Muffler Sound

[RyanL]

Hey guys,

 

So most of you may or may not know, I am the son of Akula69 who runs around on here from time to time. When I was 15 we started a restoration on my 1989 Comanche. We finished it up in August of 2010 and I have been drving it around ever since, and keeping up with maintenance. Having driven it to college and back quite a few times, the mileage has been getting up there. We found a suitable 1999 Cherokee and are planning a 97+ swap this summer. We have both looked at threads of others who have come before us, and have seen what it takes and are pretty confident either way (although working on these trucks rarely ever goes as planned as we all know). However, I was struck by an interesting thought the other day. Right now I am running a Flowmaster 40 on the 4.0. With the change to the 4.0 H.O., how will this affect the sound of the exhaust? Will the tone get "tinnier", or deeper? A trivial question I know, its just an itch I wanted to scratch.

 

Ryan

[1tonMJ]

Does it matter? :MJ 1: It'll still be beast.

[RyanL]

Fair enough :rotf:

 

My only thought was nobody likes a japanese fart can :D

[1tonMJ]

I don't think it'll sound like a ricer, maybe at 6K RPM, but not in your daily driving. Sick beast drone going on. Lol

[Lee21490]

Fair enough :rotf:

 

My only thought was nobody likes a japanese fart can :D

 

I have a 40 series on my 95 4.0L, Sounds great~

 

Doesnt sound like a ricer at all lol

[HOrnbrod]

I had one, couldn't stand the obnoxious drone. It didn't last long on my rig. I think it was caused by the 2.5" pipes all the way and the header though.

[RyanL]

What header with a bigger diameter fit?

[HOrnbrod]

What header with a bigger diameter fit?

 

What are you asking? What header do I have? :hmm:

[RyanL]

For lack of a better question yes sir. I still run the stock up to the cat

[mvusse]

I had a Thrush glass pack that I happened to have laying around on my 94 XJ and ended up installing a stock muffler because the drone was too loud for my comfort. It is now on my trail truck with just a front pipe in front of it, no cat, no tailpipe and is a lot quieter than it was on the 94 HO engine.

 

Don't know about the Flowmaster, but do expect the sound to be a bit louder than what you have now.

[sinkrun]

Lots of videos on you tube of cherokees with 4.0 HO exhaust sounds with flowmasters.

[86FUBAR]

I know this is a comparing apples to oranges but when I swapped the totally stock 2.8 out for the 3.4 with edelbrock intake I was curious if it was going to sound different and it sounded exactly the same so take it for what it's worth.

[RyanL]

I will check out some videos when I can. Does anyone have any input for headers? Mine are still good, but I figure if I'm going to go all out with the swap, might as well get new headers as well.

[Lee21490]

I had one, couldn't stand the obnoxious drone. It didn't last long on my rig. I think it was caused by the 2.5" pipes all the way and the header though.

 

I have 2.5" pipes from the cat -> to the back.

 

Mine sounds pretty nice, You can just barely hear the exhaust while driving. Almost wish it was a bit louder lol

 

Screams when you floor it though

[Akula69]

Well, I have heard it and its loud, especially in 2nd gear. However, I believe it will tone down some when we complete the 99XJ HO transplant, as we will have to splice the cat from the 99 onboard to get the O2 sensor bungs (to make the obdII work).

 

It does have a nice low tone at idle....

[RyanL]

The drone will tone down or the overall sound?

[Akula69]

The drone will tone down or the overall sound?

 

Both. Not enough to make a difference though.

[RyanL]

Guess we'll find out one way or another

[Eagle]

For lack of a better question yes sir. I still run the stock up to the cat

 

Stock is 2-1/2" up to the cat -- and out of the cat. The connector from the cat to the muffler necks down to 2-1/4", and the muffler inlet is 2-1/4".

 

I don't think the change to an HO will make the exhaust sound any different at all. I used to spend a lot of time on trail rides watching different XJs negotiate obstacles, and they all sounded pretty much the same. It isn't very exciting, because with an in-line 6 the power pulses are all perfectly evenly spaced, so the exhaust can never get that lumpy "cammed" sound you get with V8s. I ran a 2-1/2" turbo system on my '88 XJ for awhile and I hated it. It was louder than stock but didn't sound any better, plus it hurt my low-end torque and cost me gas mileage. It was the first (and last) time in my life I actually looked forward to the day when I needed to replace the exhaust system.

 

If you want a Jeep I-6 to sound good ... go Gibson.

[HOrnbrod]

It isn't very exciting, because with an in-line 6 the power pulses are all perfectly evenly spaced, so the exhaust can never get that lumpy "cammed" sound you get with V8s.

 

Unless you have a stroker. Even with a mild cam. :thumbsup: If you want a Jeep I-6 to sound good ... go Gibson stroke it. :yes:

[RyanL]

Stroke a H.O.?

[ftpiercecracker1]

Is that a question or a statement?

[RyanL]

Question.

[HOrnbrod]

Stroke a H.O.?

 

Yes, an HO is the best candidate for a stroker.

 

http://www.angelfire.com/my/fan/stroker.html

[RyanL]

I thought only regular 4.0's could be stroked. What are the costs vs. benefits of doing the coversion?