I will be building my exhaust from scratch right after the OBD2 headers. After looking and thinking about it, I want to increase the distance that the rear bank gases have to travel. That way the pulses line up evenly when they meet in the Y pipe.
I measured a difference of about 6" between banks. I can't claim it's accurate but it's something to work with. So I did some work in a sketching software, first mocking up a factory-style exhaust for a Z3. It merges into this kind of Y pipe before going into the single cat.
I've purchased a few pieces of tubing from, funny enough, Amazon. I got 1.75" stainless pipes for the downpipes, with bend radii of 2.75". I'll merge them into a 2.25" pipe at an angle, like the factory system. The cat is also 2.25". The downpipes are spaced out 3".
I want to add 6" to the length of the rear bank, which is on the bottom side of the drawing (towards the passenger side). After a few hours of sketching, measuring, and adjusting, I came up with this.
Looks kinda stupid, but it works. I can adjust the final shape if I need to, but this will use the least amount of material that I already bought. I'll find out how much room I have once I get the car on the lift. It will likely hang low under the passenger floor, so we'll just wait and see.
I'm optimistic! Never seen anything like this. Although, I won't have any way of knowing if it actually works or not. It might sound real smooth, it might not. But either way, it's a logical attempt.
What are your thoughts?
Side question: I know that the E36 platform has the two precat O2 sensors in the headers, whereas the Z3 has one precat sensor right after the merge. Does anyone know why this is? Does anyone know how this relates to the tuning? Because I assume the sensors are tuned a certain distance away from the ports, so the computer knows when the measurement is in relationship to the combustion. I'm no expert, hence the question. Can anyone elaborate on this?
Thanks!
I measured a difference of about 6" between banks. I can't claim it's accurate but it's something to work with. So I did some work in a sketching software, first mocking up a factory-style exhaust for a Z3. It merges into this kind of Y pipe before going into the single cat.
I've purchased a few pieces of tubing from, funny enough, Amazon. I got 1.75" stainless pipes for the downpipes, with bend radii of 2.75". I'll merge them into a 2.25" pipe at an angle, like the factory system. The cat is also 2.25". The downpipes are spaced out 3".
I want to add 6" to the length of the rear bank, which is on the bottom side of the drawing (towards the passenger side). After a few hours of sketching, measuring, and adjusting, I came up with this.
Looks kinda stupid, but it works. I can adjust the final shape if I need to, but this will use the least amount of material that I already bought. I'll find out how much room I have once I get the car on the lift. It will likely hang low under the passenger floor, so we'll just wait and see.
I'm optimistic! Never seen anything like this. Although, I won't have any way of knowing if it actually works or not. It might sound real smooth, it might not. But either way, it's a logical attempt.
What are your thoughts?
Side question: I know that the E36 platform has the two precat O2 sensors in the headers, whereas the Z3 has one precat sensor right after the merge. Does anyone know why this is? Does anyone know how this relates to the tuning? Because I assume the sensors are tuned a certain distance away from the ports, so the computer knows when the measurement is in relationship to the combustion. I'm no expert, hence the question. Can anyone elaborate on this?
Thanks!
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