Custom Stainless 3" Exhaust Build

Well, my car is still getting body work done to it, and I have a final for my welding class, so I thought I'd make an exhaust for it and take advantage of my current situation. And I decided to do something a little different than normal after lots of decisions and research, which I made a thread for here, and do a single 3" pipe exhaust. Nothing spectacular since a lot of the motorsport E46 people have already done this, but I just thought I'd share.

So here is the old exhaust taken out of my car. I'm going to use this as a guide so I can't chop it up or take anything off of it. The stock exhaust is super heavy too, somewhere between 60 and 70 lbs. Quality wise, it's only so so because it has to be mass produced. The slag from the welds haven't been cleaned up, MIG welding instead of the slightly nicer and slower TIG welding(like what I do), the pipes are not mandrel bent so they are pancaked slightly at the bends, and the pipe size varies a whole bunch. Right after the exhaust manifold to exhaust flange, the right side pipe is 1.80" OD and the left side is 2.10" OD. That couldn't possibly be good for flow. The rest of the exhaust is pretty close to 2.00" OD with different diameters near the bends. Also it's pretty interesting how BMW used what appear to be elastomeric vibration dampers on the resonator and rear muffler.




And just today, I got my parts from Summit Racing!
-1x 2" OD stainless J-bend
-3x 3" OD stainless 90° bend
-1x 2"x50' of exhaust wrap
-1x 3" stainless V-band clamp So I can swap at mufflers at will if the one I buy is too loud






Really big pipe.

subscribing

subscribed

ditto.

Got part of my order from HorsePowerFreaks.com today

1x Vibrant Performance "Super Quiet" Resonator 3" in/out
2x Vibrant Performance 3" stainless flanges

I meant to get two 2" flanges instead since these are supposed to connect to the OEM exhaust manifold. I'm actually tempted to keep them though at $20 a piece so that I can make the exhaust more compact and easier to deal with. But at the same time, $40 for something i won't ever need once installed is a bit much for my budget.

The new flanges are already in transit thanks the incredible customer support at HorsePowerFreak.com I dealt with Andy and he made the process so quick and easy as well as he had a great attitude about it.

Now on to the pics!

Vibrant Performance makes very high end parts. I'm very satisfied with my purchase and these parts are a bargain for what they are:


Pretty close to perfect TIG welds on the resonator. I don't think I'm ever going to have a problem with this resonator:


Very free flowing This resonator is pretty much an oversized, stainless steel glasspack and should eliminate any rasp, make the exhaust note smooth and deep, and lower the volume a good amount. I just hope it lowers the volume enough:

Intresting...

Got the rest of my order from Horse Power Freaks today as well as my order from McMaster Carr.

1x 1/2"x36" stainless steel rod (muffler hanger)
5x 3" stainless hose clamps (for exhaust wrap)
1x Vibrant Performance StreetPower muffler



And the stuff I already had I brought to welding class. I started doing a little organizing, planning, and measurements.


Only thing I don't have now, are the two 2.00" 2-bolt exhaust flanges because I messed up on my order. If I'm lucky I get them tomorrow.

Cant wait to see and hear finished product!!

+1 This looks excellent. I would look to Burns Stainless to build you a proper collector.

Originally Posted by Iceman00

+1 This looks excellent. I would look to Burns Stainless to build you a proper collector.

I looked into one and they are expensive. Just a 2" to 3" transition is $35 from Burns Stainless, and I think the dual 2" to single 3" collector is over $100.

I was planning on merging the dual 2" tubes into a single 2" tube, and immediately going to a 2" to 3" transition. Similar to the Burns Stainless design, just that this route is cheaper at the expense of a good deal more labor.

A BS dual 2inch to 3inch collector is $225

Originally Posted by Iceman00

A BS dual 2inch to 3inch collector is $225

Holy shite!

Got to pay to play. Make your own first, and when you have some more cash, have them custom CAD you one according to your powerband.

Originally Posted by Iceman00

Got to pay to play. Make your own first, and when you have some more cash, have them custom CAD you one according to your powerband.

about pay to play

Being that I live in California with our super strict emissions, I don't think that a CAD and flow tested collector will ever show its benefits. For now I am using the stock exhaust manifold with built in catalytic converters which is extremely restrictive as is.

Actually, I can't see the benefit of a super expensive collector unless I was in the upper tier of motorsports with actual sponsorship.

I can't wait to see the final product

Very cool. Can't wait to see this.

Hurry up...

Here's how i made/did mine. If you need any help (finding parts, route, etc) hit me up. How do you plan to support it in the middle - stock hangers/bushings wont work. Oh-ebay headers too on mine. Entire exhaust made from pieces cut/fitted by me/tigged by a friend over a weekend.

Oh i just saw you're using the vibrant flanges. You're probably going to have to clearance them - flanges are too big and our header outlets are too close together.