Throttle Bodies
Moderator: martauto
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coolq
- E30 Zone Newbie
- Posts: 98
- Joined: Tue Aug 23, 2005 11:00 pm
- Location: Norfolk
can anyone help me as to what they do, as ive now become confused, initially i though they were the final part which is on the end of the intake that will increase the air flow system, like the one found on the zone shop for 160 with a 17% airflow increase, ive now seen a thread where a guy has 6???? are there 2 different types and what do they do??
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Ant
- Retired Team Member
- Posts: 10496
- Joined: Tue Dec 21, 2004 11:00 pm
- Location: PD+E dept :D
Tb is indeed a sinlge throttle plate , uesd in conjuction with a plenumn of some sort to feed all cylinders in the engine.
ITBs are a throttle for each cylinder, bigger airflow due to increased overall throttle area, no pulse tuning issues to worry about and allows a massive lumpy cam and still have decent idle.
HTH simple as I can make it fella
ITBs are a throttle for each cylinder, bigger airflow due to increased overall throttle area, no pulse tuning issues to worry about and allows a massive lumpy cam and still have decent idle.
HTH simple as I can make it fella
Product Development and Endurance for Delphi.
Original performance chips, original works not unlicensed copies
Email FTW
Original performance chips, original works not unlicensed copies
Email FTW-
Turbo-Brown
- Boost Junkie
- Posts: 4705
- Joined: Tue Feb 15, 2005 11:00 pm
- Location: Aldershot, Hants
Hope you don't mind Coolq, here's the answer to the PM for people's comments:
Think the basic score with individual throttle bodies (ITBs) is that they improve throttle response and allow a clean and direct path for the air into the engine. Some people quote around 10% gains using ITBs, but this will vary from engine to engine depending on how good the original plenum type intake system was.
Thottle response is generally improved as the volume of air between the throttle plate and cylinder head is massively reduced with ITBs so the air doesn't need to fill a whacking great plenum before the engine sees it. However, on an M20 where the original engine management is a bit slow, the difference when using ITBs would be huge as you'd need to buy an aftermarket engine management system too, which in it's own right would improve the response.
ITBs greatest benefit is when using lumpy cams which, at idle, create lots of pulsing in inlet systems. With a plenum, one cylinder can kind of nick the air from another which of course means that one cylinder doesn't fire as strongly as the others giving rise to the rough idle. With the ITBs though, there is no (or much less) interaction between the cylinders as air is metered into each one indicidually. This gives a much smoother idle
Don't think of the throttle as something which gives the engine air, think of it as something which takes it away. It acts like an attenuator if you like. The engine can consume an absolute maximum amount of air per revolution, dependant on the head design, number of valves per cylinder, inlet design and a million other factors.
If there was no throttle and the engine was running, it would rev up to the air flow capability of the engine. Of course, you canÔš't have that in a car as you need the engine to be adjustable for speed. The throttle prevents the engine from consuming air in any great quantity when closed, and allows adjustment of the air flow depending on how far open it is.
The Zone BBTB has a larger bore than the standard throttle body. The fact that it increases power can only mean that the engine design is capable of consuming more air than the original throttle could flow.
Hope thatÔš's of some help!
Feel free to pop me any other questions mate
Think the basic score with individual throttle bodies (ITBs) is that they improve throttle response and allow a clean and direct path for the air into the engine. Some people quote around 10% gains using ITBs, but this will vary from engine to engine depending on how good the original plenum type intake system was.
Thottle response is generally improved as the volume of air between the throttle plate and cylinder head is massively reduced with ITBs so the air doesn't need to fill a whacking great plenum before the engine sees it. However, on an M20 where the original engine management is a bit slow, the difference when using ITBs would be huge as you'd need to buy an aftermarket engine management system too, which in it's own right would improve the response.
ITBs greatest benefit is when using lumpy cams which, at idle, create lots of pulsing in inlet systems. With a plenum, one cylinder can kind of nick the air from another which of course means that one cylinder doesn't fire as strongly as the others giving rise to the rough idle. With the ITBs though, there is no (or much less) interaction between the cylinders as air is metered into each one indicidually. This gives a much smoother idle
Don't think of the throttle as something which gives the engine air, think of it as something which takes it away. It acts like an attenuator if you like. The engine can consume an absolute maximum amount of air per revolution, dependant on the head design, number of valves per cylinder, inlet design and a million other factors.
If there was no throttle and the engine was running, it would rev up to the air flow capability of the engine. Of course, you canÔš't have that in a car as you need the engine to be adjustable for speed. The throttle prevents the engine from consuming air in any great quantity when closed, and allows adjustment of the air flow depending on how far open it is.
The Zone BBTB has a larger bore than the standard throttle body. The fact that it increases power can only mean that the engine design is capable of consuming more air than the original throttle could flow.
Hope thatÔš's of some help!
Feel free to pop me any other questions mate
)