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I have a Audi s3 1.8T BAM with a gtx3582 and a emublack. The car has a compression ratio of 8.1:1 and not the stock 9:1. The turbo is glowing red hot after a short amount of time without even getting to 1 bar of boost. And I really don’t have much power. What could be the cause of this problem?
timing too retarded at low RPM
I have the timing from the stock compression ratio. So I have to put the timing up if I have a lower compression ratio?
I suspect the engine is less efficient, so it needs more timing, have you tuned it for MBT at part throttle?
Not yet. It was a starting map for this engine from ecumaster. I was just tuning my fuel Maps with the base timing that was given but stopped when I saw the glowing turbo.
As David said, having the ignition retarded will cause both those issues.
Seems you've made some modifications, if the compression has been lowered, in addition to just the turbo-charger. Exactly what have you done?
First thing I'd check is it is correctly indexed to TDC, you may have done something to alter that?
New rods, new piston ( the piston are responsible for the lowered compression ratio) big port head, big port integrated intake, 980cc injector, external waste gate, bigger fuel rail with dash fittings.
I checked the ignition angle with my timing light, that looks fine.
How about supplying some facts
-- What is the RPM & MAP (or TPS) when you find the turbo starting to glow.
-- How long ("short amount of time" is 15 sec or 2 min) at that RPM before you can visibly see the color of the exhaust change? (if you have EGTs, then supply info about temperature, rise time, etc.
-- What is the commanded ignition timing when the problem occurs.
-- Do you know what the OEM ignition timing for this engine under those conditions?
-- Have you tried advancing the ignition by 4, 8 or 12 degrees (this is low load, so it's unlikely you are knock limited) -- what was the result?
-- What else have you tried (be specific "tried running at Lambda 0.82 and this seemed to help -- took 30 seconds longer to reach a dull red color").
If youve checked out all your ignition timing and cam timing, a clogged catalytic converter will glow your exhaust as well. the build you describe doesnt sound like you would run a cat but i suppose it depends where you live.
The car is only for 1/4 mile drag racing. It started glowing after about 10 minutes of cruising in low load and one attempt of a WOT pull. I can only test new stuff when I have a closed road to test one. Next weekend I’ll be able to test again.
We just put in EGT after the last test run because we were scared of that glowing turbo and didn’t want It to happen again. Lambda was at 0.8-0.85 at wot and 0.9 at cruising.
We couldn’t try any more because we wanted it to cool down. About 10 minutes of testing and then the turbo was glowing like this.
Ignition was at about 15 degrees while cruising.
I do have the file of the original ECU and I could look in WinOLS what the stock timing is.
I’ll try with the timing and will report
15 degrees is a VERY low advance for a light load cruise.The less dense, light throttle charge burns much more slowly than a denser charge, so it may need to be ignited much earlier - some engines like as much as 45 degrees, total, depending on rpm and load, at cruise - if the charge is ignited late the charge may still be burning as it enters the exhaust and, at a minimum, will have cooled less from expansion on the downward stroke.
If you can afford it, a headset and/or knock sensor should allow you to advance that significantly. Personally, I'd also run the lambda much closer to 1.0, maybe 1.1 at cruise.
I agree with Gord!! Add 10-15 degrees of timing (only in the cruise region) - or whatever the OEM ECU uses and I bet your glowing turbo will be tamed!
Thank you very much guys! I appreciate your help.