B series throttle body sizes?

[GSi_PSi]

Hey can anyone tell me the sizes of B16, B18C, B18B and B18CR Throttle bodies?....... also what would be the best T/B setup for a B20?

[Mugen_R]

b16a, b18c2, b18b = 60mm
b18c7 = 62mm

[Chr1s]

It's hard to hit the hammer with best throttle body for a B20, It all depends on how well you can get the air in there in the first place, ie - camshafts and intake manifold

In terms of single throttle design, a well designed/worked manifold with a 68mm throttle and capacity for the motor to breathe that hard is best. Otherwise 64mm could suffice.

[GSi_PSi]

so im bottle necking my engine hard by running 60mm throttle body and B16a intake manifold

[fatboyz39]

Unless your WOT all the time then b16a t/b and manifold works pretty well with b20. Good response and down low torque.

[ALLMTR996]

Simple rule of thumb for a STD type B20Vtec builds with anything smaller than ITR cams and a good flowing header/exhaust package.

big runner manifold large plenum small TB

small runner manifold small plenum big TB

[Chr1s]

I didn't know people built motors NOT to put their foot to the floor Jimmy?

[fatboyz39]

I didn't know people built motors NOT to put their foot to the floor Jimmy?

How far can you go for the streets? speed limit.

[Chr1s]

How far can you go for the streets? speed limit.

lol....that was a very realistic comment, should stick to your B16s then..

[Benson]

lol....that was a very realistic comment, should stick to your B16s then..

Some people like the low end torque to cruise around

[Chr1s]

You have got to be kidding me...

partial throttle on a 68mm throttle is terrible now is it?

[GSi_PSi]

well id rather a car that goes fast throughout the whole rev range. And dont B series motors love to breathe?...
If ive slapped in ITR cams what throttle body size?.....

[Chr1s]

I'd go 64mm and work the manifold slightly

[TODA AU]

My 5c worth of advice is for guys with basic to mild B-series builds is to stick to an OEM throttle & manifold.
This will not only deliver good results more easily, it’ll save you wasting money on products where your return on investment is poor.
For serious engine builds where maximum output is required…
I'm still yet to see a B-series with a plenum actually benefit from a using throttle any larger than 65mm.

For GSi_PSi I’d say keep your B16A intake manifold & use a 62mm ITR throttle or a Spoon one if you can get your hands on one.
You’ll need to sort out the entrance to the plenum too.

As for part throttle on a 68mm,
To be frank, on most B-series applications it is actually crap.
& again with most B-series applications the 68mm (or larger) throttle suffers from a lack of air speed…
This can be readily seen as a loss in power through back to back testing against smaller units.
Combined with low air speed, 100kpa (MAP) can be achieved with as little as 33% throttle application. (70mm throttles are even worse)
So the net result is a narrowing of the tuning resolution in most applications or necessitates the use of secondary tables & or TPS mapping.
Not an issue for some, but bothersome in any case. Particularly when the benefit is difficult to even measure if not justify.

On another note, what aught to be said is the intake length & diameter is a lot more important than the throttle size.

[Chr1s]

To quote you quickly,

"on most B series applications it is actually crap"

I've seen kids here running 68mm throttles on a near stock B16A, no surprise.

[Aydin]

go with oem honda man just get a b18c7 (typr r) t/b there 62mm and there oem ive herd aftermarket t/b are sticky and after driveing the car a bit hard they get stuck and u lose driverbillity

[AXS]

go with oem honda man just get a b18c7 (typr r) t/b there 62mm and there oem ive herd aftermarket t/b are sticky and after driveing the car a bit hard they get stuck and u lose driverbillity

sticky, yes thats true but not as bad as it sounds, like all cars you get used to it and adjust driving according to how the car wants to be driven, i used a 68mm tb and 68mm ported intake manifold both skunk2 and running on a stock computer i have seen a really good torque gain and overall power...B20 you say? as iv seen your build tread you have some serious internals done id go with the 70mm Tb and port your IM to the same size, that way youl have a smooth transition of air, no restriction.

hope that helps!