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Max Duty Cycle
Posted: January 23rd, 2012, 4:00 am
by atias
can anyone please tell me what would be my max duty cycle at WOT? open loop, stock injection system, OBD1.
is the stock injection system is maxing the injectors at full load WOT?
for a yj wrangler
thanks

Re: Max Duty Cycle
Posted: January 23rd, 2012, 4:35 am
by Cheromaniac
Do you have a 4.0 or a stroker? Any mods?
From my own experience, the stock 21lb injectors will cope with up to ~220 crank hp (~180rwhp) before the engine starts to run lean and ping under WOT.
Re: Max Duty Cycle
Posted: January 23rd, 2012, 5:09 am
by atias
i have your recipe for the engine you built for your own jeep(dino) ,with the crane cam (he is still alive). and a supercharger on top
the injection system is stock with all the stock sensor, i just need to know the exact duty cycle at WOT so i can calculate
the injectors size for my setup?
http://www.jeepstrokers.com/forum/viewt ... f=5&t=2867
thanks
and dino your web page used to be my homepage

Re: Max Duty Cycle
Posted: January 23rd, 2012, 5:55 pm
by SilverXJ
Are you going to do anything for the computer/injection so it can work with boost?
Re: Max Duty Cycle
Posted: January 24th, 2012, 4:27 am
by atias
yes, im getting the split second FTC1 soon with a 2 bar map sensor,
and i want to be as close to the correct injector size as posible,
so i only gonna take out fuel at idle and cruising but not at WOT ,and if so just a little but not too much.
taking out too much fuel via the map sensor can sometime advance the ignition cause the ecu thinks it has lighter load on the engine
and i think that to know the exact duty cycle of the injectors on a stock obd1 at WOT is a very good input that can be used
to calculate injectors size, and you wont gonna need to take out fuel with a map adjuster or FPR
thanks for you guys help
sorry for my english the spell checker not working properly

Re: Max Duty Cycle
Posted: January 24th, 2012, 6:16 am
by SilverXJ
If you haven't already purchased the FTC you may want to look at the AEM F/IC. It doesn't mess with the map sensor and works well on Jeeps.
Duty cycle doesn't really matter that much as a data point for what you are doing. In a stock engine the injectors should not be at 100% duty cycle at WOT.
Re: Max Duty Cycle
Posted: January 24th, 2012, 7:03 am
by atias
looks good and it cheaper too!
can you please give me the exact part no: of that AEM F/IC that will work with me OBD1?
thanks!!!!!!
Re: Max Duty Cycle
Posted: January 24th, 2012, 8:23 am
by SilverXJ
I used the AEM FIC 1913 on my OBDII. It has some circuitry difference that lets the injector circuits play well with the PCM. However, I don't know if that would matter on an OBDI.
Re: Max Duty Cycle
Posted: January 24th, 2012, 9:16 am
by Cheromaniac
atias wrote:i have your recipe for the engine you built for your own jeep(dino) ,with the crane cam (he is still alive). and a supercharger on top
the injection system is stock with all the stock sensor, i just need to know the exact duty cycle at WOT so i can calculate
the injectors size for my setup?
Looks like you're going to need Ford Racing 42lb injectors.
atias wrote:dino your web page used to be my homepage

Huh? What do you mean used to be?

Re: Max Duty Cycle
Posted: January 27th, 2012, 6:03 am
by atias
thanks for all of your help guys
i just ordered the aem fic, but i a accidently ordered the 30-1910 and its already on its way i hope its not gonna be a problem
with my obd1.
if the obd2 is a bosch chipset what is the old obd1 sbec board ??
i hope i didnt made a mistake
thanks
Re: Max Duty Cycle
Posted: January 27th, 2012, 6:53 am
by SilverXJ
I'm not sure how the universal one would work with the OBDI. You can try it and it might work or it migt throw a check engine light. However if it doesn't work you can send it back to AEM and they can turn it into a 1913 for you.
Re: Max Duty Cycle
Posted: February 3rd, 2012, 11:19 am
by atias
manage to change the order on the last minute
got the 30-1913 and hooked it up and its working flawlessly.
waiting on some big injectors
thank you SilverXJ for the tip about this think (more tips will be very appreciated

)
and thanks to dino for his website and all the knowledge that he shares
this is a great site to be a member of

Re: Max Duty Cycle
Posted: March 3rd, 2012, 1:14 pm
by flexin91xj
How did the hook up go with the FIC 30-1913 and the OBDI computer?
Re: Max Duty Cycle
Posted: March 3rd, 2012, 4:42 pm
by SilverXJ
You need a pin out for your vehicle's PCM and wires (factory service manual) and the pinout for the FIC. the FIC wires are labeled as well. You have to cut the injectors wire and each injector will have two wires from the FIC. If you are planning on adjusting timing you cut the cam and crank sensor and wire them to the FIC. The TPS, MAP, and maybe another sensor just gets teed in. The FIC isn't suppose to be used in the engine bay. It should be kept dry so I put mine in the cab, which necessitated lengthening the harness. I have a pin out and wiring guide for my 2000 XJ, but that won't help you.
Re: Max Duty Cycle
Posted: March 7th, 2012, 1:33 pm
by flexin91xj
Thanks for the info SilverXJ. Sounds like a PITA process but well worth it if you wont full control of your engine.
Are the pinouts something I buy? What exactly are they?