is there such thing as "to big" of a down pipe?
#1
tom port.. AKA streetport
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is there such thing as "to big" of a down pipe?
im looking at a couple down pipes. a 3 inch and a 4 inch. i was curious to know if there is such a thing as to big of a down pipe? ill be running a fresh streetported S4 with a HKS "LOG" manifold with a turbonetics 62-1 with .96 hotside and remaing exhaust will be 3 inch high flow cat and a 3 inch HKS HI_POWER old school exhaust.
here are the downpipes:
4 inch:
http://www.himni-racing.com/index.ph...oducts_id=1025
or 3 inch:
http://www.himni-racing.com/index.ph...roducts_id=839
here are the downpipes:
4 inch:
http://www.himni-racing.com/index.ph...oducts_id=1025
or 3 inch:
http://www.himni-racing.com/index.ph...roducts_id=839
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#8
tom port.. AKA streetport
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it has a 3inch outlet on the turbo.
i wasnt sure. i figured bigger DP = faster spooling.
plus the 4 inch is ONLY about 10 bucks more.
i wasnt sure. i figured bigger DP = faster spooling.
plus the 4 inch is ONLY about 10 bucks more.
Last edited by 88rxn/a; 08-04-07 at 06:40 PM.
#9
If it's only a 3" outlet, and you're going to be running 3" parts on down the exhaust line there, then there is no point to run 4" at the downpipe only to have it restricted before and after.
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Engine, Not Motor
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You don't need any backpressure. Turbos need as large a pressure differential between the turbine inlet and outlet as possible. The only real limitation is physical space. After about 4", it becomes difficult to package things in the engine bay (you still need room to remove and install the pipe, and for wastegate plumbing).
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tom port.. AKA streetport
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that was another issue i wondered about was packing a wastegate and piping for that. id like to have a 4 inch but i am curious as to actually how much room there would be?
#12
Let's get silly...
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Also, at some point it is a game of diminishing returns. When you are putting out power in the 700-800 HP range, the difference between 3" and 4" is quite a bit different than in the 300-400 HP range.
Depending on the turbo and fuel system you are running going from 3" to 4" may do very little for you other than cause space issues as previously mentioned.
Depending on the turbo and fuel system you are running going from 3" to 4" may do very little for you other than cause space issues as previously mentioned.
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