FI manifolds and throttle bodies

[turbo6bar]

I am planning to do some custom fuel injection work on my car in the near future. My plans are to construct a set of throttle bodies similar in dimension to the Weber/Dellorto setups we are all familar with, except with 44-48mm bores. My reason for posting is to gather any interested parties. I wish to reduce my costs by perhaps making up a few sets of these parts. Pieces will be machined aluminum bits with aluminum tubing bores, of course, with injector bosses milled out. I have no idea what costs will be, but I promise they won't be outrageous. I will be out of country for month of May with my current work to take up much of June. Throttle bodies will likely be built during July.

[Germain]

Now thi sis interesting. How are you going to measure the air flow vs. fuel mix? Are you setting this up to run turbo or a supercharger? You might want to think about using the k-jet system off an old volvo or Porsche. It has all the needed equipment, and can handle the fuel and air delivery. Just a thought...

[turbo6bar]

Air flow measured via MAP sensor. I plan to drill ports into the bodies to permit pressure to be read off the 4 cylinders via common plenum. Plenum size will need to be adjusted to get a smooth reading, and is dependent on camshaft. With wild cams, TPS will be used to determine load, but I prefer this as a last option. O-rings will be installed on the throttle shafts to permit use on boosted engines. CIS is certainly nice, but I prefer to have total control of the fuel and ignition system, which I feel is only present with modern electronic fuel injection. TWM wants me to dish out $700+ for their throttle bodies, which is more than I want to pay. My throttle bodies won't be as pretty, but every bit as functional. What can I say... I'm young, stupid, and love technology. Regards

[TFI]

are you planning on having dual throttle bodies?
why construct your own, when there are so many out there on these newer cars that could be adapted to work? what advantages are you getting by building your own?
are you opting for the multipoint injection with an injector placed in the manifold by each intake port on the heads?

[turbo6bar]

Yes, dual throttle bodies. Individual runners much like the original Weber setup for good throttle response and ability to run wilder camshafts. Which newer cars are you referring to which have throttle bodies like this. I didn't know of any 4 cylinder cars of similar design aside from Subaru.

The only advantage of building my own is that it would be cheaper, at least if there are not OEM bodies which I can pull from a wrecker.

I am certainly going with multipoint injection. However, I am not certain on my decision for injector mounting. I could put injectors in the manifolds to fire directly at the back of the hot intake valve (good for cooling valve and atomization), or higher up in the throttle body, where the increased runner length would permit better charge distribution. At this point, though, anything I do would suffice.

Any criticism, positive or negative, is very much appreciated and encouraged. Like I said, I'm young and stupid.

[TFI]

If you are building the complete setup, manifolds and throttle bodies, why not go with a couple of throttle bodies off of a wreck and build the manifold to handle the throttle bodies this way? it'll save on having to build your own throttle bodies and will leave you with plumbing it. the dodge intrepids have a nice dual throttle body setup that you could steal the throttle bodies off of.
i was thinking of taking the FI off of an engine like what i am running now (2.2 chrysler turbo) and putting it on the flat four engine. wanted to take all of the sensors and set it up like it belonged on the flat four, but i didn't know about the crankshaft positions on the type IV engine, or how to setup the crankshaft position sensor. come to think of it, i really don't know much about the type IV's.

[Tom Notch]

I'm doing a little of this on my Big T4 motor. I'm currently gathering/making parts for mine. I picked up a used Haltech brain and using a TB out of a GM car. Making a custom plennun to fit it all together. Once everything is de-clunked on the car and the 2650cc engine, I'm looking at a small turbo to add to the package. See my progress at
http://home.att.net/~drsowatt/index.html

couple of pages of engine stuff and some links to some FI stuff, plus the toys ;-)