Split 6 Exhaust - Why ?

Evenly timed exhaut pulses going into each "collector". At certain RPM's it tends to help with drawing exhaust out of adjacent cylinders. Somewhat like 180degree headers on a V8 only on a 6 it's every 120 degrees.

Frank

 

I built a few 261 Chevy's and a 302 GMC .I liked a two into one type of exhaust .Short tube headers or Fentons blended into to a single pipe about 20 inches from from the ports,then a large diameter single pipe and muffler.It's my opinion this sytem makes a wider power band for the street with sharper part throttle engine response than a traditional dual exhaust on an inline 6. Has a very smooth sound,a sort of metallic hiss like a UPS truck on Meth.To my ears,a 6 with duals sounds like a V-8 with a fouled spark plug

 

This manifold that I made for my 63 Nova has an internal splitter. The manifold did perk the 'ol in-liner up a bit. it sounds really nice at idle, but with turbo mufflers it is a little too quiet. It does have a drone at highway speed, but that's the fault of the pipes and mufflers and not the manifold.

 

You are probably correct, Like I said we were just teenagers , 16 ,and I told the installer to make it loud as that was all I were interested in . But I know they were two part cause my dad made me change it back before we traded the old car in . I'm sure it never helped it run any better , just louder. Got the 55 ford , y/block right after that , loud pipes and speed both then .

 

Here's why. Turn up the sound.
My 235 is running thru Smitties,shifting @5000, the Hemi is running open headers and you can't even hear it.

http://videos.streetfire.net/video/Old-school-32-Ford-at_132624.htm

 

Here's another one for inspiration. I'm guessing straight pipes, especially with the occasional blue flame popping out. Sounds like small diameter pipes...1.5 inch maybe?

http://tinypic.com/player.php?v=14ih74i&s=3

 

Air flow and sound. Same as any header or split manifold...

Dumb question in my book! JK

 

Not everyone. My 6 cylinder is split 3 on the left side, and 3 on the right. But then it's a V, not an inline.

Bob

 

a couple different things I have noticed...

I have a stock manifold split completely in two and capped on the ends.
sounds great

I have also taken a stock manifold and welded a piece of 1/8 flat stock with a 3/8 hole drilled in it and put a dump on the front half of the manifold.
sounds evil as hell...

spent a bunch of money on a set of Fentons with 1.75 straight pipes out the back and I think it has lost a lot of that badass tone that it had with the stock ones...

also I noticed the other day that my drivers side exhaust pops every 6 or 7 seconds at idle?

I was told that fentons do that due to the way they are split in relation to the firing order?

dunno?

any one else have any words of wisdom on the popping???

 

That's what my 383 sounded like before I tracked down all the little things wrong with it.

 

Here is my Mopar with cast iron headers, 2 inch pipes, and H tube about 2 feet after the collectors and small 14 inch turbo mufflers.

http://www.youtube.com/watch?v=AxfKQ4KMM9s

 

hkestes do you have any pics fromunder the car on how its ran and of the stock manifold?

 

Why not ??

 

No, I don't have photos from under the car after I had the exhaust installed. It is basically ran side by side down the passenger side until just before the rearend when one pipe crosses to the drivers side. The one thing I don't really like about it is that the pipes run under the gas tank due to the very tight spacing due to the spare tire well on the passengers side.

I am not running a stock manifold. I'm using cast irone headers from Langdon's Stovebolts. They are a repop of early Fenton style headers.

 

Here's a shot of mine, if it helps-

 

MONKEY...It doe's help with exaust dumping, but mostly it's for the sound. and believe me it's a tone that's very pleasing to the ear. amazingle i can hear it today, and i havn't heard 1 in 50 yrs...POP.

 

A high school friend had a '50 Studebaker with a split manifold and glasspacks. He would give me a lift to school every day, and I always had plenty of warning when he coming, as you could hear those pipes from three miles away. That sound is still with me after more than 50 years

 

Nicely done!!!

 

bttt

any one have any answers on what makes a 235 with fentons make a popping noise every 7 sec or so on the drivers side???

the motor is .60 over, howard rough idle cam, head was milled .125 and has 2 intake with fentons.

 

maybe try adjusting your idle mixture, or increase idle speed a bit?

the siamesed intakes set up the way they are, give non-perfect distribution and mixture - which could make one side of the exhaust leaner (or richer?) than the other. rough cam can make this even more erratic at idle.

maybe try a smaller gap in the spark plugs, and check secondary ignition system for any weak points (wires, plugs, cap). also check voltage at idle, make sure you are getting all the spark you need.

 

It ain't a 'why?', it's a 'what'. What it does; sounds bitchin', improves air flow.

 

Right, I understand now. And I agree on the sound - thanks for sharing the vids you guys.

An even split I understand the 'why' (or 'what'). Even if it didn't improve the sound, an even split should improve performance.

It's the uneven split (2-4) that seems like it could actually hurt scavenging, and that was my misunderstanding previously.

thx.

 

I remember reading an interview with a Chrysler Engineer who worked in the Engine division. He said when they were playing around with Slant Sixes in the 70's trying to get as much power and economy out of them as they could, they found the biggest single improvement to be splitting the exhaust and running two 2" pipes back just before the muffler, and collecting them there. The low end and mid range improvement was very impressive he said after the carb was jetted proplerly and timing optimized as well.

He didn't say what it sounded like.

 

with the typical Chevy six firing order 153624 and dual headers like the Fentons

you get an imperfect pulse order

the front manifold goes: pulse, pulse, pause, pause, pulse, pause

and the rear manifold goes: pulse, pulse, pause, pulse pause pause

so exhaust scavanging is broken, and intake pulses can be affected too
but when heard side by side they do make a unique kind of music

 

Just at idle? and pretty quietly?

 

front manifold is 1-2-3, rear is 4-5-6; right?

if that's the case, the front and rear manifold alternate puffs. it's even isn't it?

 

hmm.. you know that must be one of those things that you form in your mind and assume is correct..
I've thought that was true for a long time,
maybe I had a tuned length tube header system in mind,
maybe I was just plain wrong..

but when I lay it out in simple graph format I see your logic perfectly
at the tailpipe the pulses do alternate front back front back front back

 

good post guys, I like the vidoes and the home made split manifolds. Think that's what I'm going to try on my 235.
I've seen how to guides on ebay for $6 anyone seen these things?

 

Ive never thought of laying it down on paper like that.

 

YUP!!! buddy of mine just split my manifold on my 215 (same as a 223) straight 6... I DID IT FOR THE SOUND!... all he did was add a neck coming out of the last two cylinders on the original manifold and stuck a plate in between to make the split... 4/2.