of knock, but it will help it recover after its done knocking and you can set it less aggresive towards knock if it was a falsely induced knock.

Mike00FRC

iTrader: (1)

Blackbird,
The knock is more pronounced as the gears drop when stabbing the gas. First is alot, second I see maybe 4deg and third is almost zero. Dont know if its the corsa or not, but I can hear no audible detonation. Part throttle driving around is another story... see below.

Felton,
That may be true and I'll keep that in mind, but I think I found my part throttle problem.

I did a lot more driving around today with the same Throttle Position Angle settings and found that almost all of my part throttle knock is occuring in cell 15 or entering it. This is really making me think that the prior assumptions were correct and that the motor is starting to see enough load to get som detonation in areas that are still a commanded 14.7:1 ratio.

Just to confirm it, tomorrow I'm planning to dump a tune in to the PCM that tells it to go to WOT at any point greater that a 20% TPA. If I still get knock, then I have other things to look at, as I've never observed knock at anywhere near 20% or less TPA.

If I get no knock as I'm expecting then I need to either fine tune when the PCM decides to go in to cell 22 based on TPA/RPM. The only downside is that at too low an RPM/load I definitely felt the transition to Cell 22... probably the onrush of extra fuel being dumped in. I need to tune it enough so that if the PCM goes to enter those high load areas it skips right by them and into cell 22, but not too much so as not to bog it in too low of an RPM/load area.

I need to re-read the post on VE that currently up... as that may be a way to also tune for this event, but I'm not sure that any changes to this area may be learned out by the PCM????

Mike00FRC

iTrader: (1)

Well,

Just got back from testing out the 20% TPA across the board and got ZERO knock anywhere. Looks like my problem was that the engine was seeing too much cylinder pressure while the PCM was still tring to maintain 14.7:1. I cant leave it where its at as I'll get really bad fuel economy during normal driving and plus down low, it bogs like hell. But at least I know where I need to concentrate my tune and find a middle ground where I dont see the knock and no bog.