Exhaust History Different Finish

[davesz4mc]

Brief over view of my frankenstien exhaust>

Car was originally owned by a friend and he had the stock mufflers gutted which increased exhaust sound some but did not do anything for performance for sure. He ran into some financial issues so I purchased the car from him to help him out.

I imediatly took off the stock mufflers and ran straight pipe axel back to get rid of the gutted mufflers. Ok so this setup is really load and raspy as you would not believe lol. Definatly not condusive for a daily driver so I changed it up and dropped in a pair of series 40 flowmasters and at the same time I eliminated the stock resonator and gutted the secondary cats. Exhaust note was amazing but OMG did it drone on the highway having those flowmater cans right under the rear truck area of the z4mc.

So I ran through several options in my head on what would sound the best and eliminate as much "in car" noise as possible. I have really enjoyed using AeroTurbine mufflers as they sound great and provide a small amount of performance benefit. I purchased a 3" resonated AT muffler and installed it mid car as described next.

The car has the stock NA headers\cats but has only the AT muffler header back the rest is straight pipe. The stock center section of the z4m is two pipes from the header back through the secondary cats into and out of the resonator and the through the x-pipe section before it runs out over the rear axels, mufflers etc. We left the header flanges on and cut the two pipes off about 1.5" after the flanges then we cut the stock x-pipe section in half giving us two sections that were center in to two exits.

The rear section we left where is was so it could take the 3" pipe center in and put it back to the stock over the axel sections. We too the other half of the stock x-pipe and cut it slanted\angled over the two pipe section and matched that section to the header pipes we had cut earlier. this made it 2 into 1 3" after the headers and the rear made it 3" bact to the stock two over the axels. Then we ran a short bent section of pipe 3" tucked up tight to the transmission mount and into the center of the car where we mounted the AT muffler then it continues 3" out of the muffler to the rear section where it splits the exhaust back out. This sounds utterly amazing and beefy with min raspyness but still enough know you got an s54 in there. It also brought the interior noise level down to dare I say normal levels while cruising but still rattles your head when you down shift and get on it. There is a video in the 30 MPG thread and you can kinda hear it in the crappy cell camera audio =-). I will update this when I get some photos of the setup so you can see it in more detail. I think a euro header when I find one and the system will be complete, it will be all straight pipe and one muffler center mounted =-)

[ZStig]

Good God man. Please add some paragraphs

[inTgr8r]

^+1

[davesz4mc]

Is it bad if it all runs together like that in my head lol

[mousitch]

Have a sound clip?

[ZStig]

Originally Posted by mousitch

so you have stock headers, no secondary cats, and just 3" AeroTurbine mufflers?

[davesz4mc]

That pic is x'd for me

I have one muffler not two, the rest is straight pipe. And stock headers for now gotta locate some euro headers.

[davesz4mc]

Originally Posted by mousitch

Have a sound clip?

I said where to find it in the original post but reposted just for you.

[ZStig]

Originally Posted by davesz4mc

That pic is x'd for me

I have one muffler not two, the rest is straight pipe. And stock headers for now gotta locate some euro headers.

Attachment 642868

thx a lot for the diagram. now its much easier to understand. Does it drone much? I bet its very loud

[davesz4mc]

It has eliminated almost all the drone from the car actually due to it being resonated/muffled before the driver and out the back. It is louder outside the car than the RPI exhaust a little deeper and without as much rasp. It is quieter in the car than the RPI.

[txz4]

good meeting you the other day Dave! i can vouch for this exhaust, the sound was terrific, similar to my setup (Euro headers/cats and RPI) but the sound was a little bit more exotic IMO and certainly droned FAR less than my setup.

We did a quick little 3rd gear pull, and the cars were identical until the RPMs started to climb in which i had a very very slight advantage, almost not noticeable. This could be the RPI scoop, who knows.

All in all the setup clearly works with almost no difference compared to a standard setup, with reduced drone and i must say, a very refined exotic exhaust note.

Dave, next time you get a chance to get the car on a lift you should take some pictures, i really want to see what this setup looks like.

[davesz4mc]

If you have free time stop by teh shop today I can pm you the address. Between 4-6pm.

That 871 BDS supercharged 440 31 willis fiberglass kit car is at the shop =-)

[Finnegan]

Interesting application and design!

For those not wanting to go quite so far, the Aeroturbine resonated has been used with success before, and without the massive amount of drone folks seem to get with Flowmasters. Bignosejim's car has dual can Aeroturbine muffler (single tips) setup that sounds pretty good as well. Bignosejim bought it from another forum member, and the fabrication and materials costs were quite reasonable.

[davesz4mc]

Originally Posted by Finnegan

Interesting application and design!

For those not wanting to go quite so far, the Aeroturbine resonated has been used with success before, and without the massive amount of drone folks seem to get with Flowmasters. Bignosejim's car has dual can Aeroturbine muffler (single tips) setup that sounds pretty good as well. Bought it from another forum member, and materials and fabrication costs were quite reasonable.

Price for this was $150 for the AT muffler and $10 for a 2ft section of 3" pipe, I welded fabed it myself and reused parts from the car.

[davesz4mc]

The video was for the 30 MPG thread but at the end of it I get on it so you can hear it cruising and going. Milage drops significantly under throttle =-)

[ZStig]

I think this has potential to be a nice LTW, non droning exhaust, if you have a total of 4 of these things replacing everything after the header. 2 for mufflers, 2 for resonators

[mousitch]

I bet it does sound good. Hmm. Rethinking my decision on a $600 x-pipe and & $1800 cans. LOL. Be a good setup for someone who has stock and wants to get loud. I like the sound from the clip.

[davesz4mc]

[txz4]

Originally Posted by davesz4mc

It has eliminated almost all the drone from the car actually due to it being resonated/muffled before the driver and out the back. It is louder outside the car than the RPI exhaust a little deeper and without as much rasp. It is quieter in the car than the RPI.

I thought the aero setup had a less deep sound but a more exotic, kind of like a Ferrari how it screams as opposed to a muscle cars low rumble. a much more refined note though than my setup.

[crfine88]

sounds good, I like the design