Jobi

Hi,

I'm experiencing a weird phenomenon on a EUDM Evo 8. I need to mention that the boost is controled via a 3 way solenoid and the boost curve is now almost clean and stable.

BUT, after a given amount of time spent on high load, you can hear a sudden whistle coming from the engine bay, the boost immediately drops (from 1.5bar to 1.2bar) and then, if you stay at WOT, there is no more whistling and you got a stabilized boost of approx 1bar, which actually equals to the boost you would have by directly controlling the wastegate actuator by the plenum pressure.

This is not pressure related at all. Cause if you run more pressure, it won't happen at lower rpms. So forget the leak route: the whole intake system has been tested, and what is experienced tends to prove this is not related to a boost leak.


For example, if you try in gear launch in 4th gear from very low rpm, it will always appear at 6k rpm. If you do the same in 3rd gear, you'll experience it at approx 6.7k rpm.
On a 4th to 5th gear change (at WOT), after having shifted to 5th, the whistle thing can be heard at no more than 5.5k rpm.

Another interesting thing is that you can "cheat" on that. If you gently rev the car up to 6k rpm (in 4th gear for example), and you suddenly floor the gas pedal, you'll have your normal boost level (1.5bar) until approx 6.8k rpm!! And then, whistle again, and no more solenoid acting.

So those facts lead me to the conclusion that this is related to a certain amount of time spent above a given load value. Then, the ECU switches to a so called fail safe mode which disables the boost control until next time the pedal is floored.

Trouble is I can't find a corresponding strategy on the tables of the xml file (965300006 rom)...

Any idea? I'd like to avoid the AVCR fitting just because of that...

Jobi

No one?

rolly1818

u certain this is ecu related and not mechanical related.

i am thinking ur WG sticks open...

no offence but can u re-write ur first post i am a little confused.

GST Motorsports

iTrader: (8)

What intake? If you are using the factory snorkel and you don't have the two front clips in, the snorkel will lift into the hood and choke the intake at speed, and will do exactly what you are describing.

Mattjin

Are you watching the wastegate duty when this happens. If it stays stable it is a mechanical problem, if it drops duty then it is the ecu. Is the BOV connected directly to the intake without anything else tapped off it?

Ludo

iTrader: (1)

Is it possible that the tactrix 3-port boost control is failing?