"ported" vauum passages in Throttle Bodies

[Andy330hp]

Our company makes aftermarket EFI systems, including throttle bodies. We used to have an outside contractor build our throttle bodies, but now we've got big heads and think we can do it ourselves. However, we don't have any solid information about EXACTLY where different ports should be located for vacuum advance, EGR, etc. There's the good ol' method of measuring OEM throttle bodies I suppose, but it'd be cool if somebody knew of any good reading (SAE papers, books, etc) so we could actually, dare I say it, DESIGN something!! Thanks

Andy

 

[Marquis]

I just bought a Euro spec 3.0 litre 286 Bhp port throttled BMW M3 engine (£350 and it's only spun a con-rod bearing!) this weekend and it's sitting in my garden, the plenum is off and it won't take too much to take a look!

 

[Andy330hp]

I'm sorry, I didn't mean "port throttled", I mean the vacuum ports in a standard throttle. IE, there is a port machined for a MAP sensor, this is obviously placed way below the throttle blade. There are also slots that are machined to be gradually uncovered by the throttle for functions such as vacuum advance of the distributor, vacuum for the EGR, and various other emissions devices. My question is, how to locate and how to size these ports. In looking at some OEM throttle bodies, we've found a whole range of different locations (right above the throttle, 10 degrees above closed throttle) and different shapes (round, rectangular wide/short, and rectangular Tall/Thin). How do we as an aftermarket supplier make sure ours are correct? How soon should the distributor recieve a vacuum signal, how gradually should it come on, etc. Same questions for EGR, and for anything else you can think of.

 

[comnean]

Hy,
My opinions:
1. Is very important to know, for each engine, that are flow conditions via intake ducts
2. Is very important to know, for each engine, which EFI sistem sensor function, calibration and (i.e. BOSCH, siemens others...),ECU maping and ...
3. the simply way is to copy the intake ducts.