engine de-rate while shifting

[h22]

I was wondering if code could be implemented in the GPIO&MSII to provide for a drop in engine torque (spark retard/cut and or fuel cut) while the GPIO board is commanding a shift. Many OEM's are doing this already to "improve"shift feel and prolong clutch-pack life. While i prefer a firm shift, the reduced stress on the clutch pack is apealing to me as it could dramatically increase the life span of a trans in a high HP aplication. while i realise that something like this could problably be done now utalizing the flat shift feature of the MSIIextra code, a CAN implemented dedicaded function would be a nice (even if seldom used) feature.

[Bernard Fife]

h22,

Yes, Al has the infrastructure in place in the B&G code for this, and the MShift code will use it to reduce advance/cut fuel during a shift (the code doesn't do this at the moment, but it will soon).

Lance.

[ca434sbc4]

Retarding the timing works fine in a NA application, but may be counter-productive in a turbo app. Typically when the timing is retarded the boost increases.

[DMX]

I think he's trying to avoid shifts at full engine power, something i've wondered about as well. Could it be as simple as a 1 second window during up/down shift where the MS2 pulls say ... 4* timing? (or some user configurable value)

[tjabo]

You wouldn't want it to be for a full second I don't think! That is a long time compared to a nice, quick shift. RacerStev on here was datalogging shift times using some different controller hardware, and I don't remember what he got the shift time down to, but it was much less than a second (using valve body mods and software adjustments).

I've been wondering what you do with a turbocharged application to get this effect though (consistent with the comments above about retarding timing). Could probably do fuel CUT for an instant. It might make a cool boom sound like it does when overboost protection kicks in, and probably not damage the engine as long as it is a complete cut.

Thad

[Bernard Fife]

Guys,

My thinking was to use the built in shift timers (which are a constant plus a factor based on line pressure - which in turn is based on load in the 12x12 table) to set the duration of the 'de-rating'. Typically the total duration varies from a few tenths of a second at high loads to almost a second (or more in some cases) at low loads.

There is some work on a sophisticated turbo control application for the GPIO going on in the background, and one of the possibilities is to open an electronically controlled BOV while shifting (as well as spark retard/fuel cut) - this maintains the compressor speed so boost is immediate after the shift. The person working on this wishes to develop it further before disclosing details however, so I won't say any more.

Lance.

[tjabo]

OH! That's fantastic! ! ! !

[DMX]

Not sure if this is the place for it >> http://www.msefi.com/viewtopic.php?f=78&t=34667

Just a thought about triggering the knock sensor retard during a shift. It might be useful if any standalone controller pulls pin xxx high during shift.