Gazin

Hi all,

I noticed that after my car has been running for some time it looses a lot of power. I can't feel the turbo kick in. If the car is cold runs fine, the turbo "punches hard". It's chipped with GIAC. Is my turbo going out?

Thanks,

Jimmy

2000 A41.8 MTQS

Casablanca Avant

engine bay gets hot you suck in warm air so you don't get the same oomph out of your turbo.

Audi2ptzero

The compressor housing gets hot and as it does the air being compressed gets hotter. Same goes for the SMIC, as it heat soaks you start to lose power.

Kris Hansen

The more oxygen you have, the more fuel you can burn. That's the whole point of a turbo and supercharger, it compresses LOTS more air into the combustion chamber than would naturally be sucked in by the piston's intake stroke, especially at low rpms.

Becasue of the insane heat that turbos generate in their operation, and the fact that they superheat the charge air as they compress it, when it's cool out, the intercooler works better, the turbo stays a little cooler, and the engine just runs a little better.

Casablanca Avant

if you think the turbo is bad in the heat, drive my 911 with carbourators when its 90+

ModifiedA4

cool air means less chance for detonation.

Audi2ptzero

and was reading 125+ degs yesterday.

Devious27t

power is made by air density... the hotter the air the less dense it will be=less power....

David.Norton

but if it is real big I'd say you have a different problem. I'm having a problem with the hot weather causing the wastegate to stay open, and the car is a real dog when this happens. The torque command on the VAG was 410 Nm, it was only making peak of 176. The command on the wastegate was also going to max and just sitting there. As it warmed up it would also get a massive case of turbo lag as the controller would push on the valve, and it would suddenly come unstuck. Just came in from changing the N75 valve, hopefully that is it, otherwise I'm looking at a sticky wastegate. The darn thing is so intermittant I figure it will take a couple of days of running it before I know for sure if I got it. Anyway, if you think the power loss is excessive (more than 50% for me) I'd take a look at that.

Jimmy D

From Gazin:

Yes, the power loss is huge. What is N75 valve?

Thanks

Jimmy