g/s to cfm

[CSH-HQ]

>>>....
>> >My question is, what g/s equates to what cfm at what temperature (I 
>> >can't find any conversions in my books). the 
>> >ultimate question is, what HP level is supported by 255 g/s.
>> 
>> Depends on the VE of the engine.
>> At standard temp/pressure I thinks it's 1.09 grams/ cubic ft air.
>> So like a 231 buick turbo uses about 115 ci in per rev.   So at 4000
>> rpm uses 462,000 cu in divide that by 1728, 
>
>What is the signifigance of the 1728 .. (144 * 12  ?)  144 for cu-in 
>to cu-ft  but whats the 12 ?

12*12=144 is the number of square inches in a square foot, *12 gives a cubic 
foot.
>
>> and it's using 267 CFM.  MAF is 
>> a 255 which flows 277.  So figurun 120% VE you have max air at 3,200 (er 
>> accurately calibrated air/fuel).  
>> 
>> True is that's at 100%VE, and a Hot Turbo motor can do 140% VE.
>> Then a good street NA engine might only do 80%.
>
>I can reverse-calculate my VE by knowing what RPM I get a 255 MAF 
>reading at!
>
>for example.. a 231 V6 consuming 277 cfm must be rotating at 
>4159 rpm at 100% ve. . If a turbo 3.8 hits 255 MAF (ie 277 CFM) at 
>say 4000 rpm, thats about 4% gain in VE.. am I thinking correctly?

Sounds right at a glance
>

>I ran this calculation on my SC 5.7 litre from memory and come up 
>with 125% ve.  I'll have to look at the data to get exact. neet-o.

But, is this of what good?, strikes me as trivia pursuit.  
Like trying to develope fuel tables on a computer, without even having the 
engine running.  Ni being smart here just curious where ya going.
Also, need BMFC for figuging fuel needed.
Bruce
>
>I've sent a small calculator type application for calculating VE 
>using max-MAF-rpm and CID to bruce... if my calc's 
>arent silly to him, I'll post the app.
>
>
>
>
>> While the MAP might not be a flow restriction till 750 CFM your out of 
>> calibation area  
>> 
>> Might just use the default tps/rpm fueling for anything over 4,000 rpm or 
boost.
>
>I have tweaked that and will experiment with EGT hopefully... still 
>car not on road. 2 mo days.
>
>> 
>> If ya like the 165 use it for low TPS, and then a 749 for when your making 
>> HP, or do the chip flip and swich ecm from MAF to MAP at WOT.
>> Justin posted in the archives years ago about using a 256 prom innna 808, 
>> maybe do that and run bot set ups.
>> Bruce
>
>whooosh   whats that sound  8-)
>
>
> 
>~~~
>Dave Z. www.delanet.com/~tgp
>