I was just thinking out loud after watching some recent RC-F videos yesterday--wouldn't it be killer if Lexus could implement both torque vectoring and rear wheel steering in one car? Surely the two technologies are not mutually exclusive, and should both contribute to the car's cornering ability? I'm sure they've thought about this before, since both the GS and JDM IS already have dynamic rear steering and the RC-F is based on the two cars.

So what's preventing Lexus from adding rear wheel steering to the RC-F? Could it be cost? Or complexity in making torque vectoring and rear wheel steering work seamlessly and naturally in tandem?

 

Imagine trying to power slide through a corner with rear steering...

AVS & DRS just weren't designed to be on the powerful F cars ..

The RC F will shine with the new TVD & VDIM reprogramming

Joe Z

 

The same can be said about TVD--both DRS and TVD are designed to enhance grip through a corner, so if you're into power sliding then you shouldn't want any of these technologies in the first place.Thanks I see, but from what source or how did you gather that DRS can't handle the F's power?

 

My own opinion...

Why else wouldn't they be on the pinnacle "F" ?

Joe Z

 

My question exactly.

The pinnacle F car should include every performance trick they have in their arsenal, so the omission is particularly curious and puzzling.

 

i dont see why you would even need RWS with a TVD, since the TVD can fully control how much torque goes to each wheel

 

Because the two technologies help the car steer through two distinctly different means. TVD distributes torque to the wheel that needs it, while RWS steers the wheels in the direction that the car wants to rotate to.

TVD applies power while RWS applies direction, much like how a FWD car can have both power and steering on the same wheels. The two definitely compliments each other.

 

Right, except FWD doesn't steer by using brakes. :P

RWS seems to be a total gimmick IMO. Whereas TVD seems to be a much more effective option, given the choice. Such as "brake steer" on the 12C.

 

Don't think TVD works by using brakes. TV"D" works by using a differential.

And how do you gather that RWS is a gimmick? Have you compared two otherwise identical cars, one with RWS and one without, before? IMHO RWS is the key reason why the GS350 F-Sport has been universally praised for its agility while the shorter, supposedly more nimble IS350 F-Sport has instead received lots of remarks that it's more stable rather than agile in tight corners.

 

I never said TVD used the brakes. Only comparing it to "brake steer".

RWS is great if you're a forklift, but on a car not so much.

 

The car already has a very short wheelbase. It will want to rotate very quickly. RWS is useful for cars that are prone to heavy understeer or have a long wheelbase. That is why it was put in the GS350 F-Sport. The new Porsche GT3 has RWS primarily because GT3 cars are prone to heavy understeer that turns into snap oversteer (due to 60% of the weight hanging out behind the rear axle), which is why Porsche put RWS in order to introduce some neutral behavior.

Lexus used a lot of LFA philosophy in the RC-F. LFA has a very short wheelbase and the car is extremely tail happy and wants to rotate/change direction telepathically and under heavy power, which is why no one would ever tell you LFA should have had a RWS.

No point in adding weight of something that is not going to enhance the dynamic character of the car.

 

Well you did reply to my comparison of TVD by saying "Right, except FWD doesn't steer by using brakes" so I thought you were inferring that TVD steers using brakes.And you still don't have any evidence to back up your assertion. I at least have provided an example of the GS350 F-Sport being considered agile while the IS350 F-Sport, based a shortened GS chassis, being considered less so.

Unless someone can get his hand on both a JDM IS350 F-Sport and a US-spec one I guess we'll never know if RWS really is a gimmick.

 

I see. That kind of makes sense now. Thanks.

EDIT: But wait, can't the same be said about torque vectoring then? If a car with a short wheelbase wants to rotate so quickly, then surely TVD is redundant too? If TVD helps, then wouldn't RWS help too? Every little bit helps, doesn't it?

 

TVD has a broader application. The main goal is to split torque side to side in order to promote more power to the wheel with the most traction. It will send more power to the outer wheel to rotate the car or will send more power to the wheel with the most traction. TVD also helps straight line acceleration where it would send torque to the rear wheel with the most traction etc.

Ferrari 458 Italia, McLaren MP4, Nissan GTR etc. all come with TVDs without any RWS for the same reason.

 

Good posts