Nistune Forums

Can anyone share some info on what the injector latency should be for the 555 injectors? The car didn't Idle right when I only changed the injectors so I increased the injector latency by 25% to 2000 since I upgraded the injectors that much. The car idles and revs much better. On a side note I have been having issues with detonation when boosting above 6 or 7lb. even before any modifications (Stock Z 90,000 miles). Also any other additional tuning info for my new setup:

Dual Intakes w/ low-speed hose
Nismo 555 injectors
DP's
TestPipes
Greddy SP2 Catback
Innovate Wideband 02
UD pulley
Z1 Driveshaft
Greddy E-01 Boost Controller
PRVR Delete
TB water bypass
New Fuel Pressure Regulator
Fuel Pressure Guage

If your pinging at 8lbs then you might want to change gas stations. I use Chevron or Shell on turbo cars. Also change the fuel filter too if you haven't done it already. If it still does it then take some timing out of map where your getting the ping. Have you rewired your fuel pump yet so it get 12v all the time? Don't know about the nismo 550's but maybe someone who has a set will chime in.

nismo inj 555cc lag time .71 <~~~~~Found it on the net hope that helps.

use double that inside nistune 1420uS

Next release I'm fixing this up so it reports half of what it currently does (after checking it out yesterday)

Fuel filter is new and it also doesn't matter what gas station I use. Hi Matt there are two areas and one is injector latency, and the other is injector latency change. The first one was originally set at 1500 and the second at 204 ms I believe. It did not run right untill I set the first to 2000. But alot things say to put latency at .75-.93. How do those numbers match up to what Im seeing in Nistune? The values in Nistune are not in decimals. It does seem to run rich at idle with 13.5 average a/f. The k-value is set to 384.

Those numbers you mention are in milliseconds. Nistune entry is in microseconds (it also shows hex conversion in this window)

0.75ms = 750uS * 2 = 1500uS
0.93ms = 930uS * 2= 1860uS

Thats getting close to 2000 inside nistune. The next release will not require multiplying by two

That clears it up (latency numbers)... Well it looks like Im just gonna take this thing to Specialty Z for a full diagnostics on this detonation problem. Ive done nearly everything I can except swap CAS's or check actual timing marks. One more question: what is the difference in the two areas in Nistune

Injector Latency
and
Injector Latency Change?

Do they both need to modified when going to bigger injectors?

Injection latency is a static adjustment of microseconds to the total injection pulsewidth

The latency vs voltage is an adjustment based on amount of latency based on current level of battery voltage

I dont have much background information on this. I believe it would be some multiplier by battery voltage to add additional latency on higher battery power

In most cases should only need to modify just the latency when increasing injector size

I might have to ship my Z to you for tuning!! Thanks for the info. Have a great weekend!

Mike

Latency decreases with increased voltage. I just plotted the published values for mine at various voltages and used the latency corresponding to the actual voltage they see.

Plus the fact you don't get a latency adjustment option for CA18DET ECUs

That one might be a hard coded constant. Have to check my notes on that one as I believe I've looked for it at one time...

for the Z32, the latency voltage adjustment variable is at address 0x7F87

injector latency (in mSec) at voltage "Vx" :
(X + ((175-Vx/0.08 ) * (Y/256)))*0.01

where, X = variable @ 0x7F88, Y = variable @ 0x7F87.

-Eric

Matt wrote:use double that inside nistune 1420uS

Next release I'm fixing this up so it reports half of what it currently does (after checking it out yesterday)

Can you confirm this? I have installed my nismo 550s today and used 710ms, before I had deatchwerks 740cc ones that were set to 1100us which according to trent from status tuning was (a very high latency setting) or was trent assuming I had divided the number by two already?

Just not sure what I need it to be set to, currently the car runs fine regardless of what I set it to.

edit: just read that the "next release will not require multiplying by two" back in 08, so I'm guessing 710us is the correct setting to put into nistune for the yellow nismo 550s? I had a look for actual information from nismo but found nothing, where did this 710us figure come from? Trial and error?

http://my350z.com/forum/forced-inductio ... ctors.html

According to this denso injectors (Nismo/HKS etc) are 640us at 14v

Anyone able to confirm?

foliage wrote:
According to this denso injectors (Nismo/HKS etc) are 640us at 14v

I can confirm that Nismo hks tomei etc sidefeed injectors are not denso but JECS /bosch ...

http://www.rhdjapan.com/tomei-fuel-inje ... g30de.html

skylinegtrhr wrote:

foliage wrote:
According to this denso injectors (Nismo/HKS etc) are 640us at 14v

I can confirm that Nismo hks tomei etc sidefeed injectors are not denso but JECS /bosch ...

http://www.rhdjapan.com/tomei-fuel-inje ... g30de.html

BTW what is your voltage in NIStune? Maybe yours alternator is to weak (as on most Nissan cars)