Grimlock

rx7.com has a fuel calculator. they say that the max duty cycle would be 58% - 63% on the stock ecu.

does this mean at full wot the injectors would never see any higher than 62% duty cycle? so if you where to richen up your safc to say +20% at 8000 rpms the duty cycle would be 82%.

am i right or am i missing something?

NZConvertible

I'v read this before but it seem seally strange. I've never heard of a stock ECU that actually limits duty cycle. Can anyone confirm this really happens?

RETed

Stock ECU does not limit fuel injector duty cycle - I've seen 95%+ (YIKES!) off my A'PEXi Super AVC-R (1st gen) myself...



-Ted

Scott 89t2

I think the 62% they list is for a stock car. so at 182hp or 200hp for 88 -89 you'd be at 58-63%

and the afc is airflow readings, not injector readings so increasing 20% on the afc wouldn't be 20% of injector duty cycle, but it would go up.

Grizzly

Am i right in saying with a Uprated Ecu it will tell you your Injector Duty Cycle? I have been told when u see 80% its time to Upgrade is this right?

Can you fit bigger Injectors on a Stock Ecu?

FPrep2ndGenRX7

I would guess that when using the stock ecu and most everything else being stock the injectors are running at 58-63% of the their capacity. Having said that the stock injectors can run at a higher capacity but like anything mechanical or electrical, the harder you work it the shorter its life will be hence the reason for an upgrade to larger injectors. What size depends on your mods.

I have also heard that you shouldn't go past the 80% mark.

These are ofcourse my own opinion and you should learn as much as you can and make your own best educated decision. To learn more check out www.sdsefi.com. They have a lot of fact not fluff.

NZConvertible

No one seems to be able to answer the actual question: Is there software in the FC ECU that will not permit it to run the injectors past 63% duty cycle? This has nothing to do with injectors or any other ECU's, just the FC one.

RETed

Uh, I think I did - at least with the (N332) 1987 Turbo II stock ECU.



-Ted

Scott 89t2

is there is easy way to measure it? besides buying an AVC-R ?

Grimlock

thanks for the info!!! what car do you have? and what mods?

so an 88 TII with my mods (see sig) would see more than 63% duty on the injectors. can anyone else back this up. this would really be beneficial to alot of people!



well i better lower my corrections then!!!!!!