4g61t.org

So for some time now I have been running and open downpipe. Thats only because I cant fit a 3" exhaust in the tunnel along with the carrier bearings/supports that I have fabbed up. What else is everyone doing to run their exhaust??? Im thinking my car justs too damn low. Anyone been able to tuck their exhaust up high enough??

I managed to squeeze this 3'' exhaust in mine for a temp solution. It hung way too low, I probably had about 2.5-3'' of clearance.

http://gallery.4g61t.org/v/colt200/awd_ ... r.JPG.html

Since then I have bent the down pipe a little sharper around the transfer case area (actually rubs on it now). I was also able to make a "guard" (kinda like a drive shaft loop) around the exhaust right at the center drive shaft mount. About 1/4'' between the pipe and the floor. I shortened the hangers just over an inch, and it does rub on rear diff/lower swing arm pivot point. But it does fit. I know there are better ways to put it in but my drive shaft mount limited my ground clearance.

Look here, his is much nicer, sits up closer to the body but he did a different way of mounting the drive shaft. http://forum.4g61t.org/viewtopic.php?t=22170

http://forum.4g61t.org/viewtopic.php?t=22170


Theres some pictues of mine.

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91 colt beater..

I had no problem fitting my exhaust, though I raised the tunnel 3 inchs and had a 1" exhaust on the car .

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89 Colt GT, T4 T61, 2.0L, .
http://videos.streetfire.net/search/...3300fc1b2f.htm
04 SRT-4, 3inch exhaust, Intake, Stage 2 W/toys
87 Conquest TSi, Coilover, huge sways
01 Dodge 2500 4wd cummins (tow rig)
91 Suzuki Samurai (Rock Crawler)

I thought about getting the driveshaft re-done into a one-piece. That way I can eliminate the supports and have more room to run the exhaust. I dont think anyone has run a one-piece before have they?? Pros or Cons??

I had talked to a machine shop to make a one piece driveshaft for my eclipse, they said due to the length, it would have to be very large in diameter and wall thickness, or it would have bad harmonics causing vibrations, and possibly u-joint vibration. I know the eclipse chassis is longer than the colt, but the same issues may be there.

Go side exit!

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4g61t.org
4g61t.com

Go dual.

I was told from the driveshaft shop in Edmonton that if I went one piece it would have to be greater than 5 inches diameter. The angles that mine would of been at would of been greater than what they recommended too. So I stuck with the two piece, stock diameter, with only one bearing point which makes the angles less if the bearing is placed at the right level.

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- Works in da bush

Hmm... yeah. Thats what I was afraid of. I guess Im going to bite the bullet and just work around it. All I know is I gotta have some kind of muffler. It does get kinda old having an open exhaust. Maybe I'll try and run two 2.5" pipes where it gets close all the way out the back.

3" exhaust has an area of around 7 in2.
2.75" is almost 6 in2.
2.5" is almost 5 in2
2.25" is almost 4 in2
2" is 3.14 in2.

So, to match your 3" exhaust, you'd need dual 2.25" pipes, which will actually be freer flowing as it'll have an area of around 8 square inches. Dual 2" pipes will only get your around 6.25 sq inches, which is equivalent to somewhere between 2.75" pipe and 3" pipe, but closer to 2.75" pipe.

Exhaust systems are more complicated than most people realize. Take a look at this. http://forums.trinituner.com/forums/arc ... -64067.htm


This is the piece that I usually show people from it:

"We want to minimize friction to lower the backpressure as much as possible - larger pipes have less friction because they have less surface area per unit volume. But we want to increase the delta P as much as possible to prevent reversion and increase scavenging effects - smaller pipes increase delta P because they increase velocity."

We learned about this in college for becoming an Instrument tech, I slept in most of my classes and now know that I should of been awake for this one. Trying to convince a mechanic about the friction losses due to the surface area of the exhaust pipe is almost impossible. I would of thought that they would of taken this in class too. Just remember that everything has some friction in life, even air. Thats why some vehicles are more aerodynamic than others.

But take what you want out of all that and do whatever you seem fit.
Have a good day.

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- Works in da bush

So I assume Skrenos post would comply with Colt200's post... Dual 2.25" pipes sounds better anyway since I'll have better ground clearance.

If you're gonna go dual 2.25" pipes, use a dual in/dual out muffler... and get a recording of your exhaust note. I'd like to hear a 4g63t with twin pipes. Not sure how it'd sound with two mufflers on opposite sides of the car. it'd be an interesting look you dont see on CSM/DSMs.

What kind of carrier bearing mounts do you have that makes it difficult to fit a 3" exhaust beside the driveshaft? Mine fits no problem, maybe a little low to clear beneath the diff, but zero scrapeage so far.

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1989 Dodge Colt Turbo w/ 4g63t swap
1999 Ford Contour SVT