Strange question chaps, but a Civil engineer colleague of mine has a Ssan Yong Musso 4x4, it's a 2.9 TDi which pushes out a whopping 115 bhp,

For some reason he went to the local powerflow dealer and had a full SS exhaust system fitted, front to back and has been on at me today because "I know about modifying cars" as he's been out in my wee smokechucker. He recons that his power is now greatly reduced and that the initial surge of the turbocharger is missing.

My suggestions are that the exhaust fitter has somehow managed to restrict the exhaust further whether that is an out of spec box etc

Or for some reason the turbo intake pipework has been disconnected during fitting in some way, but he says nothing looks amiss under the bonnet,

So, a bit strange how could a 'free flow' exhaust reduce power on a turbocharged car?

Is he sure it is actually performing worse? Could be that it used to struggle at low revs but now it doesnt, this could give a feel a bit like turbo lag until the revs increased. Because the exhaust is now free flowing any "lag" could have been removed so you dont notice a step between "slow" and "go".

Hope that all makes sense.

Maybe the turbo on that car does need some decent back pressure? And maybe its been all removed by this system? Nothing would look amiss under the bonnet, as all the work done is from the cat-back I should assume?

Anyway, if he knows about cars,etc WTF did he get a Ssangyong?

No he knows nothing about cars, He's a Dr in civil engineering but he could tell you anything you wanted to know about seismic liquification of soil

Goochie, I made the same initial comment as you but he's adament that its slower in every respect, My solution to him was that he should stick it on a set of rollers and get it dyno'd to prove for sure then take the plot back to powerflow and get it fixed.

His reply was that the car has 50k on the clock and that it was maybe down on power beforehand so the plot may be inconclusive.

Seemingly this 2001 Ssanyong Musso has no cat?? is that right, i thought it was required by law after mid 90's or was that just on petrols?

Just for the record, i agree Ssanyong = pish

2001+ car for U.K roads will legally have had to have a cat. Powerflow didn't nick it did they? They nicked mine, but on request.

Common miss conception that a 'sports' exhaust will give you more power there are cases where they have been know to decrease power.... powerflow is one exhaust know for this. basically its to do with the happy go lucky approach, you pick your off the shelf back box, some monkey rips out your old exhaust and welds in new pipe work and takes a sizeable sum of money off you... forgetting the manufactures of the engine has tested possibly hundreds of diffrent exhuats to find the right amount of back pressure etc to suit the engine.. monkey comes along and screws all that up... power loss can occur some times....however if he was to go for a exhuast that again was desgined for the 4x4 by miltek mongoose blitz etc chances are he would have felt a power increase or at least not a power drop...as these would have been developed with a test vehicle

edit: didnt mean that to sound as patronising as it does sorry

Joel