Dual exhaust advice needed.

[Oregoon]

Hey all!

Go the 240 in my '66 running well and it's time to improve the exhaust system. I have a set of EFI headers from a 300, and the local shop wants around $300 to bend up a set of pipes that will discharge in front of my rear wheels. While that's indeed affordable, I just bought a welder and am thinking of doing the job myself. Tubing is cheap, and comes in a staggering array of pre-bent shapes and sizes, and so far I've done everything on this truck myself.

Regardless of who does it, what's a good recipie for a healthy dual exhaust? What diameter pipe? Do you run a balance tube? Any muffler recommendations?

I've never done duals on an inline-six before, so feel free to school me.

Thanks in advance.

[ThinLizzy13]

Ditto on this. I wanna do the same thing to the 300 on my 66

[Hunter's 64]

Shoudn't be much to it. come from exhaust manifold/ header to muffler (1) inlet (2) outlets then use bends to run out the sides


Danny

[Toyz]

Buy an X-pipe, find the distance calculation on the internet, then purchase the straight runs and bends, fit and weld; or clamp with wide base clamps. The X-pipe is definitely worth the cost and effort when installed correctly, IMO.
Paul

[foodstick]

My truck has a poorly done exhaust (don't ask) but using a split exhaust on a 300 you want them to both exit the same place on the truck.. otherwise it will sound fine in the cab.. but REALLY strange to everyone else.

The first time I heard someone else drive my truck by I though dang that sounds weird...

put put ......put , put put .......put

[Oregoon]

What is the advantage of an x-pipe?

[Toyz]

Good info here:
http://forums.vintage-mustang.com/vinta ... e-all.html
Paul

[Oregoon]

Thanks for the link. It makes sense. What are your thoughts on an x-pipe and no mufflers? The 240 is a pretty low-compression engine... Not sure I want it that loud though.

Also, any idea what diameter pipe one might use?

[tomrooster]

Might be pretty hard to find room for the x with all the stuff in the way. I'm doing mine now , I bought 2 -2" u bends some straight pipe and 2 tail pipes cut 1 tail pipe in 3 spots and turned the bends the opposite way and weld them back and the tailpipes are done. Bought the stuff at Summit and got free shipping by the time I got hangers and stuff. Tom

[mercuryv8]

Might be pretty hard to find room for the x with all the stuff in the way. I'm doing mine now , I bought 2 -2" u bends some straight pipe and 2 tail pipes cut 1 tail pipe in 3 spots and turned the bends the opposite way and weld them back and the tailpipes are done. Bought the stuff at Summit and got free shipping by the time I got hangers and stuff. Tom

Got a pic?

[milomilo]

I used Flowmaster mufflers on my 64 390. They sound great.

[1965fordf100]

$300 ain't bad at all for shop to build that exhaust for you...I paid $800 for a custom dual from manifolds back with and h-pipe and exit in front of rear wheels...and I supplied the mufflers...but I think I got ripped off a bit too

[Oregoon]

$300 ain't bad at all for shop to build that exhaust for you...I paid $800 for a custom dual from manifolds back with and h-pipe and exit in front of rear wheels...and I supplied the mufflers...but I think I got ripped off a bit too

I agree. I'm just interested in doing it myself because aside from advice I've received here, and the occasional helping hand from a friend, nobody's touched my truck but me. I'm hoping to build this 100% myself--I have access to a paint-booth, commercial upholstery sewing machine, alignment rack, etc... People often talk about "traditional hot-rods," and I'm hoping to stick to the truest definition of that theme: 100% owner-built. Not a rat-rod, but a finished truck that I've done with my own two hands.

It's all a learning pricess. I figure it'll take awhile...

[Hunter's 64]

I'm still wundering how you put an "X" pipe on a straight six motor ? I thought an "X" or "H" pipe was to ballance both sides of the exhaust on v8 or any v motor or "Y" unless you have a set of split headers http://www.jegs.com/i/Hedman/500/89300/ ... odWx8Akwon it then you have a lot of piping in a small area to fit an x pipe .

Danny

[Toyz]

Lance, you should hear my turbo 2.3 with full 3 inch exhaust! Going thru a tunnel windows down is an adventure. With the console mounted keypad controller, I can make it sound like the ol' "poppin' Johnny"
Dave, I haven't played with exhaust on a 240 slick, so I am unaware of space issues! However, with full 3" duals with correctly located X-pipe on a 521" slick, I feel it should be do-able.
I applaud your "built not bought" philosophy, BTW.
Paul

[The Big M]

Thanks for the link. It makes sense. What are your thoughts on an x-pipe and no mufflers? The 240 is a pretty low-compression engine... Not sure I want it that loud though.

Also, any idea what diameter pipe one might use?

Are you after maximum flow, or are you trying to achieve a certain tone? Because there are tricks I've read about with inline sixes that are meant for sound only, and don't really seem like they'd enhance exhaust flow. For example, a common trick was to do a homemade 2-4 split on the exhaust manifold, run two small-diameter pipes (like 1 1/2" or 1 3/4") all the way back, one straight, one with a single glasspack, and no balance tube. The idea being that two exhaust pulses would be unmuffled, so you'd get a distinctive pop.

It's my understanding that crossovers kill the rap from an exhaust, and having the mufflers as far forward as possible is the best way to enhance it.

Little bit off topic, but my 350Z is a V6 at about 213 cubic inches, 10.3:1 compression, and a 7000 rpm redline, and I've actually been designing my own exhaust for it as well. The stock exhaust uses a y-pipe configuration, dual 2 1/4" inlets and a 2 3/8" outlet. From there it's a single pipe into an inline resonator, and at the back it has a single inlet, dual outlet muffler. There are true dual exhausts available, using both H- and X-pipe configurations, but gains are actually pretty minimal. One of the most popular aftermarket systems is a y-pipe into a single inlet, dual 2 1/2" outlet muffler, stepping up to 3" tailpipes all the way back after the split. The idea being that any scavenging takes place before the single muffler, so the tailpipes can be larger without adversely affecting the torque curve. The x-pipe setups do seem to free up horsepower at the top end, but from what I've researched it seems the y-pipe is better for low- to mid-range torque and power.

What's the outlet diameter on the EFI exhaust manifolds? I would probably start there and gradually step up. The x-pipe with no mufflers could sound nice since the merge would even out the pulses, but I might consider some long straight-through resonators after the split to kill any drone or rasp. Especially if you intend to dump the exhaust behind the cab. Just my 2 cents, hope that helps!

[Mellvis]

The X or H pipe is to help with "savaging". It's really only needed if you run two opening from exhaust manifolds. With an inline engine and one exhaust port for all cylinders it's not going to assist with anything. If you have a split manifold (more than one exhaust port from manifolds/manifold) then it would be helpful. I don't know what kind of increase it makes, but on an old motorcycle it sure help!

[Toyz]

Hey all!

Go the 240 in my '66 running well and it's time to improve the exhaust system. I have a set of EFI headers from a 300, and the local shop wants around $300 to bend up a set of pipes that will discharge in front of my rear wheels. While that's indeed affordable, I just bought a welder and am thinking of doing the job myself. Tubing is cheap, and comes in a staggering array of pre-bent shapes and sizes, and so far I've done everything on this truck myself.

Regardless of who does it, what's a good recipie for a healthy dual exhaust? What diameter pipe? Do you run a balance tube? Any muffler recommendations?

I've never done duals on an inline-six before, so feel free to school me.

Thanks in advance.

[Oregoon]

Yep, the EFI header is actually two separate little headers with their own flanges that split the ports into a pair of 3 cylinder banks. By all accounts, they flow quite well and they bolt right up to a 240.

As to tone vs power, I'm undecided. Ideally, I'd like to come up with a good mixture of the two. While straight pipes and no balance tube sounds pretty mean, it gets old fast. Likewise, something as quiet as a factory 300EFI 2-into-1 set-up defeats the purpose somewhat.

I'd like a little improvement in the bottom-end and some healthy growl, but I'd like to hear myself think on the freeway, you know, when I attain blistering speeds of almost 60 mph... And the simpler it is, the better, since I'm wading deep into uncharted waters here.

[tomrooster]