4l80e POI-shift

[vwbusman66]

So I'm pretty familiar with the vaunted "Poi-shift" box used by many guys for running the white block auto trans or aristo trans.

I am contemplating doing a budget LS build this summer and would like to go the 4l80e route to save money. From my reading, it seems like the 4l80 operates on the same principles as the AW30-40 (a combination of solenoids on/off will select gears). The 4l80 also has a lockup converter, which is operated by a third, independent solenoid (lockup in all gears if you're feeling frisky).

Realistically, couldn't I control those solenoids with a microcontroller, two momentary switches, and a microcontroller (the same way ya'll run the 30-40)? For the lockup, you could just add an on/off switch somewhere convenient that can directly actuate the solenoid or use the Arduino to control it.

Also, I'm 75% certain the Arduino (or other MC) (with the correct circuitry to step up/down the 12v and 5v signals) could be used to control line pressure on these.

The 4l80 EPC (line pressure solenoid) operates using PWM typically. When there's no power to it, full line pressure is given. There are two routes I suspect you could go: the first being a potentiometer read by the Arduino to set a fixed line pressure, the second using some coding/graphing to read TPS, gear position, and lockup condition to vary the line pressure based on perceived load.

Does any of that make sense?

[RvolvoR]

buy a microsquirt box to control it

https://www.efisource.com/wp/shop/4l...-control-unit/

what engine is it behind?

[vwbusman66]

Originally Posted by RvolvoR

buy a microsquirt box to control it

https://www.efisource.com/wp/shop/4l...-control-unit/

what engine is it behind?

Key word here: cheap.
If I can build something that meets my needs for $50, why bother spending $450 for a closed-source solution that doesn't do what I want?

Going behind the cheapest non-windowed LS I can find.

[240wagonguy]

but why?

[Broke4speed]

You can TOTALLY run a 4L80e with a POI shift. The key bit of information is whether or not the solenoids require a ground signal or a 12v feed. The AW30-40 solenoids require 12v, since they ground at the case. That's why the POI shift box has all the extra transistors and such. If the 4L80E only requires a ground output to control the solenoids, you could easily do it with only the microcontroller part of the POI recipe. The BASIC stamp that's used is only there to send the signals, so for sub-$50 you could get a BASIC Stamp from Parallax, and have it firing your transmission in minutes...with almost no soldering.

An arduino could do the same thing, but as a non-coder, I've had zero success at finding functional 'shifting' code for one that rivals the simplicity of the POI box. The Speeduino crowd has a gear controller that uses an Arduino mega...but again, it gets needlessly complex for no reason, IMO. If you can fight through the muck, and again, if the 4L80e solenoids only need grounds, you could TECHNICALLY shift it with a $15 chinese Arduino Mega256 clone.

IMO, the POI shift is the way to go. The DxControl-Gears from the Speeduino crowd is not worth it yet. It can only do manual shifting currently anyway, and seems like a dead project.

[edit]HA, it looks like the solenoids use a switched ground. It would be CAKE to do with a POI shift, IMO. The only other thing you'd need to do is make sure that when in 'D', there's a ground signal going to the POI box, to let the controller know it's time to work.

http://www.msgpio.com/manuals/mshift/4L80E/4L80e.html

[vwbusman66]

Originally Posted by 240wagonguy

but why?

Because T56 is expensive, and a CD009 is slightly less expensive.

[linuxman51]

a microsquirt and a little bit of wiring, then you can have poi shift when you want it, or normal automatic otherwise. It already supports switched inputs to trigger up shift/downshift.

if you want to do it cheaper (and spend more time), get a GPIO board to do the same thing, but you're only saving a little bit to go that route. much faster and easier to use the micro.

[240wagonguy]

Originally Posted by vwbusman66

Because T56 is expensive, and a CD009 is slightly less expensive.

No, I get the reasons to use a 4L80, thats why I have one. but I got a controller with the van I yanked everything from.

[RvolvoR]

Originally Posted by vwbusman66

Key word here: cheap.
If I can build something that meets my needs for $50, why bother spending $450 for a closed-source solution that doesn't do what I want?

Going behind the cheapest non-windowed LS I can find.

it sounds like you don't legitimately have the cash to somewhat properly do what you want to do and actually have it work well. Keep it stock.

[Broke4speed]

So because someone wants to do it on the cheap, they're not able to do it properly?

[petercz]

Originally Posted by RvolvoR

it sounds like you don't legitimately have the cash to somewhat properly do what you want to do and actually have it work well. Keep it stock.

Come on, we're on TB...

[linuxman51]

Originally Posted by petercz

Come on, we're on TB...

not a great excuse.

[vwbusman66]

Originally Posted by RvolvoR

it sounds like you don't legitimately have the cash to somewhat properly do what you want to do and actually have it work well. Keep it stock.

I fail to see how building my own transmission controller that makes it a paddle-shifted automatic "proper".

I'd much rather build something myself for $50 that does what I want it to (and I know how to fix it and build it) than feed DIYAutotune $450 more for something that cost them ~$50 to manufacture.

If I'm going to spend that kind of money, I'd rather sink $450 into a good exhaust system or partially fund a set of better-breathing heads.

[vwbusman66]

Originally Posted by Broke4speed

So because someone wants to do it on the cheap, they're not able to do it properly?

^^^^^^^

I know 3 guys from this forum (Broke4speed, roadracer4life, the Poi) who have awesome builds that rely heavily on the DIY push-button shift controller outlined above.

I was looking for some corroboration/collaboration on an idea that is actually feasible.

[Broke4speed]

The POI shift would work, definitely .

[vwbusman66]

Originally Posted by Broke4speed

The POI shift would work, definitely .

That's what I needed to know.
Thanks guys! I'll update if this project gets traction.

[linuxman51]

Originally Posted by vwbusman66

^^^^^^^

I know 3 guys from this forum (Broke4speed, roadracer4life, the Poi) who have awesome builds that rely heavily on the DIY push-button shift controller outlined above.

I was looking for some corroboration/collaboration on an idea that is actually feasible.

sam's is a gpio board.

[linuxman51]

If this is meant to replace the gm native stuff in the ecu, I think you'd be better off just ditching it entirely and getting an aftermarket controller that can (inexpensively) do what you want vs hoping the gm ecu doesn't get mad when it starts seeing rpm/mph mismatches and what not.

If the concern is DIY, the gpio is a b&g thing that diy just re-sells.. but I reckon at this stage in the game your time isn't really worth anything, so whatevs lol

[vwbusman66]

Originally Posted by linuxman51

If this is meant to replace the gm native stuff in the ecu, I think you'd be better off just ditching it entirely and getting an aftermarket controller that can (inexpensively) do what you want vs hoping the gm ecu doesn't get mad when it starts seeing rpm/mph mismatches and what not.

If the concern is DIY, the gpio is a b&g thing that diy just re-sells.. but I reckon at this stage in the game your time isn't really worth anything, so whatevs lol

The plan is MS for the engine and this thing for the tranny.
I'll do some reading on GPIO, but my time is indeed worthless.

[linuxman51]

I would still do the gpio. it's more of a kit, but still integrates well via canbus. you can have the flappy paddles, and still have normal auto mode.

[Hank Scorpio]

Just get a 700r4 then.

[Broke4speed]

If you want manual without the TCU hassle, check out http://www.radesignsproducts.com/rail-controller.html. They have a couple manual shift options for the 4L80E, and are pretty cheap.

[linuxman51]

Originally Posted by Hank Scorpio

Just get a 700r4 then.

now listen, we were having a nice, civil discussion before this. No need to be rude and belligerent and start cussin' here.

[linuxman51]

Originally Posted by Broke4speed

If you want manual without the TCU hassle, check out http://www.radesignsproducts.com/rail-controller.html. They have a couple manual shift options for the 4L80E, and are pretty cheap.

if you wanted to do it really nasty cheap, sloppy has a video where he talks about what to tie to what and then you just move the shifter

[vwbusman66]

Originally Posted by linuxman51

now listen, we were having a nice, civil discussion before this. No need to be rude and belligerent and start cussin' here.

My feelings towards 700R4's exactly.