I'm reading an article in one of the cruise magazines that we have here in Florida. The name of the article is "10 Engine Wives Tales Debunked". #2 Fuel injection always makes more power - Fuel injection does a great job when throttle position changes often. For types of racing where the throttle is wide open most of the time (i.e. drag racing), a carburetor is a formidable opponet - especially when matched against throttle body injection.

I know what fuel injection is and I know where the throttle body is, but what is "Throttle Body Injection".

Is that whats on the FI Z's?

Vicky

Throttle body injection is what you see on older GM cars, where the throttle body looks almost like a carburator sitting on the intake, yet, it is not a carburator. Instead of having jets, etc.. they usually have 2-4 large injectors that dump the fuel into the intake runners. The air and fuel both are metered in the throttle body on a TBI system. The aftermarket Holley Pro-Jection systems are a TBI system, like this.

Z's have a port injection system, where the injector shoots the fuel directly into the intake port on the head, with a separate injector controlling each cylinder, while the air mix is metered before the intake.

Thanks 2ManyZs. Great explaination and super picture. I'm getting so smart................

Vicky

I wonder,,,, if you were running a set of down draft webers, could you adapt those Holley squirters somehow? That might be cool. Just dreaming folks!!!

Originally posted by ChrisA

I wonder,,,, if you were running a set of down draft webers, could you adapt those Holley squirters somehow? That might be cool. Just dreaming folks!!!

Great idea (dream) ChrisA. I'd like to here some feedback on that also.

Vicky

down draft carbys on a L6 no no

The ports in the head are designed for side draft.. they flow the best..

Originally posted by Zrush

I'm reading an article in one of the cruise magazines that we have here in Florida. The name of the article is "10 Engine Wives Tales Debunked". #2 Fuel injection always makes more power - Fuel injection does a great job when throttle position changes often. For types of racing where the throttle is wide open most of the time (i.e. drag racing), a carburetor is a formidable opponet - especially when matched against throttle body injection.

I know what fuel injection is and I know where the throttle body is, but what is "Throttle Body Injection".

Vicky

How old is that article?

I'm sure most mordern EFI is Injected right into the Manifold as close to the Intake. Not at a the Throttle Body.

And i'm pretty sure engine manufactures are expermenting with direct injection into the cylinder.

Hey Craig, I dont know how it is in OZ, but you'd be surprised how many Chevrolet trucks are TBI in the US. I have a 4 of 99 S-10 and its throttle body injected. Thats pretty modern no?

My response to 280ZX fever is: I have seen many Z's running the down draft webers that Victoria British used to sell, (they still might). I think Motorsport Auto may sell them also. Yes, they do I just checked. Weber DGV carb kit. Looks to be downdraft to me. They cant be too bad or people wouldnt run them right? My old 200SX was downdraft before I switched to twin SU's. Basically the same motor less two cylinders. Can you share as to why they would be no good?

What 280zx Fever is saying is that downdrafts are less efficent on an L engine because of the sharp turn the fuel mixture must make. On a 'V' engine the fuel mixture goes down into the heads. Sidedrafts send the fuel mixture in a straight shot as does the Bosch type fuel injection. Plus the Weber, Mikuni, or Delortos give you one barrel per cylinder.

The L28 on a 280c has 135HP with a down draft carbie and manifold.

Take that off and put on twin SU's and manifold from a Z and it will rise to at least 170HP.

Originally posted by ChrisA

I wonder... if you were running a set of down draft webers, could you adapt those Holley squirters somehow? That might be cool. Just dreaming folks!!!

Interesting idea... Somehow you could rig up an old carb, but remove everything but the throats & butterflies, then screw in 4 or 6 smaller injectors (using the stock F.I. computer) to work like a carb. You'd have to bypass the AFM somehow, so the computer gets the air flow data from the throttle linkage position instead of the flapper.

cross over to this thread guys, and you'll find out a bit more!

http://www.classiczcars.com/forums/showthread.php?s=&threadid=10145&highlight=Throttle+body