M20B27 ETA turbo with knock sensor & ignition table needed

[E21M20B27]

Ive got an M20B27 ETA build and we measured it on HubDyno 307HP @ 14psi pump gas 95. I feel this is kinda low for this engine.
I dont want to go on e85. My engine is fitted with a knock sensor and during the tune we used it. My tuner said that he senses knock so he do not wish to advance the timing any further. So we went along with the knock sensor data throughout the session.
I know that knock sensor on M20 is quite unusual... I share my ignition angle table now and I would like someone with exprerience to have a look at it.

My idea is that we might have gotten false data from the sensor that we followed and this prevented the car to make more power.
Im hoping that someone can share their working tuned ignition angle table.

[Dj Buttchug]

Can you resize the table image. Its so small I can barely see the numbers.

[TobyB]

Without a laundry list of details,
300+ hp out of an eta at 1 bar seems like you're doing pretty well.
That maths out about ight with the stock 140ish N/A.

Det counters/knock sensors are really valuable- if you can look at the unfiltered signal,
that might tell you what it's hearing. But I'll bet it's not too far off...

Me, I'd drive 300bhp until my right foot decided it needed ALL of my wallet-
in an E30 that's goingto be lots of fun,
and a little challenging to use all of it all the time.

How's the torques?

t

[e30davie]

What was he using as a knock detection? Heads phones listening ears or electronics through the ECU?

I don't have a whole lot of experience but Its a bit of a black art as to how hard to push it once you detect it.

I put a knock sensor on my m20 and an amplifier to some headphones, very difficult to discern anything even with some band pass filtration attached to the input. Just so much valve train noise to hear through. But I have very little experience so maybe an experienced person could make sense of it.

[E21M20B27]

I'm running a MaxxECU Race with a knock sensor added directly to the block. It works flawlesly. When he slightly retarded the ignition timing, the knock immediately went away — which further confirms it wasn’t false knock. I fully trust my tuner. We weren’t able to advance the ignition any further because the sensor was already picking up signs of detonation.

After several days of reviewing logs and going over every possibility, everything points to one culprit: my custom-made 3-pass radiator. The logs show water pressure surges in the cylinder head's coolant passages — reaching as high as 2.7 bar. The engine still uses the stock belt-driven water pump, which gives us no real control over flow rate. The coolant hoses go rock-hard under load, leading us to believe the 3-pass radiator is too restrictive. He also noticed irregular temperature readings on the coolant temp sensor during pulls — brief spikes and drops — suggesting possible air pockets in the system, even though it was bled before the dyno. It may be preventing hot coolant from escaping the head fast enough, which could be causing localized overheating and knock.

According to my tuner, we're missing at least 4 degrees of ignition timing. If we could safely run that, the engine would make the power it's supposed to. Right now, cooling is the limiting factor. The plan is to revert to a single pass radiator and retest.

https://www.youtube.com/watch?v=BvO057zMwNo

[E21M20B27]

...
and a little challenging to use all of it all the time.

How's the torques?

I’ve got wheel speed sensors fitted and traction control enabled. The turbo choice turned out to be absolutely spot-on — I’m really happy with the power and torque curve I’m getting. There’s no sudden or uncontrollable surge; the delivery is smooth and exactly what I was aiming for. I’m running a PULSAR PSR5455G (G30-660 equivalent), dual ball bearing, forward rotation, with a 0.70 A/R and 3'' inlet.

[e30davie]

interesting. good to hear of the use of a proper ecu.

interesting theory, though if correct you'd possible expect no knock until it becomes heat soaked? ie you'd get a few runs without knock and it should get worse with temperature. Can you see a trend like this?

[E21M20B27]

This happened during a single dyno session. In the warm-up phase we focused on fine-tuning the engine's under cold and warming conditions. Once the engine reached operating temperature, we shifted our attention to tuning for peak power. At the time we had no opportunity to investigate the issue under cold start conditions and we were initially unsure of the cause. It took us two days to identify a possible explanation and make a plan.