MBRP Cat Back

CalSgt

Member
Installed the MBRP cat back system today, looked at every brand I could think of and narrowed it down to this one and the flowmaster. They were the only ones that went the extra bit to route the pipe above the sway bar.

It’s a little droney from about 2500-3500 and at idle, so far at highway RPM’s it is hardly noticeable I’ll have to put some more time on it to be sure. If the drone gets to me I’ll add a resonator.

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CalSgt

Member
It would be nice if someone came out with an exhaust like that with a resonator as part of the kit. :(

Seems like most of the kits on the market are more about what they look like and how loud they are than how they fit or perform... I liked the way the factory one sounded and I would have kept it if I felt like dealing with smashed tail pipes and broken hangers every time it got hit.

Besides if they sold one with a great muffler/resonator combo on there, they wouldn't be able to sell you more parts...

I'll bet kids who want a loud droning exhaust are probably the majority of the aftermarket exhaust purchasers too.
 

CalSgt

Member
Flowmaster HPII

So I removed the MBRP muffler & replaced it with a Flowmaster HPII (not the shorty) that I salvaged from a custom Polaris RZR exhaust that I don't use anymore. I had to cut 5" out of the exhaust tubing to get it to fit.

The MBRP is a straight through muffler with louvers protruding into the tube for the length of the muffler, I'm guessing there is packing material between the tube and the muffler shell.


mbrp.jpg



The Flowmaster is a "Laminar Flow" (according to flowmaster) design with cones made from perforated sheetmetal coming from each end meeting in the middle, there is a layer of packing at between a double walled shell.

ETA: this picture just shows the laminar flow design the HPII is a much lower profile canister than this one.
HPII.jpg

The biggest difference is the tone, the MBRP had a raspy buzzy type sound that could sound great when on the throttle and accelerating through 3500-5500 RPM.

The HPII has a lower tone with no raspiness & is not as loud as the MBRP overall, it still has a drone but at different RPMs than the MBRP.

I still think I will be adding a resonator to see if I can eliminate the drone...
 

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CalSgt

Member
So I can confirm that a resonator makes a big difference with the drone and volume of an exhaust. I bought a flowmaster 15150S 2.5" resonator & I would guess it sounds close to stock now. It's been a while since I had the stock can on there, I might have to go drive a stock one to compare now but i am guessing its just slightly louder accelerating from idle at around the hood speeds. The drone is almost completely gone at highway speeds, sounds like a different jeep.

I drove the jeep 4.5 hours to Manteca CA on I5 this weekend & was pretty sick and tired of the drone by the time I returned home. I was fully prepared to go on Amazon & order the resonator that has been sitting in my "save for later" list for a while. Instead It was sitting by the front door when I walked up the porch, my lovely bride had seen it in my list and ordered it for Fathers day.

If you went to a low profile exhaust and can't handle the drone anymore this is the cure... Its a little expensive but worth it in my opinion.

flow .jpg

flow 2.jpg

Now I need to get rid of the ghetto clamps & weld everything up.
 

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