legacycentral bbs

I ask because I'd like to get in a discussion to get some rather advanced questions answered and to refine this "manumatic" design. I've been poring over my ideas for a while now, getting input from people... and essentially, came up with exactly the same result as Ciper. Funny how I read his posts on the subject, then experimented and asked around, and finally came around to his conclusion. XD It takes a while for all of this to register, I guess.

Anyway, what I'm envisioning is this: Manual pedal set, I/O switch on the clutch instead of a hydraulic system. Clutch would control the torque converter (depressed = unlocked, released = locked). A bypass circuit from the ECU to the TCU would fool it into thinking that the engine only revs up to 6400 RPM and the car only travels at 25 MPH. Both the electronic clutch and the TCU bypass would have to be enabled by remote, i.e. a switch, due to the fact that attempting to drive in 'D' in Power mode would result in being stuck in first gear, and attempting to drive in 'D' normally would result in being stuck slow in fourth gear.

The point here is to be able to go from a normal, average Subaru A/T to the modified version with a switch selection, probably the oh-so-useful Manual Button (which would then do as its name suggests). That way, when someone like my dad drives my car around in Drive, it won't do crazy things like stay in fourth or stay in first in Power mode.

Which reminds me, the enabling of Power mode would also have to be disabled while in the Manual setting, so that it doesn't downshift on its own when the pedal is floored.

So what I'm really doing is using what the transmission is already capable of, but changing it. Unchanged, you can stop and idle in any gear, while in 'D' the downshifts are smooth, and there's not much stress on the transmission. I've got a FWD, so I don't have to worry about power transfer stuff. What I would want is to still be able to stop and idle in any gear, downshift smoothly through the use of the "clutch" and minimize stress on the transmission (as my dad has pointed out to me, doing my rev-matching downshifts are hard on the tranny at present). Being able to be in Park, Reverse and Neutral are requirements too (I'm trying to bypass some functions, not remove ones that are already there; I still need the TCU).

I realize that some of these things can be worked around (i.e. "Just don't floor the pedal," "shift before redline," etc.), but the setup I've just outlined is what I've decided upon. If there is something seriously wrong or impossible with it, feel free to say so.

The basic fact is that despite these plans, I know nothing of the TCU's operation, so I wouldn't know how to wire the "clutch" or include a TCU-trick circuit.

Thanks in advance! And extra-uber thanks to ciper for thinking all of this up before I did. Wish he were here to see it... he knows what he's doing way more than I do. Also, thanks to vrg3 for having helped me out when I first began brainstorming over this stuff.

Okay, I just had a few thoughts as I was going over posts...

I'm not sure that even with the "electronic clutch" design it would operate properly between gear changes. Even with the TC unlocked, the fluid coupling would still be operating... so when the clutch is used and the gear is changed, the gear-shift would be felt before the clutch is released just like when the TCU changes gears in D. The only way around that would be to have the transmission in neutral between gear shifts too...

...but you can't do that efficiently with an Auto stick. There's just no way. So...

Electronic Shifter and Clutch? A custom 6-speed shifter with the following layout:

1 3 P

2 4/D R

Then, if it's not selecting anything, it stays in neutral. There would be a sleeve-handle that you'd have to pull up on to get into P or R. If in P, the shifter's locked unless you are holding the brake, just like normal. The selector for "Manual" would have to be placed elsewhere, like on the dash or steering wheel.

If Manual Mode is not enabled, then you can operate the shifter as you would a normal automatic, moving it from P to R or P to D, whatever. But in Manual Mode, the clutch is enabled and the TCU loses its ability to make shifting decisions due to getting false information from the TPS and ECU.

Yes, I realize that a lot of you with manual transmissions are chuckling and waiting to say "just get a 5-speed, man!" But this is a fun little experiment for me. It's a hobby, it's something I think is neat. But since I'm not doing an AWD or 5-speed swap any time soon, I'm stickin' with what I've got.

What I really need is some collaboration. I'm still rather new to this, so while I've got ideas and plans, I don't quite know the specifics of the operation of the automatic transmission. If most of it's electronic, that's awesome. But if there are mechanical dealies with controlling the locking of the TC or using the gearshift, those will have to be worked around, and I'd like to know what exactly I'm getting myself into.

I think what you're getting yourself into is something uber-expensive if you fuck it up. Not that this isn't a great idea, I like it. But, these ATs are not only wired up for the 25th century, but they're quite expensive when it comes to the electronics, and all that. Believe me, I just went thru it. Take your pan off the next time you change the fluid and have a look around. --looks like something related to The Terminator.
You've got a point, though.. Even when you do attempt to control the tranny via electronics, or even try to fool the TCU, there is still the fluid to be dealt with, which may mean extra parts, and probably close-tolerance hydrolics. I would say try to adjust your brake band settings to your liking, and see how that works out instead...
But keep up the research, and I'll even help, if you'd like.. these things are intersting, and there probably needs to be some AT guys around here that know a thing or two.. right?

I'm going to fire these off as they come to mind so sorry in advance if it's jumbled.

You don't necessarily need a 6-speed shifter, or lockout or anything like that. The reasoning behind the lockout on the at shifter is so you're not driving and accidentally shift into reverse, or drop it into 1 when you're doing 60 mph. It's just there to protect yourself, so I'm sure you'd be able to handle not shifting into park or reverse while driving. With that said, how would you control the lever? The only way it makes the H-pattern is by interacting with the shift forks in the transmission. Now, why do you even want to have it this way? The H-pattern is much less effcient than a straight line. What is the advantage of having the transmission go to neutral then shift? It's not quicker to shift that way, it's just the safest way to do it with a manual transmission. And I'm pretty sure that would cause massive stress to the trans by doing it that way. I think ciper was suggesting the pedal to control the torque converter being locked and unlocked to maximize effeciency. Though come to think of it, I'm not sure why you would want to have control over the torque converters locking ability. I believe the way to control this is to splice into the wiring for Duty Solenoid B. I think it's just a simple on/off switch. But then why would it be a duty solenoid? Hmmm. Anyway, about the shifter, what about using one of the BE/BH triptronic shifters? When in D you can slide it to the side and it'll go into manual mode. Though with the stock TCU on those it does shift at redline and does shift you back into 1st when you're going slow enough. That shouldn't matter if you're controlling it yourself though. Also power mode can definately be engaged without the TCU forcing a downshift. You can even go WOT in powermode without the TCU forcing a downshift. Hmm, What else?

Nothin' else, Hardy, you just ripped that poor boy's wet dream to shreds. Ass.
I'mma call the stealership today, or maybe visit it on the way back from my... ...other appointment this afternoon:oops:and see what I can drum up as far as tranny info goes. See, Nomake, you're lucky, in a way. FWD ATs are significantly less work and less... ..everything esoteric than an AWD AT. But this might be a good op to bone up on all things autos, so there'd be a few of us that are really in the know about these ATs.. some folks do like 'em, right?

I'm sorry if that's how it came across, it wasn't intended that way, I was just trying to give him some feedback.

No, no, he didn't tear my dreams to shreds (nor were they all that wet... except maybe for the fluid coupling XD). Don't worry about it; it's about time somebody replied.

Yeah, I know that the FWD auto is a lot simpler. And thanks for the info on the torque converter control.

But... lesse here. The point of this isn't really acceleration since one can accomplish this with a stock automatic. The point here is to prevent the jerky shifting that the automatic does, because the weight shift generated could cause undesirable motion if in a turn or performing a maneuver.

My dad actually brought up a few good points too, as well as some questions. First off, does the '90 FWD AT even have a locking torque converter? I assumed that it did, but my dad swears that it doesn't. Also, the clutch in a locking torque converter is designed for fuel efficiency at high speeds (prevents parasitic loss through the fluid coupling), and apparently would destroy itself if used in the same way as a manual transmission's.

Again, the point is to eradicate the jerky motion of the automatic's downshifts as well as gaining in-motion acceleration. If you've ever driven one of these and messed with the shifts, you'd find that there's a sort of disconnected feeling with the accelerator while in 'D', but when in a numbered gear it feels much more like you're actually controlling the throttle. It's hard to explain.

The lockout was simply me trying to adapt factory settings to a modified situation, but you're right, there's no real need for it (except that I wanted it to be able to operate as a normal A/T as well). But holy crap, I completely forgot about those side-manual shifters! You're right, those would be a lot better of a design for this. Scrap the electronic 6-speed.

The advantage of neutral while shifting is accomplishing the goal of this design: removing sudden motion. If the shifts are done without going into neutral, the fluid coupling is still going, which is still turning the transmission at speed, which could mean a jerk with a shift. If it's in neutral, the fluid's still turning, but you can then match the speed of the gear using it.

Yeah, ciper was talking about using an electronic clutch pedal to control the locking and unlocking of the torque converter. Same idea. The problem is whether or not the clutch in a locking torque converter can handle this or not.

Maybe we're not on the same page with the Power Mode thing. I mean that the circuits that intercept ECU signals to the TCU would have to be switched on or off depending on whether you are driving normally or using the psuedo-manual mode. Remember, the TCU would no longer be able to tell what RPM the engine is at and what speed the car's travelling at. Therefore, if you go into Power Mode at WOT in D with the circuits on, the engine would rev to redline and the transmission would do nothing, forcing the rev limiter to engage. I meant that you'd have to have it switchable. Also, I figured that removing the Power Mode from this pseudo-manual system would be fine, since it would be fairly unnecessary. Right?

But wait, how do you get it to not downshift if you go WOT in Power? If I slam the pedal to the floor, Power Mode comes on, the transmission downshifts as far as it can to get the revs up, the proceeds through the gears as each hits 6700. If I jab the pedal to get Power mode to come on, it doesn't seem to have any real effect once I actually get on it. I always thought that Power was simply the transmission changing its shift points to get higher revs, but like I said, it doesn't seem to do this if I turn it on with a stab of the pedal and then push the pedal to accelerate. It only seems to really work when I slam it to WOT all at once.

So yeah. Fooling the TCU into not knowing what it needs to know to force shifts doesn't seem all that complicated. And splicing into Duty Solenoid B should access the lock/unlock on the TC (as far as we know). So those parts are the simple ones.

The real questions to ponder here are:

1.) Can the locking torque converter handle the stress of being manually controlled without annihilating itself?

2.) Would it be required to go into neutral between shifts to prevent a 'shift jerk'?

3.) Is the fluid coupling efficient enough that controlling the locking/unlocking of the TC is unnecessary?

4.) Is there a way besides manually controlling the operation of the transmission to prevent the jerky motion that our automatic transmissions exhibit on downshifts as well as the delay between going WOT and actually accelerating?

#4 is the most important one.

At the moment, all of this stuff is in the visualize/plan phase. I haven't done any modifications to my car (transmission-wise), I haven't built TCU-bypass chips, I'm just trying to sort out the information. Since ciper doesn't seem to be very active, I'm agreeing with legacy_sleeper on this one; at the very least, we can become really knowledgeable in our A/T systems and help out others. As you said, some people do like them. ^-^