4l80e Autoshift but with 2nd Gear Start if Shifter in D2

'Microsquirt' Transmission Control development and support.

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slow94formula
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4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by slow94formula »

I would like to keep my automatic shift setup, but want to be able to place the shifter in second gear to do a burnout starting in 2nd. I've been told it's hard on parts to start the burnout in 1st and let it spin into 2nd and the easiest remedy to this would be to start the burnout in 2nd gear.

I am familiar with HP Tuners which has it's own set of tables for when the shifter is placed in 2nd gear and used that in the past to do this exact thing.

Also on a related note I'd like to be able to leave the shifter in 2nd so I can leave in 2nd gear and have it allow the car to shift to 3rd by an RPM set point.

Is it possible to add something like this to the feature set?

Thanks
HSPTuned
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Re: 4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by HSPTuned »

I second this. I too have an 4l80e and would extremely appreciate a function like this.. if I can keep the trans in 2nd the whole burnout I would be content!
nathaninwa
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Re: 4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by nathaninwa »

I drag race my 80e. On the dash I have a manual input switch which places the tranny in full manual mode. I do my second gear burnout and shift to drive part way through. Come out of the water box and turn the switch off which puts it back into auto mode

I have my line lock and trans brake on the same button. Using a 3 way toggle on the dash both switches up is manual and line lock, do burnout and while coming to a stop I reach up and move both switches down which is auto mode and trans brake


For the second gear leaver in auto mode might be tricky. Maybe use rpm based upshifting and limit first gear under peak tq at around 4800. I've done this on a slippery track
Last edited by nathaninwa on Wed Nov 02, 2016 10:00 pm, edited 2 times in total.
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slow94formula
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Re: 4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by slow94formula »

I do realize that is an option, but feel it is unnecessary with the technology we have if the code could just be added for it. Also the idea of leaving in 2nd and having it auto shift to 3rd doesn't work with it in manual mode. Thanks for the input
nathaninwa
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Re: 4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by nathaninwa »

I edited my first post about second gear option
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slow94formula
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Re: 4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by slow94formula »

I see where you're going with that, but I want to actually leave in 2nd to have the higher starting line ratio. Not sure how often it will be used, but to have the option would be nice. I know there are a few guys who do this with an auto shifting 80e, but I'm not sure what system they are using. I believe at least one is holley.
zracer
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Re: 4l80e Autoshift but with 2nd Gear Start if Shifter in D2

Post by zracer »

Old post but responding as I had the same question.

Use RPM based shifting, set first gear to 1500. Second gear launch and burnout worked fine.

I use a two step on the line so as soon as it hit 1500 the car went into second gear, then launched at 3400 like normal except in second gear.
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