Perhaps the wider pipe has more turbulent air at low RPMs, but flows better at higher RPM?
Yeah nothing out of the ordinary today that would have caused a change, I mentioned the only changes made from yesterday to today, trying to get an understanding how I may have made an improvement by just those two small things.I’ve found there are a lot of factors that play in the part throttle KR. Like weather, fuel, oil, tc.
Fuel has been a big one from my observations. Running 91 I get the occasional part throttle knock when leaving a stop. Ranges from 0.5-1.5. BUT the longer I idled, the higher the KR. For example idling at a stop for about 2 minutes. I’d instantly get a jump to 6 KR when only part throttle.
Yet when I ran an e-30 blend, not once did I get KR. Even idling for a couple minutes at a stop. Nothing.
I feel like it’s just a mixture of hot charge temp from idling, fuel, and aggressive spark causing the part throttle KR.
Im not sure but I have tried the different suggestions of Mobil1 and Castrol for direct injection engines and regardless of brand I use it doesnt change the knock issue either, also as this is super inconsistent it doesnt make much sense to me to be fuel or oil.. Like I have said the changes I made yesterday seemed to have a positive effectIsn't this issue what the newer SN PLUS oils are made for ?
Yep, I have checked all of the heat shields the exhaust seems to be clear of everything. That's interesting though, Tensioner on the serpentine or the chains?So in your case its definitely sounding like false KR. Forgive me if someone has mentioned this before hand, have you checked the heat shields? Also I’ve had in the past where a bad tensioner pulley caused KR at low rpm and high rpm.
Thanks I will give those a check!Serpentine. It’s a very easy change. I did it anyways on 2011 as it hit 160,000. It was still in very good shape but I could tell it had some resistance/squeak.
Also there are 2 hard lines that run from the bottom of the radiator at the front the engine. They run together in parallel into a metal bracket. You can actually physically move them and they will rattle. Those in the past I had to foam around or zip tie them together. I’ll try to provide pictures when I get the chance. You can see them directly from the top of the engine bay looking down behind the radiator.
Except when it's maxing out and pulling lots of timing and causing the OAR to rise substantially. Because, regardless of whether that knock is real, you're feeling the effects of it. Truck gets sluggish and won't perform until you lift and try again.downshifting or part throttle knock reading is fine and expected. You should only be concerned at WOT, that is where real damage can occur.....unless you're hearing an audible issue or the engine is missing at part throttle. That would be more serious.
Your sig also says down pipes and cat-back, most aftermarket get rid of flex pipes, you can see knock from exhaust vibration then.
Exactly and that’s my issue, I don’t expect knock readings to always be zero or negative but my problem is the get so bad so often that my oar has a hard time ever getting out of the positives and feels like I’m driving a detuned stock truck as a result.Except when it's maxing out and pulling lots of timing and causing the OAR to rise substantially. Because, regardless of whether that knock is real, you're feeling the effects of it. Truck gets sluggish and won't perform until you lift and try again.
Sent from my Moto Z3 Play using Tapatalk
If you are convinced it is a false knock, consider what I did ... lock out the OAR! You will still see +/- KR while driving and it will still adjust the overall Spark Advance. But it won't adversely adjust the OAR and pull all your power away when you least want it.Exactly and that’s my issue, I don’t expect knock readings to always be zero or negative but my problem is the get so bad so often that my oar has a hard time ever getting out of the positives and feels like I’m driving a detuned stock truck as a result.
Yes I will talk to Brett about how to approach it and what works for him. Mine might be different in that case though, my OAR I can watch drop the second I see the high knock readings come up. Also I can lift and re apply the throttle as many times as I want it almost always just keep doing it until I really put my foot into it and get it to downshift or reapply the lightest throttle possible.There's more to it than that. The OAR doesn't drop immediately. While the knock event is occuring, the OAR is steady. It's after that is over that the OAR drops in response to the knock spike.
Even aside from the OAR, it's a problem. Locking out the OAR I think would help, but I think @Boostking told me he's not a fan of that idea. Anyway, it may help, but it doesn't help in that moment when the truck is falling flat due to the knock spike, real or not, where you must lift and then reapply throttle to get it to go.
Sent from my Moto Z3 Play using Tapatalk