Turbo boost problem

[gt5r]

Since having my Volvo V70 T5 (2001 - P2) mapped I'm experiencing problems with loss of boost pressure – the remap raised boost pressure by 0.28 - 0.3 bar from a standard of 0.6 bar

Two symptoms

1. Under gradual throttle increase the car will pull 1 bar boost and hold pressure – goes like stink – no pressure drop

2. Nail the throttle flat to the floor in 1st 2nd and 3rd (especially in 3rd going up hill) and the car only pulls 0.5 bar boost max(in all gears) then spikes pressure and dumps it around 4700 rpm

I've changed the recirculating valve as I had a spare and the vacum hoses

Could it be that the recirculating dump valve or waste gate acutator are unable to hold 1 bar boost? - do I need to go to an external recirculating valve to hold the pressure?

New to all this turbo stuff - any help would be greatly appreciated

Regards

Mark

[felga]

My advice get original maps back and get it to a tuner that will remap your car on the dyno.Probably you have maps made by somone sowhere morless for this car (every car even same make and spec is different).

A

[eliot]

you can eliminate the recirc valve by blocking it off to test. As long as you dont snap the throttle shut quickly on-boost you will be ok.

[stevieturbo]

So the car has never went right since it was re-mapped ??

[gt5r]

Since the remap the car has developed this fault - before remap all seemed ok

I've also heard that the throttle body position sensor if worn can send a signal to the ECU that its at idle and shut the fuel off or go into 'limp home mode' ? - there is another thread on pistonheads about this - it seems a random fault though

[bales]

eliot said:

you can eliminate the recirc valve by blocking it off to test. As long as you dont snap the throttle shut quickly on-boost you will be ok.

What difference is it going to make if he does snap the throttle shut?

If your talking about compressor stall / surge then I have yet to see / meet / hear anyone who has actually destroyed a turbo in this way!!

Its not as if he is running 3 bar of boost through it?!

[eliot]

bales said:

eliot said:

you can eliminate the recirc valve by blocking it off to test. As long as you dont snap the throttle shut quickly on-boost you will be ok.

What difference is it going to make if he does snap the throttle shut?

If your talking about compressor stall / surge then I have yet to see / meet / hear anyone who has actually destroyed a turbo in this way!!

Its not as if he is running 3 bar of boost through it?!

Agreed - but no harm in avoiding it. OEM may of built a fragile turbo that relied on the recirc valve for all I know.