Custom intake manifold for a 4A-GE build?

[RogueMoog]

Wondering what you guys think. I'd like to just have a smallport head, intake manifold, and fuel rail, but they're not exactly in supply. I can find bigport stuff a little more easily, but I don't want to use TVIS. For my build, I'm going with a chipped Honda ECU & OBD1 distributor, and I have Acura Integra GSR injectors & throttle body at my disposal. No MAF for me, I'm going MAP. So...

I know I can get one of those $100 T3 adapters to use as a TVIS eliminator, or just have one made. But a friend of mine is a fabricator, and we've been wondering how difficult it could be to make an intake manifold for my build. Since fuel injectors mount to a bigport head, the intake would be basically a box with four runners... doesn't seem much different than making an exhaust manifold (which we are also planning to do).

Would it be just as 'easy' to modify a bigport FWD (MR2?) intake to use the GSR throttle body, rather than build a custom intake? Would I get better airflow making the custom intake, since it wouldn't have those eight runners for TVIS?

[toyotaspeed90]

if you want to make a good/efficient intake manifold then you need to understand runner lengths and velocity..... you don't want to end up having variance of velocity/pressure between cylinders.

there are some custom made ones out there (typically done on AW11's.... and you can see similar builds on SW20 3sgts's)... but they are actually designing them using varying CAD programs and testing velocties before building them.

[eage8]

you should just get a T3 ITB adapter plate

[RogueMoog]

Thanks... funny you mention CAD, my friend is hoping to get hold of software to design things like exhaust headers, and this custom intake. He's done a lot of drafting, mostly by hand, but also in CAD. Kind of hoping that my power goal of 170-200 HP won't merit super precision. But I also don't want sloppy work, and he knows that / agrees. Ideally I'd get some measurements from someone with a smallport intake and use that as a starting point.

T3 adapter plate... as a starting point? I've considered that, but I don't know what material we'll be using yet. One of the things we're wondering is if the custom intake can be made of somewhat thinner stainless steel (like an aftermarket header would be made of).

In all, what intake related sensors will I need? GSR throttle body has TPS and MAP, so I need the IAT sensor and the vacuum lines (differential, brake booster, ???) to mount somewhere.