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Discussion Starter · #1 ·
I'm getting close to taking my CJ7 in for exhaust, I've got a mild 350 with rams horn mainfolds. I used to run fenderwell headers with mufflers under the doors so there was very little restriction, maybe too little and the exhaust got destroyed on the harder trails.

I would like to run single exhaust inside the frame rails out the drivers side with a single flowmaster. One reason is that I positioned the motor 1" to the passenger side to line up with the rear pinion so there is very little room on the passenger side beside the transfercase. The second reason is that I would like to keep it simple underneath (one muffler) and leave room to access the drivetrain. Thirdly the 20 gallon factory gas tank has an angle cut out to allow lots of room to run the tailpipe out the drivers side. I'm thinking about running the passenger side pipe under the oil pan then joining in to the drivers side pipe. I was thinking that 3" pipe after the 2 pipes Y together would allow enough flow at the higher RPM's. Some shops I've talked to seem to think 2.5" single would be enough. Other shops want to run dual pipes out the drivers side I think that would be pretty tight and make it harder to access the drivetrain especially if I have a problem on the trail. Considering my stock Toyota 2.4litre 4runner runs 2" pipe and the V6 Toyotas have 2 1/4 and they aren't much more than half the size of my motor I think 2.5" would restrict my 5.7 litre at the top end. Some guys have also mentioned that I may have better bottom end for the trails with smaller pipe but I didn't notice any lack of bottom end with the fenderwell headers and 2 1/4" mufflers.

If anyone is running a setup like I'm thinking about I'd appreciate any info on how it works or if anyone knows how a 3" single compares to a 2 or 2 1/4" dual exhaust.


Thanks,
Ken
 

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I've always gone with the moto that "BIGGER IS BETTER AND BADDER". I know I'm no help.:D
 

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4Lo said:
I've always gone with the moto that "BIGGER IS BETTER AND BADDER". I know I'm no help.:D
That's right up there with "Go Big or Go Home".

I've got a single 3" on my F250 with a 5.7 and love it.
I've got a single 2 1/2" on my XJ with a 4.0 and love it as well.
Best mods that I've done.
Have not noticed a drop in the bottom end but probably a boost.
Mmmmmmmmmm more power......
 

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Discussion Starter · #4 ·
That reminds me of a shirt I picked up at Donavee Jeep in California about 10 years ago. Had a picture of a modified CJ with "Go Big or Go Home" on the back.

Mine wore out years ago but that also reminds me my wife has one that she rarely wears. Maybe she won't miss it!
 

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KO said:
That reminds me of a shirt I picked up at Donavee Jeep in California about 10 years ago. Had a picture of a modified CJ with "Go Big or Go Home" on the back.

Mine wore out years ago but that also reminds me my wife has one that she rarely wears. Maybe she won't miss it!
Oh, she'll miss it alright.
Wives never forget a thing!
 

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You might want to talk to muffler shops for the final say, but I'd go 3" or 2.75" single. You want a reasonable ammount of restriction to keep your tourque nice and high.
 

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My exhaust is two 2 1/4" pipes going into one muffler with a single 3" pipe out.
The drivers side runs under the oil pan and then runs down the passenger side beside the passenger side exhaust pipe. Works well, looks good, and really the only space you'd be giving up is the extra 2 1/4" pipe.

Just dont make the mistake of buying that awful Ravin Muffler that I had Midas install for me, cost me near half a paycheque and the only difference between my brand new exhaust and the open headers is I can't smell the exhaust anymore. That and the collector leak that they cant seem to fix, so now its actually more annoying than it was with open headers.

Dan. (no, I'm not bitter)
 

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...or just don't buy anything from Midas. Either one.

Rip you off?

Midas, we do that.

Nothing against the mechanics at Midas, but the local one has the WORST owner/operator.
 
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