Anyone here run enough compression that you pretty much have to run a octane booster on super unleaded? If so, what do you use? My motor pings BAD under a load with just super unleaded fuel, I tryed some of the NOS (not street legal) octane booster and it didn't help much if at all. I'm wondering if I going to have to run some VP, Sunoco or something?! lol

 

get a mailorder tune and your pinging should go away. Also, octane booster is basically a joke. It might add like .3 or so octane to your tank, won't do much at all...

 

I do have a mail order tune from Ion (Madz28) I'm running.

 

11:1 should be fine on pump gas (91 or better)
Octane "boosters" are worthless.

If your car is knocking, you have a problem.
You need to hook that to a computer or scanner and get a look at the diagnostics logs.

Is is throwing any codes?
Did you disable your knock sensor in the PCM?

 

Well that 11:1 is pretty much a guess on how much the heads have been milled down and the pistons were using. It could be 11-11.5:1. It's not knocking, its pinging, theres a difference. No its not throwing any codes and there is nothing logged since the last time we reset it. No the knock sensor is not disabled but Ion did desensitize it some. The computer does show us that at an idle it's pulling from 2 up to 8* of timing but once you give it some throttle it doesnt pull any. Yet, if you give a fast blip of the throttle when the headers rack back it sences a knock which we think its detecting the headers. It only sences the knock right when you let off.

 

This sounds like a problem that I was having. My vacuum is low at idle and in that part of the table, the timing is quite advanced because it thinks there is a load on the car. You need to hook a computer up and see what the sensors MAP sensor is doing. Just an idea.

Run some high octane fuel and see if the pinging goes away. If it doesn't and you still have knock retard, then you know that it is false knock.

 

I agree that octane boosters are generally a waste of money. I also wonder why he is having detonation. Running hot? Plugs too hot? Too much timing? High load/low rpm operation (a no-no for a high performance motor)?

Rich

 

Hmmmm.... 11:1 in Corpus Christi in July on reformulated fuel. Can't imagine why he has preignition.

Anyone here see that TV magazine (60 minutes or Dateline), covering octane booster fraud. Not one tested raised the octane a full point.