lofty35

My bug 2002 is loosing boost at 4000 revs.
Can anyone help me out by what may be causing this?
Ive took it to carnetix , scoobyworld and slowboy racing & still no joy.
Neil at slowboy told me to change knock sensor & front 02 sensor.
Will try this but just want a second opinion.
Thanks

lofty35

Anyone ?
This is the right section to ask isnt it?

p1junkie

iTrader: (5)

when you say losing boost do u mean it actually loosing manifold pressure or just wont boost to its target boost
first what is normal boost pressure at 4000rpm for your car
and does it achieve this or not

lofty35

Im not very mechanically minded so i will try to explain best i can
When i floor it turbo boost kicks in around 3000 revs and my psi gauge goes to 19/20 then stays there on full boost.
As soon as i get to 4000/4500 revs just looses total boost and psi gauge start to come down quickly.

scoobyricht

iTrader: (4)

are u running a td04 at 19/20 psi? if so this would be expected as the revs rise. they cant provide that much air. hope you have remapped for ur boost increase.

The Rig

iTrader: (13)

Hmm, bit strange you have taken it to 4 specialists and none can diagnose a fault, as above, if the TD04, it will run out of puff at 1.3 bar at high revs, hence the TD05 being used.

However you have increased the boost, have you tried lowering it to say 1.1 bar and see if it does the same fault, i.e loses boost pressure ? if it doesnt, raise to a point until it does lose boost and thats the limit of that turbo/your setup ?!!?!?

lofty35

I have td05 16g/pinks/walbro/full decat & sti top mount.
Mapped by slowboy last week.

DT-SPD

iTrader: (7)

Maybe the ECU is seeing some det and pulling boost to protect the engine. Is it running good fuel ?? I would take it back to the mapper to get checked out.

lofty35

Mappers 150 mile away tho.
Ordered a new knock sensor so will try that nxt week