[dadasracecar]

So I finally got and installed my cp-e exhaust. Anthony from cp-e was not satisfied with the fitment of the units they had on the shelf – seems they had a disgruntled employee for longer than they realized – so he nixed the sale and decided to rework the ENTIRE thing. He explained that he wanted zero doubts about any product they sell. Reassuring.
cp-e used my car for the redesign, or design I should say, as the whole thing has been completely redone. Anthony used their digitizing arm to get measurements of the stock exhaust and cradle under the car. He drew the design using some CAD software and then transferred the dimensions to their mandrel bender. He then set about bending the tubing and designing temporary fixtures to make the prototype. They use on 304 stainless steel for their exhausts so mistakes are costly. A single 3 ft length of tubing costs them about $50 just in material and they buy in $10,000 lots. 304 SS isn’t cheap. Hell the temporary fixture was a big brick of Al that was milled to fit the pipe using one of their CNC mills and that had to be drawn and programmed as well. With the careful digitizing and methodical measurement taking, he was able to get the X-pipe done with only wasting one piece! Incredible.

After the pipes were bent and cut, the pieces were assembled under the car and tack welded. This process took about 16 hours as each and every step was placed, measured, and setup for the next so that fitment and alignment would be perfect. Once the exhaust pieces were tack welded, the whole thing was removed and each separate piece was redigitized for the final design so that the exhaust file is of an actual exhaust and not just measurements off of stock.
With the exhaust down, Anthony had TIG welded the pieces together and remeasured to make sure they didn’t warp under the heat. He explained that this is an important part of the design process as any metal part with lots of welding can and will warp distorting fitment. It’s also very labor intensive and prone to error. With more automation and less welding used, the more precise and reproducible the final product is and that is the name of the game. Once finished, I was left to do the install.

First of all, the stock exhaust is impressive. It takes two people to remove because the whole thing is one piece from the downpipe to the muffler. It’s HUGE. The cp-e install went flawlessly. The hangers are completely vertical with no stress or torque on the rubber. Everything slid together and when I was done the tips lined up exactly as you see them – perfect. I’ve installed several exhausts on cars and I’ve never seen a fitment this good. I’m still sort of shocked about it. The whole thing is polished and looks too sexy to be under the damn car.

For me the X-pipe is the most impressive piece. I’ve tried my best to capture the design to show the bends. The whole thing is 3 feet long and consists of only two pipes welded together. The craftsmanship that goes into this has to be respected. Both pipes bend in and out of plane in different directions and degrees. To be able to visualize that under a car and in space is remarkable. But then to take each half of the X, cut it exactly where it needs to be cut, weld it together and have it fit like it did is truly astonishing. Anthony explained that cp-e’s tolerances for all of their exhaust pieces are 0.050”. Their fixtures are cut to exacting detail so that each part fits perfectly. The cuts are done robotically so they are exactly the same as well.

Now for the sound. I have to admit that I was apprehensive about a loud exhaust. The BMW is so refined and beautiful as it is and I didn’t really want to mess it up with a loud obnoxious exhaust note. The cp-e exhaust is from the downpipe back and eliminates the second catalytic converters. When I started the car, I had the biggest grin. Immediately it sounded like a European supercar with a satisfying bass tone resembling, to me, a DBS. - There is a company close by that houses cars for journalists to review and I go there occasionally to gawk.

On the road, the bass is most prevalent from ~2K – 2400 rpm. After that, the exhaust is almost silent in the cabin unless your WOT. At the upper rpm range at WOT the sound is absolutely glorious. It’s got this hard to describe higher pitched scream that sounds like a Ferrari to me. I love it. The low rpm bass reminds me of driving in my dad’s ’90 vette. It’s deep and smooth without being obtrusive. The difference is that there is no rumble to it at all. It’s just a smooth constant deep base that reminds me of the car’s potential – precision built German badass. So happy.

Now for the pix:












One thing that’s kind of interesting to me is that the tips of the exhaust will actually extend past the bumper when it gets hot. The coefficient of thermal expansion for 304 stainless is large enough that the exhaust will actually expand and “grow” in length when the system is warm after driving. You can see it when you get out of the car. The tips are about a half inch further out from the bumper. When it’s cold, they’re right back where they were to begin with. Pretty cool to me but I’m sort of a geek that way…

cold

cold

warm

warm



Vids

I did my best to capture the sound but my crappy casio microcamera just sucks for this. I’d be happy to let any locals come and go for a ride. Also, you can hear the video soundclips on cp-e’s website. http://www.cp-e.com/2043.html






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[mmm def]

Thanks for the review, sounds real nice. Do you know what size the tips are?

[dadasracecar]

The piping is 2.5". I'm not sure about the tip size. It's definitely larger than stock. THe pix don't do it justice.

[jtsherri]

Nice review. It's not in the last bit surprising to me that cp-e did just as nice of a job on the 335 exhaust as they did on the 135... I've had mine for like 4 months now and absolutely love it!

[BoostedBMW]

CP-E is an EXCELLENT company to deal with.

I sold my CP-E exhaust, but that exhaust note really did fit this car nicely. I wanted something a little more aggressive, but for daily driving that exhaust is perfect IMO.

[jam0321]

Originally Posted by BoostedBMW

CP-E is an EXCELLENT company to deal with.

I agree. I was fortunate enough to visit these guys in Maryland this summer and I got the tour of the shop and met some of the staff. We were there on a Saturday (day off for CP-E) to help a couple of customers who were having some issues with their Mazdaspeed 3 turbo kits. They really took the time to ensure everything was working to perfection.

[dadasracecar]

LOL no day isa day off for them. They're ALWAYS there.

[Makushr1]

Awesome, very nice. I love the way cp-e sounds. I plan on getting their exhaust in the next couple months.

Take some vids from outside the car, turning it on and reving up.

[BoostedBMW]

Originally Posted by Makushr1

Awesome, very nice. I love the way cp-e sounds. I plan on getting their exhaust in the next couple months.

Take some vids from outside the car, turning it on and reving up.

Any other requests?

http://www.e90post.com/forums/showthread.php?t=121450

[dadasracecar]

Here are some pix from the mock up. Again, pay attention to the bends in the X-pipe. it's amazing that he got that to fit so well. There is literally only one weld in the thing. Mo flo, lots o' sho & plenty o' go.

[Morpheus]

your car is a sedan right? So, all exhausts ordered from cpe will now be this new design?

[cn555ic]

It looks the same to me and I bought mine last year! I have to say the sound is still amazing!

[1clean335i]

Excellent choice! Ive had mine for about a year now and love it!

[emjei]

Just got mine..........keep you posted

[dadasracecar]

Originally Posted by Morpheus

your car is a sedan right? So, all exhausts ordered from cpe will now be this new design?

Yeah, mine is a 4 door - two kids. All the exhausts from now on will be this design. I believe they will make the X-pipe slightly longer for the coupe.

[possible335i2008]

how do you order it?

[f82phan]

Originally Posted by possible335i2008

how do you order it?

www.cp-e.com

[AV9]

exhaust sounds great!
thanks for the clips

[dadasracecar]

I've got about 150 or so miles on the exhaust now and the sound has gotten more mellow and deeper. The guys at cp-e claimed the exhaust would "break in" over the first couple hundred miles or so. I was fine with as it was but I have to say it has gotten better over time.

If anyone local to DC wants to hear it, PM me. It's awesome. It would really be cool if someone with a proper camera could take some video with quality sound so that a better clip could be posted.

I love it.