Two questions:

 

Most agree that the unequal lengths of the Y-pipe coming into one exhaust pipe create the Subaru growl. I believe McBrat had a dual exhaust with crossover which worked well. Did it sound like a Subaru or just like any other 4 cylinder?

 

The Y-pipe still seems to be the best choice for keeping it tucked up out of harms way and having adequate scavenging. My question has to do with conventional headers for inline or V configuration motors have equal length runners into the collector. VW flat fours did they same. Is an EQUAL length Y-pipe possible, and would there be worthy gains across the RPM spectrum?

 

thanks, r/ PK

pm sent

" Is an EQUAL length Y-pipe possible" what a silly question :-p

all you would have to do is use your imagination

I made one, but i dont know the gains of the equal length, as i upgraded the entire exhaust in one go, but it is definately better than stock.

 

Here is mine...

http://www.ultimatesubaru.org/forum/showthread.php?t=35411

Yes, it is possible. Any gains? I think so. I'll have to explain it to you when we talk. It is kind of complicated but it seems to work OK.

listen to mine i made my whole exhaust http://www.amishoutlawracing.com/VideoSubaruBuckAug13.htm doesnt sound like a 4 cyl.

Thank you gentlemen.

What ausubaru92 referenced is great. When I said is it possible?, I was thinking about keeping it tucked up like stock, having the drivers side pipe follow its normal path, but have the pass side exhaust runner make detour bend(s) to add length before joined into single pipe in normal location. Heres a rough draft:

Changing the length of the pipes before the y collector will change where your extractors create a peak in power

 

I made mine so the volume of the pipe before the collector equaled the displacement of the cylinders feeding,... in my case each pipe had a volume of 0.9 lts.

 

Look it up on google, there are a lot of subarus in small airplanes in which the exhaust is tuned to create peak power at a set engine rpm.