Part throttle KR

[skiptownmcat]

I have noticed since switching from hypertech to versatune that there is quite a lot more part throttle KR. When I had the HT I would see it occasionally and it would only flash up on the dashhawk for a second, with VT I can actually watch it count down in increments from anywhere up to 7 degrees which can take 10 seconds or so.
I have read a few threads in msf about perhaps it being a fuel optimisation logic. I would be interested to hear your thoughts on this steve, have you come across anything in the ecu code suggest this is what's happening? Also, is it worth increasing the increment that timing is retarded (currently .35 stock)?

P.S. Talking of timing, is there anything to be gained by changing closed loop timing table at all?

[Steve @ VersaTune]

VersaTuner does not change the knock management logic. Also, the VersaTuner base tunes do not change CL timing. Any part throttle knock would also be present with a 100% stock tune. Under steady state operation, ie. cruise, the ECU slowly increments timing from the base value to the max value or until knock is seen. As a result, some knock is "normal".

You can increase CL timing to improve fuel economy if you are not having knock issues.

[laxplayermjd]

i get this same part throttle KR, i tried changing different timing tables to resolve it. Latest talk on msf believes is engine resonance particularly around 3k rpm.

Lately since the temp has dropped in the 40s when i leave for work in the morning i get it about the same spot everytime and same distance. then i dont see it again all day.

I noticed logic stated KR is starting to be monitored around 160F engine temp, this seems about right around when the PT KR occcurs for me. Tho i havent confirmed by monitoring ECT yet.

[skiptownmcat]

It's defo not temp related, and I'm not saying its tune related and I'm pretty sure it's not false kr (I've been monitoring). The fact that it changed after the switch suggests something else, anyway as ling as it's not dangerous????

[laxplayermjd]

i can say i never saw mine all summer

[skiptownmcat]

It seems strange that some people get it but others don't. I'm pretty sure if it was something resonating at the frequency that the sensor picks up then it would have been the same as when I had the ht. I do a lot of motorway driving and it's always the same, just as you press the throttle slightly so your coming into boost KR shows anything up to 7 and then it counts down as long as you hold the pedal in the same position. If you accelerate or let off it just disappears. It occasionally did with HT but it was much harder to replicate. Idk, maybe I'm just monitoring a lot more than I used to and the paranoia has set in!!

[06Speed6]

Ive gotten some knock sometimes, reducing timing in the load and rpm range that it happens has always solved it.

[skiptownmcat]

I increased one of the knock values in the absolute limits table that speeds up the rate that the knock disapates, I'm not nears computer at the minute so I can't remember exactly which one. I increased it from 640 to 960 iirc, and almost all of the pt KR has gone.

[mituc]

Ignition tables -> knock retard timer decrement step size.

Now I wonder if the reason why you are or were getting KR isn't different. I've got KR up to 5 degrees when I had a kinked exhaust gasket, everything came back to normal after I fixed it even though the exhaust is far on the other side than the intake manifold where the knock sensor is. But the vibrations are still transmitted, people experienced similar behaviour with a stiffer urethane bushing motor mount. I was getting slightly more KR when I had the street unit full engine mount set.

[kevstewart]

Can part throttle knock be 'dangerous'?
If so how much and how often?
I see it now and again after flashing a new tune and just curious if it can be something to worry about