Latency + K Values

[Matt]

ECU Tuning Guide here (Based on Z32 but others very similar)
http://www.ztechz.net/id10.html

Add to this thread known latency/K values

A value with 0x means 'hexidecimal'. NIStune uses this as a 'raw' value and shows this ... now adjusts it to uS / mS in the injector latency windows

For Z32 MAF change the AFM_OFFSET to 0 in your address file to get the display adjustment working in NIStune. Use notepad to edit this file.

Injector resize will pull the 'stock' CC value from your address file and change to what you enter. It will adjust your K constant (injection multiplier) value. It is recommended to update this INJECTOR_CC value in your address file if you wanted to resize again later (save as a new address file with different name)


Bernard -
Bosch "400's" have a latency of just under 1 ms
720's have a latency of 1ms (0x66 - 0x69)
420s - mercedes injectors the value should be around 0x4B (K = 375)
012F for bosch/ford cfi 440cc injectors/z32maf

Hendrick -
420cc injectors on my z31 turbo, kconst is at 376 and latency at 79

Gabe
DSM 450CC latency timings/volts
Volts/ uS 18.70 / 495, 16.35 / 555, 14.00 / 690, 11.68 / 915, 9.34 / 1260, 7.00 / 2295, 4.70 / 3825

Matt
GTR Injectors 444CC. Latency about 740uS.

*updated 7 Sep 2009 to fix old information *

[1SIKZ31]

Im lost on Injector latency on 450cc injectors, its showing the values right there in my face, but what "digit" should the latency be set at.

For example
" 420cc injectors on my z31 turbo, kconst is at 376 and latency at 79"

It shows the values simple and understandable.

But on the DSM's im totally lost.

Damn I hate being confused on shit.

[Matt]

Injector lookup table from end of this thread
http://ibconceptions.com/Nistune/viewto ... ight=#2263

http://paulr33.skylinesaustralia.com/do ... top-en.htm

The "injector latency" value Nissan uses is at 14 volts so 14.00 / 690uS

However from the above thread, multiply x 2

So 690uS entered into NIStune would be a good starting point

The "latency change" value is a finer tune adjustment when battery voltage is higher/lower but dont worry too much about that in the meantime

*updated 7 Sep 2009 to fix old information *

[Hendrick301]

Hendrick -
420cc injectors on my z31 turbo, kconst is at 376 and latency at 79

idles well and drives well, but when i get on it, it misses/hesitates when you shift. runs was too rich up top. i need more time on the dyno to work with it.

[Hendrick301]

one other thing- if you change the offset to 0 do you have to go through and do the "change maf sensor" in the operations window?

also how does the new feedback controls work? when they are all checked it means no 02 feedback?

[Matt]

the FB_SWITCH parameter is wrong in the address files. The value at this address is a temperature value. So should be instead for 1987/1988 Z31

O2_FEEDBACK_TEMP,&H3F91,1,1,1,1,Feedback control

use this with the latest beta version which has fixed up a bug with adjusting this field and it wont appear as tick boxes

based from discussion on this thread
viewtopic.php?t=443

if you change offset to 0 it only affects the display on the screen. So it is not necessary to change MAF sensor

[Mads B (dk)]

a list with injector latency/ lag time

http://injector-rehab.com/kbse/lag.htm

[skylinegtrhr]

Hi this link from old forum doesn't work so can You post some new link with reliable injector latency, I would like to check for EVO 560 MDL560P, INP-401 (I found some not so reliable information that it is .85 and when I download latency table from EVO9 with ECUFlash it was .436 on 14,2V) , my friend order this for CA18DET so it would be good to be sure.

[Matt]

replace

http://forum.nistune.com with http://forum.nistune.com with the links above

one of the referenced pages

http://paulr33.skylinesaustralia.com/do ... top-en.htm

[DeJi]

The "injector latency" value Nissan uses is at 14 volts so 14.00 / 690uS

However from the above thread, multiply x 2

So 690uS x 2 = 1380uS entered into NIStune would be a good starting point

Are you saying that instead of entering 710uS as the injector latency for my Nismo 555cc pink injectors (I've read they're rated at 71ms), I should double it? Cause my idle is pretty unstable. I tried bumping the latency up to 850 and that cured it partially. It seems likely that if I go even higher, the problem will disappear

[Matt]

not any more. latency was incorrectly reported. enter latency for your injectors reported @ 14 volts

[Claudman]

Just tuned a VG30 1986 Z31 ECU with Bosch 0280150400 injectors.

Running stock fuel pressure

K = 343
Latency = 0750 ms (may need some work but idles very well)

[louiswun]

Some useful information on injector's latency
http://1jzmerc.com/hks-faq/hardware/#injectors

[Tbstr3]

Could use some help pinning down the latency and K of the following injectors, I cant get this car to idle very well, im sure ill be posting in other areas and spending the next few weeks on this forum haha. I can change the K till Stoich at times then it wont rev, so I set it richer, which allows to rev great, a few seconds later it goes hella lean, which tells me there maybe some other factors causing this, but I figured I need to start here and I will re go over the basic mechanical settings again.

Yellow – 510cc – EVO 1-3 and JDM VR4 – Stamped MDL510, casting# unknown – Low Impedance

EDIT: Ive found the latency I believe and the K shouldn't be hard to pinpoint, will report back, but any insight is helpful

510 CC
4.7 - 4056uS
7.0 - 1944uS
9.4 - 1272uS
11.7 - 912uS
14.1 - 696uS
16.4 - 576uS
18.8 - 480uS

[Matt]

You want to use the dead time at 14.1V

If you have stoich at 2000rpm (cruise) then when reving upto cruise it should be okay unless you have another problem. Best to do some runs, take some logs and go through the AFRs as you accelerate (say in third gear)