Jump to content
SAU Community

Motec M8 In R33 Gtr

CameronBNR32

By CameronBNR32,
in Engines & Forced Induction

 Share

Recommended Posts

CameronBNR32 Proficient

CameronBNR32

Posted
  • Author
Posted

I gave up on the idea of running it standalone.

The Motec can drive the tacho itself, but the problem is the TPS signal that goes to the ETS computer, the ATTESSA output.

You need to make a little circuit and the settings for the M800 are:

post-19425-0-89074300-1315689670_thumb.png

Setup the m800 output as function 3 – Aux Table.

Parameters –

Frequency = 10000Hz

Polarity = 1

Output Mode = 0

Set the table axis to Throttle Position.

When all connected, test with a multi meter. You should see voltages like this.

0% in the table should be ~0.5V

50% may only be ~1V

100% should be > 5V

no problem if your running a M800, but on the M8 the highest frequency I could put in was 1000hz, and I also ran out of outputs, I needed 1 x tacho output, 1 x tps signal, 1 x fuel pump, 1 x thermofan, 1 x boostcontroller, 1 x shift light. M8 only has 4 outputs, M800 has 8.

I am currently rewiring my whole engine loom to run the M8 with the stock ecu again. :(

CameronBNR32 Proficient

CameronBNR32

Posted
  • Author
Posted

Nearly finished off the loom today, but I ran into one problem...

Wiring up the crank angle sensor's power....

The crank angle sensor power runs at 12v (battery voltage) in the factory setup...

But the Motec wiring diagram has it wired up to 8v supply.. it was wired up on 8v before and working (running), but I need to wire the crank angle sensor signals into the factory ECU and into the Motec both at the same time...

Should I wire it up to 8v? or 12v? just worried about the factory ecu will not read it properly on 8v supply....and vise versa with the Motec with it at 12v supply :unsure:

R32 TT Mentor

R32 TT

Posted
Posted

Well I can tell you that my CAS is running off the stock ECU at the moment and therefore 12v supply to it. I have it wired to both the Motec and stock ECU - no problems. It was also suggested to me that it is good to run the 'clean' regulated 8v out of the Motec to power the CAS. But I haven't tried this to see what the standard ECU thinks about that...

Where did you get the info on the circuit required as a matter of interest?

R32 TT Mentor

R32 TT

Posted
Posted

Differning sensor ground impeadance between motec and ETS.

You will end up with a floating TPS.

ok, but at the moment the TPS is shared between the standard ECU and Motec..? So could you not delete the connection to the std ECU and instead run it directly to ETS? ie let ETS and Motec share this one sensor?

Otherwise I assume what I have now 'should' not be working..? But how else do you get you TPS signal to both Motec and the std ECU?

(I hope I haven't just asked a really dumb question.... there is something about it which makes me think I have..)

rob82 Mentor

rob82

Posted
Posted

ok, but at the moment the TPS is shared between the standard ECU and Motec..? So could you not delete the connection to the std ECU and instead run it directly to ETS? ie let ETS and Motec share this one sensor?

Otherwise I assume what I have now 'should' not be working..? But how else do you get you TPS signal to both Motec and the std ECU?

(I hope I haven't just asked a really dumb question.... there is something about it which makes me think I have..)

It depends upon the internal impeadances - if they are both relativly large then it wont really be an issue sharing the TPS signal. It is not good practise though. I worked for a company that made a tuning device that interfaced with various factory sensor's both analog and frequency based and impeadance matching was something we did on every vehicle.

I think that is what cameron was trying to get to with the Auxillary output - pretty much uses a frequency based signal with a cap to derive an analog output.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • brillo
      Leak from Tokico BM50 Brake Master Cylinder

      By brillo · Posted

      Hi, SteveL Thank you very much for your reply, you seem to be the only person on the net who has come up with a definitive answer for which I am grateful. The "Leak" was more by way of wet bubbles when the pedal was depressed hard by a buddy while trying to gey a decent pedal when bleeding the system having fitted the rebuilt BM50 back in the car, which now makes perfect sense. A bit of a shame having just rebuilt my BM50, I did not touch the proportioning valve side of things, the BM50 was leaking from the primary piston seal and fluid was running down the the Brake booster hence the need to rebuild, I had never noticed any fluid leaking from that hole previously it only started when I refitted it to the car. The brake lines in the photo are "Kunifer" which is a Copper/Nickel alloy brake pipe, but are only the ones I use to bench bleed Master cylinders, they are perfectly legal to use on vehicles here in the UK, however the lines on the car are PVF coated steel. Thanks again for clearing this up for me, a purchase of a new BMC appears to be on the cards, I have been looking at various options in case my BM50 was not repairable and have looked at the HFM BM57 which I understand is manufactured in Australia.  
    • Gantai
      R33 GTST Steering Rack (49001-19U05) Rebuild?

      By Gantai · Posted

      PXL_20250828_063541093.TS.mp4
    • Gantai
      R33 GTST Steering Rack (49001-19U05) Rebuild?

      By Gantai · Posted

      Well the install is officially done. Filled with fluid and bled it today, but didn't get a chance to take it on a test drive. I'll throw some final pics of the lines and whatnot but you can definitely install a DMAX rack in an R33 with pretty minor mods. I think the only other thing I had to do that isn't documented here is grind a bit of the larger banjo fitting to get it to clear since the banjos are grouped much tighter on the DMAX rack. Also the dust boots from a R33 do not fit either fyi, so if you end up doing this install for whatever reason you'll need to grab those too. One caveat with buying the S15 dust boots however is that the clamps are too small to fit on the R33 inner tie rod since they're much thicker so keep the old clamps around. The boots also twist a bit when adjusting toe but it's not a big deal. No issues or leaks so far, steering feels good and it looks like there's a bit more lock now than I had before. Getting an alignment on Saturday so I'll see how it feels then but seems like it'll be good to go       
    • PranK
      R35 GT-R production ends after 18 years

      By PranK · Posted

    • SteveL
      Leak from Tokico BM50 Brake Master Cylinder

      By SteveL · Posted

      I don't get in here much anymore but I can help you with this.   The hole is a vent (air relief) for the brake proportioning valve, which is built into the master cylinder.    The bad news is that if brake fluid is leaking from that hole then it's getting past the proportioning valve seals.   The really bad news is that no spare parts are available for the proportioning valve either from Nissan or after market.     It's a bit of a PITA getting the proportioning valve out of the master cylinder body anyway but, fortunately, leaks from that area are rare in my experience. BTW, if those are copper (as such) brake lines you should get rid of them.    Bundy (steel) tube is a far better choice (and legal  in Australia - if that's where you are).
×
×
  • Create New...