Turbo boost pressure cold different to when hot - any ideas?

[gt5r]

Anyone got any ideas why boost pressure would vary when the engine is running upto normal operating temp - basically from cold and running upto normal operating temp (so its just under its normal operating temp before I boot it) it will boost 13 psi and after about 20 miles it only boosts 10 psi - is this normal??

If you let is cool down for 1/2 hour and rerun it will boost 13 psi and after a few miles will drop back down

Checked all usual hoses and pipe work for leaks/splits etc all seems ok - its a Volvo V70 T5 P2

Thanks in advance

Edited by gt5r on Monday 13th April 18:18

[stevieturbo]

it would be more common to see low boost on some cars until its up to operating temperature, as a bit of a safety

[richies2.0gl]

May be down to the density of the cooler air when engine is colder. Called co-efficiency of thermal expansion.

[ss1turbo.com]

I know its a different car, but on a Saab turbo (I have a 9000 turbo FPT), if the system detects something not quite right, it falls back to "base boost". Favourite is usually spark plugs going off if its heat related.

Others could also be a lazy wastegate, heat soak into the Air Temp sensor..the possibilities are endless!

EDIT: Delay my last - I've just seen that you've had a remap done - have a word with the place that did your remap....

Edited by ss1turbo.com on Sunday 19th April 19:17