JoeVK

I am looking at a system that uses 4 injectors in a 4bbl throttle body, hence you just replace you carburetor and utilise EFI pump and EFI computer.

Whats the dis & advantages from performance and drivability point of view, say compared to 8 port injectors both using the same torker type manifold and throttlebody?

Cheers, Joe

greenhj

ive looked at this setup, first problem is 4 injectors need to be sized twice as big as a stock setup, if your pushing 400 ponies you need injectors capable of at least 100 odd horsepower each which is a decent size.

This might be a little hamfisted for getting the duty cycle down enough for decent idle fuelling, may as well keep the carb as the ONLY advantage with efi is idle and part throttle fuel trim.

Problem two, and this is a biggy (IMO)

Lets say on a stocker one injector fails, that cylinder gets no fuel, big deal...

Lose 1 of 4 in the throttle body, BIG PROBLEM, leanout city in all holes..Unless you can maybe use them in series where one fails and all fuel stops, wire it thru the ignition and kill the spark before you kill the engine..

One advantage to the setup, better atomisation of the af mix compared to standard because it happens in the plenum rather than the chamber so by rights it should make more power than standard efi, think about a serious efi car with individual throttle bodies, the injectors are as far from the valve as possible to get the emulsion right before its in the chamber.

I wouldnt do it personally but plenty have so maybe im an idiot lol.

hope this helps...

allports

You'll wind up with a bunch of fuel reversion in the air cleaner. I've got a mate who has this set up, he's been trying for years to sort it out. WOFTAM. By the way he doesnt listen. If your gonna go efi just go efi, dont do it by halves. You'll end up with a system that is a wet system similar to a carb with fuel in the plenum and runners with wiring and a computer and a surge tank. Why not just stay carby?

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If you plant a cucumber, you get a cucumber!
Two things are infinate,the universe & human stupidity, and Im not sure about the universe.
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Without deviation from the norm, progress is not possible. Frank Zappa

JoeVK

Thanks for your input greenhj, allports,

Why not carby? Well I was going to try this system Retrotek - Powerjection 1 System

and see if it works. It got some good reviews in the USA at SEMA. I had a look at the software and you have a VE table to tune and there is self learning capabilities in the ECM for the ones who cannot tune.

allports

The nozzle is too high in the plenum for part throttle driving. You'll get fuel up in the aircleaner. Last word on that from me on this thread.

__________________
If you plant a cucumber, you get a cucumber!
Two things are infinate,the universe & human stupidity, and Im not sure about the universe.
Albert Einstein
Without deviation from the norm, progress is not possible. Frank Zappa

TK383

The yanks love TB injection coz they're too damn stupid to figure out real injection.
Stick with carb or do it properly, 1/2 measures always turn out crap.

PS - I run injection on my ol red mota, TP intake drilled for injectors, custom fuel rails, 2x V6 dunnydore TB's on an active hat, bosch 720cc injectors, microtech LT8s with X4 box set up for direct fire wasted spark ignition with hyundai coil packs & VT dissy hooked up as a crank trigger.
Most of the bits are second hand &/or out of date - so it cost me bugger all.
Works sweet, tuning is via laptop, mate who is a decent tuner in the passenger seat with said laptop & 1/2 a day running through the hills tuning on the fly had it mapped.