Y34 Custom Magnaflow Cat back true dual exhaust

[M45Caliber]

I removed the 300 pound factory exhaust system (OK -- I don't know how much it weighed but its a heavy SOB) and had a custom Magna-flow true dual set up put in. The tech that did the work has been doing custom work for 24 years, and it shows. I showed him an aftermarket X-pipe, and he laughed at me. Said that his was less restrictive, looked better and had fewer welds -- thus the esthetics were improved. He took the pipes that come back from the cats and bent them to "touch" for about 8 inches -- then cut out a large oval on each pipe that exactly matched it's twin on the other pipe. Took both off the car and welded the two pipes together around the oval. Then re-installed both pipes and welded to the resonators. Slick as possum spit (or whatever). Check out his handi-work in the link, provided here -- Photobucket. I love the sound and overall it was a fantastic value.

http://s1005.photobucket.com/a.../Cars/

[ken in az]

I removed the 300 pound factory exhaust system (OK -- I don't know how much it weighed but its a heavy SOB) and had a custom Magna-flow true dual set up put in. The tech that did the work has been doing custom work for 24 years, and it shows. I showed him an aftermarket X-pipe, and he laughed at me. Said that his was less restrictive, looked better and had fewer welds -- thus the esthetics were improved. He took the pipes that come back from the cats and bent them to "touch" for about 8 inches -- then cut out a large oval on each pipe that exactly matched it's twin on the other pipe. Took both off the car and welded the two pipes together around the oval. Then re-installed both pipes and welded to the resonators. Slick as possum spit (or whatever). Check out his handi-work in the link, provided here -- Photobucket. I love the sound and overall it was a fantastic value.

http://s1005.photobucket.com/a.../Cars/

Here's a little help....



M45 cat back exhaust

X-pipe cutout one side

New system pre x-pipe

Old system

Stainless tips

[mcrews]

VERY SWEET

really like the sound, nice and tight!

Wen I pulled my resonator (F50 has exact same system)there was a little more 'buzz', but it went way (mostly) with the x-pipe.

[M45Caliber]

Thanks Ken! That sound clip doesn't do it justice - probably need a decent microphone to pick it up accurately.

[M45Caliber]

you are exactly right on the "buzz" -- I had it too, and went back for the X-pipe at Ken's urging. The muffler guy stated (and he's technically correct) that because my duals dumped into a single dual in/dual out Magna-flow, I essentially HAD an "X-Pipe" at the back end of the system - as the exhaust gases mix/merge in the muffler prior to exiting the tail pipes. I immediately noticed the "buzzing" that was occurring between about 1900 and 3000 RPMs is now completely absent. It sounds better across the entire rev range too.

If you look at the pics, you will see one that shows the entire system PRIOR to the x-pipe install. I think it's pretty slick the way the installer crafted that new x-pipe. And he HAD a "stock" off-the-shelf" x-pipe sitting in stock, but he refused to use it. Wanted to do something with fewer welds.

[kingpin]

Why did you cut out the duals and put a straight pipe from the cat with a HFR to a rear muffler ..cheaper in the long run less pipes < 1 less Box and better sound ..cost a bit more but sounds amazing ..

[M45Caliber]

amigo -- you are LOOKING at the OLD system -- there are titles ABOVE each pic -- the original system was a 2 into 1 into 2. The NEW system has 2 pipes into a "Siamese'd" X-pipe and duals into twin resonators then two pipes to the dual in/dual out MagnaFlow muffler at the back end. Maybe we should move the pic of the old discarded factory set up to the TOP of the page?

[mcrews]

Pe

Why did you cut out the duals and put a straight pipe from the cat with a HFR to a rear muffler ..cheaper in the long run less pipes < 1 less Box and better sound ..cost a bit more but sounds amazing ..

petrol head.......you gotta step away from the gas nozel........

[kingpin]

I know what i was looking at when it come to Y34 and Muffler setups ..what i wanted to say was this ..

Combine the Cats into >1 Y pipe then run a 3 or 3.5 inch Stainless to ONE HFR then to a rear muffler ..

Taking the 2 boxes out and running it on open helps the engine with Power and IMPROVES gas milage ..

Don't get me wrong your system is great but it could have been better with a bit more planning ..

i will take some pictures of my system ONCE THE SNOW CLEARS .. and you can see what i am trying to point out ..

[M45Caliber]

well this last post is a bit clearer than your previous attempt. I can't imagine that a single 3 1/2 inch system will flow better than dual 2 1/2 pipes with the x-pipe to equalize. Plus the sound should be that same, given the same resonator and muffler, as either solution ultimately exits out of a single muffler. You can modify the sound by the addition/deletion of resonators/mufflers and by your selection of different types or brands (Flowmaster versus Magnaflow, etc.). I chose this set up for optimal flow and a sound that is a little more aggressive than stock without being annoying while cruising at highway speeds. Mission accomplished. Love to see your single 3 1/2, although it's pretty easy to imagine based on your second post.

[ken in az]

Are you talking about something like this?



I'm not going to say one is better than the other, but it's been proven that X-pipes produce a specific sound and outflow h-pipes and single pipes by increasing low end scavenging and high end flow.

I would expect that an x-pipe would exibit the same peak horsepower but would create more power and torque in the lower rpm's than a single pipe would net.

Same in the mpg dept. as well, net the same improvement.

[kingpin]

I will put my car on the Dyno and get a number to work with ..I was never knocking the X pipes Just the Cost Factor ..

[M45Caliber]

PH -- bring it on down here --- the weathers great! We can head over to Firebird and run them side by side down the strip. I think it's around $25 for the night - run what ya brung. Last night some fool in a late model M35 thought he'd Race me. Bad decision. He slinked away before the next light and made a U-turn. So, hey -- at least I know this dual set up didn't hurt my acceleration too much!

[ken in az]

PH -- bring it on down here --- the weathers great! We can head over to Firebird and run them side by side down the strip. I think it's around $25 for the night - run what ya brung. Last night some fool in a late model M35 thought he'd Race me. Bad decision. He slinked away before the next light and made a U-turn. So, hey -- at least I know this dual set up didn't hurt my acceleration too much!

That could be a long drive for him!! - lol

Nah petrol, I know you weren't knocking it. I was just trying to give a non bias oppinion.

To be honest the only thing I didn't notice before were the crush bent pipes. I saw the pics on my cell phone and let me say, they were pretty small and that's why I didn't notice

Now everyone knows that mandrel outflows crush bent anyday of the week, but I honestly think the best pipe size for the M would be 2 1/4" so those crush bent pipes might not be hurting you at all M45Caliber.

3.5" I would imagine to be overkill, 3" might be perfect.

I say lets have a virtual dyno day where we all go to a dyno on a saturday and get some numbers! then we can spout all we want but I have a feeling that there won't be too many HP's between any of us. For some reason I think I have a factory turd and I've only gotten back to where alot of people started. - lol

[sebvox]

Is there a way to get these photos reposted? Interested in what this exhaust system looks like.