General question...

At what point does your mod list require injectors upgrade? I'm trying to foresee/order my upcoming mods, and be prepared.

How does one find out IF they need the upgrade? I would imagine 'finding out' doesn't sound too good...

I'm looking for technical information to find out how a tuner suggests an upgrade...

Any information is certainly appreciated!

 

wow...no replies...thanks!

 

Well once you start to notice your injector duty cycle rising towards 90%, you should probably consider going bigger. You should also probably upgrade the fuel pump before asking more of the stock unit.

 

Thanks, but my fuel pump has already been upgraded; I'm trying to find out if the next set of mods (cams, cam gears) are going to require the purchase of upgraded injectors...

 

With the cams, you might want to consider doing the injector upgrade shortly afterwards.. With my current tune, WITHOUT cams, my injector duty cycles peak at about 80% if I can get any more air into the engine, I'd certainly need more fuel..

I'd be more concerned with whether you can scale the injectors to function correctly, or if you need hardware/flash to do it first.. then get the injectors. The bigger fuel pump is probably enough to keep the car happy with bigger cams (264's) if you aren't pushing the boost over 19 psi through redline.. If you have cams, and boosting at 21psi, I'd certainly upgrade for safety sake... you'd hate to get a lean condition just because your unable to provide enough fuel.

 

FWIW, I have a Buschur Stage 3 installation. I recently did some datalogging and discovered that at 20psi of boost, my injector duty cycles are hitting 100% as I get near redline.

I like to track my car and run it at 25psi with 100 octane fuel. The thing goes like a raped ape but I'm pretty sure at those boost levels I'm maxing out my injectors much sooner. I'm going to upgrade my injectors and fuel pump and pump wiring before I hit the track next time. I don't want to be running a lean condition for the extended periods of WOT @ redline I encounter on a road course.

 

Somebody correct me if I'm wrong, but rule of thumb for injector duty cycle shouldn't go past 80 to 85%. The higher you go, the more risk you take in having the injector lock up.... staying completely opened or completely closed.

 

I think you're right. It's my understanding that the injectors are locked open at anything past 80% anyway.

 

forgive my ignorance, but waht exactly are you using to measure the duty cycle of the injectors.

Another thing...once my cams are installed, it is my understanding (read in grassroots motorsports magazine) that an ecu reflash will NOT be able to adjust for the new size of the injectors (once the injectors have been upgraded).

Any thoughts?

 

You can have it reflashed to account for the additional fuel you'll be using. That or the a/f ratios will simply remain the same with more fuel per air part... not sure.

Duty cycles can be logged with a datalogger... along with a host of other very important things you should already be watching if you are upgrading this much.