hey fellas, having a little trouble with my ea82t brumby. running 13psi through a legacy water to air cooler, 3in exhaust and custom down pipe and microtech programmable injection and ignition. problem is i keep breaking pistons, just pulled the motor again (2nd time) to slot in a new piston. i know its due to detonation but im buggered if i can hear it. air fuel mix measured by wideband is 11.8 t0 1 under full load which is pretty good for a boosted engine. timing at idle is 10 degrees and ramps up to about 29 degrees at 6500rpm. anyone know a good timing curve for these engines? disy has been locked.

 

 

oh, 4got to say we run 98 octane fuel here in oz..

""In most countries (including all of Europe and Australia) the "headline" octane that would be shown on the pump is the RON, but in the United States and some other countries the headline number is the average of the RON and the MON, sometimes called the Anti-Knock Index (AKI), Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2. Because of the 10 point difference noted above, this means that the octane in the United States will be about 4 to 5 points lower than the same fuel elsewhere: 87 octane fuel, the "normal" gasoline in the US and Canada, would be 91 in Europe.""

 

So your 98, is the same as our 93. No difference.

 

GD

hey fellas, having a little trouble with my ea82t brumby. running 13psi through a legacy water to air cooler, 3in exhaust and custom down pipe and microtech programmable injection and ignition. problem is i keep breaking pistons, just pulled the motor again (2nd time) to slot in a new piston. i know its due to detonation but im buggered if i can hear it. air fuel mix measured by wideband is 11.8 t0 1 under full load which is pretty good for a boosted engine. timing at idle is 10 degrees and ramps up to about 29 degrees at 6500rpm. anyone know a good timing curve for these engines? disy has been locked.

 

 

oh, 4got to say we run 98 octane fuel here in oz..

 

That should be about right. I'm surprise you've blown so many pistons. Does the microtech log? Do you have a functioning knock sensor that you can monitor the output on? Is it the same cylinder losing the piston? You could have a clogged injector leading to localized detonation.

thanks for ur reply dylan, hmmm youve got me thinking now, i pulled all the injectors and cleaned them before i did the conversion, but the first piston was the rear one on the non disy side and now its the front one on the same side. the fuel comes in on the other side of the rail so i wonder if its having distribution problems. something to check anyways. i might put a bung in that side of the exhaust and measure the mix for that bank only.

Cyl 3, right in front of the turbo, seems to blow most often (headgasket anyway). I've never heard a conclusive why (heat from turbo, heat from turbo water, reduced oil pressure from turbo line, different flow in intake, different flow from exhaust?)

I've lost a piston because of a faulty injector, but I think your timing is likely the issue.I think these disties suck. Great curve for stock terrible for modded. On all the ea82t's that I've run higher boost they've had issues with the "timing curve" I usually run around 15-20 btdc in the winter and around 10-17 btdc in the summer, depending on the amount of boost which is usually 12-15psi.