Pull-away in 2nd?

'Microsquirt' Transmission Control development and support.

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Philip Lochner
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Pull-away in 2nd?

Post by Philip Lochner »

Would I be able to configure the transmission controller so that :
1) it will pull away in 2nd under any amount of throttle below say A% (this also means that if the car is stationary and in Neutral, will go directly into 2nd as soon as I select Drive) ;
2) will downshift to 1st if throttle is more than A%;
3) will still be able to access 1st manually with the gear lever (eg if I know that a rapid pull-away will required).

With the 7.2L monster's torque, I conclude that 1st is rather academic. Pulling away in 2nd (manually, GPIO unplugged), is not laboured, still brisk, but most importantly, gives the car even more of a "just gliding away" feel.
Kind regards
Philip
'74 Jensen Interceptor 440ci (EFI'ed with MS2 and wasted spark + GM 4L60e GPIO controlled - both on Extra FW)
jsmcortina
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Re: Pull-away in 2nd?

Post by jsmcortina »

I'm sure you could set the 1st upshift point so it will do what you want.

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Philip Lochner
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Joined: Thu Feb 16, 2006 6:18 am
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Re: Pull-away in 2nd?

Post by Philip Lochner »

Just a bit of feedback...

I tried having the car in 2nd when stationary by setting the upshift points in the 1->2 map at 0 speed (Below the downshift curve for low throttle openings). The car will still stand stationary in 1st but shift to second the very instant it starts moving. The shift is still perceptible. Its an acceptable compromise although pulling away in 2nd would have been nice.

Hmmm... Maybe I should set the down shift curve to 0 as well .... :?:
Kind regards
Philip
'74 Jensen Interceptor 440ci (EFI'ed with MS2 and wasted spark + GM 4L60e GPIO controlled - both on Extra FW)
Philip Lochner
Super MS/Extra'er
Posts: 1004
Joined: Thu Feb 16, 2006 6:18 am
Location: George, South Africa

Re: Pull-away in 2nd?

Post by Philip Lochner »

Progress.

Set the both upshift and downshift curves to 0 for throttle openings up to 20%. Now it does as follows:
When going into D from N, it goes into 1st but shifts into 2nd as soon as vehicle speed is detected;
When coming to a stop it now stays in 2nd;
Larger that 20% will cause it to downshift back into 1st.
Kind regards
Philip
'74 Jensen Interceptor 440ci (EFI'ed with MS2 and wasted spark + GM 4L60e GPIO controlled - both on Extra FW)
sgilbert1967
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Re: Pull-away in 2nd?

Post by sgilbert1967 »

Hmmm wonder if I can reverse this and force my 4l80e to launch in 2nd at full power on traction limited surfaces ?
Brad-Man
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Re: Pull-away in 2nd?

Post by Brad-Man »

Bump.
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