osunick

Just messing around with my gopro, I tooled around the neighborhood to see the rear steer working at low speeds. I had never seen it before so I thought it would be fun to share.

991 Turbo S Four Wheel Steering

Dennis C

That’s cool to see. Thanks for sharing it.

lowpue

wow...that moves a lot more than I expected....thanks for sharing!

osunick

Yeah, now that I see it it makes sense that it has to be able to move as fast as you can turn the wheel, or you'll have some weird handling effects at the limit.

the_buch

Thanks for posting this. I too was surprised at how much it moved. It would be interesting to see it moving in the opposite way at high speeds.

osunick

I think that will be the sequel. I’ll get around to it next week. What’s the switch to in phase steering? 41 mph?

Lance 4c

Very cool. Hard to believe it articulates that much. Explains that funky grabing and sound when cold.

osunick

Actually all 981/991s crab at full lock with cold tires. Had to do with the amount of Ackerman dialed in and likely packaging constraints with the frunk and macstruts. Four wheel steering wouldn't exacerbate this and may make it better.

Papa Fittig

It's moving more than I thought.. . Thanks for posting.

2fcknfst

Thanks for that - had no idea there was that much movement, I thought it was only a 'couple' of degrees...

I also like the effect of the wheel as seen through the camera - very cool.

Jean

You are right. Up to 50kph it goes counter to steering wheels direction up to -3 degrees, and above 80kph in the same direction up to 1.5 deg. This has the same effect as a virtual increase in wheelbase of 500mm which is huge in terms of handling.

AKSteve

I don't know about anyone else, but this really makes me want to film my own rear wheels now just so I can make sure that this system is working on my turbo.

Agentorange

Thanks for this, way neat!

osunick

Fun fact- because of the wide rear fenders, the rear steer on the Turbos can turn as much as 2.5 degrees. The GT3 can only steer 1.5 degrees so the Turbo actually has a shorter virtual wheelbase than a GT3.

osunick

I tried to do videos of in phase steering but the problem is that at those speeds (~50+ MPH) you can't really do very aggressive turns at speed on the road and the suspension moves around enough that it's hard to see the steering in action.