With the warmer weather we've been having, my car has only been boosting to about 10psi during the daytime, then when it the air cools down in the evening it boosts to 14psi as it should.

 

Now I know that the turbos won't work so well in warmer air, but it's not a problem that I ever had during last summer. There used to be a minor difference when it was warm, but not so exaggerated as it is now.

 

I'm wondering what could be causing it to lose so much pressure, boost leak? I figure if it was a boost leak then it wouldn't be reaching full boost when the air is cooler. Could it be a faulty sensor of some sort? Or are my turbos shagged?

Easy bud,

 

It seems pretty self explanatory - I think you're already aware what is the cause, it isn't really a problem, just an effect of the environment. The engine won't allow the turbos to boost any further as it will overfuel or not have the right mix. It could be that your gauge or boost measuring device is a little out with its figures, but either way, it doesn't sound like a problem.

 

I'd be more concerned if it WAS boosting to 14psi

 

Cheers

Edited April 30, 201114 yr by leo-r32gts
open mouth, think, correct

Thanks, although I don't remember there being such a big difference last summer. Maybe I'm just being paranoid!

I'm guessing that as you say "it boosts to 14psi as it should" then you have a boost controller or jets to get that boost?

The job of boost controllers, actuators etc is to control the boost to a set level therefore it should boost to about the same level all the time irrelevent of temperature etc. so it shouldnt be able to vary by that degree imo.

do you have an aftermarket gauge or going from the standard one? 'cos they are notoriously inaccurate. I'd try another gauge to check the readings again.

Just my opinion though

If you're running standard turbo's then they'll be operating towards the upper limits of their capacity. On a hot day, they have to work harder to compress air to the same pressure. It could be though, that your air filter is dirty and restricting the amount of air getting into the engine, or possibly the intercoolers can't cool the gases effectively - so either way the turbos cannot reach the same level of boost. If you have uprated turbos and intercoolers, then i would agree it could be a problem. But if it boosts ok when the air is dense, then I think you have the answer to your problem. It might be that you just need to give your filter a clean and generally a bit of under bonnet tlc. But then again, depending on how hard you drive your car, your turbos could be reaching the end of their shelf life. How many miles have they done, are they standard or uprated etc..

 

If you were driving a naturally aspirated car, I'm sure the effects would be similar. Air density is a pretty crucial element of combustion afterall..

Yeah standard Tubs and intercoolers... just over 100k miles. Will try cleaning the air filter and let you know if that works...

Yeah standard Tubs and intercoolers... just over 100k miles. Will try cleaning the air filter and let you know if that works...

 

If that's the case (and you've not upped the boost) then stock boost is around 9psi - although you may see 10 or just over on the stock guage.....

 

.....14 is too much...:ohmy:

 

I've not had any problems with mine so far this year; but it hasn't really been hot enough yet. I have a UK car which is fine with regular unleaded - although when the ambient temperature gets above 26 degrees, I find that super unleaded can often work better....

 

Richard:cool2:

It's got a chip and boost has been upped to 14psi (all from previous owner). Only ever gets V-power.

 

I went out this afternoon and it was boosting as usual (I.e. the problem I initially posted about didn't show up). I think it may be something electrical rather than mechanical as it's so temperamental.

What series PTU do you have btw?

I think it's a series 1