Why am I knocking?
 

Had my car tuned by Jei @ Blacktrax performance in Milpitas, CA.

Car is:
1.6 L
Greddy TD04-15G
3" Exhaust
440cc injectors
FMIC
55mm CX Radiator
Toyota Coil Packs
GM Mass Pressure Sensor
MS PNP2

We ended up backing out of boost at 197 whp and a little under 10 psi. Beyond these levels the car started knocking even under extremely rich conditions, and with pulling timing (we since reset the settings to more reasonable levels at 10psi). Thinking its a weak ignition system parts causing the issues, but trying to diagnose. Any ideas where to look first?

What intercooler? Its on california gas so low knock thresholds are common. But 10psi is a little low. What timing are you running at 10psi.

Its a 24" x 12" x 3" eBay intercooler. IAT's were low on the dyno.

I'll pull the tune file to get timing #'s don't remember off the top of my head.

- Chris

By Toyota coil packs, do you mean the Toyota COP's? Are you running them sequential or wired for wasted spark? And yes, the timing table helps!

Bad gas? Chance you have 87 in it? I would drain the tank and try again with fresh gas.

How confident are you with your base timing?

No 87 .... its 91 octane. Yes, Toyota COP.

Here's the Timing Maps attached:

Attachment 178039

- Chris

Anyone here?

Your timing looks reasonable. CA 91 Octane sucks. Maybe your engine has other issues.

And please don't be offended, but the IATs you claim were low- were they measured before or after the turbo?

I didn't outline the exact IAT's - tuner said they were low, no figure in mind off my head!

Jei is a pretty well-respected tuner in the bay area, so I would expect he's giving IATs after the intercooler.

Did he datalog the dyno tuning runs on the MS? If so, do you have those logs? That would answer the IAT question quantitatively.

Some motors are just more ping-prone than others. I've heard of people using seafoam to clean out deposits that can contribute to detonation, might be worth a try. Also, how much oil is getting into the intake? If it's a lot (say, if the motor has a lot of blow-by and you don't have a good catch-can setup) then that can cause pinging -- oil has a very low octane.

--Ian

I thought about this as well but wouldn't be using a fair amount of oil to cause this?

Which spark plugs?

No catch can setup - simply vent to atmosphere (Pep-Boys filters). I think this could be one of the issues.

Will check IAT on the logs.