Opinions on Single exhaust for v8

[Joe Sr]

Have you heard it run yet. I did same thing with 2 - 21/2" into flow master and 1- 3" out on a 351W with bullet cam and Pro flo 4 EFI. Drown inside was so bad I had to replace with a turbo muffler this past week. Loved the original sound but the drown was really bad on my combination.

 

[danny]

IF and only IF you want to keep dual exhaust then run your fuel line inside your frame rail. NO heat issues, no vapor lock problems ever. We drive in 90-100deg temps all day. Got a local buddy that's done the same and we both ran Q-jets for over 25yrs each. Never an issue with vapor lock

That’s a great idea . I’ve been running Q-jet for about 17 years on my 68 . Love it

 

[danny]

View attachment 936956 View attachment 936957

Nice job , I really like it thanks.

 

[DirtDonk]

In theory, at least, and in practice in most cases, just doing a return line should help, or eliminate vapor lock problems.
Maybe that’s not always the case, and in Broncos, packaging is everything!
But a return system is a great boon to this type of thing. Even Ford did it in 73.
Not sure why they got rid of it after that, though. Maybe it didn’t help enough?

 

[ntsqd]

The return line is not the single solution. and a return line with a mechanical pump or an electric pump not at or in the fuel tank isn't going to do much. IME it takes both pressurizing the supply line (to raise the boiling point of the fuel) and running a return system (to cycle the fuel pass any hot spots as fast as possible) to prevent vapor lock. When was the last time you saw an EFI vehicle have vapor-lock?

A mechanical pump pulls the fuel up to the engine, which means that the fuel is under a small vacuum. That LOWERS the fuels boiling point. What I recall from reading up on it years ago is that even a couple of psi worth of vacuum will drop the fuel's boiling point down well into the normal ambient temperature range. If you really want to dig into it, fuel is made up of many different compounds, each with their own boiling point, but that doesn't really matter because all it takes is for one of those compounds to boil and you've got vapor-lock. Those compounds are sometimes called the "Light Ends", they're those which boil at the lowest temperature.

 

[Yeller]

I’ve seen several EFI engines vapor lock. Most of them have some form of “accumulator” device. Any device that holds fuel or slows its flow near a heat source will create vapor lock, even see fuel filters cause it. I’ve never seen it with a factory design or even copied efi system vapor lock.

 

[nvrstuk]

Or you can also run your duals down one side. Makes it just a tiny bit tighter over there, but there’s generally plenty of room on the passenger side.
Especially if you pick the right mufflers and don’t go over 2 1/2 inch tubing. Dual 3’s are still doable, but overkill, and certainly not needed for 90% of the Broncos out there. And it does make it look a little more fi

Torkman- WOW, I looked at all your pics and that build looks cleaner and much higher quality than any that ever came out of the factory! Nice job.

 

[Torkman66]

@nvrstuk thanks! I’ve enjoyed doing it. Great way to spend my retirement years (and money)

 

[Ether]

My 2:1 is a lot like Torkman66's but ugly haha, love that sound. I'll probably change my muffler at some point, it's almost too quiet. Ford motorsport shorties, 2:1 2.5" single under the passenger frame rail exit.

 

[nvrstuk]

@nvrstuk thanks! I’ve enjoyed doing it. Great way to spend my retirement years (and money)

EASY to spend the money for sure!! lol

Keep up the good work.

 

[Hultzger]

I used the BC Broncos 2 in 1 setup. We talked dual exhaust in this thread: Dual Exhaust out the back https://...the-back.309992/&share_type=t&link_source=app


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