Possible to turbocharge a 633?

[Guest]

Hey guys a friend and I are debating the possibility of turbocharging a 633. I've done as much research as I could, but there isn't all too much info out there. My main question is will the manifold from a 745 bolt up to the 633 (3.2) block? I've got just about everything else we would need. KKK 27 turbo from an old Porsche and I have everything to tap into oil lines.

Is a project like this feasible? Is it worth doing? What other obstacles would we be facing?

Thanks,
Mike

[MatthewakaMatt]

I believe quite a few 633s have been turbocharged. Yes, the manifold for the 745i bolts up to the 3.2. Before you get started, have you checked out TCD http://www.turbochargingdynamics.com/ ? Most people here have gotten better results with his kits than with 745 based setups.

[Velocewest]

There's a lot of available info. The 745i.com board has a ton of archive and tech faq info, plus a "545i" board that deals with non-e23 installs. Also the Roadfly turbo board has info, and of course this board.

[Guest]

Thanks for the replies guys I will definatly check them out. I also have looked at TCD's website and taken a few peaks at what they have to offer. The only thing that puzzles me is why they are using a log style manifold. I've been under the impression that a tubular manifold would produce better results.

Like I said I'm definatly looking into everything and gathering as much info as possible. The 745 manifold will only be used temporarily and I may end up doing some porting until I finish fabbing the tubular.

[Velocewest]

The only thing that puzzles me is why they are using a log style manifold. I've been under the impression that a tubular manifold would produce better results.

From the standpoint of making a part that is economical to duplicate and easy to maintain reliable quality, the casting shines. Tubular would have to be hand-built, and you risk bad welds or a mis-loaded jig that ends up with a manifold that's out of dimensional spec.

[Boru]

To solve the puzzlement....
Under finite conditions an equal length tubular manifold might yeild more power... at a certain rpm, specific engine load, etc. How much more? Perhaps several, maybe upwards of 10 hp.
That 10 hp in those finite conditons would add 7,8, maybe 9 hundred dollars to the kit. So, you'd have a smidge more power (maybe) in a small window, with a less durable manifold for a bunch more money.
We designed the systems to make decent power and to be durable (for the long haul) at an affordable price.
We weren't going for maximum power dyno queens, rather daily drivers that can run with and away from most other cars on the road. That being said, the power that our kits produce far exceeds the traction capabilities of the cars... if you want it to...
BTW, our "log" manifold is not a true "log" as it progressively increases in chamber size from cyl 1 down to the turbine.
I hope that clears thing up a little.

[T_C_D]

Thanks for the replies guys I will definatly check them out. I also have looked at TCD's website and taken a few peaks at what they have to offer. The only thing that puzzles me is why they are using a log style manifold. I've been under the impression that a tubular manifold would produce better results.

Like I said I'm definatly looking into everything and gathering as much info as possible. The 745 manifold will only be used temporarily and I may end up doing some porting until I finish fabbing the tubular.

A tubular manifold flows so well and adds so much volume at lower pressures that it also requires another 5/600rpm to spool the turbo.

Todd

[Guest]

Wouldn't the lag generated be related to the size of the turbo and the size of the piping used to make the manifold?

[T_C_D]

Wouldn't the lag generated be related to the size of the turbo and the size of the piping used to make the manifold?

All things equal a tubular manifold takes longer to spool a turbo because it has much greater volume and operates at a lower pressure.

These are the same reasons that it makes more top end power.

Todd

[russc]

Thanks for the replies guys I will definatly check them out. I also have looked at TCD's website and taken a few peaks at what they have to offer. The only thing that puzzles me is why they are using a log style manifold. I've been under the impression that a tubular manifold would produce better results.

Like I said I'm definatly looking into everything and gathering as much info as possible. The 745 manifold will only be used temporarily and I may end up doing some porting until I finish fabbing the tubular.

A tubular manifold flows so well and adds so much volume at lower pressures that it also requires another 5/600rpm to spool the turbo.

Todd

Is it really 5-600rpm slower for a tubular manifold? That seems exessive, but Ive never tested any, so I don't know. It would seem that the turbo would have some impact also.

So, maybe 3-400rpm?

RussC

[M635CSi]

If you're building one, go tubular. If you're building a hundred, go investment cast inconel.