CFM determination

[Smoker]

How could a person determine how many cfm's a turbo is pushing? I am remodeling my truck and I am looking for an aftercooler. I need to know how many cfm's it should be able to support.

 

[illflem]

CFMs are hard to measure without expensive equipment, your best bet is to contact the turbo manufacturer, they can tell you right off the bat.

 

[Smoker]

Anybody got a helpful Holset phone number?

 

[R.ebel]

CFM

http://www.holset.co.uk/flash/index.html Lots of interesting info on their web-site, especially the HX40V

 

[bigkid59]

If it will help here is some info on a CPL 0987 B engine to get an idea of air flow, etc. .



Advertised Power Torque Peak

RPM 2500 1600

Power Output 230 184

Torque 483 605

Fuel Consumption(#hr) 89. 7 62. 6

Intake Air Flow(CFM) 535 340

Exhaust Flow(CFM) 1531 940

Exhaust Temperature(F) 1031 980

Water Flow(GPM) 48. 9 30. 5

Charge Air Flow(lbs/min) 39. 98 24. 63

Turbo Outlet Pressure(PSI) 22. 84 19. 36

Turbo Outlet Temp(F) 304 281





In this CPL the charge air cooler has a heat rejection of 1739 Btu/min at advertised power and a heat rejection of 1100 Btu/min at torque peak.



This Cpl was used in 1991 for a fire truck application. The engine was rated 230 HP and 605 foot pounds torque. The data sheet I am geting this information from states that the pressure drop from the turbo to the manifold must not exceed 1. 97 PSI and that the charge air in the manifold must be no more than 38 degrees (F) hotter than ambient air. With the turbo outlet temperature being 304 degrees(F), you can see how much cooling the charge air cooler must do in order to allow the engine to make rated power.



Hope these figures can help get a view of the conditions that must be met in order to produce a given amount of power.



Whoops! My columns did not come out right! Anyway, the first number in each line is the number relating to the 2500 RPM speed (at horsepower peak) and the second number is relating to the 1600 RPM speed (at peak torque).



Sorry about that!!!

 

[R.ebel]

bigkid59,

Good post, very interesting info you presented. Where did you find all the numbers?

 

[bigkid59]

Thanks R. ebel!



The numbers come from a Cummins publication known as an Engine Data Sheet. I don't know how available these sheets are but they specify the conditions that must be met for an engine to produce it's rated power, so I would assume that they would be most useful to an engineer designing a machine or vehicle in his efforts to make sure that his design allows these requirements to be met.



This sheet gives more info than what I put into my post. One good example is that it shows the weight of the engine with flywheel housing, flywheel and electrics as 942 pounds dry and 1004 pounds wet.



Another interesting spec is one for maximum overspeed capability and that is 3750 RPM. There is a spec for friction at 2500 RPM and that is 44. 6 HP. Another interesting spec is available torque at clutch engagement RPM, 800, of 285 foot pounds.



I have had this sheet for a long time and don't remember just where it came from. As I said, I don't know how available this info is, but it it interesting to study.



Hope Smoker can use the air flow numbers to calculate what he needs for a good aftercooler!