Origin of Burst Knock? IAT sensitive?
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Teching In
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Origin of Burst Knock? IAT sensitive? If my car has KR down to 12.0 degrees on the first dyno run with an IAT of 87 degrees, and the second run with IATs of 117 degrees it retards to 10.5, can this be Burst Knock? The temp jump is a lot but 117 degrees is not a high temp for 8psi and 94 Octane gas right?
I thought Burst Knock was air flow sensitive. Does it also factor IAT?
Thanks for any responses.
I thought Burst Knock was air flow sensitive. Does it also factor IAT?
Thanks for any responses.
No burst knock is airflow dependent. More then likely you are seeing the base being pulled down by your IAT correction multiplier on top of your kr. Don't forget you coolant correction too.
Thread Starter
Teching In
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Thanks guys. I don't have HPT so the last tune is with someone who does and he just noticed the burst knock was the first thing that didn't match with the other FI tunes he has seen.
The inability to handle a decent amount of timing is killing my power and I can't seem to get a handle on it. I don't know anyone else with an intercooled P1SC that is having the same issues. My tuner is at a loss as well. I will post back once I have some more info. Any ideas are better than nothing.
The inability to handle a decent amount of timing is killing my power and I can't seem to get a handle on it. I don't know anyone else with an intercooled P1SC that is having the same issues. My tuner is at a loss as well. I will post back once I have some more info. Any ideas are better than nothing.
if ur getting 12* of kr u got some kind of issue, if it false better get it looked at if not you got some big problems on the way.
check if exhaust is hitting anywhere and make sure ur motor/trans mounts are not busted.by what u said with the iat going up and kr didnt get worst so might be false. put 110 in it to make sure its false
check if exhaust is hitting anywhere and make sure ur motor/trans mounts are not busted.by what u said with the iat going up and kr didnt get worst so might be false. put 110 in it to make sure its false
Thread Starter
Teching In
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No the car has been on the dyno 4 times now in search of the problem. The spiking graph I think confirms it is actual knock. Why a 4 year old install has gone south is a mystery. The previous owner went to a large and reputable shop for the original setup, and had 20,000 miles of trouble free use, although he might have not noticed a gradual decline. Supposed to be a 480 rwhp car but my first dyno was closer to 380rwhp. The only things out of the ordinary are that the car sat for most of the last couple of years while he was overseas and the cats were a bit clogged. Had COT my first dyno run. I went to an X pipe an high flows(no headers) and then an 8lb pulley with 42# injectors. I could feel the KR when I got the car but just thought it was old gas.
It does have an overheating problem in slow traffic. It ran 240 today in 85 degree weather but the timing/hp/dyno issues are in 70degree weather with the engine never approaching high temps. At 30+mph plus I can drive all day and not hit 200. I think maybe the ATI single fan is the culprit but was going to leave that until the timing issue was sorted. I drove 2000 highway miles bringing her home and the only time it heated up was in rush hour creeping traffic in Vegas.
It is a 25k mile car. New plugs and wires and Seafoam run through the intake.
The MAF if completely clean and the IAT and Knock sensors seem okay. Doesn't matter what gas I run, it treats it like **** #2 and I get mad KR.
I was even thinking head gasket issue because of the overheating but the oil is fine and the high temps are rare and only at very low speeds.
I haven't tried the 110 octane yet. That is my next step.
It does have an overheating problem in slow traffic. It ran 240 today in 85 degree weather but the timing/hp/dyno issues are in 70degree weather with the engine never approaching high temps. At 30+mph plus I can drive all day and not hit 200. I think maybe the ATI single fan is the culprit but was going to leave that until the timing issue was sorted. I drove 2000 highway miles bringing her home and the only time it heated up was in rush hour creeping traffic in Vegas.
It is a 25k mile car. New plugs and wires and Seafoam run through the intake.
The MAF if completely clean and the IAT and Knock sensors seem okay. Doesn't matter what gas I run, it treats it like **** #2 and I get mad KR.
I was even thinking head gasket issue because of the overheating but the oil is fine and the high temps are rare and only at very low speeds.
I haven't tried the 110 octane yet. That is my next step.
