I saw an ad in a local magazine here in south africa for carb to fuel injected modification. Dont know wether its electric or not. They put an injector into the venturi of the carb with fuel rail ontop. The ad was for a v8 4 choke carb in the pic.
Does anyone know anything about this setup, how well does it work, does it improve power or economy?
Ive never heard about something like this. Any info would be appreciated thanx!

Yes, it works, and works well. They probably don't have a kit for small engines, as the V8 market is bigger.

This type of setup is basic EFI . You could call it CFI (central fuel injection) instead of the better tuned-port (individual runner) system. It will increase fuel economy and smoothness dramatically if controlled correctly. You'll get at least the same horsepower as the carburetor, but probably a bit more. With a purpose built intake manifold the HP increase will be more optimized.

Here's one for Datsun A-sereies engine, on a stock manifold:


Downdraft EFI

Nice idea, in SA it is better getting a set of Toyota RXI throttelbodies (R1200-R1500) at a scrapyard, make a manifold and buy Gotech, Mr Turbo, Dictator EFI or something similar, wire it and get it mapped.

But be warned, this is a expensive upgrade.

I'm interested to know how well this EFI set-up would perform, i assume you could run a fuel only ECU?

The add was for holley v8 carb or weber, im asuming any weber will work, so i can efi my a14 and L16 with a weber swap at R380 thats around, 40 to 50 dollars us! Then just get ecu and on the way!

early mitsubishi cordias used a similar "centre point injection" idea

i think some ford falcons did too in the early days?

theres probably heaps of production models that received a similar injection system

i think the hardest part of injecting (besides paying for the ecu) is the fuel system, if your going to the effor tof everything else put in the extra what 10-20% effort to get the injection manifold sorted

What needs to be done to the manifold?
As i undestand its normal carb system just with carb mods, ecu and propably elec fuel pump. Would there be anything else?

They work well primarily because you have a (more or less) infinitely tunable setup to provide the right amt of fuel for whatever airflow/conditions/driving style is experienced at any given moment.

One thing to be careful of, however, is that the point of injection is relatively remote from the intake valve/cylinder, so you have to give more thought to fuel distribution, or more specifically how _that_ is affected by the inlet manifold choice. You're still going to risk (albeit to a likely lower extent) mixture distribution inconsistency/fuel dropout if (and its a very important if) the manifold it is fitted to isn't ideal on mixture distribution to start with.

What _will_ probably come as a shock is the fact that introducing fuel earlier on (provided you pay attention to the above issues, if they arise) gives it more time to cool the intake charge, which leads to greater intake charge density, and a small gain in power vs efi that is metered in near the manifold/head meeting point, and much nearer the valve. It's not uncommon on dedicated race setups (where allowed) to find injector placement to be very high - even outside the intake trumpet/bellmouth in some cases.

One thing is absolutely certain, it will outperform _any_ carb that isn't 100% optimised for he application (and is generally a hell of a lot easier to optimise than said carb setup)

You guys are making me think now! Im going to look into that toyota ITB With a feul only managment system

You can use many factory OEM controllers in a fuel-only setup for cheap. Get the ECU and all the wiring and sensors.

The hardest part is the fuel. You need a medium pressure fuel pump and a surge tank (swirl pot) , or a new fuel tank.