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Forum namePerformance/Engine
Topic subjectAnyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=46264
46264, Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by Kiku, Mar-08-03 03:13 PM
So today i was driving for 1 1/2 hours to finish up a turbo install in NJ, and i had my laptop hooked up to my emanage, and reading data realtime.

I am currently running RC Eng 270cc/min (close to the stock 235cc/min injectors) with a 1:1 regulator (i have to get inspected, that is why).

I have the injector harness hooked up so i can control injector pulsewidth and all. I was monitoring it and i noticed that the stock ECU has NEVER taken these injectors over 20% duty cycle. Hell i have my emanage set to add 90% in addition to the 20% and i was still not going over 30%!!!

Wouldnt this kind of explain why our 420a's need more fuel (thus our rising regulator EVEN when running 440 injectors like the DSM folks) versus other similarly setup DSMs?

Just a thought...

BTW, you *can* run 1:1 and 270cc/min injectors at 8psi of boost...you just have to be able to control injector pulsewidth ;)

Vinnie
_________________
Vinnie Lima
vinnie.lima@jvllogistics.com
AIM: Kiku888
1997 Chrysler Sebring "Silver XTC"
I4 420a w/ HRC Stage 2.45 w/ FMIC
14.7@97 mph@6psi
Proud member of the
ASOG BoOsT JuNkIe Crew
46277, RE: Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by JustOne, Mar-08-03 09:21 PM
I always wanted to see what the stock DC was but there wasn't a way until the e-manage. I know of a multi meter that will let you read DC but I never got around to ordering one.

This is good info though.

Did you get a chance to see what the DC was at during WOT? What is your base FP set to?
46280, RE: Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by MetalJim, Mar-08-03 11:58 PM
I don't know Vinnie. That sounds wrong. I mean, if that were true then that equates to something like 50cc/min, which is worth a whoppin 37hp. I'm not sure, but it just doesn't sound right to me.


95 Eclipse RS : 5 speed
Jeep TB writeup - http://www.dimensia.com:81/jimbo/JeepTBfor2gnt.html
46287, RE: Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by Kiku, Mar-09-03 06:49 AM
WOT it wont go over 20~30%.

This has to be right because i'm running 8lbs of boost WITH 270cc/min injectors and it works as long as i double the duty cycle on these injectors @ 45psi.

I dont seem to "run out of fuel" which would indicate that I am maxing out these injectors. I just dont dump more fuel because the emanage only allows you to do 100% on top of regular duty cycle (i.e. 20% + (1.0 * <current duty cycle>) = 40%.

dont worry i'm not going to do it anyways hehe just in case i'm wrong. It was just interesting.
_________________
Vinnie Lima
vinnie.lima@jvllogistics.com
AIM: Kiku888
1997 Chrysler Sebring "Silver XTC"
I4 420a w/ HRC Stage 2.45 w/ FMIC
14.7@97 mph@6psi
Proud member of the
ASOG BoOsT JuNkIe Crew
101259, RE: Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by ian_12, Oct-07-06 09:12 AM
yes i know VERY OLD TOPIC, but i noticed a similar thing. with the 310cc injectors in my friends 420a, the emanage was showing a 3-4% duty cycle at idle and maybe 6% while driving. i swore i must have hooked something up wrong or forgot something, but its all wired in just fine. so i figured the emanage was just retarded. but now after you have said this, i wonder if it is true. i can highly doubt it. i still think its something with the emanage, but im not certain.
101287, RE: Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by CarbonFiberRST, Oct-10-06 07:10 AM
the duty cycle will be low if the engine is at low rpm's and or under low load. see what the duty cycle is between 6-7k rpm at WOT.
101298, RE: Anyone notice that our engines dont go over 20% injector duty cycles at stock fuel pressure?
Posted by ner947, Oct-11-06 02:52 AM
If you are not seeing more than 50% duty cycle at max power, you either have injectors that are way too big, fuel pressure way to high, running way too lean, or whatever you are using to measure the duty cycle is messed up.