Exhaust/Muffler Tube Diameter

[airbur]

Probably a simplistic question but should the diameter of the exhaust and muffler tubing equal the header collector diameter (3")?

Dual tubes and mufflers.

Thanks

 

[rguest3]

Collectors are usually 3" and sometimes 2 1/2".

2 1/2" pipe is more than enough for just about any 302 in a Bronco. Have your exhaust shop make flanges with the pipe to match your collectors on the Headers.

I have found that dual 2 1/2" pipe inlet, single muffler and one 3" outlet works great. Similar to stock but with headers and higher flow muffler. (Gibson Superflow Muffler)

2 1/2" or even 2 1/4" all the way back with Dual Mufflers. (Dynomax Super Turbos)

I'm sure others will chyme in with their favorite exhaust set ups.

 

[airbur]

This is not stock. I will be using duals with 3" ports so that means 3" for the entire run I imagine.

 

[Broncobowsher]

No. The pipe diameter is smaller then the collector.
The collector is a meeting room where the 4 are collected together. Then they are filed out in the pipe. A 3" collector is usually mated to 2¼-2½ pipe.

 

[rguest3]

You may encounter clearance problems with the 3" on both sides all the way back.

As stated before, 2 1/2" are plenty for ANY 302 in your Bronco. Would be enough for most healthy 351s as well. May lose a lot of torque if pipes are too large.

 

[airbur]

You may encounter clearance problems with the 3" on both sides all the way back.

As stated before, 2 1/2" are plenty for ANY 302 in your Bronco. Would be enough for most healthy 351s as well. May lose a lot of torque if pipes are too large.

Gotcha. This isn't a 302 or 351w per se by I imagine 2.5" will suffice for my 427W.

 

[bknbronco]

3" is huge! id go with 2" myself to avoid clearance issues. Also usually the larger the tubing the larger diameter a bend will be. Since your running duals all the way there is no need for a 3". Also pipe size makes a huge difference on exhaust tone.

 

[ilovemaui]

These websites may help:

Calculate exhaust pipe size

http://victorylibrary.com/mopar/header-tech-c.htm

 

[broncnaz]

Your 427 should be fine with 2.5in pipe. Unless you plan on running 7000+ RPM.

 

[airbur]

Yep....I'll be fine. Thanks!

 

[nvrstuk]

Pipes

Airbur,

I've already done all this research for us.... : ) dual 2.5" mandrel bent and you/we will have all the flow needed with duals.

 

[bmc69]

Dual 2.5 is certainly more than enough..that's bigger, in many cases, than what Ford put on cars back in the day that were carrying 427/428/429 engines.

I'm running dual 2 1/4" pipes, with a cross-over the 408 in my EB and the new 408 I'm building for a different truck (roller motor with EFI) will get dual 2.5" pipes in to single muffler with one 3" tailpipe out.

Both those motors are running very large valves (2.07"/1.65") and port sizes..but I've never felt that the 2 1/4" exhaust was ever restrictive in any way, especially since the engines are built for truck use and the RPM range is lower.