need a guru to - Check My Math - please

[NorcalOBS]

I have been reading garret turbo tech all mourning and trying verify if I am getting this stuff right. If someone could just do a quick check to see if I am at least reading the formulas right and plugging in the right data(ballpark).

Flow = HP * A/F ratio * BSFC/60
Flow = 300 * 22 * .38/60
flow = 41.8 lbs/min to get 300hp


MAP = (flow * R * temp) / (VE * rpm/2 * displacement)
MAPr = (42 * 639.6 * 610) / (.85 * 3000/2 * 445)
MAP required = 28.9 PSI

I then added ~2psi for cooler/manifold inefficiency to 31psi
and then

P.ratio = MAP / atmo = 31 / 13.5 = ~2.3

So for a target 300hp @ 3000rpm at just above sea level with 1 psi intake loss and 2psi cooler/manifold loss
I should need to move 42 lbs/min at 2.3 pressure ratio(~16.5lbs of boost)

Am I at least in the ball park???
Any guidance much appreciated!

Thanks, Noah

 

[NorcalOBS]

Does this mean anything to anyone???? LOL

I can read and am good enough at math... but in all reality I really don't know how this data translates into to real world results. I feel like I just wasted the last 20min of my life in excel that I cannot ever get back... and for what, data that I cannot interpret. LMAO Please help.

I am a little sketchy on some of the numbers I have been using in the formulas. I used .38 for the Brake Specific Fuel Consumtion (BSFC)
and 22 for the Air Fuel ratio
and .8 for Volumetric efficiency
For the A/F and BSFC I just robbed those numbers from the garret turbo tech diesel article and do not know how applicable they are to the 7.3. And VE is a guestimate based on other forum data I found searching around.

Comments, suggestions, input of any kind is much appreciated.
Thanks, Noah

 

[golfer]

300hp @ 3000rpm at just above sea level with 1 psi intake loss and 2psi cooler/manifold loss
I should need to move 42 lbs/min at 2.3 pressure ratio(~16.5lbs of boost)

not sure what your end goal is with the spreadsheets...but based on your signature/injectors...to me..it's pretty obvious that you would be fine with a Garrett GTP38R, or any number of Borg Warner S300 turbochargers (62-66mm).

it's not like you have a terribly unique combination of parts...

 

[NorcalOBS]

Thanks for responding, I appreciate it. I am aware of the traditional setups.
However, I actually do want to know more about this stuff though. I know, I know, why do I care.... I am just goofy like that. I just like to know stuff. lol
I am teach myself this stuff and am getting more and more confident that I really understand the method to the madness, but I would love a little guidance from anyone willing.
I also have been talking to my cousin about starting to build turbo kits for street bikes and UTVs. Have done a couple already. I really want to know more about all of this. I really don't want to be that guy trying sell a turbo kit with turbo X in the kit, cuz turbo X is what some other shop sells in their kit and we wind up having to wait around and blindly copy others.

 

[dsberman94]

If you find a way to put a working vgt on a street bike or utv ill be impressed.

 

[NorcalOBS]

no a vgt for that stuff. LOL. I am just trying to use my truck project to absorb some general turbo selection knowledge for those things. Shoot the bike turbos almost fit in my pocket. We have talked about a compound setup for a sand drag bike though. :evil

 

[Dan V]

I would like to hang a turbo on my 3 cyl Kubota tractor.

 

[NorcalOBS]

I would like to hang a turbo on my 3 cyl Kubota tractor.

Go for it if you can get control of the fueling.


Also, I know this isn't the place for it but its just too cool.
My cousins most recent sand toy of death!
http://youtu.be/7ThGacWTmMI?t=23s
Highest number to date has been 250+rwhp.... cuz turbo are AWESOME!
http://youtu.be/mucA468CM5E?t=55s