MAF Reading at cold temp?

[atsakiri at ford.com]

> I measured it in the Texas heat (MAT of 109F!!) and I have a peak
> of 283 G/S, with more than 262 G/S the last 300rpm before the revlimiter.
> 
> My question is: Can someone tell me how much these readings will increase
> when temps drop? Say to 50F? Will the MAF diagnostics fail?

A rough estimate can be obtained by calculating the increase in density of
the ambient air.

 rho1 = p/(R*T1) = density at 109 F

 rho2 = p/(R*T2) = density at T2

 where rho = density
       p = pressure (assumed the same at both temperatures)
       R = gas constant
       T = absolute temperature (R)


 So,  rho2/rho1 = T1/T2 = (109 + 460)/T2

 At a temperature of 50 F, T2 = 50 + 460 R, and the density is about
 12% greater.  rho2/rho1 = 1.12.



Anthony Tsakiris

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The opinions expressed are my own and not necessarily those of my employer.