RE: Mercedes-Benz CLA45 AMG previewed

[Loplop]

Oddball RS said:

Ali_T said:

walsh said:

360bhp from 2000cc eh? That's some going on the specific output front, what beats that in a road car, bar some nutter evo's..

The way AMG are going on about it, it's a world first and I've heard them say it's the highest specific output on a 2 litre 4 pot of all time. Er.....no . That honour still goes to the X FQ400, which was actually 405bhp.

Edited by Ali_T on Sunday 24th February 21:18

Again for those who missed it the first time, was it 'manufactured' in that state?

I also imagine the Merc doesn't feel the need to implode or mince it's drivetrain every < 10k miles.

Or was that just an Evo 7 - 9 problem? A friend actually had a sizeable pile of clutches from his FQ360

[madevo]

Cannot wait till they open up the order books for this. I think the a45 is confirmed at 36k base so do you think we are looking at 40k base for this?

I've been waiting for something like this from AMG for many years. An ideal daily driver.

[StottyZr]

scherzkeks said:

Cars like the TTRS have proven how well the system works in a front-bias app.

Granted I haven't driven one, but I've read road test reviews from people who have, and they all claim it has far to much understeer

[Clivey]

scherzkeks said:

You don't understand Haldex 4. It is a proactive system.

From the dictionary:

Reactive

adjective - Reacting in response to a situation rather than creating or controlling it

In response to a lack of traction, the system (like others) has to apportion power to where it can be deployed. However, it is a more reactive system because with torsen etc., the power distribution is more equal / balanced in the first place and therefore more able to deal with difficult situations. Even the best cars with the transverse + Haldex layout can't get near those with more conventional AWD / permanent 4WD systems in terms of ability. - As you say, the inability to send the majority of power to the rear wheels is a major drawback for performance driving.

scherzkeks said:

In the normal Audi range, the torque bias is set to 85/15(is supposedly more rear biased in S/RS models). Since the 4th gen. system got a separately driven electronic pump, there is no wait for pressure to build for clutch engagement. Power is transferred instantly as the clutch pack is always engaged to some degree (specced by manf.). Also, power is transferred based on multiple factors, including gas pedal engagement, steering angle, axle slip, and more. In its driving characteristics, it is very similar to the old 50/50 Torsen system and imparts a good neutral feel. The system's only real Achilles heel for performance driving is that it cannot send more than 50% of torque to the rear unless in an unlikely situation such as where the fronts have almost no traction vs. the rear. Cars like the TTRS have proven how well the system works in a front-bias app. I see no reason why the A45 would not drive very, very well, so long as the suspension does not let it down.

And the TTRS is still very one-dimensional when compared to, for example, the S4 with the Sport Differential or a Mitsubishi Evo. - Look at the criticism the RS3 has had from the likes of Chris Harris (I find it funny that it has wider front tyres than rear). Contrast that for the near universal praise the RS4 gets. - Except in unusual applications such as Lamborghinis, the Veyron etc., Haldex traction is a compromise. I sincerely doubt this new Mercedes will be hailed as a dynamic benchmark but would be pleasantly surprised if I was wrong.

[scherzkeks]

Clivey said:

scherzkeks said:

You don't understand Haldex 4. It is a proactive system.

From the dictionary:

Reactive

adjective - Reacting in response to a situation rather than creating or controlling it

In response to a lack of traction, the system (like others) has to apportion power to where it can be deployed. However, it is a more reactive system because with torsen etc., the power distribution is more equal / balanced in the first place and therefore more able to deal with difficult situations. Even the best cars with the transverse + Haldex layout can't get near those with more conventional AWD / permanent 4WD systems in terms of ability. - As you say, the inability to send the majority of power to the rear wheels is a major drawback for performance driving.

scherzkeks said:

In the normal Audi range, the torque bias is set to 85/15(is supposedly more rear biased in S/RS models). Since the 4th gen. system got a separately driven electronic pump, there is no wait for pressure to build for clutch engagement. Power is transferred instantly as the clutch pack is always engaged to some degree (specced by manf.). Also, power is transferred based on multiple factors, including gas pedal engagement, steering angle, axle slip, and more. In its driving characteristics, it is very similar to the old 50/50 Torsen system and imparts a good neutral feel. The system's only real Achilles heel for performance driving is that it cannot send more than 50% of torque to the rear unless in an unlikely situation such as where the fronts have almost no traction vs. the rear. Cars like the TTRS have proven how well the system works in a front-bias app. I see no reason why the A45 would not drive very, very well, so long as the suspension does not let it down.

And the TTRS is still very one-dimensional when compared to, for example, the S4 with the Sport Differential or a Mitsubishi Evo. - Look at the criticism the RS3 has had from the likes of Chris Harris (I find it funny that it has wider front tyres than rear). Contrast that for the near universal praise the RS4 gets. - Except in unusual applications such as Lamborghinis, the Veyron etc., Haldex traction is a compromise. I sincerely doubt this new Mercedes will be hailed as a dynamic benchmark but would be pleasantly surprised if I was wrong.

The system is proactive in that it is always sending power to the rear. By your definition, Torsen is also reactive, because other than sending more power to the rear in default mode, it operates almost the same way -- by shuffling power F to R (reacting) based on driving conditions and driver input.

I agree, that having more power going to the rear by default improves balance, but only to a point, and it isn't critical. There is a reason Audi still has not bothered to set the default torque split at more than 40/60 to the rear in the new crown gear cars.

Chris Harris's test? Meh. He likes RWD, which is fine. The RS3 was faster around a track than the older 1M (it's true intended rival), in several German tests. BMW has more feel, RS is faster and grippier. Nothing new.

Regarding the front tires, though: I read that it had to do with the rear wheel wells. They could not be reworked to accommodate a larger tire size. The TT chassis, though basically a golf/a3, is slightly different at the rear, and allows wider tires, which is why it runs a matching set. The S3, for example, also runs a matching set, but only because it runs 225s.

Yes, Haldex traction is a compromise, but so is FWD or RWD for that matter. The ultimate performance setup is slightly rear-biased AWD. That way you get the added feel and dynamic ability in 10/10th situations, but you also get serious traction and stability. Audi's new crown gear setup is getting near optimal, just a shame that most all the cars that have it are 4,000-pound pigs. I don't find these Haldex-based small cars to be any more of a compromise. I'd rather go fast than have the ultimate in driver feedback and dynamics -- and if that is what you really want, you would not be looking for it in a family sedan or hatch anyways.

Edited by scherzkeks on Wednesday 20th March 16:00