BSFC and me.

joefarmer

joefarmer

MR. Supreme Overlord
600hp.

Assume BSFC of 0.38 lb/hp/hr. (Thanks Jason Sands, et al.)
Assume #2 diesel weight of 7.08 lb/gal

Divide 0.38 lb by 7.08 lb/gal to get 0.05367 gal/hp/hr
Convert 0.05367 gallons to liters for 0.20317 l/hp/hr
multiply by 600hp to account for hp and you get 121 l/hr

Am I looking for a 121 lph injector for 600hp? Something doesn't seem correct?
 
joefarmer said:
Am I looking for a 121 lph injector for 600hp? Something doesn't seem correct?
Click to expand...

Math seems correct, but why would you try to make 600hp with a single cylinder and one injector rated at 121 lph?

Much easier to use a 6 cylinder and use 20.3 lph injectors...
 
how are injectors rated (the ones that come with a flow sheet)? Is it a rating of LPM for each injector or for all 6 together?
 
GOT-Torque said:
how are injectors rated (the ones that come with a flow sheet)? Is it a rating of LPM for each injector or for all 6 together?
Click to expand...

Each injector...then the difference is calculated between the set.

If the calculation Brandon is doing is calculating for one cylinder, I do agree that the calculation does not make sense. :doh:
 
Actually The size of the engine or number of cylinders isn't even part of the equation. All it's talking about is fuel flow to support x hp. The 121 lph would be how much the injection pump would need to flow to support 600hp. It is total fuel flow, not the amount each injector must flow.
 
.38 is extremely high; a diesel is able to run extremely lean back when I dynoed a 1200 hp engine on the, the BSFC at peak was .244 to .275.
I would look at a range of .200 for a well tunes CR that is clean with opacity of .98 to .99 to .300 for a twinge of smoke , and a opacity of .75 to .80
 
that was a 13 mm P pump


DSCN1533.jpg


here are the king of diesel dynos , and numbers , where are they when you need them


02_Engine_dyno_jpg-1.jpg
 
GOT-Torque said:
Math seems correct, but why would you try to make 600hp with a single cylinder and one injector rated at 121 lph?

Much easier to use a 6 cylinder and use 20.3 lph injectors...
Click to expand...
zstroken said:
I think he was shooting for 3600HP.
Click to expand...
reformed ricer said:
that's what I was thinkin
Click to expand...
kazairl said:
Actually The size of the engine or number of cylinders isn't even part of the equation. All it's talking about is fuel flow to support x hp. The 121 lph would be how much the injection pump would need to flow to support 600hp. It is total fuel flow, not the amount each injector must flow.
Click to expand...

Y'all are right. I was misthinkin' it. Kinda gives you the willies when you think about the big tractors making 3500+ hp. :evil No wonder there's 5gallons of fuel missing at the big end and 2.00" fuel supply lines... :evil

COMP461 said:
.38 is extremely high; a diesel is able to run extremely lean back when I dynoed a 1200 hp engine on the, the BSFC at peak was .244 to .275.
I would look at a range of .200 for a well tunes CR that is clean with opacity of .98 to .99 to .300 for a twinge of smoke , and a opacity of .75 to .80
Click to expand...

I'm a bit baffled- When I look around to various vendor sites I see CP3's that put out up to 494 mm3/stroke and rated to 1200hp. That equates to .41lb/hp/hr. If we carry the assumption down to 600hp, that would mean the CP3 would need to put out 247 mm3/stroke? If yes, the stock pump will put out 110 mm3/stroke and only support 300hp? Am I in the ballpark or out in the corn field?
 
Going by the data tag on my '94 engine, its 175hp at 84mm^3. If I remember right, Mork's '03 tag said 114mm^3 for a 305hp engine.
 
a stock tuned CR would be in the .250 range the more highly tunes ones would drop to close to .200

this is the great party of a diesel
 
Greg, your BSFC numbers are pretty far off.

0.3 is an extremely good value - 0.35-0.45 will be more typical, with the normal overfueled engine being higher (less efficient).
 
joefarmer said:
Assume BSFC of 0.38 lb/hp/hr. (Thanks Jason Sands, et al.)
Click to expand...

Huh? Who's talkin' about me? I get something right? Jason do good!!?? :lolly:

All kidding aside, most of the overfueling we see in diesel motorsports I think is used to drive the turbos rather than to make power. I think a compound setup with a turbo and a mammoth Procharger (F3 or F4) could make 1,500 hp or more with no smoke.

I also think you're making a tad more than 600hp at the crank, although with your traction issues, who knows?
 
JQmile said:
Huh? Who's talkin' about me? I get something right? Jason do good!!?? :lolly:

All kidding aside, most of the overfueling we see in diesel motorsports I think is used to drive the turbos rather than to make power. I think a compound setup with a turbo and a mammoth Procharger (F3 or F4) could make 1,500 hp or more with no smoke.

I also think you're making a tad more than 600hp at the crank, although with your traction issues, who knows?
Click to expand...
LOL Yes, Jason do good!

I also agree that the current setup was making >600hp, but not putting near all of it down. It shouldn't be any secret that I'm going running a CR for the 2011 season.


Here's my next question- How much does BSFC change when RPM is at full torque output?
 
joefarmer said:
Here's my next question- How much does BSFC change when RPM is at full torque output?
Click to expand...

On a stock application, BSFC should be very good...in competition, well that's another matter. Cummins engines are severley airflow limited for what we're all trying to do with them, so they're probably not the most effective things in the world at high rpm, but they'll still make power because we're running 1 million psi of boost.

Injector ratings are only part of the puzzle anyhow, it takes 80lpm injectors to make hp on a First Gen, but only 30lpm to make the same hp on a common-rail. Injection pressures and multiple events will all play a factor in efficency also.
 
I can't mention the specific engine, but this is data from an in-line 6 cylinder turbocharged common rail diesel, of around 14L displacement. Values obviously aren't accurate for a 5.9 cummins, but trends are.

View attachment Data.doc

--Eric
 
You must log in or register to reply here.
Back
Top