Nissan RB25 CAS, how can I help?

Testing and development of Megasquirt 3

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Dookie454
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Re: Nissan RB25 CAS, how can I help?

Post by Dookie454 »

winstonusmc wrote:All in all its running good. I get a hesitation almost everytime when going into boost above 3000 rpm. I am posting up a pic of one hesitation and have noticed that the RPMdot is pretty messy, is this normal? I am just trying to figure out if the CAS programming is 100%. I may still go crank trigger anyway.
winstonusmc wrote:All in all its running good. I get a hesitation almost everytime when going into boost above 3000 rpm. I am posting up a pic of one hesitation and have noticed that the RPMdot is pretty messy, is this normal? I am just trying to figure out if the CAS programming is 100%. I may still go crank trigger anyway.


I'm one of the LT1 Optispark users and on the problematic MSD opti I normally see a real sync loss event as rpm dip immediately followed by MAP dip... as you are seeing. On my setup I was "hearing" sync loss as a small pop or misfire under load.. most noticable under boost and higher RPM... No sync loss was being recorded at 15pts/sec but I know that is what was occuring since I caught one event showing 0rpm but no sync loss. Any way you can log to SD card? TS logs at about 15pts/sec.. my SD card logging is about 150pts/sec.

With the MS3 I usually see pretty smooth RPM logging aside from any sync loss under load, with the stock PCM I see very jagged RPM logging under load.. not sure why yet but I'm starting to suspect OEM PCM "Sync Loss" type events.. just averaged.
MS3X on 2010 Camaro LS3 + Whipple @ 10psi + HPT + AEM 30-0333/0334 WB
MS3 Knock Module + JBPerf Dual VR v2.1 (Removed), didnt play well with LS3 DBW Motor, works for VSS.
OLD: 1997 Chevy Z71 Vortec 350, + BOSCH 0261231036 WB Knock Sensor
OLD: LT1 TA 700hp + MS3X
winstonusmc
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Re: Nissan RB25 CAS, how can I help?

Post by winstonusmc »

I think my problem is more ignition timing related. I can throw an SD card in and see though.
Nissan Skyline R34 RB26DETT ran MS3/MS3X w/ factory Hitachi CAS (sold)
Nissan Silvia S14 RB25DE ITB/NA ran MS3/MS3X w/ factory Mitsubishi CAS (disassembled)
Datsun 240z RB25DE ITB/NA with MS3/MS3X
jason
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Re: Nissan RB25 CAS, how can I help?

Post by jason »

Is the Hitachi CAS on your rb motor the same pattern as the sr? IE: if we get it working for 1 they all work

for reference this is my CAS http://dl.dropbox.com/u/29301287/IMG_20 ... 010208.jpg
winstonusmc
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Re: Nissan RB25 CAS, how can I help?

Post by winstonusmc »

no, the RB motor uses the 24,20,16,12,8,4 pattern. Six slots for six cylinders. The SR uses 16,12,8,4. Four slots for four cylinders.

Image
Nissan Skyline R34 RB26DETT ran MS3/MS3X w/ factory Hitachi CAS (sold)
Nissan Silvia S14 RB25DE ITB/NA ran MS3/MS3X w/ factory Mitsubishi CAS (disassembled)
Datsun 240z RB25DE ITB/NA with MS3/MS3X
jason
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Re: Nissan RB25 CAS, how can I help?

Post by jason »

thanks winstonusmc, after looking through the crank datalogs i totally got it now.

so i have a question. have you experienced high rpm sync loss which can be attributed to the ms? or is it hard to tell?
winstonusmc
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Re: Nissan RB25 CAS, how can I help?

Post by winstonusmc »

I havent experienced high rpm sync loss at all. On the drift car, it runs the Mitsubishi CAS and the only time it ever lost sync was low RPMs. In this log, the only time it lost sync was when the engine stalled, probably from a spinout when the engine sometimes gets kick backwards.
2012-01-21_15.23.26.msl
Nissan Skyline R34 RB26DETT ran MS3/MS3X w/ factory Hitachi CAS (sold)
Nissan Silvia S14 RB25DE ITB/NA ran MS3/MS3X w/ factory Mitsubishi CAS (disassembled)
Datsun 240z RB25DE ITB/NA with MS3/MS3X
Dookie454
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Re: Nissan RB25 CAS, how can I help?

Post by Dookie454 »

I think you will get a sync loss anytime the motor is stalled, or stopped with the MS powered up (key on). It's not a real sync loss event, It's from the trigger wheel stopping creating sync loss, sync basically that's what it is. At least this is true in any of my testing. This probably isnt noticeable with an automatic, mostly manuals.
MS3X on 2010 Camaro LS3 + Whipple @ 10psi + HPT + AEM 30-0333/0334 WB
MS3 Knock Module + JBPerf Dual VR v2.1 (Removed), didnt play well with LS3 DBW Motor, works for VSS.
OLD: 1997 Chevy Z71 Vortec 350, + BOSCH 0261231036 WB Knock Sensor
OLD: LT1 TA 700hp + MS3X
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Re: Nissan RB25 CAS, how can I help?

Post by jsmcortina »

Yes, the engine stopping is by definition sync loss. The code cannot stay in sync with something that is stationary.

James
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jason
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Re: Nissan RB25 CAS, how can I help?

Post by jason »

Hi James, that wasn't a troll, honest. I was just trying to wrap my head around how the ms is coping with the 1 degree wheel.

8000rpm is approx 133 rps. 133/2*360 is 23940 interrupts per second which is a boatload of interrupts (if indeed each rising or falling edge generates an interrupt).

this may be a dumb question, but i haven't found any schematics for how PT4 gets to a pin on the cpu.

jason
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Re: Nissan RB25 CAS, how can I help?

Post by jsmcortina »

The PT4 input is shown in the MS3X schematics.

James
I can repair or upgrade Megasquirts in UK. http://www.jamesmurrayengineering.co.uk

My Success story: http://www.msextra.com/forums/viewtopic ... 04&t=34277
MSEXTRA documentation at: http://www.msextra.com/doc/index.html
New users, please read the "Forum Help Page".
jthiani
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Re: Nissan RB25 CAS, how can I help?

Post by jthiani »

Im very curious to see how this turns out. I will be running a 300zx with a vg30dett which has the same cas as the rb series. Am i safe in assuming that once this is working well on the rb the same will be true for the vg??
winstonusmc
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Re: Nissan RB25 CAS, how can I help?

Post by winstonusmc »

It worked well with both of my RBs. The RB can be ran with a VG30DETT ECU, so yes it will be the same. Of course with a slight firing order change.
Nissan Skyline R34 RB26DETT ran MS3/MS3X w/ factory Hitachi CAS (sold)
Nissan Silvia S14 RB25DE ITB/NA ran MS3/MS3X w/ factory Mitsubishi CAS (disassembled)
Datsun 240z RB25DE ITB/NA with MS3/MS3X
winstonusmc
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Re: Nissan RB25 CAS, how can I help?

Post by winstonusmc »

jason wrote: 133/2*360 is 23940 interrupts per second which is a boatload of interrupts
Thats only 24kHz, not that fast compared to a high speed processor
Nissan Skyline R34 RB26DETT ran MS3/MS3X w/ factory Hitachi CAS (sold)
Nissan Silvia S14 RB25DE ITB/NA ran MS3/MS3X w/ factory Mitsubishi CAS (disassembled)
Datsun 240z RB25DE ITB/NA with MS3/MS3X
nissmo127
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Re: Nissan RB25 CAS, how can I help?

Post by nissmo127 »

So I am thinking about going this route for a RB20DET using oem sensors and jumper harness.
I searched and this seems to be the only How to page. Is there a designated page for setting the CAS up yet?

If not is it basically...

Wiring in pull up resistors as per Optispark Manual under MS31.1.
Connecting the low-res input to the "crank" tach input and the hi-res input to PT4.
Install Firmware
Adjust settings per image below
Adjust timing/phasing...

Is there something else am I missing? What firmware would I need for Nissan CAS?


Image
n1tro5
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Re: Nissan RB25 CAS, how can I help?

Post by n1tro5 »

Bump...

Been watching this post for a while and just wondering if nissmo127 has the right idea...wanting to buy a megasquirt but i want to sus it all out first :RTFM:

Cheers Guys,
N1TRO5
Bardabe
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Re: Nissan RB25 CAS, how can I help?

Post by Bardabe »

So how is the code coming along? I will be ordering my MS3 for my 300ZX VG30DETT this weekend, My car currently runs but it's on a rom tune and I've always tinkered with my own cars ECU, this time around i want to give MS3X a shot instead of the traditional Nistune / Haltech route. with the new firmware are we running into any Sync or Timing issues?
Matt Cramer
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Re: Nissan RB25 CAS, how can I help?

Post by Matt Cramer »

The code's been out for a while; I haven't heard much in the way of problems with it.
Matt Cramer -1966 Dodge Dart slant six running on MS3X
sheek
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Re: Nissan RB25 CAS, how can I help?

Post by sheek »

brett
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Re: Nissan RB25 CAS, how can I help?

Post by brett »

winstonusmc wrote:All in all its running good. I get a hesitation almost everytime when going into boost above 3000 rpm. I am posting up a pic of one hesitation and have noticed that the RPMdot is pretty messy, is this normal? I am just trying to figure out if the CAS programming is 100%. I may still go crank trigger anyway.
Image
2012-01-28_19.00.26.msl
I'm having a very similar problem this but at just below 2000 just wondering if you managed to find out a cure for it?

Cheers
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