Valve Diameter, Throat Area, Port Area?

Posted By: @#$%&*!

Valve Diameter, Throat Area, Port Area? - 12/22/09 06:04 PM

Just wondering if there are any rules-of-thumb or general guidelines on the relationship between the valve diameter, throat area below the valve, and the minimum area of the port tract.
Thanks in advance and happy holidays.

Posted By: B G Racing

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 06:54 PM

Quote:

Just wondering if there are any rules-of-thumb or general guidelines on the relationship between the valve diameter, throat area below the valve, and the minimum area of the port tract.
Thanks in advance and happy holidays.

This subject can be discussed endlessly,but the most important is a smooth transition from the valve pocket to the port runner and gain as much area and the lest obstruction as possible without weakening or damage the head.

Posted By: moderncylinder

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 08:14 PM

Quote:

Just wondering if there are any rules-of-thumb or general guidelines on the relationship between the valve diameter, throat area below the valve, and the minimum area of the port tract.

yes,,, there are

Posted By: sg66mopar

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 08:38 PM

Hey Cory

Does this mean we're going faster next year?

Posted By: BradH

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 08:40 PM

You need to ask this on SpeedTalk.com; Moparts isn't technical enough anymore to answer this kind of question...

Posted By: moderncylinder

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 08:57 PM

i did answer his question,, all he asked was if there were general rules for a few parameters,,, he didnt ask what they were..

Posted By: LA360

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 09:10 PM

From memory it was around 90-93%

Hopefully Jeff corrects me if I am wrong.

As mentioned, Speedtalk is an excellent forum for these kind of questions, do a search there before you ask.

AL....

Posted By: @#$%&*!

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 09:50 PM

Quote:

This subject can be discussed endlessly

Well, I wouldn't want to start an endless discussion, and certainly not a debate.

[yes,,, there are

The thanks-in-advance weren't meant to be sarcasm in advance... Merry

to you.

Quote:

Hey Cory, Does this mean we're going faster next year?

I know you are. This is about another engine/car entirely. If I get that roller cam for xmas then yes, WE are going to be faster. Still, I don't plan to run under 10 any time soon, unless it's to PO a track manager or something.

Quote:

You need to ask this on SpeedTalk.com;

Join another forum, no thanks. If moparts fails me I'll just come up with my own ideas. That's my usual way of solving problems anyway. Anyone who's seem my sh1t knows that.

The reason I'm asking is that I have some heads I've been working on that are 1.84/1.56 in the valve size area and I'm changing them to 2.0/1.6 and just want to size the port and throat correctly, or close anyway. Min area in the port is now about 1.8in^2 and the Wallace calculator I tried said max torque at about 4100 rpm, fwiw. There's room to make the port bigger.

Posted By: moderncylinder

Re: Valve Diameter, Throat Area, Port Area? - 12/22/09 10:54 PM

it really depends on chamber style, valve job angles, valve back profile, port floor height, and operating range with a respect to cros ssection and displacemnt.

usually 92% on the intake and 89% on the exh,, with 45 degree seats and atleast a 30 degree top ngle thats .060 or so wide,, nothing flatter for a top or else you make the throat smaller. if its a flat machined chamber you make the throat smaller, if its a 30 degree seat you make the throat smaller,,, if its a 55-58 seat you make the throat larger..

also depends on seat width,, if its a true sreet car you run wider seats to help dissipate heat off the valve head,, so then you make the throat smaller,, if seat widths are .050 or wider, the above 92% intake is for a .035 or so wide seat, exh .045

if you take alot of factory heads and goto oversize valves you can get into trouble going 92% cause the casting wont support it, the bowl cant be made large enough.......