Gen II throttle-per-cylinder intake manifold

[ALLTRBO]

I have one in my possession and I'm debating on whether or not to buy it from Will to use on my Gen III turbo 3200 destroker build. From what I understand, there were only something like 6 of these built, for midget racing (if you know of these and have more info than that please let me know).

It would take a lot of work to make it work with EFI because it was designed for mechanical injection, and it's rather extreme (even for an 8000 rpm 3.2 I think) because each throttle bore is 50mm and the as-cast runner length is about 4.5". It appears that the designers considered an intake manifold to be nothing more than a necessary restriction to the head ports.

Those of you who are knowledgeable in the mysterious ways of the 60*, please let me know what you think about the feasibility of using this for my build.

I took tons of pics and measurements (and pics of measurements) but don't have time at the moment to put them all up. For now I have only a couple general pics uploaded.

[trotterlg]

Neat stuff, not sure what you would do with it. You could use some mechanical fuel injectors with it, airplanes using engines like a IO470 use systems that simply valve in a fixed amount of fuel regardless of the air flow depending on throttle opening, and they work fine, or you could go with a 15 to one compression and inject propane, it has an octane rating of about 140. Endless thing to do with it. Larry

[Superdave]

Well, that won't fit Gen 3 heads at all so you are pretty much hosed there. I suppose you could have a welding shop add a ton of material and you might be able to relocate and re-shape the ports to match Gen 3 heads. That will be a ton of work and you could probably make something better on your own.


ITB's are extremely fun though, 60v6's run and sound totally different with them. I have around 8" of runner after mine and 6" stacks with 45mm TB's.

[ALLTRBO]

I know the ports don't match up with Gen III heads, and adding material if necessary and reshaping was on my mind but as I said, the whole deal would be a lot of work and I don't know if it would be worth it. I do have a nice 240V Miller mig with a spool gun setup so I can weld aluminum, just not well enough to properly fill in the ports to reshape if needed. The ports are hogged out pretty extensively already. I'll post my pics with the digital calipers present as soon as I get a chance.

Making it hold 30psi would be a challenge in itself, the throttle shafts don't have O-rings so something would need to be done about that and the mating flange on the top of the bores is pretty thin so I don't know that it would hold gaskets together especially because there are only two small bolts per bore. For that I suppose making sure the surfaces are perfectly flat and fabbing up a solid 3-hole flange (similar to a header flange) then using some copper spray-a-gasket could take care of it, but I'm not even sure then. Otherwise, I could weld on thick wall ~1-1.5" high tubes with smoothed out beads at the top and that would give me something to clamp silicone couplers to (like typical IC tubing) to mount the custom plenum to.

That's all on top of a custom fuel rail, injector ports, some type of IAC manifold/system, throttle linkage and TPS provisions (those should be easy) and several other things.

How would I go about making something better? I was thinking about using a 3400 lower and putting the 'usual' setup on top of it (motorcycle ITB's) but I haven't gotten very far with that idea, though I think it would be doable. I somehow missed the fact that you have ITB's on your setup, do you have a build thread/pics/video?
The sound wouldn't be as much of a difference (unfortunately) with a common plenum on top, but the individual throttles go a long way in taming a big cam (which I'll need) and making for snappy throttle response so for those reasons I want to do it, plus it's just cool.

[Superdave]

http://60degreev6.com/forum/showthread.php/45628-My-89-Camaro-Project

Mine helped out with the big cam although i have less idle vacuum now which is just another thing to tune for. The throttle response is very nice and general driveability is pretty good too.

[geoffinbc]

ITB's and boost don't work well together. Tuning is a major pain in the ass. Perfect syncronization of all the shafts is very hard.

My friend machined a custom ITB system for his 240Z with EFI. All the throttle bodies pulled from a plenum under pressure. He ended up machining tubes to take the place of the throttle bodies and slapped a big throttle body on the front of the plenum.

My friends setup was extremely precise. With individual adjustment built in to the butterflies. He also has an inline setup which all ran off a common shaft. A V setup would be harder to work with. He just could never get it to idle properly and when you would slam the throttle shut and one butterfly that did not close 100% would still get boost from the spinning turbo and caused a backfire out the exhaust and weird popping sounds in the intake. The single throttle body on the front of the manifold solved the issues.

For N/A apps a tuned IR manifold is the best you can get. Plus it is very easy to change the runner length. About the only thing that comes close is a tunned cross ram manifold. However any adjustment means making a new manifold.

[ALLTRBO]

Wow, I knew tuning would be difficult, but not that bad. Who knows, maybe it would be the death of the project, and maybe it would be a breeze on my setup. I don't think I'm wanting to find out though.

Still haven't uploaded the rest of the pics, been very busy.

[02dohc]

hey if you cant use that manifold i will take it off your hands. just let me know