VCT Control points for S14/S15 found

Matt · Post by **Matt** » Sun Oct 26, 2008 12:26 am

Hey guys

I've had a good run tonight and found the VTC limits for these ECUs

Add the following to your address files and let me know how it goes

Background info: I started with the known VTC points on Z32 8 bit ... which are the same addresses as Z32 16 bit. Using the VTC routine on the Z32 16 bit, it was just a matter of hunting down similar code where temp, TP and RPM were used around the same location

I'll work on ER34 next since I've been asked that a few times now...

VTC_TEMP_MIN_CUT,&HE7D0,1,1,1,1,VTC Solenoid ON > min temp
VTC_TEMP_MAX_CUT,&HE7D1,2,1,1,2,VTC Solenoid OFF > max temp
VTC_SPEED_CUT,&HE7D2,1,1,1,1,VTC Solenoid ON > speed
VTC_RPM_RECOVER,&HE7D3,2,1,50,VTC Solenoid ON > min RPM
VTC_RPM_CUT,&HE7D4,2,1,1,50,VTC Solenoid OFF > max RPM
VTC_TP_CUT,&HE7D5,1,1,1,1,VTC Solenoid ON > min TP

Matt · Post by **Matt** » Sun Oct 26, 2008 1:04 am

ER34 ....

VTC_TEMP_MIN_CUT,&H2C00,1,1,1,1,VTC Solenoid ON > min temp
VTC_TEMP_MAX_CUT,&H2C01,2,1,1,2,VTC Solenoid OFF > max temp
VTC_SPEED_CUT,&H2702,1,1,1,1,VTC Solenoid ON > speed
VTC_RPM_RECOVER,&H2C03,2,1,50,VTC Solenoid ON > min RPM
VTC_RPM_CUT,&H2C04,2,1,1,50,VTC Solenoid OFF > max RPM
VTC_TP_CUT,&H2C05,1,1,1,1,VTC Solenoid ON > min TP

some of the tooltips are stopping activating these I've noticed. I'll fix that up soon

Legionnaire · Post by **Legionnaire** » Sun Oct 26, 2008 2:45 am

Sweet!! You are a legend, Matt!

But can you please elaborate how does cam timing routine work in R34's?
As far as I understand, its like

Code: Select all

bool VtcSolenoidPosition (unsigned char TP, short speed, unsigned short RPM, int temp);

Where ECU checks the status of its inputs and compares them to predefined values:
- engine temperature is above "min temp";
- engine temperature is below "max temp";
- load exceeds "min TP";
- speed exceeds "speed"

If above conditions are true, then it turns on at "min RPM" and off after "max PRM".
If at least one of the above conditions is/becomes false, then RPM parameter is overridden and VTC solenoid remains/turns off respectively.

Is this correct, or did I get it all wrong?

PL · Post by PL » Sun Oct 26, 2008 8:56 am

Sweet!

So looking at S15 the temperature range is -50 to 120, so effectively active all the time. And Max speed cut is at 0, so I assume that means it's also active at any speed.

RPM window is 1050 - 5700 so it looks like inlet cam is advanced once you're above idle and it stays that way until 5700. I just went through the manual and it mentions those figures.

Looking at the power curves we recently got for std S15 you can clearly see the switchover point:

http://www.plmsdevelopments.com/custome ... i_edit.jpg

Good stuff. I love it when things add up!

PL

Matt · Post by **Matt** » Sun Oct 26, 2008 9:17 am

Hi guys

If you have a look at the commenting at the end you will see

VTC solenoid ON (min - max temp)
VTC solenoid ON above min speed
VTC solenoid ON (min - max RPM)
VTC solenoid ON above min TP

Yes current vehicle inputs are used to calculate this. That is how I found the routines on these other vehicles. I'll plough through the other address files now (KA24DE etc)

Adam · Post by **Adam** » Sun Oct 26, 2008 10:02 am

Hey Matt,

Does this apply for the GA16DE as well? (N15)

Cheers
Ad

Legionnaire · Post by **Legionnaire** » Sun Oct 26, 2008 10:54 am

Confused

Just looked at VTC related values on different RB25 Neo .bin's from rompack and found the following:

- temperature range is 70 to 120, so if I have a 62 deg thermostat, there is no go for NVCS (minor detail);

- "TP min" is 56 on all .bin's. I'm going to test and to find out what is so special in TP being 56, maybe it is 0 psig in an intake or something;

- minimum speed is 0 km/h. It sounds quite logical to me that there is no reason for engaging NVCS when revving engine on neutral gear. But this is the case only if VTC routine uses > and not >= in comparison expression;

- The most confusing of all is that ALL of ER34/WC34 .bins (except two) have the "VTC on" and "VTC off" RPM points set to a same value - fixed at 5400. I dont know, what does this mean and what is the reason for this, actually, this means than VTC is not working at all. The two .bins that have these points different are -AA500 IMPUL MT, where "VTC on" is set to 4000 RPM, and -AA560 MT have "VTC on" point set to 2400 (this is from ER34's after restyling in 2000, according to nissan those SII engines have slightly increased torque of 370nm as opposed to SI 350nm).

What do you guys think?

Petros.

PS. And a little, purely cosmetic request. Matt, can you please either make sidebar resizeable, or get rid of the word "solenoid" in sidebar buttons (or, maybe, make bar button names customizable through adr files)?
I've added a screenshot to illustrate

Matt · Post by **Matt** » Sun Oct 26, 2008 4:27 pm

see if I can check it out tonight... the TP sounds about right

RPM ranges.... those are definately the two memory addresses but I havent 'read' the code too closely

didnt get time to test last night since i only just found it and posted in excitement?!

see what I can do about the horizontal scroll. hopefully the grid control lets me get rid of it since we dont really want it there. agreed it is annoying!!

chris2712au · Post by **chris2712au** » Sun Oct 26, 2008 5:32 pm

yeah baby,

was waiting for this one... just another reason why people should go nistune.. now just to play around with the standard cams.. see if I can get a little bit more...

Cheers Matt...

PL · Post by PL » Sun Oct 26, 2008 10:09 pm

Yeah, see what you can get from just using a T28 + decent intake and exhaust + a good tune. You may be surprised. See how close you can get to Graeme's 200 with the 2871.

I've seen 195 out of my S13 SR and T28 (std cams) so you should get close. And keep your boost response!

PL

Matt · Post by **Matt** » Sun Oct 26, 2008 10:33 pm

the N15A GA16 looks like completely different code

Heres some starting addresses to try out:

E7C8 - temp check
E91E/E91F - speed check (based from above temp check)

E921 - temp check2
E923 - temp check3
E924 - speed check2 (based from temp check 3)

Table at E400 - RPM indexed lookup table against current RPM compared against some RAM variable (TP?) used to determine VVT on/off. Need to check this on the bench

JasonKemmerer · Post by **JasonKemmerer** » Mon Oct 27, 2008 5:51 am

Matt

Are there more settings for the VCT on the Z32?
Trying to get it to kick on at will by throttle position. Right now the car needs to have speed involved to kick on.

chris2712au · Post by **chris2712au** » Mon Oct 27, 2008 8:36 am

hey pete,

would love to see this on graemes car on the dyno... looking at those switching points makes you want to kick it in a little sooner.. like 5K or what do you think ?

PL · Post by PL » Mon Oct 27, 2008 10:57 am

Dunno about that one. When the car was standard it definitely looks like moving the VCT point downwards would help.

But with the bigger turbo and more boost it's hard to tell. Only one way to find out I guess. Must sort that throttle body first.

PL

kenbam · Post by **kenbam** » Mon Oct 27, 2008 12:38 pm

One method i had read about to find best switching point (on my z32 at least), was to do 1 run with VTC powered up (no switch off at 5XXX rpm) and one run with it disconnected. Torque curves should be a completly different area. Simply lay one graph over the other and set the RPM to the point where on graph (going down) overlays the other graph (going UP). Hadnt had a chance to do it yet as last time i was on the dyno my VTC springs were not releasing. Fixed that but havent been back on dyno yet to play with that part.