Horsepower after remap

by **treeman** » Sun Jan 27, 2013 7:15 pm

Great info...very interesting. Thanks

by **nutron** » Mon Feb 04, 2013 11:54 pm

What he is saying is that power is a measure of the rate of production of force (torque).

HP = lbft * rpm / 5252

This can be converted into NM

HP = NM * rpm / (5252 * 1.367)

Trying to use fuel quantity to directly calculate hp output is not going to work though.

by **Relic** » Wed Feb 13, 2013 10:11 pm

Brake specific fuel consumption is how much lb/hr of fuel is required to make 1 bhp.
The civic varies from roughly 0.34lb hp hr ~ 0.38+ from 4000 rpm
BSFC @ 2000RPM = 0.34 LB HP HR ...75MG/STROKE FUEL = ??? POWER / TORQUE
BSFC @ 4000RPM = 0.38 LB HP HR ...75MG/STROKE FUEL = ??? POWER / TORQUE

So if we mash the pedal and are requesting 75mg of fuel at various rpm...
75MG *(2.204 LB PER KG/1000000) * (2000RPM *2 STROKES) * 60MIN = 39.672 LB HR FUEL USE @ 2000RPM
75MG *(2.204 LB PER KG/1000000) * (4000RPM *2 STROKES) * 60MIN = 79.344 LB HR FUEL USE @ 4000RPM

Once we know how much fuel we are using at any rpm, we can use the BSFC for that rpm to work out the power/torque.
39.672 /0.34 = 116.7 BHP @ 2000RPM (116.7 *5252/2000RPM = 306.454 LB FT)
79.344 /0.38 = 208.8 BHP @ 4000RPM (208.8 *5252/4000RPM = 274.154 LB FT)

clue ;)

You can use your IQ vs rpm + dyno vs rpm to workput your BSFC

by **vagnostics_ltd** » Tue Apr 02, 2013 12:41 am

Very useful information :thumbup:

by **Admir85** » Thu Jul 04, 2013 5:31 pm

Shouldn't Z - value be different for every car ?

Alfa Romeo 156 1.9 jtd 16v 140 hp - 305 Nm
max hp 4000rpm * 305 Nm / 7120 = 171 hp
or
Golf V 1.9 tdi 90 hp - 210 Nm
max hp 4000rpm * 210 NM / 7120 = 118 hp

Or this (see images):
http://safe-chip.com/ista-snaga-na-2-nacina.html#
292 Nm 150 hp at 3750 rpm,and it had 150 hp on dyno.

Does someone have better way or tool to calculate this ?

Thanks