RWD - FWD - LSD - No of Cyls. Can You Really Tell?

[C70R]

RobM77 said:

I'm sure that C70R's point is true for a proportion of people, yes, not all though obviously.

I realise this wasn't central to his argument, but regarding the weight issue, it's a lot more than a tank of fuel's worth between a 4cyl and 6cyl Beemer (eg 330d saloon is 1615kg, and the 320d 1505kg, so almost double that for a tank of fuel), but the crucial thing is where the weight is. It's laughably easy to feel a 110kg lard arse passenger in a 3 series, or similarly even less than that on the roof. Incidentally, in a Caterham, removing the spare wheel (10kg maybe?) makes a huge difference to ride and handling, because it's mounted so high, but brimming the tank with more weight makes much less difference - again, it's where it is that counts.

Edited by RobM77 on Wednesday 19th October 17:09

To be honest Rob, it's probably true for the vast, vast majority of people. Including most of PH's 'soi-disant' driving gods.

At any rate, the (utterly ridiculous) comparison that was made on that thread was the E46 318/320. Carfolio reckons there's 100kg in it, which is equivalent to a 6.8% weight reduction in the 320. A full tank of petrol (65L) in the 318 would be roughly 50kg added to the rear end, yet I don't seem to see the same "experts" talking about how much more "tail-happy"/"playful"/"adjustable" (whichever Chris Harris has used recently) their cars are with a full tank.

It's just cringeworthy. It's people using post-rationalisation to try and convince themselves that they are in that "top 5%".

[RobM77]

C70R said:

RobM77 said:

I'm sure that C70R's point is true for a proportion of people, yes, not all though obviously.

I realise this wasn't central to his argument, but regarding the weight issue, it's a lot more than a tank of fuel's worth between a 4cyl and 6cyl Beemer (eg 330d saloon is 1615kg, and the 320d 1505kg, so almost double that for a tank of fuel), but the crucial thing is where the weight is. It's laughably easy to feel a 110kg lard arse passenger in a 3 series, or similarly even less than that on the roof. Incidentally, in a Caterham, removing the spare wheel (10kg maybe?) makes a huge difference to ride and handling, because it's mounted so high, but brimming the tank with more weight makes much less difference - again, it's where it is that counts.

Edited by RobM77 on Wednesday 19th October 17:09

To be honest Rob, it's probably true for the vast, vast majority of people. Including most of PH's 'soi-disant' driving gods.

At any rate, the (utterly ridiculous) comparison that was made on that thread was the E46 318/320. Carfolio reckons there's 100kg in it, which is equivalent to a 6.8% weight reduction in the 320. A full tank of petrol (65L) in the 318 would be roughly 50kg added to the rear end, yet I don't seem to see the same "experts" talking about how much more "tail-happy"/"playful"/"adjustable" (whichever Chris Harris has used recently) their cars are with a full tank.

It's just cringeworthy. It's people using post-rationalisation to try and convince themselves that they are in that "top 5%".

So as you just said, the difference between those two cars is double what a tank of fuel weighs, rather than what you first claimed, which was that it was similar. Furthermore, fuel is stored as low as possible, right down on the floor of the car, whereas the engine's CofG is considerably higher. Whilst it might be hard to detect 50kg at floor level, you can sure as hell detect a difference with for example your wife (65kg) and kid (35kg) on board!

It's just a bad example though, I can see the point you're making . However, we must be careful to look for real evidence that people are thinking in this manner, we can't just discount everyone using reverse logic.

[C70R]

RobM77 said:

C70R said:

RobM77 said:

I'm sure that C70R's point is true for a proportion of people, yes, not all though obviously.

I realise this wasn't central to his argument, but regarding the weight issue, it's a lot more than a tank of fuel's worth between a 4cyl and 6cyl Beemer (eg 330d saloon is 1615kg, and the 320d 1505kg, so almost double that for a tank of fuel), but the crucial thing is where the weight is. It's laughably easy to feel a 110kg lard arse passenger in a 3 series, or similarly even less than that on the roof. Incidentally, in a Caterham, removing the spare wheel (10kg maybe?) makes a huge difference to ride and handling, because it's mounted so high, but brimming the tank with more weight makes much less difference - again, it's where it is that counts.

Edited by RobM77 on Wednesday 19th October 17:09

To be honest Rob, it's probably true for the vast, vast majority of people. Including most of PH's 'soi-disant' driving gods.

At any rate, the (utterly ridiculous) comparison that was made on that thread was the E46 318/320. Carfolio reckons there's 100kg in it, which is equivalent to a 6.8% weight reduction in the 320. A full tank of petrol (65L) in the 318 would be roughly 50kg added to the rear end, yet I don't seem to see the same "experts" talking about how much more "tail-happy"/"playful"/"adjustable" (whichever Chris Harris has used recently) their cars are with a full tank.

It's just cringeworthy. It's people using post-rationalisation to try and convince themselves that they are in that "top 5%".

So as you just said, the difference between those two cars is double what a tank of fuel weighs, rather than what you first claimed, which was that it was similar. Furthermore, fuel is stored as low as possible, right down on the floor of the car, whereas the engine's CofG is considerably higher. Whilst it might be hard to detect 50kg at floor level, you can sure as hell detect a difference with for example your wife (65kg) and kid (35kg) on board!

But this is exactly the sort of justification I'm talking about. Think about the following rationally for a moment...

• If 100kg is so clear and obvious, why can only the 'privileged 1%' tell the difference in 50kg?
• Are you honestly telling me that the engine is mounted significantly higher than the fuel tank? To the extent that you'd be able to tell the difference? This is absolutely splitting hairs.
• Do you really think 99% of drivers would be able to categorically tell the difference in a 1.4 tonne car with a partner and child as passengers? Where is their CofG relative to the engine/fuel?

None of the above make any sense on a rational level, and completely ignores the fact that BMW will have engineered the car to accommodate the increased weight (spring rates etc.).
It's that 'feel' we keep going back to, which is largely b*llocks.
In fact, I'd go so far as to say that a double-blind test with 6.8% weight difference (irrespective of location/CofG) would fool 99.99% of people.

[kambites]

I suspect that most drivers would not notice the effect adding of 100kg of ballast to a 3-series as long as it was between the axles. I'm not even sure I would spot it in our Octavia unless I was looking for it and that's a considerably lighter car to start with.

I suppose in the lower powered models they might spot a different in straight-line speed, but since many people quite happily drive around on almost completely flat tyres without noticing, I don't think the handling difference of a ~7% increase in weight would be sufficient for them to spot it. I'm not even convinced most people would notice 200kg to be honest.

[gavsdavs]

RobM77 said:

They cause understeer by resisting the differential rotation of the driven wheels, which is something that needs to happen for a car to go around a corner.

I noticed this - I switched gearboxes on my car and it gained a good, new, LSD, as opposed to a worn out, poor, 20 year old manufacturers one.
The manufacturers one was about as effectve as an open diff and i didn't think i'd notice much difference.
On the new diff the car wanted to go in a straight line under power and seems to have more traction.

Under low loads i doubt i'd notice it, but when under hard acceleration I suspect i could tell the difference now. (in an equivalent car, of course)

[s m]

gavsdavs said:

I noticed this - I switched gearboxes on my car and it gained a good, new, LSD, as opposed to a worn out, poor, 20 year old manufacturers one.
The manufacturers one was about as effectve as an open diff and i didn't think i'd notice much difference.
On the new diff the car wanted to go in a straight line under power and seems to have more traction.

Under low loads i doubt i'd notice it, but when under hard acceleration I suspect i could tell the difference now. (in an equivalent car, of course)

Viscous or clutch type?

[Shakermaker]

Can I really tell? Yes

Could my wife? Not a chance. She is very much "I learned to drive in a Corsa, so I'm going to buy a Corsa" and, sure enough, she now drives a Corsa, and probably knows that it says "1.4" on the back, but she won't know what that means much, and she does that same look when I talk about cars that I do when she watches the Kardashians on TV.

[RobM77]

C70R said:

RobM77 said:

C70R said:

RobM77 said:

I'm sure that C70R's point is true for a proportion of people, yes, not all though obviously.

I realise this wasn't central to his argument, but regarding the weight issue, it's a lot more than a tank of fuel's worth between a 4cyl and 6cyl Beemer (eg 330d saloon is 1615kg, and the 320d 1505kg, so almost double that for a tank of fuel), but the crucial thing is where the weight is. It's laughably easy to feel a 110kg lard arse passenger in a 3 series, or similarly even less than that on the roof. Incidentally, in a Caterham, removing the spare wheel (10kg maybe?) makes a huge difference to ride and handling, because it's mounted so high, but brimming the tank with more weight makes much less difference - again, it's where it is that counts.

Edited by RobM77 on Wednesday 19th October 17:09

To be honest Rob, it's probably true for the vast, vast majority of people. Including most of PH's 'soi-disant' driving gods.

At any rate, the (utterly ridiculous) comparison that was made on that thread was the E46 318/320. Carfolio reckons there's 100kg in it, which is equivalent to a 6.8% weight reduction in the 320. A full tank of petrol (65L) in the 318 would be roughly 50kg added to the rear end, yet I don't seem to see the same "experts" talking about how much more "tail-happy"/"playful"/"adjustable" (whichever Chris Harris has used recently) their cars are with a full tank.

It's just cringeworthy. It's people using post-rationalisation to try and convince themselves that they are in that "top 5%".

So as you just said, the difference between those two cars is double what a tank of fuel weighs, rather than what you first claimed, which was that it was similar. Furthermore, fuel is stored as low as possible, right down on the floor of the car, whereas the engine's CofG is considerably higher. Whilst it might be hard to detect 50kg at floor level, you can sure as hell detect a difference with for example your wife (65kg) and kid (35kg) on board!

But this is exactly the sort of justification I'm talking about. Think about the following rationally for a moment...

• If 100kg is so clear and obvious, why can only the 'privileged 1%' tell the difference in 50kg?
• Are you honestly telling me that the engine is mounted significantly higher than the fuel tank? To the extent that you'd be able to tell the difference? This is absolutely splitting hairs.
• Do you really think 99% of drivers would be able to categorically tell the difference in a 1.4 tonne car with a partner and child as passengers? Where is their CofG relative to the engine/fuel?

None of the above make any sense on a rational level, and completely ignores the fact that BMW will have engineered the car to accommodate the increased weight (spring rates etc.).
It's that 'feel' we keep going back to, which is largely b*llocks.
In fact, I'd go so far as to say that a double-blind test with 6.8% weight difference (irrespective of location/CofG) would fool 99.99% of people.

To be honest, we probably agree on that last bit. I think that most keen drivers could tell, and that probably does leave 99.99% of other people who can't tell, yes. Most people in the UK are not car enthusiasts, which is something this thread covers very well.

As for your arguments above though, can anyone tell if they have a 100kg passenger on board? Yes, of course . Are you really suggesting that most people can't feel the difference if a massive great fat man gets into their car? 100kg is an enormous weight.

[gavsdavs]

s m said:

Viscous or clutch type?

Quaife - which is a clutch type ? The manufacturer one was viscous.

[s m]

gavsdavs said:

s m said:

Viscous or clutch type?

Quaife - which is a clutch type ? The manufacturer one was viscous.

Ah I see, yes the OE viscous ones will eventually fail to 'open' after lots of heat cycles.

Quaife is usually a gear type so no clutches to wear out

Edited by s m on Thursday 20th October 11:49

[C70R]

RobM77 said:

can anyone tell if they have a 100kg passenger on board? Yes, of course . Are you really suggesting that most people can't feel the difference if a massive great fat man gets into their car? 100kg is an enormous weight.

This excerpt perfectly illustrates my point.

You, rightly or wrongly, personify yourself through your posting style as 'the 0.01%'. You may or may not be, but that's certainly not for me to decide. However, your car ownership (Caterham, Lotus, single-seater etc.) puts you in a significantly different mindset to the typical person driving a 1.4 tonne BMW (not a sporty car, by any stretch of the imagination), be they car enthusiast or not.

As such, I strongly believe the bolded bit. I'm not looking for a quarrel, but I don't think you (or your persona) represent "most people".

[RobM77]

C70R said:

RobM77 said:

can anyone tell if they have a 100kg passenger on board? Yes, of course . Are you really suggesting that most people can't feel the difference if a massive great fat man gets into their car? 100kg is an enormous weight.

This excerpt perfectly illustrates my point.

You, rightly or wrongly, personify yourself through your posting style as 'the 0.01%'. You may or may not be, but that's certainly not for me to decide. However, your car ownership (Caterham, Lotus, single-seater etc.) puts you in a significantly different mindset to the typical person driving a 1.4 tonne BMW (not a sporty car, by any stretch of the imagination), be they car enthusiast or not.

As such, I strongly believe the bolded bit. I'm not looking for a quarrel, but I don't think you (or your persona) represent "most people".

Oh yes, I'm a self confessed car geek. I agree with you about the average person. We only disagree about the percentage on car enthusiasts, PHers etc.

[bennyboysvuk]

RobM77 said:

Yeah, just a bit! I'm surprised you bother with a 135i to be honest - after the R1 doesn't that just feel similar to a 120i? Personally I find that after driving a single seater, road cars just all feel slow and unresponsive, regardless of whether they're a 'fast' model or a slow model.

The 135i is the sensible car to pick my son up from nursery, collecting ebay furniture etc. It's also my winter wheels. It feels like a sleepy armchair after the R1. I'm seriously tempted by a 911 (996) though since I've realised that the experience is what it's all about and the speed doesn't matter, hence more noise and less nannies is what I'm aiming for without going for something too old.

I know what you mean re the single seater. After my Palmersport day, my 120d at the time really felt like the commuter car that it was.

[CABC]

C70R said:

But this is exactly the sort of justification I'm talking about. Think about the following rationally for a moment...

• If 100kg is so clear and obvious, why can only the 'privileged 1%' tell the difference in 50kg?
• Are you honestly telling me that the engine is mounted significantly higher than the fuel tank? To the extent that you'd be able to tell the difference? This is absolutely splitting hairs.
• Do you really think 99% of drivers would be able to categorically tell the difference in a 1.4 tonne car with a partner and child as passengers? Where is their CofG relative to the engine/fuel?

None of the above make any sense on a rational level, and completely ignores the fact that BMW will have engineered the car to accommodate the increased weight (spring rates etc.).
It's that 'feel' we keep going back to, which is largely b*llocks.
In fact, I'd go so far as to say that a double-blind test with 6.8% weight difference (irrespective of location/CofG) would fool 99.99% of people.

it's funny to read because you clearly are unwilling to listen to several people explaining in detail whats going on. Confirmation bias indeed.

It would be good if you could try two beemers side by side for yourself and report back.

[C70R]

CABC said:

C70R said:

But this is exactly the sort of justification I'm talking about. Think about the following rationally for a moment...

• If 100kg is so clear and obvious, why can only the 'privileged 1%' tell the difference in 50kg?
• Are you honestly telling me that the engine is mounted significantly higher than the fuel tank? To the extent that you'd be able to tell the difference? This is absolutely splitting hairs.
• Do you really think 99% of drivers would be able to categorically tell the difference in a 1.4 tonne car with a partner and child as passengers? Where is their CofG relative to the engine/fuel?

None of the above make any sense on a rational level, and completely ignores the fact that BMW will have engineered the car to accommodate the increased weight (spring rates etc.).
It's that 'feel' we keep going back to, which is largely b*llocks.
In fact, I'd go so far as to say that a double-blind test with 6.8% weight difference (irrespective of location/CofG) would fool 99.99% of people.

it's funny to read because you clearly are unwilling to listen to several people explaining in detail whats going on. Confirmation bias indeed.

It would be good if you could try two beemers side by side for yourself and report back.

As per the original thread, I have driven both - and plenty of E46s to boot. I'm approaching this from a position of logic, rather than this undefinable, intangible 'feel' that emanates from the mouths of Harris, Clarkson et al.

[CABC]

C70R said:

As per the original thread, I have driven both - and plenty of E46s to boot. I'm approaching this from a position of logic, rather than this undefinable, intangible 'feel' that emanates from the mouths of Harris, Clarkson et al.

your logic is wasted on me.
good luck with your track car.
ciao

[C70R]

CABC said:

C70R said:

As per the original thread, I have driven both - and plenty of E46s to boot. I'm approaching this from a position of logic, rather than this undefinable, intangible 'feel' that emanates from the mouths of Harris, Clarkson et al.

your logic is wasted on me.
good luck with your track car.
ciao

Thank you!

[M4cruiser]

Dr Jekyll said:

M4cruiser said:

Yes I can - there are loads of 3-cylinder cars now, compared with say 10 years ago, and most of them have awful engines.

The strange thing is that when BMW made two bikes with 3 and 4 cylinder versions of what were basically similar engines (K75 and K100) the three cylinder bike was noticeably smoother.

That's because the K75 had properly designed balancer weights. Vauxhall can't have bothered with the Corsa 1.0. Some are ok, e.g. the Daewoo Matiz 800cc 3-cyl was tweaked by Tickford and is addictive.