GPRP for motorcycle gearboxes (1N23456) and half-shift N

[burn4005]

Hi there,

I'm currently evaluating an M150 for a Formula race car that uses a Kawasaki motorcycle engine and gearbox and a pneumatic actuator for up/down shifts. the gear layout is 1N23456 with neutral requiring a half shift, usually with some opposing duty cycle to gently nudge it out of 1st into neutral.

is the GPRP package capable of this functionality now? I looked into it years ago for a different project and it was not supported but thought I'd revisit.

[David Ferguson]

No. Geartronics (sold through Race Data Systems) has a package that some use for motorcycle engine applications.

Here is a place to start:

https://www.racedatasystems.com/pages/m ... pment-html

I have built firmware to do PWM control of the actuators, and support a throttle blipper for cable throttles. If you are building your own firmware, I will be happy to give you a sample starting point.

[Stephen Dean]

Hi,

GPRP does not have support for 1N2 pattern gearboxes at this point, but it is being investigated for addition into a later release. In a vehicle that I have driven using GPRP and a 1N2 gearbox, I found that a slightly dragging clutch at idle when going from first or second would pick the box into Neutral most of the time (around 9 times out of 10) that it was requested. Having the clutch fully depressed would do the 1-2 or 2-1 shift.

[Scott Crawford]

A lot of Kawasaki models have a feature that no other Japanese manufacturer uses (to my knowledge) called a "positive neutral finder". It uses ball bearings on the transmission output shaft that keep the driven gear from shifting past neutral from first when the bike is sitting still and the output (drive) shaft isn't spinning. When the output shaft is spinning the centrifugal force moves the balls out and lets the gear engage second. This only works from 1>2 and not 2>1.

I know the current generation ZX-10 and zx-14 both have this. You'd want to look at the parts breakdown of what you are using and see if there are 3 individual 5/32 ball bearings on the output shaft.

[greenamex2]

Hi,

GPRP does not have support for 1N2 pattern gearboxes at this point, but it is being investigated for addition into a later release. In a vehicle that I have driven using GPRP and a 1N2 gearbox, I found that a slightly dragging clutch at idle when going from first or second would pick the box into Neutral most of the time (around 9 times out of 10) that it was requested. Having the clutch fully depressed would do the 1-2 or 2-1 shift.

Very interested in this...early Hewland touring car gearbox (used a Honda selector barrel I believe)

[J&R]

Hi All,
I have been working on a version of this in GPRP and now for some time with some of the engineers. We have a version that is almost ready for release. The Neutral is selected via a button(keypad/steering wheel) as long as the following conditions are met.
Engine running
1. vehicle speed is < threshold
2.the rpm is below < threshold
3.the clutch is disengaged
4. gear is either 1st or 2nd

or
Not Running
1. gear is either 1 or 2

Some sensors must be used as below:
Vehicle speed must be being calculated by the ecu
proper Gear position voltage must go directly into the ecu. not an estimate
Clutch position or pressure



I have this working on a Hyabussa hillclimb car as well as a Hewland gearbox in a GT Car

There are some things to consider when doing a motorcycle engine such as engine oil temp is the same as gearbox oil temp. This needs to be compensated for as the viscosity of the oil vastly differs from cold to hot therefore effecting the pulse width required to select N.

If you need to discuss this further please email me at info@motecqld.com.au

[greenamex2]

Thanks J&R, have bookmarked your site for when I get that far...having fun trying to start the engine and learning the differences between Motec 130's and Pectel T6's at the moment!