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Okay....exhaust time...have a wierd idea

B

Beezil

Member #Nay
NAXJA Member
Location
Indiana-Missouri
I do not have room to run a 2 or 2.25" exhaust all the way back.

gong through the floor is not going to work.

I am pretty much all in the clear except for two places.

these areas are right around the crossmember area, and are only around 16" between one-another....

here's my idea....

in order to squeak by these areas, the way i see it, since i can't fit a 2.25" tube, why not run 3 1.25" tubes????

I could have a nice splitter, run t he three seperate tubular noodles, and re-connect after the obstruction.

should be groovy
 
Why not run a 1.5x4.5 rectanglular tube?? You could always notch around any obstructions. Who says exhaust tubing has to be round?

Now....if you don't have room for this...then the 3 tube idea is not bad, I would have a very large collector at the end to prevent colliding exhaust pulses from hampering performance.

Rev
 
Last edited:
Queer Eye for the Straight Pipes

I like Rev Den's idea. That's what the NASCAR boys do to get under the frame rail with minimal clearance.

Make sure to chrome it to match up with all that bling bling under there.
 
should I account for more volume if I go rectangular tube?
or something close to 3.5" (apprx inside radius *pi )

its not like I'm worried about shaving miliseconds off of my 1/4 mile time....

a touch more backpressure would actually be helpful.
 
I'm no rocket scientist, but my hunch is that a rectangular tube would create more turbulance than round ones? Maybe one of our pipefitter members would know about this? Or maybe this could eliminate your need for a muffler?
 
So why dont you run it through the roll cage?:D


If you cant use round exhaust tubing, what about oval tubing? I remember from somewhere that nascar used ovel shaped tubing because of clearance issues. Have you though about side exit?

AARON
 
straight pipes through the hood --- :)

i would think that rectangle or oval would work. we're not talking a million HP or anything.

could you get it to exit right in front of the rear tires? and avoid going the whole way back?
 
BJ,

It's been over a week since I've been under your machine. But, if I remember correctly, you could run it in the stock location (snaked under the bellhousing, then above the crossmember on the passenger side) all the way to the area where the rear shocks will come through the floor. Cut away more sheet metal (to make Sean happy) and come up through the floor in the "bed" on the passenger side. Realizing you now have the rear links in place, this may not work. Is there room to go above the crossmember?

Flowers
 
Just thinking here....if you used rect. tubing you could weld in baffles the whole way.....kinda combining the pipe and muffler in one. I have no idea what the formula is to figure flow capacity, but I would think that you could figure that out. If it were me...I would just eyeball it and shoot from the hip, hell....its only exhaust.

Rev
 
Beezil said:
should I account for more volume if I go rectangular tube?
or something close to 3.5" (apprx inside radius *pi )

its not like I'm worried about shaving miliseconds off of my 1/4 mile time....

a touch more backpressure would actually be helpful.
Click to expand...

Not sure if you want more volume, as I would think you want the cross sectional area to be the same, or slightly larger.

Also, if there is room, run a small H-pipe between the three to even out the gases.

So those are my thoughts, let us know how it goes.

Fergie
 
Just some thoughts:

1. Surface area of walls = friction = less effective flow.

2. Flat sections of light gage metal = reflection of sound waves = drumming & other (generally) undesirable sounds.

3. More small round sections = much more wall surface = much more friction.

Round = Greatest volume / surface area of walls.

Oval = Best balance of volume-to-surface-to-restricted depth.

Rectangular = Best volume-to-restricted depth; if weight isn't a major factor, heavier walls (3/16 +) will prevent the drumming of light gage.
Sound waves will still be reflected and *possibly* reinforce each other into undesirable tones.
Line the sides with adhered/pinned dense fiberglass board insulation, and call this heavy son-of-a-gun your muffler.

Photos expected, of course. :D

-Rick
 
Beezil,
If I remember right, earlier you said you didn't want some super loud exhaust, but more of a quiet one. Well, the way air, exhaust, or anything else performs accoustically in a port or pipe has absolutely nothing to do with volume, but rather cross sectional area and length.

It IS effected by friction from the walls of the exhaust tube; this is what defines what it sounds like. So if you went rectangular, make the cross sectional area about the same, and the length about the same to get the same sound characteristics.

I have no idea how this relates to performance, but rectangular tube should not be more restrictive than round. They both flow the same "numbers."
 
That technology has not been made available from Tandy as of yet. You can try giving Underboky and Associates a call for more information. Oh, and by the way, the work you are doing on that assault vehicle that looks like a Cherokee is bitchin.
 
Run it out the drivers fender like a snorkel and put a stack out there :)

I don't see anything wrong with using rectangular tube.
 
Just an FYI: The NASCAR guys run round exhaust to the frame rail,then get converted into an oval for clearance, then converts to rectangle at the outlet. The rectangle sections have these "splitter" sections,kind of like baffles,only they face the direction of the exhaust flow. I'm not sure,but I'd have to bet they are there for flow characteristics and avoiding exhaust pulse cancellations more than anything. Maybe you could do like the above suggested. Build a heavy guage rectangle box with an inlet and outlet,and experiment with different baffle designs until you come up with a combination you like. You could feasably build the "enclosure" and make the bottom panel temporarily removable. That way you could tune it to your liking,then weld the panel in solid when you're happy with the sound. Just a redneck's thought process :anon: so don't laugh at me too hard :D
 
exhaust choices

Airflow through a pipe or duct (whether round, oval, or square) is "laminar"....it stays close to the walls. It is nice to use a transition piece when going from round to square; it helps to redirect the airflow and alleviate "eddy currents" or tumbling and distortion in the airflow. Square pipe is fine, you have round AND square ductwork in your home, don't you?
The key is to keep a certain feet/minute velocity in your flow, this is how you attain your effficiency and helps to alleviate resonance.
I can't tell you what that # is, too many variables.

BLUTO :)
 
Beezil, you opened the post saying you were thinking of running three 1.25 pipes instead of one 2.25. I take it you have enough clearance for the 1.25 then? Well the area of a single 2.25 pipe is 7.07" where only two 1.25 pipes would already exceed that at 7.85" which is indentical to one 2.5" pipe! It would seem alot simpler to me going that route. Even two 1" pipes would give you 6.28" the same as a single 2" pipe which would help the torque at low revs but will have slightly more friction than a single pipe of twice the diameter so maybe a couple of 1.1/8" ( 7.07" ) if you need that little bit of extra clearance and still compensate for any extra friction.
 
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