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
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
