Learn me: Geo throttle body injection

So for my turbo Fiat project, I am looking for a TBI that would be easy to modify to work with a Megasquirt to manage fuel and ignition. Since the manifold is for a weber, should be easy to build an adapter plate to use something like below, which is for a Geo Metro. Since the little 903 cc Fiat motor and about 10 pounds of boost, the question is whether the 1.0 or 1.3 Geo Metro has a large enough injector to keep it from going lean.

So can these work for a blow through turbo application and how can they be modified for more fuel flow?

The earlier ones, I believe pre 95, and non xfi were 38mm vs 36 so I would use that one. They can be used for blow through, been done many times, but I can't tell you what the injector is, though I might be able to find that out. Somebody on geo metro forum might know, but be warned, that place is about as 'tard heavy as it gets and I would not take any tech advice seriously.

The closest to actual info I ever found on the injector size was the results of a Witchunter clean and test

If it really is over 600cc that is massively oversized for its use case. But it would be plenty for yours.

It has been a long time since I had one in my hands. I do not remember if there was a vacuum line to the fuel pressure regulator that would act as a "rising rate" unit. 
 

This might be "fine" at 10 psi though. I ran a fixed 45psi fuel pressure and even at 21 psi it worked well enough, it is just that with 10psi of pressure in the intake, you now only have 36 psi at the injector which could negatively affect the spray pattern and cause your map to look a bit odd after tuning. 

In reply to Peabody :

Was hoping you'd chime in

Those tbi's run at about 10psi fuel pressure normally, and I do believe they are vac sensing

Peabody said:

Those tbi's run at about 10psi fuel pressure normally, and I do believe they are vac sensing

That would explain the 621cc at 43.5 psi bit.

10 psi would not be enough to counteract the boost pressure. 10 psi in the manifold and 10psi of fuel would result in no fuel being injected

I'm pretty sure it has the vac/boost sensing ability, but I was just surprised they would test it at that high pressure. Is there any TBI that uses high pressure like that?

I do know most, if not all of the low budget turbo installs on metros were using extra injectors, or cold start injectors for enrichment, but they also were on the stock ECU. If I recall the stock TBI/ECU was capable of about 4psi with no mods or tuning at all.

So it sounds like this is a viable option for getting started. As always, this forum is the best!

I asked about injector flow rate on a couple of the Suzuki groups on FB. I was just thinking, the pressure regulator on these is internal. I'm sure there's a way to bypass or modify it. Like I said, it's been done,  just have to find the right people.

I still have not ruled out using Retroject or even doing a Jenvey single throttle body. The nice thing about that would be able to easily size the injector since they use Bosche or Pico injectors. The Retroject has all the sensors included and can also size the injectors to my application. But if I can play around with something cheap that will do the job, that is what lead me to look at the Geo TBI, when I saw the small footprint and that it was small engine displacement.