Newb getting started - need injector advice

boosted2000 · Post by **boosted2000** » Tue Jan 31, 2006 7:29 pm

I recently purchased a V2.2 board and assembled it for my dragbike project. After several years of racing Kawasaki's I made the switch to the Hayabusa powerplant.
The Hayabusa is a 1300cc 16 valve motor that makes around 165 HP stock. I plan to run a turbo at low boost to start (~4 PSI) and work up from there. A recent dyno session with a friends bike proved that we can expect about 12.5 HP per PSI of boost. With just 4 Lbs of boost I should be in the 8.40's in the quarter!

Finally, here are my questions:

-What is the largest injector size that I could run and still expect to idle (I could idle and 1k to 1.5K RPM)? Bike redlines at 11K. I calculated around 550cc injectors to give me some room to grow, but I was concerned that the injector tables were based on a car and may be skewed for a motorcycle that is lighter and higher revving.
-Would I need to use a rising rate regulator? Currently many are using the stock electronics, a PowerCommander to alter the fuel map and a rising rate FMU to compensate for boost and alter the A/F ratio to the 11.7:1 ratio that is kind of accepted as a safe place under boost.

Jocko

grawill · Post by **grawill** » Tue Jan 31, 2006 8:18 pm

What is the largest injector size that I could run and still expect to idle

I am running 47lb injectors on my 4 cylinder car with no idle issues. My injectors idle around 2.2ms squirts and it runs as smooth as a stock ECU. It may not be a bike.. but it does give an idea of a somewhat large injector with a "perfect" idle.

I was concerned that the injector tables were based on a car and may be skewed for a motorcycle that is lighter and higher revving.

The fuel and spark tables are based off MAP and RPM readings (among other things).. it shouldn't have anything to do with a car or bike.

Ted.

boosted2000 · Post by **boosted2000** » Thu Feb 02, 2006 8:22 pm

TTT Any suggestions. There are three of us with basically the same setup, different performace goals.
Thanks,
jocko

PS Grawill, thanks

whittlebeast · Post by **whittlebeast** » Thu Feb 02, 2006 9:06 pm

see http://www.ncs-stl.com/fuel/ReqInjectors.xls

boosted2000 · Post by **boosted2000** » Fri Feb 03, 2006 8:05 pm

I already had the spreadsheet and filled it out. It sized the injectors in the 50# range. I was wondering if I could get these to idle. How do I calculate the injector opening time at idle? I know the 1.7ms time is about the minimum.

The project has passed the point of being able to go with a second set of injectors, so I would really like to make this work.