GT4094 and GT4202 cfm flow
- Thread starter bigbird
- Start date
Turbochargers are constant volume (vs constant mass) airpumps. First, you get the rated volumetric flow rate, then convert it to mass flow rate using rho from your existing elevation and temp. .072-.074 is typical density near seal level and standard pressure. A hot day up in Denver would be .061. FWIW.
Constant volume as opposed to constant mass.
The point I was making is that we start with volumetric flow rate, then convert to mass, not vice versa. Under constant boost, you observe MAF decreases as you climb, for example. But volumetric flow rate is not changing.
The point I was making is that we start with volumetric flow rate, then convert to mass, not vice versa. Under constant boost, you observe MAF decreases as you climb, for example. But volumetric flow rate is not changing.
BS.
static pressure on supply side of a centrifical pump changes so does volume discharge.
basicly what your saying by principle would be compound twins dont work. :rofl:
seam i need to post pump theroy for you.... iirc had this convo on DP
static pressure on supply side of a centrifical pump changes so does volume discharge.
basicly what your saying by principle would be compound twins dont work. :rofl:
seam i need to post pump theroy for you.... iirc had this convo on DP
I honestly don't know. The compressor map is pretty easy to read though. If it is shown in lb/min, then you must use .072 lb/ft^3, typical STP used by the manufacturer of the turbo to calibrate the map in testing. This equates to around 80 F and 600 ft MSL elevation...or thereabout...each manufacturer seems to like something a little different than the standard.
Don't forget also, this excludes restrictions. You will never get the map flow rates because it is a CONSTANT HEAD DESIGN!!!
It will be less. How much less depends on how poorly the plumbing and CAC are designed, among other things.
Don't forget also, this excludes restrictions. You will never get the map flow rates because it is a CONSTANT HEAD DESIGN!!!
It will be less. How much less depends on how poorly the plumbing and CAC are designed, among other things.
I honestly don't know. The compressor map is pretty easy to read though. If it is shown in lb/min, then you must use .072 lb/ft^3, typical STP used by the manufacturer of the turbo to calibrate the map in testing. This equates to around 80 F and 600 ft MSL elevation...or thereabout...each manufacturer seems to like something a little different than the standard.
Don't forget also, this excludes restrictions. You will never get the map flow rates because it is a CONSTANT HEAD DESIGN!!!
It will be less. How much less depends on how poorly the plumbing and CAC are designed, among other things.
still trying to split a frog hair i see
due to so many varibles.. hence the reason i used (~) when i said cfm.
80lbmin /.072= 1111cfm
80lbmin/ .061= 1311cfm
hummm .061 you said would be a hot day in denver ie thinner air.. yet it flows more..
highly highly doubt thatcommon arent you the engineer here? dont you remeber pump theroy?????
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Here's the thing, a stock charger, stock tuning, will go up to ~60lb/min at 3000rpm running ~35PSIA (21lb boost).
Now we can push a GT4202R to pump 70PSIA (55lb boost) at 3000rpm. Twice as much air if efficiencies are similiar, so 120lb/min. But, we can carry 75PSIA at 4000 RPM, or over 140 lb/min based on my testing.
Now we can push a GT4202R to pump 70PSIA (55lb boost) at 3000rpm. Twice as much air if efficiencies are similiar, so 120lb/min. But, we can carry 75PSIA at 4000 RPM, or over 140 lb/min based on my testing.
I don't really know anything about what is being discussed, but if you are moving 80 lbs of dense air, wouldn't it be less volume (cu. ft.) than 80 lbs of thin air?80lbmin /.072= 1111cfm
80lbmin/ .061= 1311cfm
hummm .061 you said would be a hot day in denver ie thinner air.. yet it flows more..
Garrett does say 95lb/min at 35psig (50psia).
But what fun is running it at 35?
Yes, we grossly overspeed all these chargers. Garrett's maps are for sustained duty for the planned MTBF (lifespan).
But we like to shorten their lives...
But what fun is running it at 35?
Yes, we grossly overspeed all these chargers. Garrett's maps are for sustained duty for the planned MTBF (lifespan).
But we like to shorten their lives...