On the very week before the first Gulf War, Ford showed an innovative engine design for the ‘90s, modular in its layout and calling back to the most luxurious automobiles ever made. This is the story of “T-Drive” and Ford’s modular straight eight that never made it to production.
Welcome back to Auto Archives, the show in which we dive into my personal collection of Car Styling magazine back issues. These issues are packed with never-uploaded-online pictures, sketches, and interviews. I wish I had time to go through every page.
Straight-eights are some of the rarest engines you’ll ever encounter, pretty much only under the long hoods of Cruella DeVille-grade land yachts of the 1920s and ‘30s. Why Ford took a stab at making a modern version is an interesting question, but maybe even more interesting is the time when Ford gave this idea its shot at revival. It was really the only time a design like this might get attempted, and it’s also probably the main reason why it never made it past that experimental stage.
Before I go on, let me explain what this engine was. It was a straight eight, so like a straight six or an inline-four, you got eight cylinders in a (very long) line. In Ford’s T-Drive system, though, there were four cylinders on one side, four on the other, and power was taken out in the middle of them to the transmission. You can imagine a kind of “T” shape, hence the name. Instead of a very long hood, with T-Drive you got a kind of short but wide one. This is how most modern cars look anyway, so T-Drive meant that Ford could cram a relatively big engine into a relatively small car. Indeed, the running prototype for T-Drive wasn’t a Mustang or a Crown Vic. It was the compact Ford Tempo. You probably didn’t have a hope in hell of cramming a 4.0-liter V8 under the hood of a Tempo, but you could get a 4.0-liter T-Drive straight 8 in there. You can see how Ford shoehorned the thing in there in our old recap post on this from 2010, linking back to the original source for all this info. That would be DrivingEnthusiast.net.
DrivingEnthusiast.net also dug up the patent for T-Drive. In the video at the top of this post, I spared you having to listen to me read the whole thing aloud, but since these are written words here, please enjoy this from the U.S. Patent Office filed in 1991 and published in ‘93:
A T-drive power transmission mechanism comprising an engine with a crankshaft disposed perpendicularly with respect to the axis of the transmission gearing, the transmission including a hydrokinetic torque converter and a right angle drive connecting the torque output element of the gearing with transverse axle halfshafts, the torque input element of the gearing being connected drivably to a crankshaft gear located at the midpoint of the crankshaft.
There are some nice technical drawings of how that all works, so I’ll include them here, including one of the loooooong crankshaft:
There are a couple of reasons why T-Drive made it all the way onto the show floor of the 1991 Detroit Auto Show, but not into showrooms and driveways. Here’s DrivingEnthusiast.net laying out the pros and cons, detailing that this is a system that has a huge degree of flexibility. You could make four, six, or eight-cylinder engines all using the same batch of parts, and you could set them up in similarly-sized cars, and you could use it with any kind of front-, rear-, or all-wheel drive:
- Family approach to a range of engines
- Because of the size of the engine, and placement ahead of the axle centerline, front-, all-, or rear-wheel drive configurations could be engineered
- Rear-wheel drive could have used variations of existing off-the-shelf transmissions (saving money)
- Packaging advantages for “cab-forward” design
- The transmission is located in-line with the midpoint of the crankshaft. This allows for a very low engine placement, and correspondingly low hoodline
- Marketing: provide Ford with centerpiece engine technology, as Subaru has with its boxer engine family.
- Packaging, NVH, durability
- Harmonics, torque pulse and gear rattle
- Limited bore size (torque, breathing, valve area) and displacement
- Engine weight over front axle-line, creating weigh-balance issues as in a front-wheel drive car
- Front- or all-wheel drive would have required engineering variations on existing transmissions
- Bulky transmission placement behind the engine - requiring specific design changes on existing front-wheel drive-based platforms (when one of the points is to be able to use existing transmissions).
That explains the particular points of T-Drive itself, but it misses out of two other issues for T-Drive.
The big benefit of T-Drive was that it was modular. We see this no in the revival of straight-six engines like at Mercedes. A modular design lets you easily build small engines into big engines, like playing with little Lego blocks. A problem, though, was that Ford already had a modular engine system. Anyone who has heard a 1990s Mustang doing a burnout on the far side of town will know it. The “Mod Motor” was Ford’s main V8 for the entire duration of the 1990s, and it used common parts so that it could be made with various numbers of cylinders and various levels of tech.
While we only got V8 and V10 Mod Motors, PopSci reported in late 1990 that Ford could make Mod Motor V6s down to 2.0-liters. We never got them in production, but Mod Motors came in all kinds of displacements, with single and dual-overhead cams, and lots of flexibility. That wasn’t a big break from the norm.
Finally, I can’t stress enough the timing of T-Drive. In 1991, the world was on the precipice of a global recession. Again, the ‘91 Detroit show was literally a week before the Gulf War helped scare the world into a financial shit show. And the Japanese Bubble Era was about ten seconds away from bursting. The country would be sent into what was termed the “Lost Decade,” a depression that ended up lasting two. The Bubble Era had fueled ambitious tech development particularly in Japan but also pressured the rest of the world to catch up, too. In the 1980s, we saw revivals of V12s at BMW and Mercedes, we saw twin-cam engines become mainstream, and turbo engines, and twin-turbo engines, too. Japan was churning out commuter hatchbacks with engines that revved to 9,000 RPM. There were engines the likes of which have never been seen again, like Mazda’s triple-rotor design seen in the incredible Eunos Cosmo.
The scale of progress was unhinged, and it looked poised to continue right up until that economic collapse of ‘91. Pretty much every player in the car world had to shrink their budgets to nil. Ford was struggling to stay alive altogether. I can’t imagine trying out experimental engines reviving old tech from before WWII was high on anyone’s priority list.
So T-Drive died. And that’s a bummer! The car we saw it in, the Contour concept did make it into production, but just as a boring jellybean with conventional engines. There was no T-Drive. There wasn’t a bonded-aluminum chassis, like the concept, or razor-thin projector headlights, or wheels that only had spokes on one-quarter of the rim.
I often wonder what cars would have looked like in the ‘90s if the Bubble never burst. But these are idle dreams that have no end, T-Drive cylinders in a line to the horizon.