Throttle body

[anton1o]

exactly, freind made 97rwkw with cai&v8 tb.

 

[stockvp]

if ya got a series 2 just take out the plastic bellmouth out in between the inlet manifold and throttle body this you will definitely notice even without upgrading the throttle body

 

[greenfoam]

exactly, freind made 97rwkw with cai&v8 tb.

But what did he make before the CAI and TB on the same dyno on the same day, because plenty of VNs and VP have pulled 105 rwkw dead stock. The stock V6 can only breath about 380cfm of air. The stock TB flows almost 500cfm. Where's the extra power come from?

 

[1991_Vn2nV]

I dunno if this is right or not.. But isnt that because it only sucks in air every second rev as is a 4 stroke?

The throttle body is capable of almost 500cfm at a constant flow rate, but the engine is capable of well over 600cfm at a constant flow rate, its just that the engine only sucks in air every 2nd rev... But effectively, it is being restricted by the throttle body?

 

[CSL]

i dont think power can be made, the difference your feeling is all response, and they aint nothing wrong with that

 

[1991_Vn2nV]

Cubic Feet per Rev is perhaps a better measurement than cubic feet per minute as the engine only sucks in air every second rev, so after alot of calculations I managed to get the following figures & a headache:

3.791L = 0.13386021 cubic feet per rev maximum

63mm Throtte Body = 0.0882915957 cubic feet per rev...

71mm Throttle Body = 0.1263783741 cubic feet per rev...

But I believe after the throttle body it is restricted to 68mm at some point, so a 71mm throttle body is only going to get as much as a 68mm throttle body...

68mm = 0.1110259392 cubic feet per rev...

So I THINK they are the max flow rates for the throttle bodies, in comparison to the max flow rate for the engine. But there would be more air in the engine past the throttle body too, so the actual amount of air that the engine sucks in is higher than the max flow rate of each throttle body... But the point is a larger throttle body DOES help.

 

[stocky]

i wonder what the surface area of the TB opening is like compared to the original intake or the neck of the VS CAI

 

[greenfoam]

Cubic Feet per Rev is perhaps a better measurement than cubic feet per minute as the engine only sucks in air every second rev, so after alot of calculations I managed to get the following figures & a headache:

3.791L = 0.13386021 cubic feet per rev maximum

63mm Throtte Body = 0.0882915957 cubic feet per rev...

71mm Throttle Body = 0.1263783741 cubic feet per rev...

But I believe after the throttle body it is restricted to 68mm at some point, so a 71mm throttle body is only going to get as much as a 68mm throttle body...

68mm = 0.1110259392 cubic feet per rev...

So I THINK they are the max flow rates for the throttle bodies, in comparison to the max flow rate for the engine. But there would be more air in the engine past the throttle body too, so the actual amount of air that the engine sucks in is higher than the max flow rate of each throttle body... But the point is a larger throttle body DOES help.

Do all the crazy sums you want I'll try find you a calculator.

Ok something like this

http://www.4secondsflat.com/Carb_CFM_Calculator.html

The stock V6 has a VE of about 85% and peak revs no more than 5500

Going from a 65 mm throttle to a 70 on the 304 does give you a little 5-10rwkw increase (only in the very last 1-2000 revs) on a semi worked motor but that's an engine that breaths ALOT more air than the V6

 

[greenfoam]

i wonder what the surface area of the TB opening is like compared to the original intake or the neck of the VS CAI

The CAI can flow to about 170rwkw? as seen in a certain supercharged UC hatchback

 

[1991_Vn2nV]

Bah each to their own

I believe it makes a difference and I believe cubic feet per rev is a better way of measuring it, you believe it doesnt make a difference and that cubic feet per minute is better way of measuring it... Im not disputing the calculator because its obviously correct... Yes the engine needs 318.629 cubic feet per minute flow. But the engine only sucks in air every second rev, so I think measuring it by the amount of cubic feet of air it needs each time it sucks in compared to what the throttle body allows is a better way of measuring. But its just a difference in opinion