yedister

I have read “That a 3/8 inch line on a fuel injected setup can support around 1000 HP at 80 PSI. Calculating / estimating horsepower range using BSFC from .45 to .50 lbs/hp/hr

This is the fuel volume needed to support 1000 HP
1000 HP multiplied by .45 BSFC equals 450 lbs./hp/hr
1000 HP multiplied by .50 BSFC equals 500 lbs./hp/hr

Injector size for 1000 HP, using Duty cycle 80% (0.80), Rail Fuel pressure @43.5 PSI
.45 BSFC approximately 70.72 / .50 BSFC approximately 78.58 lbs./hr.

Injector size for 1000 HP, using Duty cycle 80% (0.80), Rail Fuel pressure @80 PSI
.45 BSFC approximately 51.85 / .50 BSFC approximately 57.61 lbs./hr.

Information taken from http://www.rceng.com/technical.aspx#Conversion_Formulas

Using the Graph:



The relationship between fuel pressure and volume is inversely proportional. As fuel pressure increases, the pump volume decreases. How can a 3/8 inch line support 1000 HP, when the pump can’t flow enough fuel at the 80 PSI? Is the fact that the engine will not be operating at the max horsepower level for an hour, is that the reason a 3/8 inch line support 1000 HP?
Please educate me.

Yedi

THE 383 admiral

A typical race car 500 HP above. runs 8an lines or 1/2 tubing. To prevent fuel starvation.
When I upgraded to 8an just after the tank. On a previous car. I had to re- adjust my FPR. My pressure increased. After increasing the line size.

leesvet

You said it yourself...

Vol is the key. As pressure is raised by way of restriction, thus limiting volume by the increase in pressure. You do not necessarily need high pressure as much as you NEED hi-vol. The appropiate injectors will flow at a lower pressure so that vol can be maintained.
Its a balance but as previously stated, running the next size UP in pressure line doesn't hurt...

yedister

Thanks for answering