Exhaust Recommendations

I am looking for recommendations on a complete exhaust system, headers, catalytic converter, muffler, etc. My exhaust manifold is cracked and my muffler has taken a beating, so, sounds like the perfect time for an upgrade.

What are you guys using and how do you like it? What is the best system for the money?

If I had to choose, I would rather have better low end torque than high end horsepower.

Thanks,

Since low rev torque is what you want, stick to the 2.25" pipe size. Here's what I suggest:

Borla stainless steel header
Carsound 2.25" high-flow cat
Magnaflow 2.25" muffler
Stock tailpipe with weld-on tip

I've done 91k miles with my Borla header and had no problems at all. It fits like a glove. I have a Flowmaster muffler which sounds really badass and is as tough as nails, but it drones too much at 2500-3000rpm. The Magnaflow doesn't drone as much but still rumbles at idle like a V8, and it's very well put together. There's also the option of stainless steel.
I also have a 3" single Pacesetter Monza chrome tip with resonator (Summit Racing) on my stock tailpipe.

I can only give my opinion on exhaust, but I have a Gibson 2.5" cat-back system on mine. I did notice some power gains from it, but probably more in the mid to upper rpm range. One problem I have with my Gibson is the muffler is a cylinder and sticks down pretty far which makes it prone to getting nailed, but from what I have seen it looks like they might have changed the shape of their muffler so it might not be a problem anymore. All in all I do like mine.

I'm running a banks torque tube header w/factory cat forward/back. The header is awesome (only $359). However, I didn't really notice any performance gain until I installed a poweraid throttle body spacer. That seemed to make a big difference in power and the engine breathes better. Next step would be to install a dynaflow catalytic converter and muffler. Finding non-factory mandrel tubing for the whole thing is difficult though.

I have been running Borla headers for some time now. Had not noticed any gains. Weekend past I added Rusty's Catback whick is 2.5". Too loud for me below 2500 RPM. At highway speeds it is hardly noticable. It will take a bit of getting used to. I would like to say that it does have more responce all around. Still need to put it to the test to be more definative. The old 4.0 do have a lot more vacumn now to operate the cruise control. More vacumn should translate to better milage (I hope). In short, I swear by my Borla. The Catback... I would get something a little more quiet if I had to do it again.

I didn't think they had strict emissions laws in Kansas. Living in Oklahoma, we have no inspection. So I lopped the cat a couple of inches past the collector and welded on a Flowmaster and dumped it off right out of the muffler. 1 muffler hanger and heat shield later and I have a wicked sounding, free flowing exhaust that is more out of the way (because it's only as thick as the "frame" rails) than even the most tucked OEM system. And I havent noticed any low end loss either.

What is the stock exhaust manifold outlet OD on an '87 4.0? 2.25"?

thanks

I belive that's what mine was, at the flange

I haven't started on my exhaust yet, BUT I am planning on Borla header, no cat (Indiana, all that needs said ) Flowmaster, and 2.5 Al SS tube front to back.
I work at a air and emissions (exhaust) prototype fab shop so exhaust is my thingarty:

Only problem I can see is room at the rear next to spring and tank. I think it will fit as long as I end it a bit short (before the hanger)

The stock tube looks to be 2" but I have not checkd O.D. yet. I will cut original tailpipe off , bring into work and match the bends via our computer (this is sweet...... it has a wand type deal that you touch to certain points and it makes a program you can load into the bender , next thing you know it will bend a tube to match. Any O.D. tubing. How awesome)

exhaust choices

I just installed my Rusty's FlowMaster 50 series cat-back last night. I was very impressed by the ease of installation and the change in flow volume . The FlowMaster is one THICK piece of metal! (I've had one on my GMC 4x4 for 2-1/2 yrs now...in the RustBelt...and going strong!)
The new system is got a nice rumble, and I haven't heard any interior resonance yet . It also seems that I picked up at least 1mpg on my trip computer and my engine runs and shifts a little easier too. I'm running 30 x 10.5 x 15 tires, 3.55 gears, AW4, and 242 TC. Going from 28" tall tires to 30" tires made me lose some low end and 2-3 mpg . As soon as I get my K & N filter and TB spacer on, I should be able to see at least a total of 1.5 mpg total recoup on my gas milage (based on the 1 mpg that I gained in the exhaust alone)....not to mention the better throttle response. I notice she really PULLS from 2800 thru 4500 rpms now.
I've had FlowMasters on several types of vehicles now and I've always been happy with the 50 series mufflers

BLUTO

exhaust choices

I want to make a correction to a thread that I posted to earlier this week. I've been a big fan of FlowMaster mufflers for a while now and found that they hold up well. I did have a problem once with a 360 CID 1999 Dodge P/U. I put a larger (V-10) catalyst and Flowmaster on it and it droned me to death!
Now that I've had some more time behind the wheel, I want to set the record straight about the 50 series FlowMaster. It sounds REAL NICE at idle (kinda lopey...like it has a mild cam), but once you get on it....well, that's where personal tastes and tolerance come to play. At a steady cruise of 2000rpm and below it is unobtrusive (quite tolerable). But at a steady cruise of 2200 to 2500 rpm, it sounds like a Ricer exhaust! . The six becomes a four (sounds like a coffee can full of angry bees)! The power is OK, but it really sounds like SHIT! uke:

I've been playing around and doing some research: I added a K&N style filter (can REALLY hear intake air when engine is cold), that reduced the exhaust noise a little. I also reread gojeep's page about reducing the tailpipe diameter to speed-up the velocity of the gasses thru the system. I will cut-off the nice SS tip from my 2-1/2" tailpipe and stick a 2-1/4" testpiece on there to see if it works for me. If not, I will look at resonator tips to help get rid of the droning and "bees". I am alos going to be doing a gear change (4.10's) soon, that should change my RPM's at cruise (maybe out of the "Angry Bee band") and create less "lugging" of the motor (which my 3.55 gears and 31" tires tend to do). Last resort, I will cut out the Flo and install a DynoMax in it's place. They have been recommended on this board and from guys at work.

I thought I would repost this to give and honest and detailed (although personal) analysis to a question that pops-up a lot on this forum. Otherwise, the FlowMaster isn't a bad OFF-ROAD exhaust. A friend of mine here a DCX builds and races at the strip, he told me DynoMax - "hands down!". They produce more power and no droning!

BLUTO

Well I have to agree with the Flowmaster on both accounts. Great at start up and low rpms, on the highway that bugger is loud. Mine finally rusted out, and I was replacing the engine so the cat and exhaust was time to go (also failed emissions State of MD). So I put in a Car Sounds Cat and Borla Exhaust. It's almost like I have a new jeep, the sounds are gone that "bee" noise. I will say the Borla wasn't cheap but after 5years and 139 for the Flowmaster/Rusty's Exhaust and the Dynomax I had for 115 first. I figured for the few extra dollars why not go with stainless steel. The only real problem was the tip. It was way to large and had a "S" bend in the tailpipe. Chopped sawed it off and no it's fine and out of the way. I have the muffler up as high as I can get it but from what people say that don't last on rocks. Well over time what does? So you have Flowmaster, Dynomax, Borla, Gibson, Spintech Muffler with a tail pipe. I did have Gibson 3" on my Dakota years ago. That was a great sounding exhaust that made some power. Choice is yours. Juice

exhaust choices

I got rid of a lot of the resonance in my FlowMaster exhaust by:
1) Cut off the 2-1/2" tailpipe after the over-the-axle pipe and installed a 2-1/4 tailpipe extension. I is expanded on one end and fit into the ID of the 2-1/2" piece...welded that up. That got rid of quite a bit of the "bees".
2) Added a Hedman Headers resonated (glass-packed), twin-outlet tip to the end of the 2-1/4" tailpipe (making sure that the tips didn't stick out too far and interfere with my departure angle). This quieted things down (under load and at freeway speeds) a little bit more. Now, my XJ sounds nice and throaty down low, tolerable on freeway, and heavy-breathing bat-out-of-Hell when you stick your foot into it!
Hope that helps those of you who are infested with "angry bees"
BLUTO

I whacked my Flowmaster off right after the muffler & before the axle. Did a little turndown there to blow the exhaust downward. Works fine & I dont get any exhaust smell inside like most will say, however I have alot of air under my Heep so results may vary.

I run the Gibson stainless exhaust manifold with a Flowmaster 3 chamber muffler and a high flow cat, 2.5 in all the way. I had the exhaust installed about 4 years ago and it's still in good shape. The manifold, down pipe, and cat came just a couple months ago. I also bought the Twin Air intake advertised in the back of a couple magazines. It uses a foam dirt-bike style filter. It came with 2 filters and cost $100. Easy to install and I figure since it's all foam it probably has less resistance than the K&N. I agree with the resonation people complain about with the flomaster mufflers, but I have gotten used to it. The main improvement I've noticed is that I can put my foot in it with the a/c on and it won't cut out like it used too. As for pricing, I had a shop do my work, not good with welding and the stock exhaust was rusted all to hell. So the manifold ran about $600, the cat and downpipe about $390, and the muffler about $60-all installed prices. The shops around here don't carry Borla, one said he was sick of dealing with them whatever that means. But be sure to get a quality manifold, the cheaper ones usually include crappy gaskets that leak after a couple months and they tend to rust quickly. Also check to make sure it comes with a downpipe. Mine didn't, but I understand that different manufacturers do include one. I was very happy with the fab job the local shop did, so you might compare the prices before you order. Oh, and the earlier quote is right about the open element intake, if you have cold weather where you live, expect a noticable sucking noise when you fire her up. But it does diminish after warming up.

I finally got the Borla header and Dynomax exhaust installed. Good fit and nice sound. No driveshaft contact at 4.5" of lift. Not loud and abnoxious, just a good mello rumble. Seemed to give me back a some power after going from the 31s to 33's, although its tough to tell since I had been runnin around with a cracked header for so long.