engine and drivetrain Custom intake manifold for injection

[Todd21]

Fans of the 02,

I'm looking for input for a custom intake manifold. I'm working on my turbo project and I'd like to have something custom. My concept is to have the injectors mounted inline with the intake tubes. I'm thinking of an arrangement where the injectors are opposite the intake tubes allowing for a more direct path into the flow path. The fuel rail would be outside the air plenum.

This would be for a engine management system on a non-Kfish engine. Not really looking for a wild application as the turbo is a very mild K03.

My thoughts come from the vintage photos of the Alpina set ups where the injectors were mounted at the extreme limits of the intake runners.

Please let me know your thoughts.

[TobyB]

I'd start with the 318 manifold and start cutting and machining.

The injectors are actually very efficient if they spray onto the hot intake

valves- good atomization.

The thing is hellaciously ugly, but very efficient FOR WHAT IT'S DESIGNED FOR,

so while it would be aesthetically nice to chop it up, it would take a bit of

work to make it work better.

fwiw,

t

[philv]

interesting looking exhaust manifold. Did you build it for your turbo setup?

[Pinepig]

I made one for mine and started with a 318 mani ( why reinvent the wheel )

Post is here,

http://www.bmw2002faq.com/component/option,com_forum/Itemid,50/page,viewtopic/t,319747/highlight,/

I have had a few problems with it, since the tubes are just butt welded on the original 318 mani they have cracked a few times, I think I finally have a grip on it now.

If you are doing it this way, weld it up, then cut doublers, wrap them around the weld you already have and weld those up too.

Make a damn bracket that goes from the side of the block to the bottom of the plenum part of the intake, it's just too much weight flopping around out there without some support.

Weld another doubler along the line between the flat plate of the plenum and the top and bottom pieces, it flexes like a balloon and they will crack, I used .125 thinking there would be no way it would do that but I was wrong. Where the half tubing welds are I haven't had a problem at all.

[Todd21]

Phil,

Yes I built the manifold in the photo specifically for the K03. I have a 320 manifold that I have been looking at for mock ups but I just don't like the looks of it. I'd like to develop something a little cleaner.

My exhaust manifold has a split collector box to help dampen the pulse flow from the cylinders. 1 and 4, 2 and 3, just to keep the pulsation down as it feeds into the turbine.

Todd

[Zenon]

For a street car, the 318i manifold's injector placement and general design is ideal. Excellent cold-engine driveability, lots of torque down low, wide powerband, bulletproof one-piece casting. But it is boring, I'll admit.

Putting the injectors way out at the end of velocity stacks or runners is only good at high rpm/full throttle. The theory is that the farther upstream placement results in more time for the fuel droplets to mix more evenly. At low rpm, however, and especially during light throttle application, there would not be enough air flow/velocity to keep the fuel droplets in suspension. Even worse when cold. So, for a street car, the idea is a non-starter - almost literally.

I have heard of setups using two banks of injectors, one at the ports and the other upstream, to get the best of both worlds and to increase the range of fuel delivery tune-ability for a highly supercharged motor that is being used on the street. That would be pretty cool...