Custom Exhaust - 986 Forum - The Community for Porsche Boxster & Cayman Owners

yellowboxster01 · 08-17-2009, 09:09 AM

Well I have the Stebro Race exhaust and it's just too loud for my liking. I kicked around the idea of buying a new exhaust but, don't think it would be that difficult to make one.

My idea is getting two Flowmaster or Magnaflow universal mufflers with 2" in and 2" out. Then get some mandrel bent pipe and weld it together. It doesn't seem like it would be that complex especially looking at the current muffler I've got. While I'm at it, I'd like to make some mandrel bent bypass pipes. I have a friend with a mandrel pipe bender so, that takes care of that.

How much am I looking at in piping material, such as the cost of the correct grade of steel piping for an exhaust?

The mufflers are around $75 each.

BYprodriver · 08-17-2009, 09:33 AM

mild steel tubing cost is minimal, try McMaster-Carr if you don't have a local source for all your fabrication materials

23109VC · 08-17-2009, 02:45 PM

would it sound very good? given that so many of the aftermarket units drone...you would run the risk of spending the $ to make it, only to find that what you custom made is also too loud???

Boxtaboy · 08-17-2009, 03:12 PM

Both these guys fabricated an exhaust from Magnaflow mufflers...

http://986forum.com/forums/showthread.php?t=15541&highlight=magnaflow

http://986forum.com/forums/showthread.php?t=5175&highlight=magnaflow

yellowboxster01 · 08-17-2009, 03:57 PM

Quote:

Originally Posted by 23109VC

would it sound very good? given that so many of the aftermarket units drone...you would run the risk of spending the $ to make it, only to find that what you custom made is also too loud???

Flowmaster 50 series mufflers are what I've decided on. It's a 3 chamber design and after reading reviews, there is little to no resonance in car. I'm going to go 2.25" from the headers all the way out. I was thinking about putting resonators in the cat bypass pipes like the Fabspeed 986 exhaust but, I'm not thinking it will be needed with the 50 series.

Can't be more than about $400 to make one. All the welding will be done by myself. If nothing else it will be kind of fun, I'll run it with pride. haha

Thanks for the thread links.

j.fro · 08-17-2009, 05:12 PM

I've been thinking of making a muffler as well. After you've built the Flowmaster setup, how about weighing it vs the stocker.

70Sixter · 08-18-2009, 10:30 AM

I hope you can do it without too much loss of power and highway droning. Matching exhaust backpressure and timed pulses for max power is very hard to do. With some decent arithmetic you can probably get close to equal length exhaust paths Especially for the street.

Weight of the exhaust is secondary to engine performance.

I saw one guy spent $20k for a custom new CGT exhaust that sounded better to him, but produced net zero hp or torque.

I'd try Pedro's muffler mod first.

yellowboxster01 · 08-18-2009, 10:32 AM

Quote:

Originally Posted by j.fro

I've been thinking of making a muffler as well. After you've built the Flowmaster setup, how about weighing it vs the stocker.

I know the stock muffler on my 2.7L weighs in at right around 47lbs is I remember correctly. I put the stock vs. Stebro race on the scale during my installation. I have it all recorded somewhere but, the Stebro was right around 14lbs.

That's another thing that I "can't lose" on is weight loss. The setup I'm going to build will still be lighter than stock. I like the quietness of the stock muffler but, the weight is a huge disadvantage especially on the track.