Killing Spark During Shifts
- Thread starter Echo
- Start date
i know what he's trying to do, but have been there done that wasn't successful, as you need to cut the fuel as well, i eventually gave up and bought a system, and you could adjust the cut time in mili sec for each up shift, quicker as you go up, it also cut the fuel and fed both fuel and timing back on in a ramp effect, the end result was absolutely no head movement during an upshift and no unsettling of the car even when changing up mid corner. only way to go with a dog or sequential box.
cheers John
cheers John
Well, the FRPP is drive-by-wire, so you can't just manually move the throttle. I'm thinking the easiest way to do this is to intercept the pedal signal and, during shifts, bring throttle back and restore after the shift electronically. So, basically a throttle blipper, but electronically.
Do you have a reference plot for how much to back off, how quickly to back off, and how quickly to ramp power back up?
As I mentioned above, I think I'm going to have to do this electronically with a small micro controller. I'm just not sure how quickly the FRPP will react to a quickly changing pedal signal.
i can give you my cut times they were 1st to 2nd 80ms 2nd to 3rd 60ms, 3rd to 4th 50ms, 4th to 5th 40ms and 5th to 6th 40ms.
the ramp back on was done electronically by the little black box supplied with the strain gauge operated shift lever.
I bought the kit from Competition systems down here in Sydney. it was identical unit to what they run in the V8 super cars.
cheers John
the ramp back on was done electronically by the little black box supplied with the strain gauge operated shift lever.
I bought the kit from Competition systems down here in Sydney. it was identical unit to what they run in the V8 super cars.
cheers John
Wow, those are pretty short! Which engine are you running? Drive by wire/cable operated? ITB or large plenum? Also, does your system close the throttle completely, or just partially?
Thanks!
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Ah, I realized I didn't answer your question fully before. I am trying to cut engine torque during shift events to save the transmission.
My first thought was just to kill spark during a shift to get an instantaneous torque reversal that unloads the transmission for the shift. The only "issue" with this is that I'll get a bunch of unburned fuel in the exhaust.
There is a reasonable chance that unburned fuel in the manifold will increase back pressure on other exhaust valves. There are cases where this increase back pressure will actually force other exhaust valves open. If these valves open, it can cause preignition which might actually stall the engine.
Lastly, the PCM is actively looking for misfire events, so it should throw a code if I kill spark outside of the calibration. Just throwing a code might be okay, as long as it doesn't put the engine in a reduced power mode.
Wow, those are pretty short! Which engine are you running? Drive by wire/cable operated? ITB or large plenum? Also, does your system close the throttle completely, or just partially?
toyota 3SGE on itb's with a Quaif 6 speed sequential box.
cut dosnt touch the throttle as your foot stays flat, cut is generated by load on the shifter, via a fitted strain gauge, as you pull the shift lever it dose the business,
cheers John
toyota 3SGE on itb's with a Quaif 6 speed sequential box.
cut dosnt touch the throttle as your foot stays flat, cut is generated by load on the shifter, via a fitted strain gauge, as you pull the shift lever it dose the business,
cheers John
Ah, okay, so you're going momentary lean to achieve power reduction, right? Kill spark and fuel simultaneously with load on the shifter.
