h701micra
Deactivated Account
With many a conversion going on and different setups and power figures, I thought I'd stick a little guide up as to how to work out what fuel pump you need 
We need both pressure and flow rate
First you'll need;
A: Target boost
B: Target HP
C: Base fuel pressure
For me its A: 10psi, B: 200 & C: 6psi (mines carb'd)
Next we need to work out our fuel pressure losses from tank to engine. It varies car to car. The more bends etc you have, length and climbs. I'd give a ball park figure of 5psi
So our formula for pump pressure is
P=(Base pressure)+(Boost pressure)+(Line losses)
So in my example:
P=6+10+5 = 21psi so at max boost I need 21 psi of fuel pressure
Also to add if you use a non return style regulator you'll need to add 15psi to your fuel pressure
Next up out flow rate
Introducing BSFC (Brake Specific Fuel Consumption) this is the weight in pounds (lbs) needed to support 1hp for 1hour or (lbs/hr)/hp
Typical values are:
N/A: .45/.55
Turbo: .55/.60
S/C: .60/.65 (superchargers run off the engine so require more fuel)
Here's the formula:
Flow Rate = (BSFC)×(Target HP)
So my flow rate is in my turbo application
FR = .6(lbs/hr)/hp x 200hp= 120 lbs/hr
If you need it in gallons/hour divide by 6. Fuel is approx 6lbs per gallon
So mine would be; 20gal/hr
So to conclude my fuel pump needs to run at:
21psi @ 20gal/hr (120lbs/hr) @ +12v
I hope this is of some help to you all
We need both pressure and flow rate
First you'll need;
A: Target boost
B: Target HP
C: Base fuel pressure
For me its A: 10psi, B: 200 & C: 6psi (mines carb'd)
Next we need to work out our fuel pressure losses from tank to engine. It varies car to car. The more bends etc you have, length and climbs. I'd give a ball park figure of 5psi
So our formula for pump pressure is
P=(Base pressure)+(Boost pressure)+(Line losses)
So in my example:
P=6+10+5 = 21psi so at max boost I need 21 psi of fuel pressure
Also to add if you use a non return style regulator you'll need to add 15psi to your fuel pressure
Next up out flow rate
Introducing BSFC (Brake Specific Fuel Consumption) this is the weight in pounds (lbs) needed to support 1hp for 1hour or (lbs/hr)/hp
Typical values are:
N/A: .45/.55
Turbo: .55/.60
S/C: .60/.65 (superchargers run off the engine so require more fuel)
Here's the formula:
Flow Rate = (BSFC)×(Target HP)
So my flow rate is in my turbo application
FR = .6(lbs/hr)/hp x 200hp= 120 lbs/hr
If you need it in gallons/hour divide by 6. Fuel is approx 6lbs per gallon
So mine would be; 20gal/hr
So to conclude my fuel pump needs to run at:
21psi @ 20gal/hr (120lbs/hr) @ +12v
I hope this is of some help to you all
