[Pony XTC]

All you mechanics out there please explain something to me. These Bullitts come with TWIN 57mm throttle bodies. Where I went to school thats an opening of 114mm. Why the heck are people putting on different ones? In other words, How can a 70mm opening draw more air than a 114mm opening? I'm really confused. Help this naive boy from Cleveland. (Please no Cleveland jokes)

 

[BULLITTBRO1]

I have no Idea Drew, cleavland rocks, Cleavland rocks

 

[BULLITT680]

Pony XTC...
We're not dealing with just the size of the opening, we are concerned with the total "area" of the opening through which air may flow. Please follow along:

Given a Twin 57mm diameter TB, then the radius of each throttle bore is 28.5mm. Radius squared is 812.25 square milimeters. Area is equal to pi (3.141592653589 it goes on and on) multiplied by the square of the radius (812.25 square milimeters) which comes out to 2551.7586 square milimeters. Now; since there are two of these throttle bores, 2 x 2551.7586 square milimeters is equal to 5103.5172 square milimeters of area.

If you will follow this same process, you will find that a single 80mm TB will give you an available area for flow of 5026.5482 square milimeters. Thats about as close as it gets to being equal between a single 80mm TB and the Twin 57mm TB.

On the other hand; a single 114mm TB would have an area of flow equivalent to 10207.0345 square milimeters.

Hope this helps

 

[Mus408]

Ah,but the velocity of the air would be greater thru those two 57mm bores,which helps throttle response and torque.

 

[Blakwing]

But doesn't there come to be a point where velocity restricts flow? Meaning you if you move X amount of air through a given point it will move at a certain velocity, but if you increase the diameter of the tube you will increase flow. After all .. engines are just big air pumps anyhow.

 

[Jimmy Ray]

JET engine stuff!!!!! As pressure drops, velocity increases, or as velocity decreases, Pressure increases. Convergant and divergant ducts...... Makes jet engines suck and blow. Isn't it something what a round hole can do to air.

_________________
Jimmy Ray and Kay
Bullitt1007
73 MACH1 351 CJ
67 Fastback

<font size=-1>[ This Message was edited by: Jimmy Ray on 2002-03-08 23:09 ]</font>

 

[Maddawg]

Everybody's right on this one, that's what makes design so interesting. What do you want to give up to gain something else? For a steady flow where mass in equals mass out: Mass flow rate = fluid density x pipe area x fluid velocity. So you can decrease area and increase velocity for a given flow rate, but eventually friction effects kick in and you would need more power to force the fluid through. See why supercharging/turbocharging is so appealing? Anyway, I got to get out of this thread, all this math is getting me aroused. :nerd:

 

[Pony XTC]

Boy, I'm glad I asked. This is like reading Steven Hawking's theories on singularities caught in the event horizon of a black hole. The General relativity theory is easier than this (E=Mc2). No really, keep 'em coming guys this is really interesting.

 

[Mus408]

It's all a give and take kind of deal. The size of the head port,valve size,intake runner and plenum,will determine where in the RPM range the engine will be most efficient. Of course things get real busy,with today's variable cam timing and intake systems!!! Best of both worlds. Some years back,I built a variable plenum divider,for a single plane intake,for a 340 Dart I had. It worked by a cable,and you could adjust the height of the plenum divider while the engine was running. All the way up,and the engine smoothed out at idle, and low speed. Push the control in,and the divider would drop down by half,for better top end. Worked fairly well.

 

[Pony XTC]

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[TXBullitt]

Anyone else notice that the supercharged 03 Cobra has returned to the same twin 57s that we have instead of keeping the twin 62's from the 01?

 

[Joe Bullitt]

.....................head ...............hurts.....aaaaahhh..tooo.........much...think..ing.......ooooowwwwwwwwwww

_________________
Joe Bullitt
True Blue #5467
<marquee scrolldelay="25" scrollamount="4">MODS: Steeda Tri-Ax,100mm DenseCharger,Sequential Tail Lights,Tinted Windows,Viper 800ESP with Remote Start and windows, MGW stuff, Foglights are here!!</marquee>

<font size=-1>[ This Message was edited by: Joe Bullitt on 2002-03-14 14:03 ]</font>

 

[TBBullitt]

My meager contribution to this discussion will be 2 words:

Bernoulli's principal.

There, now I feel smart

_________________
Chris Pedersen

100mm Densecharger
Steeda HD Upper Rear Control Arms
More to come.....

<font size=-1>[ This Message was edited by: cpeders on 2002-03-14 14:24 ]</font>

 

[SILVERBULLET]

cpeders did you get my private message.

 

[TBBullitt]

Yep, I did and PM'ed you back...

 

[SILVERBULLET]

I never got it.

 

[BULITNV]

words, words........

 

[SILVERBULLET]

Never mind I got it. Okay folks carry on.HHHEEE