My first FD is a non sequential stock twins with intake, dp, twinpower, exhaust and a high flow cat. It had 800 primaries and 1600 secondaries. No matter how much timing I would pull and how much fuel I would add I would get a ping of 100 during pulls every now and then.

I then bought a second FD that came with a stock mapped PowerFC, twinpower, dp, intake, exhaust and a stock cat. It has stock twins, stock boost, and a stock fuel system. I have yet to datalog but I've started to notice that this car also will throw up a 100 knock every now and then during a pull.

What the hell?

 

I guess there r a lot of lil tings you'd need to check, I'd start by checking the fuel pump output, make sure its more than capable, secondly, the fuel quality, 95 octane & above , what spark plugs are you running? Maybe use BUR9EQ's all round.
From what I've heard, the Base mapping on the PFC comes suited for 100 octane, so maybe the ignition mapping maybe to advanced, would have to be retarded.

Basically you need to get a proper hands on tune.....

RR

 

my experience says not to worry too much about just knock. my car always runs 85 knock and that is at 10.5 afrs. In the manual it says there is no good or bad number so you kinda have to make your own reference number. Although they do say anything over 60 is considered bad. It really depends on the car. changing motor mounts and trans mounts will make knock change. Also just changing the knock sensor will give you different values

I would start by getting a wideband on it and get some logs on exactly when the knock is jumping to that level or is it consistenly staying at 100. Maybe it don't like the timing in a partcular area of the map or its going lean in some area and evcen might be nasty rich in an area causing a hiccup.

 

It is normal to get some high knock during normal driving due to gear changing and differential gear slop due to loading and unloading.

Mine does it.

Only high knock that occurs after getting on boost and before getting off boost is of concern. During this time, all slop and loosness movement has been removed.

 

both car's AFR have been low 10's during a pull. This knock is also during a pull not driving around.
I pulled the engine out of the first FD and it has been a while since I've driven it, but I did have a wide band and was logging it, the ping would be there during solid 10 AFRs, I've even felt and heard it. I don't have exact timing numbers on hand but I was pulling quite a bit and even playing with the split. I also tried different plugs as well as the moped race plugs. The gas was 91 (RON+MON/2) octane.
Now that I think about it I believe before I PNO'd the car I disabled the trailing plugs and had no issues at all after that. I just never got around to it.

The second FD just puzzles me since it too has a wideband and is pulling good AFRs during the pull and the engine is stock. It has a datalogit and am about to start logging when I get off of my butt.
I've only felt and heard the ping once on the 2nd FD but the numbers do hit 100 during pulls once in a while. Normal knock readings from driving around are in the 50's.
I'd hate to pull timing but Is there an ideal amount of timing to pull back with 91 octane? Does anyone have the stock ECU timing maps? Would pulling timing be across the board, peak torque and/or during boost? I guess its time to bury my nose in your notes, Chuck.

 

Unless your car is noisy I would not ignore knock, does your knock read high when you rev the motor in neutral?

Post up your datalogs for folks to see. There's alot of data buried in the logs, when you say you are running 10's on AFR we don't know if that a consistent 10.2 or if there's misfire with wide margins between max and min AFR in each logged cell, misfire will have you pulling you hair out trying to tune and troubleshoot a car.

We also don't know what boost you are running. And what the hell are moped plugs???

Running low 10's is very rich, leaning it out to a still safe but leaner AFR should transform how fast the car feels at WOT.

 

Boost misfire can also read as high knock. This happened to me after installing a higher capacity fuel pump while running old plugs. After installing new plugs and reducing fuel, the knock went away.

 

As long as the tune is good you should be good. I see knock in the vicinity of 60-80 before when i was running the hks twin plate clutch. Since changing out to OS strangely i have seen a reduction, never passes 50. Drivetrain slop and other parts contribute largely to knock imo.

 

I'll try and get some logs up tonight on the 2nd car. I'm running stock boost on this one.

To clear up the confusion on the "moped" plugs in the first car I called them that because they were smaller than stock and I didn't have them in front of me. They are the B10EGV.

 

For sure, it's important to determine if PFC reported knock is from drivetrain noise or from pre-ignition/detonation ... experience really helps.

 

Ok I've attached a snapshot of the "worst" part of the log. I put both basic and advanced knock in the upper chart as red and blue along with boost as a very dark blue.
RPM is Green in the center chart and AF is in the bottom chart.
I couldn't get it to hit 100 but it was pegging 60-70 during pulls, looks real noisy so it does look like drive train noise.

However the car has a rough idle now after a few pulls, seems like its misfiring. It also seems to misfire a bit coming off idle in neutral. Once I'm driving it everything seems normal but goes back to **** once I'm idling.

I've had a blown apex seal before and this does not feel like it at all.

 

The car ran fine this morning. I'm wondering if one of the coils may be going out.

 

Post a WOT 4th gear datalog file with AFR, basic, and map reference. If there's misfire it should show up in the datalog.