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

[skog]

Gojeep you are wrong.
the area for 2x1.25 is 2.45 in^2
the area for 3x1.25 is 3.68 in^2
the area for 1x2.25 is 3.97 in^2
the area for 2x1.00 is 1.57 in^2
you found the circumfrances. you used pi*D
the correct formula for area is pi*r^2

so [email protected] is still lower in volume then [email protected] and has 166% of surface area of the 2.25. that is going to result in alot more friction.

i personally like the stack like a snorkel idea then run it along the roofline with a muffler in there

skog

 

[4ward]

Our Corvette runs square tubing for most of the system. Must not be that bad. It's the same size as the round on either end.

 

[XJTripp]

Flow

Skog is right. If you assume all other things being equal except pipe size, Mannings equations for flow resolves down to this:

Q = K X (Diameter)^2.67.

That is, flow varies with the diameter to the 2.67 power. Small changes in diameter equal large change in cross sectional area. If you double pipe size, you increase flow area by 400% but you increase the friction causing perimeter by only 100%. It would really take almost 5 of the 1.25-inch diameter tubes to equal a 2.25-inch. Would you feel the difference over a short length of pipe. I doubt it.

The thermo properties of exhaust would mitigate this some. The above derivation is for water which is incompressible. With exhaust, extra cooling of the multiple pipes increases density and would help some. How much I don't know.

 

[Ed A. Stevens]

You have to love the math ...


Go with round of the size desired for collected flow extraction to the cat (120 ft/sec) and muffler, and then run oval or rectangle to the rear.

Rectangle duct airflow is impacted by the aspect ratio of the rectangle, square being best. Flatter duct, width to height, ratios are more flow restricted. A flatter aspect ratio rectangle must have a higher cross section area to flow the same as a round or square duct.

Fittings in rectangle duct are extremely restrictive, compared to large radius round duct/tube. The killer with rectangle exhaust is fittings and noise (the resulting sound can be ugly).

Run the pipe up the A-pillar and down the side of the roof rack.

 

[JJ13]

Geez I wish someone in the other exhaust thread would have suggested to build some rectangular rock rails that would also serve as mufflers........oh wait they did... Drill a hole in the framerail ( I KNOW), sleeve it with pipe and then run your exhaust tube through that to a rectangular rock rail converted to a muffler

 

[Gojeep]

Yep my bad guys Should have remember the old 2pieR rule! I must be getting too old for this Too long out of the work force it seems

 

[Gojeep]

See there I go again I still used the circumference rule. Sorry skog I should have read your post more carefully. I am really having a bad night. You guys wont believe anything I say again that involves formula's anyway

 

[Flowers]

Geez I wish someone in the other exhaust thread would have suggested to build some rectangular rock rails that would also serve as mufflers........oh wait they did... Drill a hole in the framerail ( I KNOW), sleeve it with pipe and then run your exhaust tube through that to a rectangular rock rail converted to a muffler

It won't work. You guys throwing out ideas need to crawl under your XJ on a creeper and just lay on your back and look. Although Beezil's exhaust routing problem is a bit different since everything (suspension, crossmemebr, etc,) is now changed.


Flowers

 

[Rev Den]

It won't work. You guys throwing out ideas need to crawl under your XJ on a creeper and just lay on your back and look. Although Beezil's exhaust routing problem is a bit different since everything (suspension, crossmemebr, etc,) is now changed.


Flowers

Judging by what I have seen in the photos....the only truley workable idea is to run it thru the hood, I do not envy Beezil in his quest. However, brainstorming frequently generates silly, unworkable, far-fetched, half-thought, and totally bizarre ideas. One of these ideas can generate a workable soulution, or a path toward one.

If I where Beezil, I would do one of two things:

1. Run flex pipe the whole way.
2. Take it to an exhaust shop and tell them to call me when its done.

I cannot even imagine trying to run a pipe of any size or dimension thru that jungle he has created, but, I know that he will again amaze us all.

Rev

 

[Beezil]

there's only one area that's troublesome, and i think i will just cut more floorboard out and "hop over" the obstruction.

flowers is my passenger in moab, so he'll have to deal with the hot asspipe, not me.

 

[KY Chris]

there's only one area that's troublesome, and i think i will just cut more floorboard out and "hop over" the obstruction.

flowers is my passenger in moab, so he'll have to deal with the hot asspipe, not me.

I doubt that the hot asspipe will bother him too much.

 

[Flowers]

I have never dealt with hot asspipes, but I'm sure it will be fabulous. Can you use water soluble products in it?



Flowers

 

[Georgia Mike]

Speaking of that! Did anyone catch the "Biker Buildoff" on the Discovery Channel a few weeks ago? Billy Lane routed the exhaust system on one of his bikes under the seat and made the rear fender a chromed fender/drag pipe combo. It looked trick as hell,but while riding it,it actually set his pants on fire! :laugh: Gotta love choppers!!!!

 

[macgyvr]

....well

whatever you do, make sure ya mama welds a coffee can for a tip on the end of the pipe whether its round/oval/square.....


mac 'low rider' gyvr

 

[Fullsizexj]

Hey Beezil, here is the answere to all your exhaust problems

 

[sarvermr]

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.

that has to be the quote of the day... "not volume but cross sectional area and length."
volume = area x length.
same thing! i'm just messing with you. please don't take it personally. i just thought it was funny when i saw it. wish i had something constructive to add to the debate, but i don't. its pretty much all been said.
matthew

 

[Beezil]

hey flowers.

the exhaust is done!

the exhaust comes up through the floorboards right near where your browneye will be (when yer seated).....

I put exhaust wrap on da pipe, but if worse comes to worse, and the seat begins to melt, I'm gonna need to remove the seat, so you'll have to thumb wrestle mrs. rose for the passenger seat to the fug-mobile.