Silly question! Reducing 3" to 2.5" in exhaust ?
17 June 2009, 05:23 PM
#1
Silly question! Reducing 3" to 2.5" in exhaust ?
Im looking at getting a new down pipe but it is 3" bore all the way through, the stock pipe on my 2005 WRX is 2.5" I think. Avoiding buying a new centre section to, I have looked at these 3" to 2.5" flange adaptor kits, heres my silly question...
Do you need an adaptor kit? The flanges will still marry up but there will be a 'step' in the system where the flanges meet and ity steps down to 2.5". Would this be a massive flow disruption and cause any other damage? eg, heat or leaks etc?
Only reason I ask is 0.5" is not really a huge difference, considering it would only be 0.25" each side in the pipe
Any advice?
Do you need an adaptor kit? The flanges will still marry up but there will be a 'step' in the system where the flanges meet and ity steps down to 2.5". Would this be a massive flow disruption and cause any other damage? eg, heat or leaks etc?
Only reason I ask is 0.5" is not really a huge difference, considering it would only be 0.25" each side in the pipe
Any advice?
Last edited by scoober101; 17 June 2009 at 05:24 PM.
17 June 2009, 05:43 PM
#2
Why not just get a 2.5" downpipe?
Anyway, the adapter won't work as you've not left any space in the total length to allow for it.
Mating 3" to 2.5" won't work. 0.25" really does make all the difference when lining things up.
Anyway, the adapter won't work as you've not left any space in the total length to allow for it.
Mating 3" to 2.5" won't work. 0.25" really does make all the difference when lining things up.
Last edited by Butty; 17 June 2009 at 05:45 PM.
17 June 2009, 05:46 PM
#3
17 June 2009, 06:17 PM
#4
Found the answer myself, I will port the 2.5" centre pipe end that meets the down pipe. Similar to porting the headers, this way there will be a smooth reducing angle and not a flat 90 degree step for the gases to overcome.
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