Strange Factory Details: Unexplained Facts

Hello,

After studying the informational material about the G5 more closely, I find some of the details to be somewhat strange.
Der G5 PD TDI mit 77kw/105PS bei 4000U/min und 250Nm bei 1900U/min ist mit einer Höchstgeschwindigkeit von 187km/h angegeben. So far, so good.
The G4 variant with a PD TDI engine, producing 74 kW/100 hp at 4000 rpm and 240 Nm of torque at 1800 rpm, is stated to have a top speed of 188 km/h.
VW specifies the weights as 1251-1425 kg (curb weight 1850 kg) for the G5 and 1300-1500 kg (curb weight 1900 kg) for the G4V.
This means that the older, but heavier and weaker, car is faster! This raises the suspicion that either the gear ratios are not sufficient to achieve a higher top speed, or the aerodynamic drag (air resistance?) of the new car is much higher. I find both of these possibilities quite embarrassing, as they mean the car's potential is being wasted.
Here are a few more values for comparison (G5 / G4V):
0-100 km/h: 11.3s / 12.7s -> The G5 is almost 1.5 seconds faster here!! Is the gearing shorter, or is the increased power/reduced weight making a difference?
Consumption: 5.0-5.3L/100km / 5.1-5.4L/100km -> okay, the heavier car requires more fuel.

What is your opinion on that?

What is your opinion about it?

Only trust your own scale, your own GPS, and your own stopwatch.

but my Octavia is also only specified with 178 horsepower (automatic). However, it performs well thanks to the short gearing .

Perhaps the G5 was intentionally translated slightly differently to make it sound more sporty.

CU Gremlin.

Gremlin wrote:

Only trust your own scale, your own GPS, and your own stopwatch...

Correct! But they are all "lies" from the factory... Excuse me... specifications.

Quote:

Perhaps the G5 was intentionally translated slightly differently to make it sound more sporty...

...with the risk that it might rev higher during the EU emissions cycle and potentially produce more emissions than necessary? ... I don't think so (at least not for the 5th gear).

As far as I know, the GV has increased in both height and width. Therefore, if it's only 1 km/h slower than the old model despite having a larger frontal area, that would suggest a good drag coefficient (Cd).
However, you're also comparing the Limo with the Variant. How fast was the G IV with 100 horsepower?

felix wrote:

As far as I know, the GV has increased in both height and width.

... Only the width is different (+2.5cm); the height remains the same.
However, the frontal area is supposedly the same (with a more rounded shape), and the drag coefficient (Cw) is supposed to be better!

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If, with its increased frontal area, it is only 1 km/h slower than the old model, that would indicate a good aerodynamic coefficient (CW value).

The Vraiant likely has the worst aerodynamic drag coefficient (Cw) value you can get.

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However, you are also comparing the Limo with the Variant.

The intention is to get the weight roughly right. With the G4 limousine, the difference in weight compared to the G5 is too significant.
The station wagon consistently has the worst aerodynamic performance compared to other body styles.

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How fast was the G IV with 100 horsepower?

Please provide the text you would like me to translate from German to English.

Hello,

The vehicle's weight is irrelevant for reaching a certain maximum speed; it just takes longer. The main limiting factor is air resistance.
Air resistance is the result of multiplying the drag coefficient (cw) by the area.
The Golf 5 has a significantly larger frontal area.
The extra 5 horsepower of the Golf 5 isn't enough to compensate for that, and you can't fix it by changing the gear ratio, no matter how you try.

Best regards,
Albrecht.

Hi,
The unladen weight of the vehicle is indirectly factored in. This then requires larger wheels, bearings, etc.
In my experience, the amount of cargo loaded has only a slight effect on fuel consumption and top speed. I find statements like "0.5 L/100 km" or "X kilograms" that are often mentioned in magazines and other publications to encourage people to declutter their trunks to be completely incomprehensible.

Albrecht wrote:

The Golf 5 has a significantly larger frontal area.

Unfortunately, that's not the case! The difference is rather insignificant!

The G4 has a frontal surface area of 2.10 m², while the G5 has 2.13 m² (approximately a 1.5% difference!).
Since I assume the new model has a better aerodynamic efficiency (cw-value), the air resistance should play the smallest role.
The cw value for the 4-series is 0.31, and I don't have the value for the 5-series.
I'm starting to suspect that the drag coefficient (Cw-value) of the Golf 5 might actually be worse than that of the Golf 4. The new Audi A3 is stated to have a Cw-value of 0.32. If the Golf is similarly "bad," the lower top speed would be understandable.
A lower cw value than the previous model would certainly be amazing.

Hi Bertil,

http://www.doppel-wobber.de/

...and then to Golf 5, and then to General. There's something mentioned about a cw value of 0.325.

However, there is no information provided for the 4-liter engine, while 0.32 is specified for the 3-liter engine. If that's correct, and we add your 0.31 for the 4-liter engine, then that's a real outrage by VW!

Best regards,

Jan.

Why is that rude?

Nowadays, a car doesn't sell because of its good aerodynamic efficiency (low drag coefficient), but rather because of its appearance. The old saying "form follows function" no longer applies. And that's the problem. A 1.5% difference is a lot!

What forces act on a car traveling at 180 km/h? Even small differences play a significant role, and that could be the 1 km/h difference that's missing in the manufacturer's specification. And 0.325 isn't bad when you compare the Golf 5 to other cars in its category.
And if the drag coefficient (CW value) is slightly worse and the frontal area is only slightly larger, then, in my opinion, the solution to the problem has been found. And 5 horsepower is nothing to overcome the increased air resistance.

In practice, it's probably more beneficial to have an advantage in acceleration than in top speed.

I believe BMW has similar issues with the new 5 Series; the new model is slower than the old one, even with the same engine.

Hi Jan,

Jan6K wrote:

... There's something about a cw value of 0.325.

... welch ein Fortschritt. I suspected it.
G4 -- 2.10 * 0.31 = 0.65
G5 -- 2.13 * 0.325 = 0.69
So, an increase of more than 6% -- that explains why the "5" is so "slow."

Quote:

For the 4-cylinder engine, there is no information provided, but 0.32 is specified for the 3-cylinder engine. If that is correct, and we add your 0.31 for the 4-cylinder engine, then that is a real outrage by VW!

The 0.31 values came from here: http://www.vw-otmc.de/golf4/design.htm, but various AMS tests have also consistently shown a cw value of 0.31.
With that, the Golf 5 is probably the first time a model is worse than its predecessor... hopefully not in other aspects either .

x world one wrote:

That 1.5% difference is quite a lot, isn't it?

Initially, no, but when multiplied by the CW value, it results in a dramatic change.

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... And 0.325 isn't that bad when you compare the Golf 5 to other cars in its category.

That's a far cry from what's achievable! An Audi 100 (Type 44) already had a drag coefficient of 0.30, almost 20 years ago!

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And if the CW value is slightly worse and the frontal area is only slightly larger, then, in my opinion, the solution to the problem has been found. And 5 horsepower is nothing to overcome the increased air resistance.

Absolutely!

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...I believe BMW has similar problems with the new 5 Series; the new model is slower than the old one, even with the same engine options.

... but the new car is even 150kg lighter compared to the G5.

Hi,

At least, the decline since the Golf III has a clear trend:

Golf III, 85 kW, 196 km/h.
Golf IV, 85 kW, top speed: 195 km/h.
Golf V, 85 kW, top speed: 192 km/h.

That should at least answer the question about cw x A...

"Quote from Bertil"

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The Vraiant likely has the worst cw value you can get.

Not always. In the case of the Fabia, the Combi version also has a better drag coefficient (Cw value), which means it's specified to be 2 km/h faster with the same frontal area.
Enthusiastically studying model development.
OlBe.

I simply cannot understand statements like '0.5 L/100 km' and 'kg,' which are often mentioned in television magazines and other specialized publications to encourage people to declutter their trunks.

I already have.

My driving profile rarely involves consistently high speeds.

Here in the countryside, you constantly have to brake and accelerate... and in that case, the mass is especially important when considering fuel consumption .

CU Gremlin.

Automatics don't count. This doesn't fit in here. *g*

@Everyone

Why is the aerodynamic drag coefficient (Cw value) worse in a Variant model?

Best regards, WarLord.