custom exhaust

i have been looking around for a new exhaust and everything is so expensive, so i decided to build my own. I have a STI axleback on my stock exhaust for a 96 impreza brighton. I am thinking of making the axleback section interchangable so i can have a couple different choices. That may be a stupid idea but just a thought. I was looking for headers and can only find the ebay specials, which would work but i want something unique. I am wondering how hard it would be to fab up my own headers and what material would be the best to use? Like what guage and diameter tubing and flanges. Any suggestions are welcome.

Thanks,
Jake

 

It's times like these that many wish Nate still had the shop. Making headers seams difficult, I wonder if Grimmspeed would do a PnP on an older Impreza?

 

you know they will

 

I would suggest using 421 stainless with a mandrel equipped tube bender, not sure what gauge you would need though. I have wondered about headers myself since all the ones I see online are for wrx/sti which means they are probably bigger so they work for the 2.5l flow which I want to avoid.

 

2.5 headers work fine for 2.0s!

my suggestion would be to copy someones borlas

 

it is pretty straight forward to make headers. I had Nathan custom make me some unequal length headers. What we did is we took two of the same side collector from stock manifolds and then custom bent pipe to route them back to the stock position. For a first attempt they turned out AMAZING!

These are fujis notorious single port headers



Having a modular exhaust design is very nice. I have mine setup so that i can run a stock exhaust, an STi catback or a 3" TBE all from the stock or UE headers. I love it.

Here are some pics of the headers Nathan made.

 

did you notice any improvement in performance? Are your heads single or twin port?

 

mine are dual port, fujis were single.

I noticed a decent improvement. almost no change down low, above 3.5k rpms though there is a big difference. well worth the money imo. Are yours dual or single? if they are dual I might have some extra collectors laying around, i have been collecting them ;-)

 

mine are dual. Does your car still have the rumble? and is it much louder?

 

what diameter pipe was used?

 

going to unequal headers brought out more of the rumble. I am very pleased with the sound on these. we actually did not measure the individual tube lengths for sound maximization when we made these so they dont have the traditinoal borla header sound. on Borla NA headers the pipe length from the passenger side head to the collector is exactly double that of the drivers side head.

I am not exactly sure what size pipe it is. IIRC it was just over 1 3/4"

 

I think it was 1 7/8 piping (ie just over 1.75)

 

how much do you want for 2 collectors? and where did you get the exhaust flanges?

 

Are the pipes mandrel bent? and what type of welder was used?