Performance turbo downpipes.

[funkihamsta]

Why.
The stock is already likely to be at least 3 inches diameter, they all still end up going through a narrower exhaust pipe in the end (well unlikely to be greater than 3")
And WHY ARE THEY SO EXPENSIVE? Its a manky iron tube. I see peeps charging £600 plus for prole turbo cars (not prestige makes) so what do they do?

[boosted ls1]

Hi, do you mean the pipe immediatly after the turbine outlet? If so this is often large o/d because the gas is very hot and expanded at this point. It's also turbulent. It cools as it flows down the system to the tailpipe, so the o/d can be reduced to a size more practical for the car. As for why the pipes are so expensive then I can't say. Maybe it's because some people will pay that kind of a price?

[lotusguy]

Why.
The stock is already likely to be at least 3 inches diameter, they all still end up going through a narrower exhaust pipe in the end (well unlikely to be greater than 3")
And WHY ARE THEY SO EXPENSIVE? Its a manky iron tube. I see peeps charging £600 plus for prole turbo cars (not prestige makes) so what do they do?

Hi,

Is there a particular tube or system you're talking about?...Jim '85TE

[funkihamsta]

Well the 850 T5 volvo aftermarket downpipe is some £500. I'm just wondering if its a snake oil device as l can't logically see any advantage to a big pipe made of manky iron or a nice custom one when they're the same. And even if its larger, what use is that unless you are going to have an equally large diameter exhaust system throughout?

[accident]

cant comment on the volvo
but all other turbo cars ive owned have seen real improvements from having downpipes at least as big or bigger than the outlet on the turbo.ive yet to find a car that needs(that is NEEDS)bigger system than 3" but the kids love to pay the big bucks for 4",5", whatever.
i know someone with 2 9" oval tail pipes on a 1600cc atmo motor.
kids will buy anything.
real bhp=less than pub talk bhp

[funkihamsta]

Well my stock is 3" downpipe to a 2" all the way through exhaust. I 'could' increase it to 3" all the way through but it would sound awful (only 1.7) and as far as l'm concerend would do nothing. Surely a 3" exhaust SYSTEM is only needed for 300bhp applications.