Formula for PW = fuel delivered???

Mr Gadgets · Post by **Mr Gadgets** » Mon Aug 21, 2006 8:40 pm

Can someone tell me how much fuel per hour I am using with qty8, 65#/hr injectors on 8 cylinder motor with 2 injections per cycle/ alternating, with a PW of 15ms at 5000rpm??

Trying to figure out if I am running so rich my WB is indicating lean or is this in the ball park. With a BSF of .5.. I should be able to tell if I am injecting enough fuel to make how many horsepower???

If there are any math guru's out there.. could you give me a clue??

Thanks for your help...

Dick

krisr · Post by **krisr** » Tue Aug 22, 2006 2:58 am

I've been thinking about this too. I'd like to see a gauge in Megatune to show the fuel consumption between resets etc. It will do the job to calculate economy properly if you make a mental note where your odometer is before/after your trip etc...

jsmcortina · Post by **jsmcortina** » Tue Aug 22, 2006 4:00 am

Ok, I'll try:

With 2 squirts per cycle (720deg) alternating that is one squirt on each bank per 720 deg cycle.

5000rpm -> 2500 cycle per min -> 24ms per cycle
(60000 / 2500)

15ms pulse = (say) 1.0ms opening time = 14ms
So, true duty = 14/24 = 58%

58% of 8*65 = 303lb consumed per hour

Hope I got that right.

James

Mr Gadgets · Post by **Mr Gadgets** » Tue Aug 22, 2006 7:20 am

James,
Thanks.. I was headed down that road, but didnt know how to figure in all the variables..

This tells me that I am supporting about 600hp with a BSFC of .5..

That means I am short a couple of hundred horsepower. So something is a miss and it isnt that I am over fueling the motor.. I made some changes to my combination this year and expected to gain 500rpm instead of lossing 500rpm.

So now the quest begins to find out what is wrong in that respect. The motor seems to be running fine, but just short on top end.

Thanks
Dick