Injectors and Coils.

[Jeffrey]

What is the injector size (Lb/Hr) on the CBR 600 F4i and what is the charge time of the stock coils.

thanks

[B Lewis @ PE Engine Management]

Hi Jeffrey,

If I remenber correctly, the last test that we tested F4i coils (Denso units) we measured just over a 2 ms charge time to saturate.

[Jon @ Electromotive, Inc.]

... and our flow rates after coming back from cleaning was about 270cc/min. I don't remember the conversion off the top of my head.

[B Lewis @ PE Engine Management]

Hi Jon,

That sounds pretty high. How were those measurements made? 270cc/min is about 26 lb/hour. That's almost twice as much as required for an engine that makes 115 HP at 50 psi. I'm thinking thy should be somewhere around 12-15 lb/hr.

[Chris Boyden]

The conversion is roughly a factor of 10

15 lb/hr ~ 150 cc/min

www.rceng.com (http://www.rceng.com)

[Jon @ Electromotive, Inc.]

That's what the data sheet that R/C Engineering sent said when we got them back from cleaning. The measurement method is theirs.

[Charlie]

I was told by an injector shop that they were around 21 lb/hr. They are fairly large, would be tough to run batch fire.

[BryanH]

The conversion factor lb/hr to c.c./min is X 11
Large injectors are required in high rpm engines so duty cycle stays below 88% at max rpm
Firing injectors every second rev will give you good control at idle/light load, assuming you're going with an aftermarket ecu.
Bryan Hester

[Jon @ Electromotive, Inc.]

Yeah, I went and verified, they are actually closer to 220cc/min which is closer to what Charlie said. Good luck!

[Chris Boyden]

Ok Halfast, if you must split hairs,
the conversion is 10.5 http://fsae.com/groupee_common/emoticons/icon_wink.gif.
I suppose that you're gonna spec out the temperature
next.

[BryanH]

Add my name to Rob's list of idiots

[Cement Legs]

hmmm... Rob who???

[Daves]

220 cc/min sounds very high. Is that for 1, 2, or 4 injectors? Assuming 220 cc/min for a single injector, I calculate only a 15% engine efficiency for an OEM CBR600 F4i engine. Please see the following image (may need Internet Explorer to view):

http://fif4183.tripod.com/images/efficiency.txt

[Charlie]

Please don't take offense but I'd say your nose is too far in the textbook. http://fsae.com/groupee_common/emoticons/icon_wink.gif Step back and take a look at what that rating means, and how an ECU uses the injectors. It's not dumping that much fuel into the engine.

[DanO]

the rating is that of 100% duty cycle and you dont want to run at 100% duty cycle.

You can use whatever size injectors you want depending on what type of duty cycle you deem appropriate for the maximum fuel flow.

Its all in how you program your ecu....

[Daves]

Thanks, Charlie and Dan. I'm not offended, and I understand that 15% efficiency is way off, and so is the 63% we calculated based on the compression ratio of an ideal Otto-cycle engine. For preliminary design of our car, we're using the volume of fuel/air that can fit in two of the cylinders, and we are calculating the efficiency at 11,000 rpm. This yields an efficiency of about 29%, which is pretty close to what we've tested.