at what point does the stock MAF become a restriction?

 

TTT

 

i am also curious to that question. When is the stock throttle body a restriction too? I have ported heads and 230/236 and i wanna know when those should be swapped out


trav

 

TB, probably 400 to the ground.

 

at what point does the stock MAF become a restriction?

 

Its been a while since math class LOL, but my understanding is basicly where the 52mm TB becomes a restriction is where the stock MAF becomes a restriction aswell.

To find the area of a stock maf you go 3.14X(75)squared

so 75X75 X3.14 = 17662.5

a 52mm TB goes like this

52X52 X3.14 = 8490.56 multiply this by 2 since there is 2 holes this gives you 16981.12

So a stock maf will flow a little more then a 52mm TB will, but a 58mm tb will be 21125.92, now the MAF is the restriction if you see where I'm going with the AREA of a circle here.

to have a MAF that will flow more then a 58mm TB you need an 85MM MAF like the Granatelli or the Z06 MAF. Which will have an area of 22686.5 which is more then a 58mm TB will flow.

This ofcoarse means that your engine will suck that much lol, we are just referencing the MAF restriction to your TB size, & since ppl claim 33rwhp gains from 58mm TBs on some setups this means their maf is next on the list LOL.

Hope that helps

Matt.

 

Here is the "lame" way I did it.....

I logged a WOT run with the MAF on the air path and One Logged WOT run with the MAF removed from the air path.

Then I compared the MAP readings..... there was less vacum build up past 3500 RPMs inside the Intake manifold with the OEM MAF removed.

Tryed it for a second time (total four WOT runs logged) and I had the same results.

Because of my stock set up I had to remove the restrictive OEM plastic conection from the MAF to the air filter on the first WOT run to even things out with the second WOT run (MAF physically removed)

Based on this test the MAF becomes a somewhat of a restriction after 3500 RPMs on my stock engine.


Marvin

 

From what i've been told and have read on this and other boards, the stock MAF, is good for up to 400 hp.
zoso

 

bunker where does the 75^2 come from??? for the 48mm tb

..and how do you like your holley 58mm do u have any problems w/ it? I've heard of people haveing problems upgradeing there tb. I've also heard on realitively stock engines upgradeing to that size tb will actually hurt performance.
-b