What is an E-diff?

One of the technical features that sets the F430 apart is the E-Diff or electronic differential. This solution has been used for years in F1 single-seaters and has been continuously developed and refined, effectively transferring massive torque levels to the track under extremely high cornering g-forces. The E-Diff is now standard equipment on the F430 - the first time that a production car has been equipped with such a sophisticated system for high-performance roadholding. On the track, the E-Diff guarantees maximum grip out of bends, eliminating wheel spin. On the road it is a formidable technological refinement that improves roadholding. This system is available both on the F1-paddle shift version as well as on the manual gearbox model and consists of three main subsystems:
- a high-pressure hydraulic system, shared with the F1 gearbox (if present);
- a control system consisting of valve, sensors and electronic control unit;
- a mechanical unit housed in the left side of the gearbox.

Torque is continuously distributed between the wheels via two sets of friction discs (one for each driveshaft) controlled by a hydraulic actuator. The amount of torque actually transmitted to the driven wheels depends on driving conditions (accelerator pedal angle, steering angle, yaw acceleration, individual wheel rotation speed) and brings considerable advantages in terms of performance, direction stability, active safety and handling feedback. Again, F1 racing was a vital testbench that enabled Ferrari’s engineers to develop a highly sophisticated system that perfectly matches the requirements of a road car designed to reach over 315 km/h and generate considerable cornering forces.

The electronic differential actively helps reduce Fiorano lap times by 3 seconds compared to the 360 Modena. For the driver, the E-Diff increases handling balance and grip (which noticeably improves acceleration), improves roadholding on the limit and also guarantees even better steering feel.

 

thanks for the write-up, nberry.

 

In the AutoCar article 7 Sept 2004 they give a description of E-Diff.

Here is their description.

The E-diif is intended to make the F430 much easier to drive at or close to the limits of adhension, and is clearly Ferrari's answer to the Lambo Gallardo's four-wheel drive system. "We want four-wheel drive capability in terms of transferring torque to road, but all-wheel drive has a 70 to 80kg weight penalty, and it produces a specific characteristic that we don't want: understeer." The challenge was how to transfer the torque to the road without four-wheel drive.

So while the F430 enables you to go faster through a corner, its stability at or near the limit - and the ease with which it can be driven there - is heightened by E-diff, which can apply what Felisa (General Manager at Ferrari) describes as "an intervention" during a moment of a 'high lateral acceleration' - aka a slide- 'and balance the car in safety.' The idea is that a typical driver can enjoy cornering the F430 at high speeds 'without being Michael Schumacker.'

If Felisa and his team have succeeded, they will have eliminated a flaw long-present in Ferrari's midengined road cars, which have often proved slightly treacherous on the limit. The logic controlling the E-diff - and the suspension, ESP, traction control and F1 shift speed - can be altered via a rotary switch on the steering wheel boss which Ferrari calls the 'manettino'. Schumacker and Barrichello play with similar switch in their cars. 'It improves the capability of the car to follow requests of the driver,' says Felisa, by providing four settings - sport, race, ice and wet, all of which relate to surface conditions, and a fifth position which enabled you to switch out the traction control and ESP anti-skid system. 'Sport is Normal in a Ferrari of course', says Felisa, grinning and race is for track work, or, as Felisa describes it, 'if you're a very experienced driver and you want to exercise yourself.'

So there you have it. Sorry if it is a little long. I thought you would rather see it all.

Enjoy.

Cheers

 

It came from the Ferrari techical specifications of the car.

 

So that means the 430 has *3* clutches to deal with and maintain? I wonder what the maintenance and costs will be like on these beasts...

 

Not gonna be cheap, but those extra clutchs are better then ever, so it should be much stronger....

 

It would be fascinating if they broke out the effect of the EDiff. Let's face it, 4.3 liters and nearly 500 hp had some effect on the 3 second improvement, also!

Gary

 

Hmm. I have been very impressed with the honest response of my 360 at the track. Far from treacherous, in fact considering how high the limits are it's among the best I've ever driven.

Gary

 

tdf360,

I would also agree with you. The 360 handles beautifully. But if you watch a pro really push the 360 on the track. When it starts to go it goes fast and not all the people who buy the 360 have the skill set to handle or deal with the 360 under that situation.

Some of the best driving I have seen has been Best Motoring Videos. These guys do not play around. They push every car they test. It is amazing to watch.

So the F430 should be terrific to drive. I can't wait.

Cheers

 

Nberry, excellent description and explanation. Many thanks.



Cavallini

 

The std 360 diff can be rebuilt to have a higher static pre-load which help considerably on traction and turn in stability. This can be done in around 4 hours of labour with no parts required, although all the tech info suggests to replace the crownwheel bolts every time ........

A Modena Engineering diff is fully adjustable too, and can be fitted without the need to remove the gearbox. It has studs and nuts too, so the stretch bolt replacement is not an issue......

 

My appologies for a possibly rediculous question but... could someone elaborate a little more on how this differs from a normal limited slip diff? Is it similar, but the use of electronics and clutches let it put more power down sooner, or is it a completely new concept? I never really understood how limited slip diffs work but it sounds like a similar concept. Thanks for any input.
joe