PD4104 stock dual exhaust pipe size?

johns4104 · March 12, 2015, 08:05:39 PM

Mine were 2 3/4" before getting bent up. Oh the mufflers were 3". There were a lot of welds so don't know if they are original pipes. Anyone know what was original diameter? RJ, Gusc, ??

Now mine are 3 1/2" mufflers and tail pipes!

Nel · March 13, 2015, 05:52:11 AM

John, mine are in about the same condition.Can't tell you what size are on my 4104 because they are still buried in the SNOW! What new mufflers did you use and do you have any pictures of the new ones installed? I am probably going to do the same thing this spring. Thanks Nelson

luvrbus · March 13, 2015, 06:01:43 AM

3 inch for a 6L-71 according to Detroit 3.5 should be better

eagle19952 · March 13, 2015, 08:17:47 AM

Quote from: luvrbus on March 13, 2015, 06:01:43 AM
3 inch for a 6L-71 according to Detroit 3.5 should be better

definitely the same as the manifold output size, or larger, never with smaller in the middle $:-\$

muldoonman · March 13, 2015, 08:19:02 AM

Can you get too big on these 2 stroke motors? How about straight or with a resonator?

gus · March 13, 2015, 11:04:01 PM

Quote from: johns4104 on March 12, 2015, 08:05:39 PM
Mine were 2 3/4" before getting bent up. Oh the mufflers were 3". There were a lot of welds so don't know if they are original pipes. Anyone know what was original diameter? RJ, Gusc, ??

Now mine are 3 1/2" mufflers and tail pipes!

Best I remember they are 2-1/2 or 2-3/4". If you really need to know I'll go out and measure mine tomorrow.

Singles were larger, at least 3".

If you decide to replace the mufflers I'll send you a drawing of my smaller conversion with JCW smooth top mufflers that don't catch water.

johns4104 · March 21, 2015, 10:21:01 PM

Sorry I didn't Internet for a few days. We went to the Parump rally.
Gus I figured the original was about 2 3/4". I used your info. To get some new mufflers to fit in, worked real good!

Muldoonman: I think da book says 2 1/2 psi Max but no minimum pressure! So you decide how loud you want it!

Red Rider · March 22, 2015, 12:21:02 PM

OK John, After following you over the hump from Pahrump I had a wonderful time listening to your new exhaust system. When I was younger I had a 40' ford coupe that didn't sound that good. If you could record that sound you'd out sell Elvis. Great job.

Sure had a fun time with you and the family.

luvrbus · March 22, 2015, 12:35:49 PM

Don't they sound nice Mikey I can follow a old Eagle with the 8v71 and dual exhaust all day I love the sound but a 6L-71 is in a different class by it's self kinda like the old 6 cylinder Chev with dual pipes

johns4104 · March 22, 2015, 05:00:39 PM

Yea Mikey I wondered if you would hear it.
I think it sounds good too!
We had a good time visiting you too!

TomC · March 23, 2015, 11:24:02 AM

Plenty of internet access at the Pahrump rally-if you were using a cell phone hot spot. Highly recommend-72mps. Good Luck, TomC

Jim Eh. · March 23, 2015, 02:58:21 PM

You could go with 2-3/4" but part availability would be less than 3" or 3-1/2".

FWIW Ford Trucks (Heavy) started from 2-3/4" then progressed all the way to using a 4" system near the end of the run on their Louisville cabs and it didn't seem to matter much which Detroit engine was installed.