Custom muffler help needed!

kellzey · 12-02-2002, 11:14 AM

Attn: Flaumeister and other homebrew muffler consuctrors:

I've searched the archives here on everyone's various attempts (and successes) at making custom mufflers (ala Flaumeister), etc.

I can find the correct muffler at JEGS or Summit Racing, and I can find the 90" pipes, and tips, etc.

How do you mate the exhaust to the headers or heat exchangers?

For example, I'm going to be running either 1 5/8" or 1 3/4" headers. I need something (i.e., flange) that will mate the fabricated muffler to the headers.

I don't see flanges listed on the Summit or JEGS sites. What is everyone doing to mate the two together? Is there a standard Porsche flange, or are they all pretty much the same?

Also... the Flowmaster units and similar (Dynomax) have 2.5" or 2.25" pipes in and out. This is significantly larger than the header diameter.

Are you using a reducer to transition from the smaller to larger diameter pipes?

I'm just looking for a little more detail on the process.

Your assistance is appreciated...

Regards,

masraum · 12-02-2002, 01:55 PM

The measurement that you are referring to is the primary pipe measurement. I'm not sure what the collector size is on the headers that you are buying, but the collector size on the cat outlet on my '88 is 2.5 inches. Those 1 5/8 pipe combine into a larger pipe.

Summit does have a set of 2.5" header flanges w/2.5" outlets for about $23. I haven't looked them up in a while, but I want to say they are summit part # HOK-11026
They are listed somewhere in the exhaust section of the online catalog and are made by "Hooker".

Of course you would need to verify that your headers had a standard 2.5" round 3 bolt flange before you bought those flanges.

Bill Verburg · Bill Verburg's Garage

As Steve said the collectors are bigger, an even bigger pipe just serves as an additional step. No harm.

There is nothing special about the flanges unless you want ss. I have purchased both SSI ans B&B ss flanges from the header manufacturer for a reasonable price. If mild steel is acctable they are stock items at most speed shops.

masraum · 12-02-2002, 02:40 PM

My local speed shop had a set of 2.5" collectors, but they had 2" outlets which was too small for my car, but headers might be different since they are dumping out of two sides except of just one.

kellzey · 12-02-2002, 02:45 PM

Thanks. That makes sense (about the primary pipes from each exhaust port into the collector pipe).

My first time dealing with exhaust. I've always purchased an off-the-shelf unit.

Regards,

SK · 12-02-2002, 04:37 PM

Hey Bill, What manufacturer did you go to? I need a ss flange to connect to the outlet of my cat bypass....and I was convinced I would need to make my own (this is the triangular shaped flange w/ 3 bolts)

Bill Verburg · Bill Verburg's Garage

B&B can supply just about any size flange that you want, I am sure the SSI can do the same, here is a pic of 2 ssi flanges that I bought from B&B, they are ss and much nicer than the speed shop equivalents, also much more expensive.

SK · 12-02-2002, 05:01 PM

Duh. It looks like SSI and B&B. I guess I should read slower.. This is what I get for babysitting while reading Pelican. I'll give them a call.