Individual throttle bodies. How to size them?

[Milanoguy]

Hi

I’m looking for some guidance on building an individual throttle per cylinder setup for a street legal 60 degree V6 motor.

How should I size the throttle plates ? The motor has one intake valve and one exhaust valve, and electronic port fuel injection. The intake valve is 44mm. I’m assuming that the throttle plate should be sized in relation to the intake valve.

The big reason behind this project is my understanding that individual throttles give better throttle response. If this is not the case, I ‘d be interested in hearing why.

 

[mattsooty]

I don't have the info to hand about throttle sizing - however I would be interested to know how you intend to sort out the idle speed control....?

MS

 

[awhittle]

see

http://www.ncs-stl.com/crx

That car was a Honda CRX with a B16A Honda V-tec motor with 4-42mm throttles. The big problems will come in the low speed low throttle angle driving. That motor would go to full torque any time below about 4000 RPM and about 15% throttle application. This all looks great at the car show but living with them is another story. Most of the HP fun will fade away when you try to build a effective air filter/ air box.

Andy

 

[Warpspeed]

I don't see this as a problem. The throttle size just matches the port cross section at the point of mounting. For practical reasons they cannot be made any larger, and making the throttles smaller makes no sense.

There is going to be a definite relationship between intake valve size, and port cross sectional area, and that just about fixes the throttle diameter.

 

[ramblerman]

I'm using an open source engine management system called MegaSquirt. On their website they have a calculator to use based on the expected horsepower of the engine. The algorithm it uses appears to be this:
((# of throttle bores) * (throttle bore in mm)squared)*.0575=horsepower
For more info, you might want to go here:

http://www.megasquirt.info/v22manual/mfuel.htm#inject

and here

http://www.megasquirt.info/v22manual/minj.htm

hope this helps!