7 replies to this topic

[AdamLarnachJr]

OK... I figured you guys had the knowledge to help me out a bit, the rest I could manage on my own.

I'm embarking on several season of open class road racing, and I have come to a point on deciding which powerplant to run. I have a choice between 2, a 446, and a 338ci... the 446, I cannot find any sequential transmission that will hold the torque load of that engine, and the only way I can get away with the 338 and still be as quick as the 446 is by turning 9000+ rpm, not good for something that doubles as a possible street car.

I could spend $40,000 on a Hewland gearbox... HAH! Or I could use my current Richmond Six Speed with some beefed up internals... only problem is I want to possible convert it to sequential.

So I figured I could program a solenoid to operate the clutch lever when only needed when shifting... but the thing I dont get is a hydraulic operated shifter.

Anyone know how this works or how I could convert an H-gate shifter to hydraulic actuated... hydraulic H gate?

THanks

[desmo]

I don't think a hydraulically actuated H-pattern shifter is a feasible project for a non-factory effort.

[AdamLarnachJr]

Yes, I was going over that today when I was doing some sketching and prototyping. I found it would be easier to use an electronic engaged clutch with a solenoid and still use the H-pattern.

I could possibly have a sensor on the shift linkage would would engage the clutch after the sensor detected a certain amount of movement within the linkage, then the clutch would engage, the engine would hit the "soft" limiter then into the next gear and disengage the clutch.

Any thoughts?

[Croaky]

Audi tried that on some of the very late Quattro rally cars in the 1980s, before group B was abolished. (They were producing something like 500bhp by then) They had a switch on the gear lever so when you grabbed it, the clutch pedal went down. The thing was, the pedal physically went to the floor and sometimes squished the driver's foot under it.
It's not a new idea, people started playing with electrically operated clutches controlled by a switch on the gear stick in about the 1930s, so it's certainly possible.

Just edited the post to stick in a link to a pdf file I found. (size about 1.5M) Some guy converted his car to semi-auto. I think it might frighten you off...

http://www.automatum.com/thesis.pdf

[desmo]

Porsche actually had a "clutchless manual" option on their 911 back in the '70s similar in concept to the Audi rally car. I cannot remember what they called it, AutoStick or some such.

[Limey]

The Porsche model was a Sportmatic. It used a 4 speed Porsche transmission, a torque convertor and an electronically operated clutch. Grabbing the gearshift knob disengaged the clutch using a micro switch. (Road & Track - April 1971).

[desmo]

Thank you, I wasn't too sure of the name.

[Croaky]

The first one I'm aware of is the "Manumatic" system on some British cars in the late 1950s. It used a centrifugally operated plate clutch, which was disengaged by a microswitch on the gear lever. The gearbox was a standard 4-speed manual. The system was pretty clever, matching engine speeds during shifts and making sure the clutch re-engaged smoothly. The vacuum from the inlet manifold was used to work the clutch. The system didn't last long because it was unreliable and difficult to diagnose faults.