106% duty cylcle?

[HYPNOTIK]

I was bored tonight so I got out my Nissan Data Scan and datalogged a couple runs. How the fuck can you hit over 100% injector duty cycle?
http://i302.photobucket.com/albums/nn87/SkylineGT_01/datalog-dutycycle.jpg
http://i302.photobucket.com/albums/nn87/SkylineGT_01/datalog-rpm.jpg
http://i302.photobucket.com/albums/nn87/SkylineGT_01/datalog-speed.jpg
http://i302.photobucket.com/albums/nn87/SkylineGT_01/datalog-timing.jpg
http://i302.photobucket.com/albums/nn87/SkylineGT_01/datalog-airflow.jpg

[!Zar!]

Whatever you see over 100% duty cycle is calculated. You can't actually go over 100% because all that means is your injectors are open all the time.

[S14_Kouki]

wow man something is wrong, I know ppl from Okinawa

[HYPNOTIK]

So I'm basically at the limit of my stock injectors. I guess it's time to upgrade.

[S14_Kouki]

what size injectors do you have what turbo setup

[xpertsnowcarver]

106%!! No bueno man!

[chibo]

So I'm basically at the limit of my stock injectors. I guess it's time to upgrade.

Stay below 80% theoretical duty cycle unless you want to blow things up.

[HYPNOTIK]

Stock turbo, stock maf, stock injectors, 248 cams, 12psi.

[HYPNOTIK]

and a walbro.

[S14_Kouki]

Really damn what kinda fuel mang you got?? Thats really weird unless the turned up boost uped your duty cycle for more fuel.

[fliprayzin240sx]

IIRC, no tuning what so ever. I told him he needs to do something to change the fuel map. Stock fuel map aint gonna keep up with it at 12 psi.

[HYPNOTIK]

Time for some off base gas.:)

[!Zar!]

11psi is 100% stock last I remember.

So that extra 6% is based off of cams/1psi/theory.

What does that mean? Nothing really. Just speaking aloud.

Time for some injectors and some sort of tune. Or at least injectors/fpr.

[S14_Kouki]

I was right your boost is to much for your stock injectors..... wait really dont ppl run 18psi on 380's or whatever stock sr's are???

[HYPNOTIK]

Stock boost is 7 psi or .5 bar. Stock injectors are 370's. I didn't think I could max this shit out on a stock turbo, lol.

[clark]

Danger to manifold!!!!

[blackej7]

Stock boost is 7 psi or .5 bar. Stock injectors are 370's. I didn't think I could max this shit out on a stock turbo, lol.

the stock turbo is gated for 7psi.

stock boost for sr is 11psi. if you look at a FSM, they come with boost pressure sensor and "waste gate control solenoid valve", to "control the boost pressure precisely"

I too see over 100% duty cycle. this was at 11psi... you dont see it until high rpm which i think is nothing to worry about on a stock sr on stock boost.

http://img27.imageshack.us/img27/2362/103dutycycle.jpg

[HYPNOTIK]

What turbo are you running? You're pulling alot more air through the MAF @ 11psi than I am at 12.

[blackej7]

What turbo are you running? You're pulling alot more air through the MAF @ 11psi than I am at 12.

Stock turbo.

not sure whats going on there. I do have a front mount/intake with all new piping. maybe your maf is dirty, or something... or maybe my maf is going crazy. i never compared maf readings with another stock sr, so im not sure what kind of readings you should be seeing...

[cotbu]

I maxed my maf out at 13psi but i't not dependent on boost it's flow that maxes it out.
blackej7 I would say that you are a candidate for an Air Flow Meter upgrade or a tune!

HYPNOTIK that looks pretty normal, but i would overlay all the data to read it more accurately

[HYPNOTIK]

I have a whole spreadsheet, I just made litte charts for ease of viewing.

This is what I got.
-S14 SR20DET swap
-SR20DE cams, 248 dur/ 10.5mm lift vs 240 dur/ 9.5mm lift for stock turbo cams.
-Greddy manual boost controller
-SR20DE 60mm throttle body
-XS Power exhaust manifold
-S-tec Motorsports turbo outlet
-Braided stainless oil/coolant turbo lines
-Walbro 255lph fuel pump
-Blitz Stainless Mesh filter
-Apexi exhaust
-Decat pipe
-3" downpipe
-Greddy FMIC
-Blitz BOV

[clark]

are you running lean?

let's not forget, not all software is perfect. it could be a bug or something in the software that causes a reading like that...

I have a stock SR ....stock t25, stock injectors, stock cam, stock maf, stock smic.

walbro 255, KN air filter, boost controller. that's it, i spike at like 17 psi, and boost holds around 14-15 psi. i've been running like this for 2 years, not a problem. i'll admit i've always been curious what my A/F is, but no indication of running lean. but yeah judging by the flow rating of these injectors, i wouldn't be surprised if you've maxed out the duty cycle and the injector is just at a static flow condition.

[HYPNOTIK]

I did notice that my alternator is going bad, it's only charging @ 11.8~12.4v. Maybe if I change out the alternator and the fuel pump is getting 13.5v it might lower my DC a little bit. It's just a theory though.

I don't know if I'm running lean, no wideband. You'd think if it was knocking though that it would pull timing in the top end, it doesn't appear to be doing that.

[steve shadows]

anything over 80% is basically FULL OPEN ALL THE TIME

just fyi guys