Someone with Excel please help me out

[kjewer1]

I think I finally stopped being a dumbass and figured out how to get my fuel pump/injector spreadsheet to work for people with excel (without having to actually rewrite it in excel). I just posted it, the last link at the bottom of this page:

http://www.posracing.net/AFR.html

Try it out and see if it works. The user fields are grey I believe. Play around with some numbers and see how it does. Let me know here as soon as possible, if its good everyone can finally access this POS.

[scottsee]

works just fine. good work

[kjewer1]

Shit, I could have done that years ago. Leave it to my little sister to give me the hint I needed to straighten it out. I'm a dumbass.

So to recap, this spreadsheet will do all the math that I have spelled out in other threads to determine fuel requirements. I like to size fuel components to the max the turbo is capable of, so you dont have to worry about running out. The injector page should be pretty self explanatory. Just put in the size and enter fuel SG and what the richest AFR you plan to run, and you get an airflow capacity. Adjust the injector size until its enough. You can also figure out what the duty cycle will be by adjusting the injector size to get the exact airflow you are running or will be able to run.

For example, 4 950s at .724 and 12:1 can support 76 lbs/min airflow. Lets say you are flowing (or plan to flow) 65 lbs/min. Adjusting injector size to 860 gives you 65 lbs/min. So 860/950 is 90% duty cycle. This should work out, but I reserve the right to be wrong. At any rate, the numbers given assume 100%, or fully open, assuming the injector is rated at wide open.

THe pumps, same thing, input SG and AFR. rewired is assumed, but everyone should have rewired his/her pump. Its free fuel flow. Look to the next highest boost row, and go across to airflow. For example, if you are going to run 25 psi, but only 15 and 30 is given, use the 30 line. You can estimate what it will be, but pump flow vs pressure is not linear. Its fairly close though up until you max it out. So if boost is between 15 and 30 psi, choose the flow number between the two given, but at your own risk. Over estimate fuel requirements to be safe.

43 psi is assumed, which is 2g base pressure, and what injectors are rated at. 1g is 38 psi, so 650 injectors will not actually flow 650s, since pressure is lower. There is a formula easily found on the internet to determine the change in flow for a given change in pressure. At some point I will incorporate this into the spreadsheet. Probably a box where you can put in any base pressure, since people do sometimes raise it to get a little more from smaller injectors.

Enjoy.

[scottsee]

A+ there math wiz

[kjewer1]

The best part is I dont know shit about math. Dave and Tom and others on the DSMlink have skooled my azz more than once. But I know just what I need to know to blow up these DSMs

[JoeWagon]

I did some estimating and it appears that what I'm looking at going with, EVO 8 560cc injectors and EVO 8 pump rewired, I'm looking at 41lbs/min max at 23-25psi. It's not worth looking at if I can support more at lower boost, because the 16g won't hit 40lbs, if ever, lower than 20psi. Seems that the 190lph/550cc combo is perfect for eachother, and the EVO8 pump is almost the same as a 190, with 560cc injectors. Those engineers at Mitsubishi are smart.

On another note, "getting more from smaller injectors" seems to be what shep does; he's only running 1000cc injectors, if he hasn't changed recently. Wonder what the base pressure is.

[kjewer1]

People running race pumps (like the aeromotive A1000) can run much higher pressures and still get enough flow. And dont forget that people making 2 or 300 of thier HP on nitrous arent using that much of the injectors, since the fuel supply for that HP is provided by the fuel jets in the nitrous setup. So a 700 hp car may only need enough injector for 4-500 hp, etc.