DS vs ZF weight distribution

[Wanderer]

I cant get my head around this...

DS:

47%/53% Front/Rear

ZF:

49%/51% Front/Rear

Now, as we know The DS is engine front, clutch/gearbox/diff rear, the ZF is engine/autobox front, diff rear. How can sticking all the gubbins at the front make the weight distribution better?

Is a slush box lighter than a clutch/manual box?

 

[Oneball]

DS is a transaxle so the gearbox is at the back too much weight at rear like a 911

 

[Wanderer]

DS is a transaxle so the gearbox is at the back like a 4200 CC

Yeah I know so in my Alfa 75 eyes that means near-ideal weight distribution? Surely having the engine and outbox at the front is not an ideal way to achieve a an even weight distribution?

 

[Oneball]

Depends on how heavy everything else is and where it and the wheels are placed. The QP already has the engine almost in the cabin so sticking the gearbox out the back probably didn’t help.

Which came first GT or QP? I know one is based on the other but not sure which way round.

 

[Rwc13]

I cant get my head around this...

DS:

47%/53% Front/Rear

ZF:

49%/51% Front/Rear

Now, as we know The DS is engine front, clutch/gearbox/diff rear, the ZF is engine/autobox front, diff rear. How can sticking all the gubbins at the front make the weight distribution better?

Is a slush box lighter than a clutch/manual box?

Forget what the numbers say, for me the DS always handled better even though I also loved my GTS Auto. There was a twisty road in the Peak District that I swear I was faster in the DS down than any 997 or GS

 

[Wanderer]

Forget what the numbers say, for me the DS always handled better even though I also loved my GTS Auto. There was a twisty road in the Peak District that I swear I was faster in the DS down than any 997 or GS

Yeah, had the Alfa 75 TS and the 3.0, at the same time - the TS had less oomph, but was better balanced, wish I'd kept them both....

River Road here in Dublin 15, narrow and twisty, some times hardly possible to imagine two cars could cross at the same place, but the QP DS, despite being massive, does it easily, goes EXACTLY where you point it. What it lacks in oomph it makes up in agility. (for a big car)

 

[CatmanV2]

Loved my 75 3.0 although it appeared that the back end was only loosely attached to the rest of the car....

C

 

[Wanderer]

Loved my 75 3.0 although it appeared that the back end was only loosely attached to the rest of the car....

C

And the tiniest boot ever!

 

[Oneball]

And the tiniest boot ever!

Alfa 916 spider has the tiniest boot ever.

 

[CatmanV2]

And the tiniest boot ever!

It was only a matter of luck if I still had the boot when I parked....

C

 

[rs48635]

the numbers make sense.
Is the optimum distribution 50:50? Think a recent article by Tiff Needell mention numbers closer to the DS figures. Maybe rear bias gives more controlled leverage, plus takes weight off the front wheels which need to be pointy and avoid understeer.

 

[bigbob]

The 2% points difference front to back of the two models is about half a tank of fuel max of mass. So are you boys telling me you can tell the difference between a full tank of fuel and half a tank in terms of turn in and driving balance? Really?

 

[Rwc13]

I could very clearly tell the difference between the two cars, but as I said, I think it adds up to much more than the 2% difference. There are probably other contributing factors in the different set ups

 

[flat-12]

Yes it is a 2% difference in weight distribution at each end, but the overall effect is a 4% difference - as you have to consider both ends together. I would guess that would be a perceptible difference.

 

[Oishi]

Its not just the weight distribution, the more important factor is polar moment of inertia. A cannon ball might mass the same as a dumbbell, and have the same center of gravity, but has a much lower polar moment. Putting mass at the ends of the car might balance, but the car won't turn in as fast, and once rotating will be hard to stop. Lots of factors here.

 

[azapa]

I've never seen under the back of a non-transaxel GT car. Whats under there? A Diff hung from some point on the chassis with a torque tube heading in, and CV jointed drive shafts coming out left and right? Might there be some weight saving with the transaxel car?

 

[Zep]

Its not just the weight distribution, the more important factor is polar moment of inertia. A cannon ball might mass the same as a dumbbell, and have the same center of gravity, but has a much lower polar moment. Putting mass at the ends of the car might balance, but the car won't turn in as fast, and once rotating will be hard to stop. Lots of factors here.

I’m glad someone said that!

 

[Wanderer]

Its not just the weight distribution, the more important factor is polar moment of inertia. A cannon ball might mass the same as a dumbbell, and have the same center of gravity, but has a much lower polar moment. Putting mass at the ends of the car might balance, but the car won't turn in as fast, and once rotating will be hard to stop. Lots of factors here.

I get that, my point is a car with all the heavy gubbins up front can't be as balanced as a car with half the gubbins up front, and half the gubbins out back. Unless an autobox and transaxle don't weigh that much in the scheme of things....

 

[CatmanV2]

I get that, my point is a car with all the heavy gubbins up front can't be as balanced as a car with half the gubbins up front, and half the gubbins out back. Unless an autobox and transaxle don't weigh that much in the scheme of things....

The problem is that 'balance's is ill defined. If all your heavy gubbins is up front, you'll still turn pretty fast I suspect, but in a slightly odd way. You want most of it sort of in the middle so it turns around that point. Ish.

C

 

[Wanderer]

The problem is that 'balance's is ill defined. If all your heavy gubbins is up front, you'll still turn pretty fast I suspect, but in a slightly odd way. You want most of it sort of in the middle so it turns around that point. Ish.

C

When I had my twin 75's (both at same time) I found the TS was like it was on rails, unstick able, very much like the DS, and the 3.0 was good, but mine used to plough down on turn in, presumably weight - like turn hard left, the left front felt like it was dipping and the rear right felt looser if you know what I mean. To mean that means with all that power and weight up front you'll lose lighter rear more easily.

On the other hand, I'm no press-on driver so I'm probs talking ****.

I had a 3.6 Caddy CTS with RWD and boy was that twitchy, any sign of snow and I shat myself....