Fuel Injection Design

Clive Apps Techno-Logicals 416 510 0020 clive at problem.tantech.com
Tue May 5 15:07:51 GMT 1998


> 
> I am new to the DIY_EFI list and some what new to fuel injection.  And was
> wondering if someone tell me of some good books and literature to read on
> the design of fuel injection.  Main areas I am looking for are how to get
> a fuel curve for my motorcycle.  Friend and I are working on applying fuel
> injection to a dragbike I have and it seems the only draw back we are
> having is where to start with the fuel curve.  Any good homebrew books out
> there??  I tried the link on the DIY_EFI web page for books and got a NOT
> FOUND.  Any help appreciated.


you can do the calculations yourself
if you have an estimated torque curve for the engine
on a highly tuned bike VE should be in the 110% range or maybe 120% on a race 
bike
max VE will be very near max torque
the VE curve will look almost exactly like to torque curve less mechanical
losses (if you can get a dyno curve for the frictional losses you are laughing)
compute the amount of air you consume per revolution

multiply the RPM x air comsumed at RPM x VE at RPM x frictional loss correction
to get an air comsuption curve

once you know the amount of air you require
you can calculate a fuel curve for WOT at 14.7:1 ratio for stoic
12-13.5:1 for power, and 15:1 or more for cruise

you want the curve to be rich at idle about 10% better than stoic, lean at
cruise, and rich when power is required (IE when vacuum drops)

you should be able to find the info to figure the rest out from there

start too rich and tune it back as required

Clive 



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