Has anyone fitted a dual exhaust on a 3.7Ltr.?

[Ry' N Jen]

Good Day,
I have looked upon this forum for quite some time for information on dual exhaust. Both double side exit and classic "Dual" pipes exiting out both sides out back.
I've looked in the parts and accessories threads and found a list of manufactures, but nobody seems to offer 'em! I have found some cat-back systems, but thats it.

I figure that one would be able to extract a few more pony's from the addition of a new cold air intake, but would certainly gain even more with a dual exhaust system!

Or would adding just a high quality cat back system do the trick, and a dual system have too little back pressure?

Thanks
Ry

 

[JJsKJ]

Unless you are supercharging or turbo-ing your KJ, the factory 2.5" exhaust tubing flows plenty. Add in the muffler of your choice to the stock tubing and save the money for other mods. If you go w/ an aftermarket intake, realize that you will lose some of the cold air flow to it that the stock system takes advantage of and please use a filter that FILTERS, not the K&N unless you want additional flow of dirt into your engine. The factory air box and filter are plenty big for the flow capabilities of the 3.7L.

BTW, this topic will always stir up many different opinions just like mine. Mine is based on some fact though and not advertising hype.

 

[CRD4Liberty]

4WD&SUV magazine did a cat back, intake change to the Lib a few months back. No much power found, they did find a little better fuel mileage, only problem is you'd have to own the rig a really long time to recupe you costs. It came out to about $200 dollars a hp ,and you'd have to drive it like 180,000 miles to get you money back.

 

[kjpilot]

As they said above, you won't see much improvement. Typically, when a high flow exhaust & intake are installed on a vehicle, any gain in power is in horsepower at the top end of the tach. Unfortunately, it is usually accompanied by a drop in torque on the low end of the tach, and we spend most of our time at the low end.

A bit of back pressure is beneficial for low end power. Some high flow exhausts have ways to compensate. Supertrap made a tunable system where you placed restricters on the end of the tailpipe. I was watching the tail of a newer BMW 3-series of stop & go traffic, & noticed a flap in one of its 2 tailpipes. you could see the flap was closed at low RPMs & would open as it built up some steam. I thought it was interesting 8-[

If you ever plan to off-road, I think it would be a silly investment. The potential loss of low end torque is not what you want on the trail, & one well placed rock or stump will damage an expensive custom exhaust $$$. ](*,)

 

[Ry' N Jen]

Good Day'
I now understand why I don't see them offered anywhere!
Cheers
Ry'

 

[indieaz]

BTW, this topic will always stir up many different opinions just like mine. Mine is based on some fact though and not advertising hype.

I agree with this post 100%. Our LIberty simply doesn't have the valvetrain setup to make enough power to warrant a dual exhaust - or any different exhaust for that matter. 2.5" ins plenty. If you want a different sound buy a $60 muffler and have someone weld it in.

I also agree with the filter comment - no filter can really flow that much more air without filtering less. I don't have a link handy but there was an article showing the efficiency of filtering on K&N (and similar "free=flowing" filters) which showed they actually filter very little when completely clean. That's find for a vehicle driven in fair weather conditions on paved roads...but going off road your vehicle will be breathign tons of dirt. Keep the stock airbox and filter and forget about the 2 horsepower you're losing over it. What is 2 horsepower anyways when you have the optiont o go into 4-lo?