Throttle Bodies size??

[Davey]

I too went for 38mm throttle bodies for my V6 2.9 Cosworth lump, mainly because they were available cheaply but also because its close to the same CSA as the inlet ports on the heads. The butterflies are close to the 200mm optimum (for road use) from the valves so I anticipate it will be a very tractable power plant from low revs. Personally I really don't get on with peaky high revving motors where all the power is at the top end, I much prefer some good honest low down torque. Torque turns wheels!

D.

[Cyberbeej]

Originally Posted by Davey

I too went for 38mm throttle bodies for my V6 2.9 Cosworth lump, mainly because they were available cheaply but also because its close to the same CSA as the inlet ports on the heads. The butterflies are close to the 200mm optimum (for road use) from the valves so I anticipate it will be a very tractable power plant from low revs. Personally I really don't get on with peaky high revving motors where all the power is at the top end, I much prefer some good honest low down torque. Torque turns wheels!

D.

Hey davey, can i ask if your using the BOA or BOB engine?

I'm currently building 6 individual butterflies for the BOB (would say throttle body but the injector is in the head) Using 45mm butterflies as the cross sectional area is just slightly over the head port size so as not to cause any restriction and they were also what was available at the time.

I prefer torque over high rpm, hence 2.9 V6 cosworth engine.

[monsterob]

Pictures work ok on my phone I can't get the forum links as I'm on the phone

[TheArf]

Do those come with a flake

Arfon

[Toyotus]

Maybe a bad example of Toyota attempting to re-engineer an ancient engine, but the Blacktop 4AGE has 45mm throttle bodies, injectors in head, and only a claimed 165hp, so something like 41hp/cyl, compared to the 65hp/cyl listed here for the 45mm throttle body. It appears they were just throwing more air and fuel in hopes of higher outputs, as opposed to smaller diameter increasing intake velocity. Similar to the 16v 4AGE attempts at more power with larger intake ports, and steeper valve angles, then later going to shallower angles and smaller intake ports.

Interesting figures though, obviously lots of trial and error I'm sure too!

[robo]

Originally Posted by Toyotus

Maybe a bad example of Toyota attempting to re-engineer an ancient engine, but the Blacktop 4AGE has 45mm throttle bodies, injectors in head, and only a claimed 165hp, so something like 41hp/cyl, compared to the 65hp/cyl listed here for the 45mm throttle body. It appears they were just throwing more air and fuel in hopes of higher outputs, as opposed to smaller diameter increasing intake velocity. Similar to the 16v 4AGE attempts at more power with larger intake ports, and steeper valve angles, then later going to shallower angles and smaller intake ports.

Interesting figures though, obviously lots of trial and error I'm sure too!

I think its a valid point. years ago I had a twincam escort which was tuned <or should I say ruined> and most people were saying stick some 45`s on it, when I got to the weber agent he choked down the 40`s I had to 33mm . That was a 150hp engine.

Bob.

[Davey]

Originally Posted by Cyberbeej

Hey davey, can i ask if your using the BOA or BOB engine?

I'm currently building 6 individual butterflies for the BOB (would say throttle body but the injector is in the head) Using 45mm butterflies as the cross sectional area is just slightly over the head port size so as not to cause any restriction and they were also what was available at the time.

I prefer torque over high rpm, hence 2.9 V6 cosworth engine.

I have the BOA from a 1990 Granny, 64,000 miles and full service history:-D.

D.