M30 OEM Turbo project

[CorvallisBMW]

O I know. My 2.5 on the late model drones like a mofo would just do it for the power gains. I'm gonna run this one first for a while.

Just for reference:

2" dual: 6.28 sq in cross-section
2.25" dual: 7.95 sq in
2.5" single: 4.91 sq in
3" single: 7.09 sq in

Stock on the 745i was 2" dual, so I'm actually loosing some flow with my setup. My plan is to get it on the dyno some day soon and be able to measure backpressure during some pulls to see how much efeect it's having.

[ThatOneEuroE30]

All 745i's were factory dual exhausts all the way back; yours was cut up and modded in to a single at some point in it's lifetime. If you're going to a 3", you might be able to reuse the wastegate tube and just tie that in to your new downpipe setup. Just be aware that 3" single exhausts tend to drone like a bitch.

O I know. My 2.5 on the late model drones like a mofo would just do it for the power gains. I'm gonna run this one first for a while.

[CorvallisBMW]

All 745i's were factory dual exhausts all the way back; yours was cut up and modded in to a single at some point in it's lifetime. If you're going to a 3", you might be able to reuse the wastegate tube and just tie that in to your new downpipe setup. Just be aware that 3" single exhausts tend to drone like a bitch.

[ThatOneEuroE30]

I'm tripping they are the same he just left me more of mine which made me think it was different.

When I get to doing mine I think I'm gonna have a 3 inch down pipe made up so I can run more boost and the tail wastegate.

[CorvallisBMW]

You know that's a really narrow downpipe. If the V-Banded section is 2.5", your diwnpipe itself is, what.. 2"?
I think EGT's are going to get the best of you when trying to make power.

It's all factory, so I'm definitely limited to say 10psi max (stock was about 6psi). Yes it's narrow, so is the 2.5" system after the merge, but I'm not shooting for crazy horsepower here. If I can get a reliable 250whp, I'll consider the project a success :)

Gonna have to pop into the storage shed and snap a pic of mine.

Please do, i'd like to see it. I was under the impression that all the m102/m106 downpipes were the same.

[Zacm829]

Don't know how I missed this for so long, looking forward to the finished product. Makes me want to clean up my garage and have a designated "tinker" space.

[ThatOneEuroE30]

Gonna have to pop into the storage shed and snap a pic of mine.

[ak-]

You know that's a really narrow downpipe. If the V-Banded section is 2.5", your diwnpipe itself is, what.. 2"?
I think EGT's are going to get the best of you when trying to make power.

[ThatOneEuroE30]

M30 OEM Turbo project

Mine looks like yours except the wastegate comes back down into the turbo pipe and exits with the turbo

Basically take the Y off yours and just keep running the pipes straight from the turbo flange back and then somewhere along the line add the piping up to the wastegate flange and a O2 sensor bung

[rzerob]

^ I have been wanting to do something similar.

[CorvallisBMW]

Check this out! A month ago I started on this project to mount a voltmeter in the check panel:


Well I broke the faceplate trying to cut out a relief for the gauge to show through, so I needed to get another one. I sourced one from Wishno87 and decided to try a different route. The black coating comes off really easy with brake clean, so I just taped off the window I needed and went to town!


Looks perfect!


Reinstall the guts


Run the wires through the open bulb holes in the back:


And voila!

[CorvallisBMW]

That is weird that your down pipe is twin piped mine is only one.

One pipe is for the turbo, the other is for the wastegate. What does yours look like? Where does your wastegate dump to?

Looks great!

Does that O2 sensor really fit sticking straight up like that?

Actually yes, it fits in the trans tunnel between the chassis and trans.

[AndrewBird]

Looks great!

Does that O2 sensor really fit sticking straight up like that?

[ThatOneEuroE30]

That is weird that your down pipe is twin piped mine is only one.

[CorvallisBMW]

M30 OEM Turbo project

Got a pic from my exhaust guy. Factory down pipes with an added bung for the wideband sensor, combining in to a 2.5" single with v-band clamp and factory O2 sensor. Eventually (after the picnic) I'll have this whole section ceramic coated.