4 speed and TC with lookup

'Microsquirt' Transmission Control development and support.

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martin2day
Experienced MS/Extra'er
Posts: 169
Joined: Tue Nov 01, 2016 11:56 am

4 speed and TC with lookup

Post by martin2day »

Hello together,

my manual transmission T5NWC in my replica Cobra is bad... the torque from my SBC is to much.
So i plan to change the transmission. Here i can use a Tremec TKO500...
I have drive a car with such a gearbox... it is harder to shift like my BorgWarner T5... Gearchange i think i can't do very quick.

So i have a stupid idea:

Can i take for example a 4L80E, a TC with lookup und a MegaSquirt to build a gearbox.
In first gear i use the TC, but from 2th - 4th the TC is looked.
I only want to shift manual, so i think so i can build a gearbox that i can switch from 2th to 4th like a manual sequential transmission.
What do you think? Is it possible to do this? Can i shift up and down with looked TC under full and under light TPS?

My Cobra is a racer and i want to looked the engine and the wheels...

Thank u for help.

Martin
nathaninwa
Super MS/Extra'er
Posts: 2637
Joined: Tue Sep 14, 2004 4:17 pm
Location: Aberdeen, Wa

Re: 4 speed and TC with lookup

Post by nathaninwa »

So let me understand. You want to swap out the manual in favor of say an automatic 4l80e and do an auto 1/2 shift but have a manual 2/3/4 locked converter scenario? I can tell it's kinda violent but programming should be able to get done. Not in the trans ecu, as it has race mode which leaves the converter locked but stock settings is 50% tps and greater. I've heard you can change the ini file to suit your needs. But you might be able to program an engine output using gear position and some mph or something to lock it up. I'll tell you, the trans will need to be built with some billet steel parts inside, from the input to various hubs and intermediate shafts to handle the constant abuse, along with even a triple disc converter to handle the under load type lockup
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babbit bearings
Helpful MS/Extra'er
Posts: 38
Joined: Thu Nov 27, 2014 9:17 am
Location: Racine, Wisconsin

Re: 4 speed and TC with lookup

Post by babbit bearings »

If you are using a 4l80e then you can just supply power to the converter lockup solenoid at all times (key on). The valvebody hydraulically can not engage the lockup in P,R,N or 1. Note that the 1-2 shift will be very harsh with this arrangement.

You don't actually need any electronics to do what you are requesting, just a terminal strip.

Image

For a race car I would recommend two additional modifications.

1. eliminate the reverse boost circuit.
2. drill the pump to prevent aftermarket converters from partial lockup .

My coupe has had this setup with a 4l80e for about 10 years. street, dragstrip, salt flats, etc... Originally with a blown 496 chevy, now with a turbo 5.3 LM7.
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