e30 m50 turbo manifold help!

[Rowleym]

So.. instead of spending like 500+ on a decent manifold, I would like to make my own for the experience of it. Yes I do have a tig welder and argon purging, yes I have all the proper tools, blah blah. I was just wondering what sized ID tubing I should use? Anyone have a log manifold on a turbo m50 e30? I think it would be great for the transient(Sp?) response because this car is going to be drifted and sometimes on the track. Power goals are around 400bhp and Im using a Holset Hx40 with a 16cm housing. thanks

[Ginsterman98]

Sch 10 stainless 304 pipe should do the trick. Tubing will be to thin and prone to cracks, use pipe.
this might help you out.

http://www.mcmaster.com/#stainless-steel-(schedule-10)-pipe-fittings/=kgcvkf

[Good & Tight]

1 1/4" schedule 10 piping is what I use for manifolds, you can get them at Ace stainless.

[Rowleym]

sweet. Thanks guys. Now that I have the manifold material, does anyone have anything to say about a log manifold?

[Rowleym]

Also, Do you use a stainless manifold flange?

[Ginsterman98]

A log manifold will work fine, just make sure you place the wastegate at the collector and not off to the side like a single runner. I would use 3/8'' Stainless plate to make the flanges.

[Rowleym]

Why has no one ran a log manifold on the m50? Kind of curious haha.

[Good & Tight]

Why has no one ran a log manifold on the m50? Kind of curious haha.

A log will work fine. But if your going to take the time and fabricate a manifold why not make a nice tubular one? It will perform much better than a log.

[Rowleym]

aren't log manifolds better at transient response? Like betweens shifts and it spools up faster? I mean, I am kind of doing it for the simplicity. Does anyone do m50 turbo manifold adapters? Like they do on m20?

[Ginsterman98]

No, a proper equal length tubular manifold will always preform better than a log. The volume difference is negligible at best. If your running a proper sized turbo spool wont be an issue and a good tubular manifold will help spool. Main downside to a log style is the exhaust pulses won't be "timed" correctly because the runners won't be equal length. The other downside is usually poor wastegate placement which can lead to boost spikes or other boost control issues.

[Rowleym]

I guess. Thanks man. Anyone know anything about a turbo manifold adapter for the m50 like they do for the m20?

[Ginsterman98]

Check with the guy above my last post, good&tight.

[einstein57]

Log manifolds are very common in e36 and e46 applications. Not sure if there is enough room to run an off the shelf bottom mount on an e30.

[Good & Tight]

IMO you would be better off just buying one of my top mounts, they fit perfect and would save you a lot of time. For $530 shipped you can't beat it.
Do it right the first time or you end up spending more doing it twice.

[Rowleym]

yea you are definitely an option for me right now. The reasons I'm building this car is for the experience, not just to go fast and show off, so making a manifold would be a great option. I just don't understand why no one uses a manifold adapter like on m20's?