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Ignition cut quickshift

Posted: Sun Jul 22, 2018 4:04 am
by Borla
Can anyone tell me if using an aftermarket ignition cutting quickshift on an S80 would do any harm to the internals of the S80?
Many thanks.

Re: Ignition cut quickshift

Posted: Sun Jul 22, 2018 4:55 am
by stevieturbo
Depends what it is, how it cuts, and why you need it in the first place ?

Re: Ignition cut quickshift

Posted: Sun Jul 22, 2018 5:10 am
by Borla
Quick shift is a Lohmann, it's from a works superstock BSB bike. Unfortunately I don't know how it cuts. We need it because we need it. Can't get the S80 quickshift to work and have the Lohmann unit on the lorry that will plug straight in.

Re: Ignition cut quickshift

Posted: Sun Jul 22, 2018 12:18 pm
by Alex DTA
What do you want to do?
How do you want to tell the ECU to cut? Switch, pot or load cell?

Re: Ignition cut quickshift

Posted: Sun Jul 22, 2018 5:41 pm
by Borla
Hi Alex, away from the track now so not so urgent. We've spent a fair amount of time trying to get the onboard dta shift cut working and failed, I noticed today on the datalog that the selected gear was changing more than it was in reality, also not changing sequentially or matching throttle and rev traces. If the voltage output is monitored in the shift cut settings window with the engine running and in neutral it does fluctuate between about 490mV and 1400mV (IIRC) and the indicated gear on the real time info screen randomly jumps between gears 1,2 & 3. The gearpot on the S1000rr is of the same appearance as the TPS pots we had all the trouble with early on in this great adventure, so I'm now thinking the BMW gearpot is not suitable for the dta (edited for clarity). We don't currently have the time to engineer a 'mecanical' old school pot onto the S1000rr gearbox so hence the question.

The quick shift mentioned earlier in the thread is what we used to use with the stock ecu, it's a stand alone unit that plugs inline into the four COPs (that's where it gets it's power from too) and there is also a pressure transducer mounted inline in the gearshift rod. When the transducer feels a pressure on the shift lever it momentarily cuts some sparks, it gives enough of a gap in power for the rider to smash into the next gear without lifting off the throttle or using the clutch. They are a pretty common addition to older sports bikes, most newer stuff have them built in.

So, the question above stands, would the S80 get upset if the signal from the ecu to the coilpack was interrupted? I still can't confirm how the spark is interrupted, I'll do some more research on that one.

Given time I may be able to fit a mechanical pot to the geardrum and have another go at getting the onboard shiftcut working, but the above is a far simpler solution right now.

Re: Ignition cut quickshift

Posted: Mon Jul 23, 2018 2:15 am
by Rob Stevens
You could feed the load cell / switch straight into the S80 and use the conventional timed gear cut. It does sound like you have issues with the gear position sensor so it will never work correctly. I wouldn't bother with yet another device when the S80 can do all you need. I don't believe the DTA has an issue with hall effect sensors as I use one in my bussa and its bang on, it even lives inside the engine.

Re: Ignition cut quickshift

Posted: Mon Jul 23, 2018 2:27 am
by stevieturbo
If it works with other ecu's then it shouldnt pose a problem, although sometimes playing with inductive loads can be funny.

Re: Ignition cut quickshift

Posted: Mon Jul 23, 2018 2:29 am
by Alex DTA
If it's the same as the TPS, it sounds like it's failed.
Hall effect are fine for the ECU, but the reading shouldn't fluctuate more than 5, aybe 10mV at the most.
Could be a grounding issue as well.

The ECU won't be affected by the coils being cut.
However, cutting the power to the coils at random times is gioing to fire the coils at random times. This means you lose all control of your timing. Any coil that is partially charged will fire the spark plug when the ignition is cut.

I would recommend a different option if possible.
As Rob says, wire in the load cell as per my monthly newsletter, and you will be able to flat shift without the pot until that's resolved.

Re: Ignition cut quickshift

Posted: Mon Jul 23, 2018 4:36 am
by Borla
Thanks for all the useful input, plenty of food for thought. Looks like load cell is way forward, only problem may be finding wiring information for the load cell we have. Will update with outcomes when progress is made.

Re: Ignition cut quickshift

Posted: Mon Jul 23, 2018 4:47 am
by Borla
Rob Stevens wrote:........... I don't believe the DTA has an issue with hall effect sensors as I use one in my bussa and its bang on, it even lives inside the engine.
Sorry, I've edited my post above to clarify it, it now says BMW TPS/pot. As you say I'm sure there are some/many hall effect pots that the dta is happy with, but we couldn't get the BMW ones to work and we tried quite a few that were all working with the stock ecu. I'd be very surprised if they were all dud.