Is there a facility for flat shift on a sequential gearbox?

Fitzie · Post by **Fitzie** » Wed Jan 14, 2009 7:26 pm

Is it possible to configure a protocol within either megajolt or megasquirt units to be able to operate a "flat shift" with a paddle gearchchange system.My friend is bulding a Blackbird engined westfield and I have volunteered to do the loom and electrical installation but we both would like to use the paddle gearchange if possible as the car will mostly be used for trackdays.

Post by **brentp** » Wed Jan 14, 2009 11:03 pm

Hi Fitzie,

So how do you imagine that working- Upon gear change power would be interrupted for a split second?

Regards,

Fitzie · Post by **Fitzie** » Thu Jan 15, 2009 7:43 pm

Thanks for reply Brent. I am thinking of a load sensor (expensive) or a microswitch fitted to either the gear selector rod or even the paddles on the steeering wheel to cut ignition momentarily on upshifts only. The switching would be controlled by a channel within the control unit (possibly a shift light channel or output channel)which would cut ignition for a set time (milliseconds) obviously the first change 1st to 2nd would be of longer duration than the rest as the initial inertia/torque would require a longer shift time.
Its only ideas we both have at the moment and any comments from yourself will be welcomed. Incidently I am about to fit the MJLJ to a westfield that I have swapped engine from xflow to zetec and as soon as the installation is completed I will upload photos for you to see.
Thanks again Fitzie.

Post by **brentp** » Thu Jan 15, 2009 7:49 pm

Very interesting idea, thank you.

Fyi- you replied identically 3 times- so I deleted the redundant posts. Are you experiencing problems posting?

Regards,

Fitzie · Post by **Fitzie** » Thu Jan 15, 2009 8:19 pm

Thanks again Brent. I dont know why my post appeared 3 times... Would you consider me for your Beta test with the Race capture? To be used with the zetec engined car I am currently finishing
Regards
Fitzie

Post by **brentp** » Thu Jan 15, 2009 8:30 pm

I was thinking customizable logic feature for RaceCapture would address this problem nicely. Drop us an email at sales@autosportlabs.com.

Thanks,

Fitzie · Post by **Fitzie** » Thu Jan 15, 2009 8:37 pm

Magic.... I will drop you an email tonight
Regards
David Fitzgerald (Fitzie)

sunray · Post by **sunray** » Fri Jan 16, 2009 5:34 am

Are you using a "manu-matic" paddle shift or a proper sequential-manual transmission?

Fitzie · Post by **Fitzie** » Fri Jan 16, 2009 6:47 am

Its a proper 6 speed sequential transmission this time,but a future project is pencilled in to be a bike box but principals are the same,cos as a youth I used to shift my bike gears without the clutch anyway

Dean924s · Post by **Dean924s** » Sun Jan 18, 2009 5:20 pm

If you just want to cut timing by a fixed amount you should use the aux input bit configure it basically to be an on / off switch. Or you could make a second box that would look at rpm and depending on the RPM's of detected when you initiate the shift it would output a voltage to the aux. This could then be calibrated to the amount of retard in the aux calibration table.

>>>>>BETTER IDEA<<<<<

ONE WORD >>>>> TPS

I think that you should consider using a TPS. You just need one that outputs a 0-5 volt signal. It would be best if it was a low to high versus small to large amount of throttle input but it could be made to work if it is reversed. You could also mount the TPS on the opposite side of the carb / throttle body. Hack you could just get a 0-5 volt rheostat. Anyway.. . feed the 0-5 volt output to the AUX input on the MJLJ. A simple switch would activate the circuit.

A very simple circuit to put in place and programmable/adjustable by the calibration table in the MJ.

If I had a choice I would set it up so that the lower the voltage sent to the AUX the lower the amount of retard. IE 0 voltage detected = 0 retard The more throttle angle the higher the output voltage from the tps to the AUX and the more retard induced.

Is this what you are looking for?

Fitzie · Post by **Fitzie** » Sun Jan 18, 2009 5:46 pm

Hi Dean, I understand your idea behind the switching and it looks very probable,but the ignition cut would have to be instantanious and measured in milliseconds and I am very new to the programming bit (but the theory is more manageable in my mind) so would that be possible with the mjlj?
Regards
Fitzie

Dean924s · Post by **Dean924s** » Sun Jan 18, 2009 7:34 pm

Brent can answer that much better than I.

Nothing is instantaneous but the cut will measured in milliseconds. You will have to back the numbers out and possibly put a small (probably undetectable) delay in the shift to ensure that the timing has been cut.

Isn't development fun!!!!

Fitzie · Post by **Fitzie** » Sun Jan 18, 2009 7:58 pm

Yes youre right! Brets got to be the man for that. If it wasnt for a phone call from a friend telling me about mjlj I would never have known about autosportlabs or Brent and what a shame that would have been. Its an affordable user friendly system that flys in the face of the "big boys".
I am certainly a convert and cant wait to get our zetec westfield on the rolling road and as soon as its done I will post pics on here..

Regards
Fitzie.