I have a jdm sti, which has a vf37 twin scroll...

I will be looking to change the current 3" system and downpipe to a milltek sport (which I already have), but was wondering if the downpipe has to be "twin scroll specific"?
The milltek I have is from a single scroll car.

Essentially, do I need another downpipe or can I use the one I have??

Matt

 

You'll need a twin scroll specific downpipe as the flange on the turbo is different to the single scroll turbo.

 

Yes you need a twin scroll downpipe .Twin scroll downpipe holes are in different postions and the shape of the flange

 

Depending on the exhaust you may also find that if you change the downpipe to a sports cat for instance, it wont be the same length as a single scroll downpipe so you could be at a disadvantage there too

Tony

 

There is always the option of cutting and welding, but would probably be more cost effective to sell the down pipe you have and buy a twinscroll one, Gaz.

http://cgi.ebay.co.uk/SUBARU-Impreza...item1c16827728

 

Think he would still be a bit screwed there Gaz, the twin scroll dp is a different length due to the sump and equal length headers (hence why your and my Spec C's would run a classic size mid section and a UK car would run a shorter centre section).
They changed it for the MY05 cars though, still thats one of the down sides to trying to put single scroll stuff on a twin scroll car....

Tony

 

I bought a 3" Hayward and Scott twin scroll downpipe for mine, i'd go for one of those mate.

 

Thanks for all the input.

Was thinking of ordering the milltek twin scroll downpipe, but wanted to be sure that the single scroll I have will not fit!

Had a look at the OE downpipe and it is the same shape as the adapter in the ebay link.

 

If you have full 3 inch milltek system with cat in centre pipe then the rear box and centre pipe are same part numbers on single and twin scroll just the downpipe is different so would be easy option just to buy one and then fit the whole system, I looked into this when looking for an exhaust for my car I also found that pre 05 cars as STD have classic shorter centre section and a 1 piece long downpipe and 05 onwards have same length centre as newage uk cars and a 2 piece downpipe the short resonator section between downpipe is same length as 2.5 uk cars as I ended up fitting a 2.5 ppp sports silencer section between downpipe and a Haywood and Scott deres centre followed by a genome rear silencer, I kept my standard cat for now but the rest is all stainless. Thinking of a downpipe myself though now but got a few other things to get first