So, within the next month or so, I'm looking at going for a catback. I know it's been said before that gains going to full 3" are minimal in terms of power, but has anybody done a before/after dyno with one?

I'm on coilovers now, so I'm not really looking into the Hahn anymore. It's pretty much my last mod potentially. I know it looks good, and from what I can tell from the vids MPX put up, it seems to sound good too.

What are everybody's thoughts on it that has the MPX Catback? Have you noticed any difference when tuned as far as power and/or gas mileage?

 

Even if you did pick up a few ponies from the 3 inch exhaust you would never feel the difference. I have Hahn with the muffler cut off of it. If I could do it again I would have went with MPx. It's so irritating when the exhaust clings every time you hit a bump.

 

Yes I did a before an after with a catless dp with stock exhaust, and catless dp with 3" side exit (can't get much more free flowing than that unless you used a cutout)... I literally saw a 1whp gain (nominal due to normal small variences in power numbers when doing dyno pulls) and the tune needed zero modding

 

I have the MPx cat back w/ cated d/p.....the MPx has a nice note to it , I have ran the catback with the stock d/p also.....it depends on what you want as far as sound , you will feel a little more response with the cated d/p......but the exhaust has a nice note with the stock d/p also...the MPx system is very nice, the fit is excellent, you can lower with it too....lots of room over the cross member...Modern Performance I give high marks to also.....good experience with them.....hope this helps.

The only h/p gains you can get with an exhaust upgrade is to replace cats with more effecient d/p or no cat.....or of course replace the header......cat back systems only effect the exhaust note.....the cliff hanger is emissions ...but there are ways to beat that **** !

 

Ok. Thanks for the input y'all! It sounds like what I've been hearing in general is fairly accurate... basically it's a sound mod and real-life performance gains are minimal.

 

Didn't notice much gain if any but it sounds real sweet lol! I figured by opening the exhaust to full 3" it can't hurt and for that price it was cheaper than any C/B I've ever seen for this car.

 

I am currently running a mpx exhaust n there catless dp. Everything else stock. Love the sound great deep tone with lots n lots of gurggles n pops at wot shifts aswell as normal driving. I purposely run the heat in the car so I can crack my window down n listening to her howl. As of performance gains...none that I can feel, slight more repsonse of the turbo maybe due to less back pressure, then again it could be my amagination. Very pleased with the system, I recommend it

 

Well, I picked it up today. It was the last one they had right now (display model). They let me listen to their current version, with no resonator, and took me for a ride a couple times around the block to listen to it. I was sold.

On the way back home with it, I beat an E46 M3 and G8 GT... and it's not even on yet! It must just be that badass... lol

 

Thank you guys for chiming in with your input.

We've been very happy with the MPx exhaust we designed and think theres no way we could improve on it!

Thanks for stopping by and purchasing with MP! Post an update on the forums when you get the exhaust installed !

 

2 1/2" moves enough air to satisfy 400 hp, its a sound mod only

 

Most of the gains come from getting rid of the bastard factory d/p....those two cats are the size of the big rolls of scotts butt paper........there is so much resistance there is like trying to fart thru three extra thick cushions in lawn chairs.....behind the cats is just tone qualities by design of the pipes with their fart restriction...

 

Yeah, after talking with some of the peeps on here and a few other tuners, I have concluded it's sound only for the most part.

Love the metaphor!

 

I'm thinking about adding a flange to the muffler so I can remove it, that would be the only thing I would change about this C/B.

 

Got it installed today. I sounds incredible! It sounds exactly how you'd want it to when you'd want it to if that makes any sense. lol

One problem I'm having though is getting the flanges tightened up. I got the DP/CB flange done no problem, but the other flanges after the DP/CB flange are smaller... so much so that I can't get a box end or ratchet end around the bolts/nuts because they're so close to the pipe.

Right now I've got an exhaust leak that I'm not sure how to fix. I can't get a wrench or box end up on the top nut/bolt and can't get a ratchet end on there either due to their proximity to the pipe. I'm at a loss as to what to do. The only thing I can think of is to try to find a "thinner" 17mm ratchet end at a pawn shop or something.

Does anybody else have any ideas/tips?

 

I had a similar issue, the bolts are too close to the pipe itself for the closed and I was swearing like crazy for a good while lol. I ended up using the box wrench but the open end. Get them all as snug as you can so that everything is lined up then drop the pipe off the hangers from the middle back and finish it off with the same wrenches (open end). No leaks, no issues.

 

So wait, Modern Performance are making their exhausts w/ an optional resonator delete? If so, that's really cool cuz I would've just had the res removed anyway once I got the exhaust.

 

Are you guys having any trouble blowing cats. I have a 2007 Cobalt SS Supercharged Factory Stage 2. I blew my stock cat and put a magnaflow hiflow cat with while keeping the stock exhaust system and blew it as well. All this under "normal" street racing conditions. What is a good cat to use while retaining low and mid range power and not blow it?

Thanks,

Tony

 

Yup!

Edit: I got the current version with the resonator. The demo car has the version without the resonator that either just came out or will be coming out soon.

 

stamina how do you like it?

 

I love it! It sounds incredible and seems to flow very well as well. I picked up some horses somewhere, because I was putting cars on a friend of mine that was pulling me before... and that's even after a stronger tune on his car.

The only minus I had was with the flanges. I ended up having to take it to a shop to get some differently sized hardware put in to be able to tighten everything down properly.

Other than that, I've been very happy with it. It's quiet when you want it to be, loud when you want it to be, and just rumbly when you want it to be. They did a very good job tuning the sound on this exhaust.

 

I guess I was confused by the issue with tightening the rear flanges. was it just you didnt have the right tool to get into the space?

 

I think it was a combination of the tools I had, the order I did it in, the hardware I received, and the design of the exhaust.

The flange was small enough that the bolt holes were so close to the pipe, that the washers rested on the flange welds and you couldn't get a ratchet or box end over the bolt head to tighten them either. I tried using regular wrenches, but the angles I was working with while assembling the pieces made it very difficult at times.

The shop I took it to gave me smaller diameter washers and bolts that had the same diameter body, but smaller heads on them. That way I could tighten everything down without the washers sitting on the welds and I could use the ratchet to get up in the hard to get to places.