Nismo 740cc Injector latency?

Episode180 · Post by **Episode180** » Tue Sep 13, 2011 11:12 am

Hey guys
Have been going thru the run down with installing nismo 740cc injectors. I've found the latency that best for me to be 850 in nistune. Prior I was told 660 but that had the idle very unstable. So I am just asking those who have dealt with experience or installed these injectors what latency worked for you?

Cheers

jmac636 · Post by **jmac636** » Wed Sep 14, 2011 2:57 am

I have been using 720 latency for my nismo 740cc for several years now. I am currently running a built ka24de with a holset he351cw, z32 mafs, 740cc nismos, stock fpr, and several other mods. I am using the same latency on 93 octane and E85 fuel. Just changing my K-value for each fuel.

Episode180 · Post by **Episode180** » Thu Sep 15, 2011 11:34 pm

Interesting... I thought at first it was one size fits all for the injector latency (example nismo 740cc = 66ms for all

) but I am now seeing that you have to find your own sweet spot. Took me (4) days to get start up, idle, cruise & wot but i finally got mine feeling like stock injectors now.

. I found a stable latency of 835 and k constant of 9637. For my nismo 740cc installation.

jmac636 · Post by **jmac636** » Wed Sep 21, 2011 5:37 am

I changed my latency to 850 over the weekend just to see what a difference it would make. It feels more like stock but wants to die sometimes when revving really hard then pushing in the clutch. Almost like the symptom of the mafs being to close to the turbo. Otherwise drivability was improved. I may drop mine down to 835 just to try it. Whats wierd is if I go back to 720 it runs super lean at idle now and didn't before. It would run slightly lean before at idle. I'm addicted to this tuning stuff I guess. I can never leave it alone.

sssbassil · Post by **sssbassil** » Wed Sep 21, 2011 5:45 am

jmac636 wrote:. Whats wierd is if I go back to 720 it runs super lean at idle now and didn't before. It would run slightly lean before at idle. I'm addicted to this tuning stuff I guess. I can never leave it alone.

LTFT and STFT maybe why

Episode180 · Post by **Episode180** » Sat Sep 24, 2011 8:42 pm

sssbassil wrote:
jmac636 wrote:. Whats wierd is if I go back to 720 it runs super lean at idle now and didn't before. It would run slightly lean before at idle. I'm addicted to this tuning stuff I guess. I can never leave it alone.

LTFT and STFT maybe why

What is LTFT and STFT?

I had the same issue with my engine wanting to die after hardreving/hard driving then clutch in. The solution I found was to adjust the IACV untill the AAC value on nistune was at 50%.

sssbassil · Post by **sssbassil** » Sun Sep 25, 2011 11:56 am

long term fuel trim and sort term fuel trim,

ltft 128% means no change, 118% pulling fuel, 138% adding fuel
stft 100% means no change, 90% pulling fuel, 110% adding fuel

only works in closed loop, O2 flags on

but its good tool to check how close your latency and k are

say ltft was adding 8% fuel all over closed loop u mite add 8% more fuel by adding 8% more k,(maybe)

there is alot of info on google about evo's and ls1 being tune by ltft and stft
not much info about nissan's tho

i use datascan to clear self learn after i burn in a new tune, so i know the ecu's not trying use the last tunes self learn settings

mite like to read this, its about ve trims but its the same sort of thing

Matt · Post by **Matt** » Sat Oct 01, 2011 12:24 pm

You can clear inside Nistune also under Display - Consult Active Test

Nistune Forums

Nismo 740cc Injector latency?

Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?

Re: Nismo 740cc Injector latency?