Help me design an all electronic 4R70W drive train?

[lbperry]

I’m trying to design and build a drive train that’ll shift as close to an F1 or sports racing car as I can get using reasonably priced (read cheap) parts.
I want a fully electronically shifted 4R70W. In fact I already have a junkyard one that I plan to use during the build to make sure everything will fit and possibly for a core for my final “built” transmission.
My plans are for console mounted pushbuttons (or maybe rocker switch/pushbutton combination) to control the Forward-Neutral-Reverse-Park functions. And a set of microswitches integrated into the steering wheel for up/down shifting. I have a Retrotek paddle shifter that I picked up on eBay but would prefer the steering wheel switches, I think. I may test both.
These inputs would feed the transmission controller. From my research, the Compushift seems like it may be the best choice.
It sounds like a contradiction, but right now I’m working on the build of a carburetored 351W.
This would require, at a minimum, a throttle position sensor to work with the transmission controller. I might have to wind up going EFI; if a carb/TPS setup can’t be made to work satisfactorily. But that would hit the budget pretty hard.
The actual transmission specifications are where I’m the foggiest. Except for my daily drivers, every thing I’ve had has been a manual.
I expect the engine to be in the 350 – 400 hp, 400 ft-lbs torque, range
For a road course car, I’ll need plenty of transmission cooling.
I think engine braking would also be desirable.
How would the transmission build differ from what I would expect from the typical drag oriented build? My transmission guy knows drag cars but has never done one for a track car.
I don’t have any idea what I’d need in the way of a converter, stall speed, etc.

Lots more questions than answers at this point.
Any input would be appreciated. Pretty much everything is open to review, debate, criticism and change at this point.

Thanks in advance for your help,

[oestek]

I run a 4R70W in our '62 Galaxie, and it's controlled by the Baumannator TCS controll box. The TCS is fantastic, it will allow you to do just about everything you're looking at, and you can run a junkyard TPS and make it work with a carb. Ours is EFI, but I've seen it done before. It also allows for 2 seperate shift / pressure strategies as well as paddle / switched shift inputs.

You'll have to make your own pushbutton interface I believe, but the '98 and newer transmissions have the digital range sensor on the side, so it should not be too hard to make that work.

I'm not the world's expert on converters, so perhaps someone with more road race experience can chime in.

[MonzaRacer]

How you going to control the manual valve connected to the lever?

[lbperry]

Thanks, Kevin, the Bauman is one that I'm looking at too.

MonzaRacer, as I understand from what I've found on the web so far, the connector that the shift lever attaches to on the side just sets contacts inside the transmission and it's all electronic. Some transmission controllers bypass the mechanical part and work directly with the electronics. This isn't gospel, I might be reading what I want it to say instead of what it really says. Thanks for the input.

Thanks for chiming in, guys. Keep 'em coming.

[Steve Chryssos]

I’m trying to design and build a drive train that’ll shift as close to an F1 or sports racing car as I can get using reasonably priced (read cheap) parts.
I want a fully electronically shifted 4R70W. In fact I already have a junkyard one that I plan to use during the build to make sure everything will fit and possibly for a core for my final “built” transmission.
My plans are for console mounted pushbuttons (or maybe rocker switch/pushbutton combination) to control the Forward-Neutral-Reverse-Park functions. And a set of microswitches integrated into the steering wheel for up/down shifting. I have a Retrotek paddle shifter that I picked up on eBay but would prefer the steering wheel switches, I think. I may test both.
These inputs would feed the transmission controller. From my research, the Compushift seems like it may be the best choice.
It sounds like a contradiction, but right now I’m working on the build of a carburetored 351W.
This would require, at a minimum, a throttle position sensor to work with the transmission controller. I might have to wind up going EFI; if a carb/TPS setup can’t be made to work satisfactorily. But that would hit the budget pretty hard.
The actual transmission specifications are where I’m the foggiest. Except for my daily drivers, every thing I’ve had has been a manual.
I expect the engine to be in the 350 – 400 hp, 400 ft-lbs torque, range
For a road course car, I’ll need plenty of transmission cooling.
I think engine braking would also be desirable.
How would the transmission build differ from what I would expect from the typical drag oriented build? My transmission guy knows drag cars but has never done one for a track car.
I don’t have any idea what I’d need in the way of a converter, stall speed, etc.

Lots more questions than answers at this point.
Any input would be appreciated. Pretty much everything is open to review, debate, criticism and change at this point.

Thanks in advance for your help,

Sorry for missing this thread. Let's get started:

Let's dismiss some notions. First, put the F1 thing out of your mind. Your expectations should be for a great automatic--nothing more. Shifting is greatly simplified. Therefore a manumatic will free you up to concentrate on that thing in front of you called the road. Throttle, brake, steer. No worries about ill-timed or missed shifts.

Second, we don't prescribe to electronic control of the PRND function. It is our opinion that electronic control should be limited to the forward gears only. So 1-2-3-4 and 4-3-2-1. As far as I'm concerned, PRND is a safety critical function that should be handled entirely by a human. If you insist on electronic PRND control, contact Mastershift as their system has comprehensive and redundant fail safes.

If you can get past human PRND operation, then shifts can be controlled electronically by way of a Compushift standalone transmission controller. Their excellent TPS sensor kit is easily adaptable to your carburetor. We provide Compushift controllers with application specific calibrations that are very close to accurate. With regards to the 4R70W, you will need to confirm year of manufacture or at least provide a full description of the case connectors.

Have your trans builder set things up on the firm side. We can always dumb it down through the TCU. But we can't add what isn't there. You don't NEED a road race savvy trans builder to make shifts happen, but I strongly recommend a builder who understands how to build quick shifts that are not harsh. If he says "No such thing" walk away.

As for the converter, it needs to be small diameter and on the tight side of your typical drag race spec. A lot of shops cannot do small AND tight. Keep that in mind. I recommend a heavy duty lock up clutch that engages against a billet steel front cover. That billet front cover is emulating a flywheel in terms of contact surface. Stamped covers are for suckers. Compushift allows for a wider range of operation for converter lock up. But the clutch needs to be up to the task. I won't give a diameter/stall recommendation without detailed vehicle specs, but most combinations that we've done land south of 3000 rpm stall. Sorry for the sales pitch, but your best bet for a torque converter is to get it thru us, Twist Machine. You are likely to get a loose, sloppy street/strip or drag race piece from all of the usual big name suspects. We bought three converters from three different brand name sources. They all exhibited the same issues and no one was willing to listen. Now we have converters custom built for us by Pro Torque.

If you must use buttons to actuate shifts, mount them on the backside of the steering wheel. That way you can use your fingertips. Your thumbs should stay hooked around the steering wheel rim. The advantage of paddles is that the driver squeezes them towards the steering wheel. Grip increases. And paddles are simply more intuitive than buttons. Please don't mount buttons on the console, they need to be line of sight. Likewise, you should mount your Compushift display/tuner line of sight for critical data view and easy tuning. In automatic mode, the Compushift display show 1-2-3-4. In paddle shift mode, the display shows S1-S2-S3-S4. There's even a built in dyno simulator.

Feel free to call me any time. Anyone here can attest to the fact that I'm happy to answer any question without pressure.

[lbperry]

This was exactly what I was looking for, Steve; detailed information backed up with knowledge and experience. You can be sure I'll be on the phone to TwistMachine when it comes time to make my Compushift and associated buys.

First, I know that I'm not going to get F1 level shifts out of a production street car based transmission. That was said very tongue-in-cheek; I guess I should have used an appropriate smilie. But I assumed it would be obvious.

From my research, I do believe that it should be possible to get quick, firm (not harsh), on-demand shifts out of such a transmission; if the right mods are made to the transmission and the proper associated parts are used with it.

No, I am not married to the electronic PRND operation. It just seemed that instead of using a mechanical shifter to make electronic settings inside the transmission (that is what happens with the 4R70W, isn't it?), it would make sense to bypass the mechanical and go all electronic. I assumed, probably incorrectly, that the transmission controller would have "save me from myself" logic that would prevent catastrophic PRND moves under pushbutton control. If it doesn't, I agree that a mechanical shifter with those capabilities would be necessary. Or, like you say, the Mastershift shifter might provide that capability.

Since you seem to have a very good handle on what is needed in the way of transmission mods and converter, I would think that I would be wise to go through you (TwistMachine) for those or recommendations on where to get the trans mods done.

Your comments on the shifter button location make a lot of sense and would point me toward the use of a standard paddle shifter rather than pushbuttons.

Again, thanks for the excellent comments. I had hoped to find at least one person that, instead of just telling me to go away and forget about it, would say "Here's a way we can make that happen". I was hoping to find a person that could advise me on a total, coordinated set of parts that will work together to get me what I want.

I really appreciate your time and detailed response.
Thanks,
Lawrence

[Jake's Performance]

Steve has you started as far as good advice for the electronic side of it.

On the transmission build side,
use a 98-up 4R70W if possible. It already has the mechanical diode for better reliability.

4R70W is an AOD or AOD-E with all the updates, it's a damn good unit.

You can go back to the AOD ratios of 2.40/1.40/1:1/.67 or stay with the 2.84 low ratio.
This would be combo dependent.

What part of the country are you in?
Maybe I can refer you to a good local builder.

The Baumann kit and controller are both excellent pieces. I'm not familiar with using the paddle shifters with their controller though, I would check with Baumann.

[MonzaRacer]

Again you still need manual control of the shift lever especially to place it in park. Shifting can be done if it is a tcm controlled trans. but you still need some type of hard link.

[lbperry]

Thanks for the input, Jake's.
I picked up an '02 3.8 Mustang V6 4R70W that I understand has all the right goodies in it and can easily be upgraded to V8 specs during the build. And the bellhousing mates up to the 351W bolt pattern.
I'll record those ratios and take them into consideration when I come up with a final set of specs for the build. I figure that I'll have to take a lot of things into consideration on that: rear end ratio, engine cam, etc, etc.
I appreciate the info and comments. Keep 'em coming.
I live in north AL so I'd be surprised if a Maine guy has many contacts way down here. But if you do, great. I've been in touch with a couple of builders, at least one with a pretty good national reputation.

Sorry I didn't take your earlier comments more into account, MonzaRacer. Looks like I'm going to have to look a lot more into a mechanical shifter setup. Since it'll only have to handle the PRND functions and not shifting, I would think that I'd be able to use a suitably modified Mustang or other Ford shifter. Seems like I read on one of the forums that one of the Lincolns had a nice low profile shifter that might work well.

I appreciate the comments form both of you and hope you'll continue to keep an eye on what I'm planning and try to keep me straight.

Thanks,
Lawrence