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Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 1:00 pm
by kmpowell

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 2:58 pm
by Markp
Nice to think the cars consistently put out more power but I wouldn't trust a margin of 3% on any rolling road. Not significant unless replicated across others.

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 3:52 pm
by Paulm
more is always better than less and torque is up over 8%:thumb:

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 6:10 pm
by cuttsy
Could someone enlighten me on why it is this way as there are also reports of much better 0-60 times than quoted?

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 7:11 pm
by Terminator_X
Markp wrote:Nice to think the cars consistently put out more power but I wouldn't trust a margin of 3% on any rolling road. Not significant unless replicated across others.
36 more torque is 8% more.

TX.

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Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 7:15 pm
by RS Owner
and the hp increase is 2.3%

from ( (460.2 - 450) / 450)
In the video he confuses hp, bhp and PS.

This reminds me of the recent video by a well known "moto vlogger" where he takes a car to 2 dynos in south London, one directly after the other. The results were quite different.

cuttsy wrote:
Wed Jun 13, 2018 6:10 pm
Could someone enlighten me on why it is this way as there are also reports of much better 0-60 times than quoted?
I can only think of 2 explanations. Either Audi (and also BMW and Porsche and pretty much every other car I have seen dynoed on YouTube) are under selling their cars, or the dynos are over estimating the hp.

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 7:33 pm
by FaisalJ
RS4 Owner wrote:and the hp increase is 2.3%

from ( (460.2 - 450) / 450)
In the video he confuses hp, bhp and PS.
You’re mixing up BHP and PS there

450PS = 443.8BHP

+3.7%


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Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 7:52 pm
by RS Owner
FaisalJ wrote:
Wed Jun 13, 2018 7:33 pm
You’re mixing up BHP and PS there

450PS = 443.8BHP

+3.7%
But aren't you comparing HP to BHP ?

Bear in mind 1 PS is equivalent to 1 HP. (I hope you accept that)

The dyno result is in hp (equivalent to PS remember).
The dyno says 460.2 HP and I am assuming that is because the result is expressed in HP and not BHP.
Audi quote 450 ps (444 bhp) which is 450 hp.

so the increase is 460.2 - 450 = 10.2 :thumbs:
2.3%



If you want to work in BHP then you need to convert the dyno 460.2 hp to 453.9 BHP
(453.9-444) / 444
= 2.2%
BHP.png

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 8:14 pm
by MikeFish
cuttsy wrote:
Wed Jun 13, 2018 6:10 pm
Could someone enlighten me on why it is this way as there are also reports of much better 0-60 times than quoted?
I think that forced induction cars can vary quite a lot in total power output as we can see when they are dynoed. If you look at the dyno figures for standard C7 RS6 cars some were a fair bit higher than the manufacturers figures and some were just over. I think Audi quote the minimum guaranteed figure you might get to ensure no-one has a car with power less than their quoted figure and know that most cars will be well over this figure. And they quote the 0-60 time based on the minimum output figures so in reality most cars will go faster than this.
In some other models I think they deliberately under quote to make a big enough gap between models to warrant the extra money e.g. S cars generally have a much higher output than Audi quote otherwise the gap between the S and RS might not be big enough to make people pay more for an RS.

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Wed Jun 13, 2018 9:48 pm
by Markp
RS4 Owner wrote:
Wed Jun 13, 2018 7:52 pm
FaisalJ wrote:
Wed Jun 13, 2018 7:33 pm
You’re mixing up BHP and PS there

450PS = 443.8BHP

+3.7%
But aren't you comparing HP to BHP ?

Bear in mind 1 PS is equivalent to 1 HP. (I hope you accept that)

The dyno result is in hp (equivalent to PS remember).
The dyno says 460.2 HP and I am assuming that is because the result is expressed in HP and not BHP.
Audi quote 450 ps (444 bhp) which is 450 hp.

so the increase is 460.2 - 450 = 10.2 :thumbs:
2.3%



If you want to work in BHP then you need to convert the dyno 460.2 hp to 453.9 BHP
(453.9-444) / 444
= 2.2%
BHP.png
Tough crowd you lot ;)
I rounded it to 3% because I wasn't sure what was what after watching the video (3 being half way twixt both your answers). Hedging my bets...

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Thu Jun 14, 2018 9:57 am
by FaisalJ
RS4 Owner wrote:
Wed Jun 13, 2018 7:52 pm
FaisalJ wrote:
Wed Jun 13, 2018 7:33 pm
You’re mixing up BHP and PS there

450PS = 443.8BHP

+3.7%
But aren't you comparing HP to BHP ?

Bear in mind 1 PS is equivalent to 1 HP. (I hope you accept that)

The dyno result is in hp (equivalent to PS remember).
The dyno says 460.2 HP and I am assuming that is because the result is expressed in HP and not BHP.
Audi quote 450 ps (444 bhp) which is 450 hp.

so the increase is 460.2 - 450 = 10.2 :thumbs:
2.3%



If you want to work in BHP then you need to convert the dyno 460.2 hp to 453.9 BHP
(453.9-444) / 444
= 2.2%
BHP.png
Ah - yeah, but no! :wink:

I was going by the fact that he compares the dyno figures to 444 bhp, and reads off the resuts as "brake horsepower" - to mean the dyno is indeed bhp.

E.g. See 1:31, 1:43

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Thu Jun 14, 2018 10:16 am
by Brooner
that was my taking on the video too

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Thu Jun 14, 2018 12:09 pm
by MK2Golf24v
Do you really think Audi base the figures quoted on a car spec sheet on a car strapped to a dyno??????

I'd suggest a figure based on an engine dyno in a climate controlled cell is much more likely..........



Any dyno figures will ALWAYS be a backward calculation based on the measured TORQUE, and as such will have errors due to assumptions made during the calcs.

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Thu Jun 14, 2018 2:08 pm
by Markp
MK2Golf24v wrote:
Thu Jun 14, 2018 12:09 pm
Do you really think Audi base the figures quoted on a car spec sheet on a car strapped to a dyno??????

I'd suggest a figure based on an engine dyno in a climate controlled cell is much more likely..........



Any dyno figures will ALWAYS be a backward calculation based on the measured TORQUE, and as such will have errors due to assumptions made during the calcs.

Of course Audi don’t strap cars to dynos. No one is suggesting they do.
The debate is around reliability of dynos - does a higher reading mean the car is producing more than spec? I am not convinced due to huge margins of error.

Re: Carwow dyno their B9 RS4 - the results (video)

Posted: Thu Jun 14, 2018 4:40 pm
by RS Owner
This outfit is in Farnborough. That's just down the road from me. They have a "£40 Saturday" on 30th June with lots of free space.
So I could go down there and tell them they're a bunch of amateurs (no fuel info, no calibratiion cert for dyno etc) or I could take my car but it's an RS5 so it will be at least 500 hp :)