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I want to benefit from having a test mule I can risk. Powershifting maybe?

I have two clutch pedal signals, I guess the logic would be mostly about limiting RPMs at particular values according to gear ratios? Anyone eager to provide details on the logic which would need to be implemented?

The "semi-proper" thing to do is put a strain gauge on the shifter. Many higher-end sequential transmissions actually require this. The idea is that the strain gauge picks up force on the shifter, momentarily kills power from the engine (usually kills spark) and allows the shift to happen without full power.

Another thing that is "semi-proper" is to put a pressure sensor (usually Honeywell 10bar gauge) in the clutch hydraulic line. Again, like the strain gauge gives a pretty tunable level of pressure being applied to the clutch before the ignition is retarded/cut.

If you're looking to do this "ghettostyle" (as many of the aftermarket stock ECU kind of stuff does it) you really don't need to do anymore more than apply a lower rev limiter when you have the clutch pressed. Monitor one of the clutch switches, change limiter when it's pressed, done. Typically want to space it 500-1000 RPM lower than the normal main rev limiter so that the engine is likely to be above the clutch cut but below the main rev limiter.

blundar wrote:The "semi-proper" thing to do is put a strain gauge on the shifter.

Wow, that's a cool device! Realistically it's not happening simply because I cannot afford one (the lowest I've seen is about $500)

blundar wrote:Another thing that is "semi-proper" is to put a pressure sensor in the clutch hydraulic line.

I think I'll begin closer to the ghettostyle approach, maybe a bit less ghetto if I consider vehicle speed and use touching the clutch pedal (touching just to make the switch happy, not applying) as an input signal, that should be something for a start.

Load cells are reasonably low cost, typically around $10 to $20 ish. You would need to mount to your shifter such that it measures the deflection of the shifter, and it not directly a structural component.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0&_nkw=load+cell&_sacat=0

Also "proper" cars don't use clutch pedals. They use a dog box, which basically just smashed the gears together, forcing the engine, or wheels to synchronize. The clutch is only used for switching to reverse, and for stopping with the engine running.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0&_nkw=load+cell&_sacat=0

From an ECU standpoint, I would say you can expect to get a digital signal, which will indicate you are shifting and should limit power for a short period of time. The strain gauge circuit, pressure gauge circuit, or clutch switch can produce the digital signal.

How long should it inhibit spark? I might guess it takes 10 to 20mS to switch gears. So why not simply skip the spark and fuel for that time period. I don't think limiting fuel will do much unless you squirt direct into the cyl. You probably have enough fuel on your manifold wall that you are probably just pumping the fuel into the exhaust any how. The next item I can see, is what RPM you want to limit power at. For example, skipping spark at idle while shifting into gear could be bad, but when at higher RPM the engine inertia makes it fine.

So I would think you might want TS to allow you to choose if you want to skip fuel and/or spark for a configurable amount of time. As well I would think you would want to config the RPM where it starts to happen, perhaps 2kRPM.

blundar wrote: ↑

Tue Dec 23, 2014 5:15 am

The "semi-proper" thing to do is put a strain gauge on the shifter.

Does that always mean hx711 https://www.digikey.com/htmldatasheets/production/1836471/0/0/1/hx711.html with it's serial output or is there anything with analog output?