ok, what the fuck is a "throttle body" and why should i care about how big it is?

[chr|s sedition]

see subject line.

educate me,
-sedition

[Degsy]

It's the fuel injection version of a carburettor, and the bigger it is, the more fuel flows through it and the faster the bike goes.

[ancosta]

The throttle body is the mechanism where air comes in from the air filter and into the intake manifold.

In an TBI, or throttle body injection setup, the throttle body functions like a carb, as the fuel injectors sit in throttle body, and the air/fuel mix is sent into the manifold.

Today virtually all manufactuers (of cars and bikes) use "port" fuel injection, otherwise called EFI. Air is routed into the intake manifold, where it is mixed with gas via fuel injectors. The atomized mixture is then routed into the combustion chamber to be burned.

Bigger is not better with throttle bodies. They have to be matched according to several factors, including: fuel injector size, pressure regulator & fuel pump rates, intake port length & size, cam size & timing, ignition timing, exhaust flow, head port flow, etc. etc. etc.

All parts of the fuel system should be matched to yeild a stoichiometric (fancy word for 'ideal') air:fuel ratio. For gas engines, the ratio is 14.6 parts air to 1 part gas. This condition will lead the fuel and o2 to be completely consumed, resulting in more efficiency, power and reduced emissions.

In my exerience it's generally best to use a proven combination of parts, usually selected by the manufacturer, aftermarket tuner, or otherwise "wicked smaht" person.

[Suf Daddy]

Motor is a air pump.

More air in means more power out........

Its like breathing through a straw. The bigger the more air you get.

-Suf Daddy

[Daytona440]

Originally posted by ancosta
The throttle body is the mechanism where air comes in from the air filter and into the intake manifold.

In an TBI, or throttle body injection setup, the throttle body functions like a carb, as the fuel injectors sit in throttle body, and the air/fuel mix is sent into the manifold.

Today virtually all manufactuers (of cars and bikes) use "port" fuel injection, otherwise called EFI. Air is routed into the intake manifold, where it is mixed with gas via fuel injectors. The atomized mixture is then routed into the combustion chamber to be burned.

Bigger is not better with throttle bodies. They have to be matched according to several factors, including: fuel injector size, pressure regulator & fuel pump rates, intake port length & size, cam size & timing, ignition timing, exhaust flow, head port flow, etc. etc. etc.

All parts of the fuel system should be matched to yeild a stoichiometric (fancy word for 'ideal') air:fuel ratio. For gas engines, the ratio is 14.6 parts air to 1 part gas. This condition will lead the fuel and o2 to be completely consumed, resulting in more efficiency, power and reduced emissions.

In my exerience it's generally best to use a proven combination of parts, usually selected by the manufacturer, aftermarket tuner, or otherwise "wicked smaht" person.

Well said. Kudos!

[Honclfibr]

Originally posted by ancosta
The throttle body is the mechanism where air comes in from the air filter and into the intake manifold.

In an TBI, or throttle body injection setup, the throttle body functions like a carb, as the fuel injectors sit in throttle body, and the air/fuel mix is sent into the manifold.

Today virtually all manufactuers (of cars and bikes) use "port" fuel injection, otherwise called EFI. Air is routed into the intake manifold, where it is mixed with gas via fuel injectors. The atomized mixture is then routed into the combustion chamber to be burned.

Bigger is not better with throttle bodies. They have to be matched according to several factors, including: fuel injector size, pressure regulator & fuel pump rates, intake port length & size, cam size & timing, ignition timing, exhaust flow, head port flow, etc. etc. etc.

All parts of the fuel system should be matched to yeild a stoichiometric (fancy word for 'ideal') air:fuel ratio. For gas engines, the ratio is 14.6 parts air to 1 part gas. This condition will lead the fuel and o2 to be completely consumed, resulting in more efficiency, power and reduced emissions.

In my exerience it's generally best to use a proven combination of parts, usually selected by the manufacturer, aftermarket tuner, or otherwise "wicked smaht" person.

You, sir, are no fish

[chr|s sedition]

Originally posted by ancosta
or otherwise "wicked smaht" person.

in this case, that person would be you. thanks for ed-u-ma-cating me.

-chr|s sedition

[Stoneman]

ancosta: could you be a bit more specific???

Good descript!!!

[richw]

E lectronic F uel I njection

Nozzles at each cylinder are

Multi port fuel injection
Seperate nozzles just above intakes so no gas wetted down the inside of a manifold so computer give tree hugger gas amount at each firing not the 12 to 1 for max power.

Also you always want the air after leaving the air cleaner to stay moving with inertia so that the thottle bodies one you control and one the computer controls open at a rate the engine can inhale so no "bog"

[ancosta]

Originally posted by Stoneman
ancosta: could you be a bit more specific???

Good descript!!!

Sorry got a little rainman with my answer. One of my biggest character defects

[Stoneman]

Originally posted by ancosta
Sorry got a little rainman with my answer. One of my biggest character defects

Not at all! it would be a flaw I had asked you if you wanted a drink and replied with something that in depth...

[RandyO]

Originally posted by ancosta
Today virtually all manufactuers (of cars and bikes) use "port" fuel injection, otherwise called EFI. Air is routed into the intake manifold, where it is mixed with gas via fuel injectors. The atomized mixture is then routed into the combustion chamber to be burned.

YES, almost all vehicles have EFI (Electronic Fuel INjection) but I'm not sure about the rest of your statement

some vehicles have multi-port fuel injection, some have throttle body injection

on my bimmer I have individual injectors for each cylinder (multi-port) on my winter bomb chevy, it's one injector in a throttle body

[ancosta]

Originally posted by RandyO
YES, almost all vehicles have EFI (Electronic Fuel INjection) but I'm not sure about the rest of your statement

some vehicles have multi-port fuel injection, some have throttle body injection

on my bimmer I have individual injectors for each cylinder (multi-port) on my winter bomb chevy, it's one injector in a throttle body

I thought that it rolled off in the early 90's. Maybe some of the pushrod motors still used it later than that? I think it would be tough to find a OHC motor using TBI, but that is more of a guess.

[R7]

Originally posted by RandyO
YES, almost all vehicles have EFI (Electronic Fuel INjection) but I'm not sure about the rest of your statement

some vehicles have multi-port fuel injection, some have throttle body injection

on my bimmer I have individual injectors for each cylinder (multi-port) on my winter bomb chevy, it's one injector in a throttle body

It doesn't matter what type of injection system or carburator it has, it still has a throttle body

[ancosta]

http://auto.howstuffworks.com/fuel-injection.htm

They 'splain it better than I can

[GMAN226]

Originally posted by Degsy
carburettor

You spelled that wrong .. Damn Brits


G-man

[RandyO]

Originally posted by R7
It doesn't matter what type of injection system or carburator it has, it still has a throttle body

there's nothing called a throttle body on my old Vanagon or bimmer.... air flow meter? the injectors go right into the head... both have antiquated Bosch K jetronic

[R7]

What's your throttle cable hooked to??

[richw]

Your metamorph catapiller is residing in your manifolds throttle body

[RandyO]

Originally posted by R7
What's your throttle cable hooked to??

the air flow meter

[benVFR]

I think with bikes maybe they are using the terms different?

The throttle body is the housing with the throttle butterfly in it right? It opens with throttle input to allow more air in? Same place where the mass air meter is in a car, but the bike is missing the air flow sensor?

[R7]

Originally posted by benVFR


The throttle body is the housing with the throttle butterfly in it right? It opens with throttle input to allow more air in?

You sir, are correct You can call it a air meter, air valve, throttle boby or whatever other fancy term each manufacturer wants to call it.

BTW, my bike has a twist grip on it and not a twist throttle

[RandyO]

Originally posted by R7
You sir, are correct You can call it a air meter, air valve, throttle boby or whatever other fancy term each manufacturer wants to call it.

BTW, my bike has a twist grip on it and not a twist throttle

But my point is I DON"T have throttlebody injection,

[R7]

Originally posted by RandyO
But my point is I DON"T have throttlebody injection,

I know you don't, you told us that a few posts up
But it does have a thottle body

[RandyO]

Originally posted by R7
I know you don't, you told us that a few posts up
But it does have a thottle body

If you want to call it that, but if you go to a parts store looking for one you won't get one,