I Math


Formulas

Rod ratio= Center line to center line length of the rod / Stroke

1.74 or greater is most desirable for racing

Air temperature = every 7 degrees F >60 degrees F= 1 % loss in
horsepower

CI displacement = bore x bore =__ x .7854 =__ x stroke: divide by .061
for CC x number of cylinders

Compression ratio: Volume of the cylinder, piston dish and head dish and
headgasket from top to bottom of the stroke, divided by the head, piston,
and headgasket volume or:

bore(in.) x bore(in.) =__ x .7854 =__ x stroke (in.) =__/ .061=__cc of
cylinder + (head cc +piston cc + headgasket cc) / (head cc+ piston
cc+headgasket cc) = compression ratio

Piston speed in fpm= stroke (in.)x rpm/ 6

Piston speed desired= 5800 fpm or less

Horsepower= rpm x torque/5252

Altitude effects on HP: every 1000 ft + = 3% loss in HP

Engine CFM approximation: RPM x C.I. displacement / 3456 = approximate
CFM: Example, Civic 1.6, 97 C.I x 7200 RPM = 698400 / 3456 = 202
approximated CFM

Calculation for CFM from HP: HP x .5 (BSFC) = __lb. per hour fuel x 13.2
air/fuel ratio = __lb. air per hour / 60 minutes per hour = __ lb. per
minute / .07 = CFM. Example: Civic 1.6, 127 hp x .5 = 63.5 lb. per hour
fuel x 13.2 air fuel ratio = 838.2 lb. air per hour / 60 minutes per hour
= 13.97 lb. per minute / .07 conversion to CFM = 199 CFM


Injector flow increase vs. fuel pressure increase:The square root of the
new fuel pressure / original fuel pressure x the original fuel injector
flow =__ new flow in lb. per hour: Example 1.6 liter Civic with Auxiliary
Fuel Pressure Regulator: Take the square root of 70 psi(new rail
pressure) / 40 (original rail pressure) = 1.3229 x 24 lb. per hour =
31.75 new flow rate in lb. per hour


Injector sizing for horsepower: Desired HP x .5 (BSFC)=__ lb. of fuel
required for desired HP / __amount of injectors =__lb. per injector x
__duty cycle = __lb. per hour per injector


Fuel pump or injector horsepower capability = Pounds per hour@fuel
pressure desired x 2 =__ HP capability


Gallons per hour to Pounds per hour= __ gallons x 6=__Lbs per hour


Enjoy!

Ryan

 

thanks, but my head hurts now...

 

Wow looks like you had some time to kill there. Thanks for the info

 

cut n paste ownz

 

awesome...copy, and pasted

 

vtecvoodo, you rock, thanks for all the formulas (i also math)


I don't think a single production honda engine has a rod ratio above 1.65, but I could be wrong (just going of the top of my head)

 

the B16 is 1.75

 

rock! great stuff!

 

my bad
b16a2=1.74
h22=1.49
h23=1.58
b18c=1.58
b18b=1.54
d16=1.52
d15=1.59

 

you know what's funny ryan.. there is no Honda Book that conrtains any of this formulas.. yet I have a VW engine builders book that has all of that info plus more.. guess it just shows how serious the other Car fanatics are over the Honda guys so to say oh well good info for all the guys here to read thru..I love working at the library I get all the best engine books =P

 

they have to be more serious..their pos's are built in mexico...so you pretty much have to start from scratch

 

haha

 

hahah yes sad to say VWs and domestics are all Made in Mexico =x

 

D15Z and D15B VTEC = 1.62

 

What about the F20c1?

 

My favorite formula is 1.

Formula 1

 

B16B = 1.86

 

c27a4 =2.04

 

isn't it just f20c?
Any one know its rod length (stroke is 84mm right?)

 

Doing some k series homework for something I might build and thought I`d bump this. Very useful info

 

on the compression ratio...all the dimensions have to be of the same family. You have bore in inches, when it should be converted to centimeters so it's the same as cc of the cc and so forth..I just skimmed over so I might just be seeing things

 

I stand corrected, it was converted to CC's!!

 

damn im confused , o well

 

damn im confused , o well

btw// math sucks

 

Simple, but cool stuff that everyone should know.