tell tale

[Laurence]

We were testing today and during one of our acceleration runs one of our drivers snatched a neutral and revved the engine up . Everything was fine with the engine afterwards and its running fine. However the tell tale rpm on our steering wheels system (Farringdon instruments sw10-x) is showing 17300rpm! Is this number just a nonsense created by the confusion of the logging system filters? or can R6s (03) actually peak at such rpms if the throttle is wide open under no load.
Our rpm limit is currently set at 14000 in our ecu and is badly mapped to boot. What rpm do you guys set as your hard and soft limits at?

[Laurence]

We were testing today and during one of our acceleration runs one of our drivers snatched a neutral and revved the engine up . Everything was fine with the engine afterwards and its running fine. However the tell tale rpm on our steering wheels system (Farringdon instruments sw10-x) is showing 17300rpm! Is this number just a nonsense created by the confusion of the logging system filters? or can R6s (03) actually peak at such rpms if the throttle is wide open under no load.
Our rpm limit is currently set at 14000 in our ecu and is badly mapped to boot. What rpm do you guys set as your hard and soft limits at?

[murpia]

Filters tend to lag so they would underead rpm...

How is rpm measured by the Farringdon? It's own crank sensor? The tacho output? Spark plug lead? Does it have a software filter? If so what is the spec?

You'll quickly find that with data systems nothing is as simple as it first appears, particularly period or frequency measurements such as engine rpm or wheelspeeds.

Vibration and noise can have a big effect. For arguments sake lets say the Farringdon averages rpm over 4 pulses for a 4 pulse per revolution signal. The vibration induced by your driver hitting a 14,000rpm rev limiter could generate an extra rpm pulse in the sensor or as electrical noise. You have 5 pulses instead of the usual 4, so 14,000rpm * 5/4 = 17,500rpm (well not quite but you get the idea...).

Is this post useful or just confusing?

Regards, Ian

[Superfast Matt McCoy]

I think the 2006 R6 is actually advertised to rev to 17500, though there was some argument about whether or not that was true. Also, the '06 has Ti valves and the '03 does not. In any case, I would believe that it could hit 17300 for a moment. I would at least check the valve lash to make sure you didn't yield the valves after almost certainly lofting them.

If your ecu has a limiter set at 14, then obviously it is either not working or the tach is wrong.

You shouldn't be anywhere near 17, or 14 for that matter. Your restrictor starts to choke well before that and once that happens you're just adding mechanical loss to your power curve, decreasing power and fuel efficiency.