OBX Manifold - Yay or Nay?

[mwhis936]

Hey all - curious to get some first hand perspective on the OBX top mount manifold. Specifically I’m wondering how bad the boost creep is on them. I’m putting together a build and really the last thing I haven’t made a decision on is top vs bottom mount, taking into account performance, stability, ease of install and of course price point.

Thanks!
-Matt

[Hova]

How much power are you trying to make? The OBX manifold has been known to creep slightly, but the bigger issue is the quality of the welds and the possibility of the manifold cracking.

If you want a top mount get the Otis manifold.

https://www.ebay.com/itm/BMW-Turbo-M...-/152821412625

[lbennyboobool]

Hey all - curious to get some first hand perspective on the OBX top mount manifold. Specifically I’m wondering how bad the boost creep is on them. I’m putting together a build and really the last thing I haven’t made a decision on is top vs bottom mount, taking into account performance, stability, ease of install and of course price point.

Thanks!
-Matt

Hey! you aren't too far from me. If you want to check mine out sometime, let me know. To answer some of your questions, mine does boost creep slightly like Hova mentioned. It hasn't bothered me a whole lot. I have seen several of these manifolds crack. Mine hasn't yet to my knowledge, but it's just a matter of time. I had to cut my hood slightly to get it to close. Some have to cut allot more than mine. I'm not running AC for simplicity. It can be done, but it would be a challenge with the lines.

If you want to go top mount, go with the Good & Tight manifold. If you for sure want AC, go with a bottom mount. Just my opinion though.

I have a friend selling his bottom mount setup if you choose to go that direction I could see if he could give you a good deal on it.

[Turbo E36]

I have one on my Z3 its top mount with working A/C no problems at all yet 15000 miles on it. The wastegate is a little close to everything.

[NOTORIOUS VR]

How much power are you trying to make? The OBX manifold has been known to creep slightly, but the bigger issue is the quality of the welds and the possibility of the manifold cracking.

If you want a top mount get the Otis manifold.

https://www.ebay.com/itm/BMW-Turbo-M...-/152821412625

Which also crack BTW

[Mklock]

Gotta use thickwall pipe for stainless tubular manifolds to not crack. The ones that are built like that are 1400$+ just the way she goes. My steedspeed seems to be holding up.

[NOTORIOUS VR]

Gotta use thickwall pipe for stainless tubular manifolds to not crack. The ones that are built like that are 1400$+ just the way she goes. My steedspeed seems to be holding up.

Also not true... my AR designs manifold is a real POS let me tell you...

Just had to repair it for the 2nd time now.

What needs to happen is whoever is making/welding the manifold needs to know what they're doing and back purging helps a ton too.

[Hova]

Also not true... my AR designs manifold is a real POS let me tell you...

Just had to repair it for the 2nd time now.

What needs to happen is whoever is making/welding the manifold needs to know what they're doing and back purging helps a ton too.

So what do you recommend then?

[Mklock]

To be honest I'm not sure for a topmount. A lot of the bigger companies don't do E36 stuff anymore. You'll have to do research but maybe comtact 88lab for one? There's other people out there just gotta look around on websites / FB.

[NOTORIOUS VR]

So what do you recommend then?

I can't recommend anything else I don't have experience with anything else.

Only AR and the China made Otis as linked above.

Tubular manifolds in general have a higher chance of cracking - so who ever is making them needs to know what they're doing, choose the right materials + properly weld it. Beyond that - just expect that it can crack eventually.

[Mklock]

As NOTORIOUS has said they will crack. ESPECIALLY more so if you don't support the turbo with a nice brace. Ontop of all that, it's stainless look up the proporties of stainless guys, it's absolute trash for sustained high heat loads. The car world confuses a lot of things this being one, welds are supposed to be *colorless* no purple blue what have you and all that crap is for looks. It's a manifold make it strong, make it from steel, ceramic coat and your done.

Then, you slap a 35lb turbo with a 30lb exhaust hanging off it and expect it to hold? It won't. That's all the reason I went with a billet steel manifold. No worries.

[NOTORIOUS VR]

As NOTORIOUS has said they will crack. ESPECIALLY more so if you don't support the turbo with a nice brace. Ontop of all that, it's stainless look up the proporties of stainless guys, it's absolute trash for sustained high heat loads.

Exactly... realistically I believe you want to use a high carbon steel for manifold material.

[Robocop]

^idk if they have manifold adapters for e36 but i've ran one for years in my e30
even though it was super long and un braced and a thinner wall, it never cracked.

the chinafold cracked 3 times on the weld at the turbo flange.

[NOTORIOUS VR]

^idk if they have manifold adapters for e36 but i've ran one for years in my e30
even though it was super long and un braced and a thinner wall, it never cracked.

Similar experiences with up pipes/manifold adapters on various cars (M20, VR6, etc). NO issues.

That said there are less points of stress with an adapter vs. fully tubular manis where different runners like to pull/expand at different rates and angles, etc. That is why material choice and weld quality are even more important.