Hey folks, I am trying to understand why everyone throws really large injectors on their cars instead of running lower injectors to their fullest potential. As long as your not leaning out, why would you not want to run something to its fullest potential?

 

If you run smaller injectors at 100% duty cycle (aka "fullest potential"), you run the risk of having your injectors stuck at open.

 

YOU NEVER WANT TO RUN INJECTORS OVER 90% DUTY CYCLE. Injectors will potentially run in unpredictable manners and spray patterns at their limit.

That is all.

Tom

(OK 90% may be uber conservative, maybe 95% but I'm sure the true tuners will chime in with the same or close to the same answer)

 

You can run 90% IDC but you need to monitor that very closely especially in the NE or any place that has wide range of temp changes. The reason is that if you are already 90% IDC in the Summer then you will be most likely go way above that in the Winter because the ECU will add more fuel to compensate for the colder/denser air. Most tuner will recommend not to go above 85% for the reason I stated, it just give you more more room on colder weather.

 

Cool, thanks for the info.

 

The other point being that the cost is the same and the low impedance injectors handle short pulse width just fine (e.g. HKS 1000 cc)

 

anything over 90% and you are just asking for trouble

 

would one of those sensors plugged into the ODBII port tell me what I am currently running my injectors at?

 

Another thing...dont do it

 

+1000

I have always been told keep it under 80%. It's not worth the trouble.

 

Trying sprinting at full speed. How long can you do that?

 

About 30 seconds before I need a cold beer.

 

What EMS do you have? If you can get the pulse width then it is easy. Here's the formula, (PW X RPM)/1200. I have ran 90% IDC for almost 2 years but I only hit 90% at redline, I dont hit redline everyday and if I do I only hit 6750rpm in a very short time. I know I'm pushing mine but I do pay close attention on my tune and IDC. Hitting 90% IDC in a very short time is not the end of the world But you do reduce the margin for error...

 

LOL...I can go about 1/4 of that before I need a cigarette