My 1st Post! Need forum advice on exhaust mods...

Hello fellow ZHP owners. I'm waiting on the delivery of my "new" '06 silver convertible from California, and had a few questions about some mild performance mods, such as the exhaust that I'd like to try. I did a little research on the exhaust issue, and now I'm even more confused. I'm pathetically old school when it comes to performance mods on late model cars. I've restored and modified '60's and 70's Triumphs, Porsches, Austin-Healey's, etc. for SCCA regional racing and fast road/track day applications, but after looking at the exhaust schematic for the ZHP, it's obvious I need a little help.

My last fast road, track day restoration of was on a 1964 Triumph TR4. I used two Burns 2 stage stainless steel racing mufflers and loved the sound. I'd like to use the same on my ZHP, but have no idea what to throw out and what to keep on the existing setup. The factory schematic shows both exhaust outlets eventually running into one tube and then to the muffler at the back of the car. Ideally, I'd like to remove all non-essential restrictions in place between the exhaust manifold and the exhaust tips.

With that in mind, I have the following questions:

a. What can be removed without the risk of failing an emissions test?
b. Should I use two lengths of tubing from front to back with two mufflers, or transition from two lengths of tubing to one, then to the muffler like the factory did?
b. Where should the muffler(s) be placed...cat-back...axle-back?
c. Is the return on investment, BHP-wise, for downpipes and headers on the ZHP worth it?

Thank you all for not only allowing me to join, but to reap the vast brain trust of the ZHP Mafia! :conversation

With that in mind, I have the following questions:

a. What can be removed without the risk of failing an emissions test?
b. Should I use two lengths of tubing from front to back with two mufflers, or transition from two lengths of tubing to one, then to the muffler like the factory did?
b. Where should the muffler(s) be placed...cat-back...axle-back?
c. Is the return on investment, BHP-wise, for downpipes and headers on the ZHP worth it?


a. anything after the exhaust manifolds can be replaced. Catalytic converters are part of the exhaust manifold so this would essentially be a catback.
b1. there is merits for a y-pipe from the exhaust manifold to a single muffler like bimmerworld does for spec e46. You probably will gain more top end power this way.
b2. it really doesn't matter. I would prefer axleback.
c. headers will violate emission testing but if you tune out the check engine lights for failure for no cats, you will gain "dirty" HP.

Honestly a nice used Corsa TSE3 exhaust would be simpler and IMO one of the best sounding exhausts without removing any emission equipment.


Congrats on the car btw!

Congrats and welcome! Please introduce yourself in our new members thread. Many options for minor HP increases, the main being a Perf Intake and an s/w tune. We have a whole section on exhaust (with sound samples) one of the favorites is the TSE3 but it is loud in a vert (ask me how I know :) ). Just go cutback full exhaust. Headers on top of that would do it for you but as said, you have to deal with SMOG, etc.

Quote:

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Originally Posted by derbo

Honestly a nice used Corsa TSE3 exhaust would be simpler and IMO one of the best sounding exhausts without removing any emission equipment.


Congrats on the car btw!

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+1


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Thanks for the advice guys. I like the sound of the TSE3 but the website that sells them states that it will not fit a convertible. What's the difference between the coupe and convertible chassis that limits it's usage? Is it easily addressed? Also, why does the TSE3 setup have 6 resonators or baffles front to back...some type of anti drone feature???

Quote:

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Originally Posted by Bludsport

Thanks for the advice guys. I like the sound of the TSE3 but the website that sells them states that it will not fit a convertible. What's the difference between the coupe and convertible chassis that limits it's usage? Is it easily addressed? Also, why does the TSE3 setup have 6 resonators or baffles front to back...some type of anti drone feature???

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Usually the issue is the V-brace on the bottom of the verts (I believe M3 has a similar if not the same brace) that makes clearance tougher. JR will know better since he owns one. :)


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Yup, it's that V brace on verts for extra stabilization that you have to work around. it's tight but it would fit. I don't have mine anymore due to the family complaining about how loud it was, so I went to magnaflow. I essentially traded with JP, so he has my TSE3. :)

Yea, suppose BMW had to account for body flex due to the missing hard top. No family to complain, so no worries there!
I listened to a clip on U-tube of an Eisenmann/330ci set up that I really liked. I'm most likely going to go with the same setup the guy from U-tube used:

1. Schmiedmann Headers & sport cats + Eisenmann sound pipe and rear Eisenmann race muffler.

Here's a link to the U-tube clip: https://youtu.be/4d-qVQTp7C4

Welcome.


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"ZHP is a garbage option anyway- just some cosmetic upgrades with a different cam and diff to claw back some of the performance lost fitting those hideous and heavy wheels. Any 330 with a 3.46 diff will smoke a ZHP every time. The whole Mafia thing reeks of childish behavior." - anonymous E46 fanatic

Yup, I've heard (no pun intended) good things about the Eisenmann.