Loss Of Power/boost

[jimmytt]

Recently I have noticed on my V300 vertex that while squeezing the accelerator pedal, I get an initial spped up but then the more I press I seem to get a lot what sounds like a lot of induction noise (induction kit fitted) but severe lack of boost pressure/acceleration?...but it doesnt happen all the time, sometimes the induction noise stops and the car picks up like it should....I have a dump valve fitted and wondered if this could be dumping or not closing fully all the time venting the boost air instead of allowing it into the inlet manifold. Or could it be a blocked intercooler?...or maybe faulty plugs/coil pack?...there is no warning lights up on the dash and when on the motorway, its really annoying as I have to press 3/4 accelerator and jump down sometimes 2 gears to overtake....when the car is on boost its totally awesome!!. The only mods it has is custom exhausts/induction cone/dump valve/adjustable springs + shocks lowered all round on 19 inch volk racing split rims so looks the dogs doo-dahs!! any help much appreciated ta

[Mr Morse]

Is it the stock recirculating BOV or an aftermarket vent to atmosphere?

For stock, check the integrity of all the vacuum hoses

For aftermarket, check the seal between the BOV and the flange

[dangerous brain]

My guess is a loose clamp on your induction pipework somewhere that will act normally under lower boost and be forced open under higher boost. Might also be split in a hose that only opens under full boost. Take a good look at all your inuction pipework from the turbo's to the SMIC and then from the SMIC onto the inlet manifold.

[Dave-Ellen]

Check all intercooler connections.............

[goodoldgrandad]

If you have an aftermarket Blow off Valve - check to see if it is one with an adjustable valve (ie: a small screw that can be tweaked to set the point at which the pressure release valve operates). I've known one on a previous car come loose and had a similar effect - either fit a couple of nuts on the adjusting shaft to lock it in place or glue it once you have adjusted the blow-off-point. By it's nature the BOV vibrates significantly, and so does the pipework around it, so have a good look around for something gone loose.

If you have the stock BOV still then maybe pop it back on and try it - at least that will narrow down where the fault lays.

Other daft thing to check - the induction filter. Being in the season of falling leaves you haven't got something stuck or flapping about in there - mine this year looked like a hay stack.

[jimmytt]

If you have an aftermarket Blow off Valve - check to see if it is one with an adjustable valve (ie: a small screw that can be tweaked to set the point at which the pressure release valve operates). I've known one on a previous car come loose and had a similar effect - either fit a couple of nuts on the adjusting shaft to lock it in place or glue it once you have adjusted the blow-off-point. By it's nature the BOV vibrates significantly, and so does the pipework around it, so have a good look around for something gone loose.

If you have the stock BOV still then maybe pop it back on and try it - at least that will narrow down where the fault lays.

Other daft thing to check - the induction filter. Being in the season of falling leaves you haven't got something stuck or flapping about in there - mine this year looked like a hay stack.

I've got a sard BOV straight to atmosphere....could this be a problem?...sometimes she goes like a rocket and others is lacking boost???...but the BOV still gives a healthy whooosh on lift off and thats why I suspected the BOV...but how do I adjust it?? - SARD R2D2 And also, under slight lift off it chatters....is this compressor surge??? cos last thig I want is shelling out on new blowers

[goodoldgrandad]

I don't know that particular BOV - but if has an external nut or screw then chances are it is adjustable to different pressures, but I'm not sure how you would set it up without the manufacturer's instructions. The BOV is likely to make noises anyway, but the critical thing is to set the release pressure level so it vents at the proper time.

[Ahhhh__Aristo]

Does this only happen when #2 turbo is about to come online??