Spark Knock

**DSkyles** · 01-16-2006, 11:02 AM

Hey everyone, just wanna start off by saying this site kicks ass! I have a 99 Z28. I Have Flowmaster exhaust, a Granatelli air box, K&N filter and a smooth air bellow from SLP. I just put on a Granatelli Mass Airflow Sensor with the cold air tuning. When test driving it I noticed some spark knock at high RPM's right b4 it's gonna shift when I get on it. Would an air temp. inlet sensor take care of the spark knock?

**keliente** · 01-16-2006, 12:42 PM

Doubt it.

I would bet that the new MAF is the problem. You should consider either getting the car dynotuned, or selling the MAF (stock is good for over 500hp by the way).

**DSkyles** · 01-17-2006, 12:14 PM

I don't really wanna take it back off because I noticed such a huge difference. I know a guy with a dyno so I'll probably have to talk to him.

**SteveC** · 01-17-2006, 01:35 PM

The "huge difference" is because you are now running the engine extreemly lean, which is why you are getting the detonation. You need a tune, or as stated above install the stock MAF.

SteveC

**02z28ls1** · 01-20-2006, 01:59 AM

Isn't the engine management capable of compensating for this? I asking here -I've never messed w/the aftermarket stuff before.edit-I'm now reading an interesting article in Jan. 06 Hot Rod magazine "LS-1 Cookbook" where they do an extensive dyno flog of a stock crate motor with stock computer's fuel and spark timing curves.Stage one is totally stock-stage 2 is replacing throttle body,MAF and intake manifold (FAST 78 mm TB and Granatelli 85mm MAF and FAST LSX intake).They dont detect any lean out condition with this set-up-as they do in stage 3 and 4-which they correct with increasing fuel pressure(in stage 3+4).Interesting article for anyone with a LS-1 F-body.