RB26 Speed Governor?

[Duncan]

I am not sure what the Japanese rule is, but in Australia the speedo is required to read 0-10% higher than actual speed, I note every nissan I've had has read at least 5% above actual.

Since they dyno is reading actual speed I reckon the difference is due to tyres + factory speedo error.

When you change out the ECU after you modify it, the speed cut no longer affects you.

Or, go total old school and just cut wire 53 (speed input) at the ECU, the car still runs fine.

[joshuaho96]

23 hours ago, Duncan said:

I am not sure what the Japanese rule is, but in Australia the speedo is required to read 0-10% higher than actual speed, I note every nissan I've had has read at least 5% above actual.

Since they dyno is reading actual speed I reckon the difference is due to tyres + factory speedo error.

When you change out the ECU after you modify it, the speed cut no longer affects you.

Or, go total old school and just cut wire 53 (speed input) at the ECU, the car still runs fine.

It runs fine but it'll cause a bit of weirdness, the ECU definitely uses the speed sensor input for idle. Sounds like OP needs a tune anyways so just do a power run in a lower gear to avoid hitting the ECU speed limit for a baseline and then run a standalone to sidestep the issue. RB26s seem to really hate going much below 1000-1200 rpm especially if you put any kind of load on them so it's nice to keep around for refinement reasons. Or maybe I just need a new harmonic balancer.

[Dose Pipe Sutututu]

On 17/03/2024 at 7:15 AM, Duncan said:

Since they dyno is reading actual speed I reckon the difference is due to tyres + factory speedo error.

I reckon the car was run in 3rd gear not 4th on the dyno.

[GTSBoy]

1 hour ago, Dose Pipe Sutututu said:

I reckon the car was run in 3rd gear not 4th on the dyno.

Yeah, this.

[Dose Pipe Sutututu]

1 minute ago, GTSBoy said:

Yeah, this.

muricannnnn

 

[Duncan]

Maybe, but 3rd or 4th gear does not affect the speed the dyno roller is turning, that is actual speed at the tyre

[GTSBoy]

Nah. Per the other thread, in which he posted the dyno chart....

Wheel spin bitches!