Size of openings MAF-->TB-->Intake?

[bchilt]

Hey guys,

I got to thinking if it's important to match the size of the Intake opening to your TB, for example, a 70 mm TB to an Edelbrock Performer 5.0 (70 mm, I think), then why is not as important to match the MAF to the TB? Stock MAF for our cars is 70mm. Wouldn't it make since to match everything? MAF (70mm)-->TB(70mm)-->Intake(70mm).

Your thoughts!!!

B

 

[wytstang]

My thoughts
http://www.accufabracing.com/article 3.htm
And a good thread (the search button sometimes works well)
http://forums.stangnet.com/showthread.php?t=681069&highlight=Throttle+body
Good luck

 

[bchilt]

Ah yes! I have read those threads. Perhaps, subconsciously, these links are what prompted me to post.

Flow rate = Volume/Time

if the openings for the Intake, TB, and MAF are equal, you have, in effect, created a cylinder. Volume = Pie r^2*h

If the Intake is 70mm, the TB is 75mm, and the MAF is 85mm = a cone. Volume = 1/3 pie r^2*h.

Flow rates would be slower for mismatches.

 

[5spd GT]

Flow isn't determined by the millimeter, that just gives a general ball park.

A 70MM MAF may flow more than a 75mm TB. The obstructions are different.

It appears few know this but the actual intake opening is much smaller than where the throttle body bolts up to the intake. Just take a quick peak in the intake and see how it necks down. A Holley Systemax has a 75mm opening, but it necks down to around 65mm so I 'laugh inside' when I see people saying that it 'needs a 75 or 90mm TB to get the most power'...

 

[final5-0]

When got my 80mm ProM shorty meter, I noticed its inside diameter was
almost the same size as the inside diameter of some 3" pvc pipe I had
around the garage.

I felt for my na combo, that 3" pipe was more than sufficient so I used
it for my cai pipe.

That meter was chosen more for its accuracy than its 3" inside diameter.

From that point on ... things get smaller with a 65mm tb and a
70mm elbow and the opening on my RPM upper.

Grady

 

[wytstang]

Ah yes! I have read those threads. Perhaps, subconsciously, these links are what prompted me to post.

Flow rate = Volume/Time

if the openings for the Intake, TB, and MAF are equal, you have, in effect, created a cylinder. Volume = Pie r^2*h

If the Intake is 70mm, the TB is 75mm, and the MAF is 85mm = a cone. Volume = 1/3 pie r^2*h.

Flow rates would be slower for mismatches.

Not quit; we're dealing with CFM and only CFM. And the question is how much CFM can the entire induction system handle/use? Putting parts that flow twice the amount the motor can use/handle is a waste of money. Here is a great thread over on Hardcore50 were Accufab (Gearge Klass) gives his input.
http://bbs.hardcore50.com/vbulletin/showthread.php?t=26335&highlight=Cobra+intake

 

[Therian]