Dyno of RS6 at AWE Tuning

[Erik]

A really nice daytona grey RS6 with sports exhaust (as far as I can see).

AWE Tuning RS 6 (http://www.awe-tuning.com/pages/gallery/rs6/index.cfm)

Watched the video. Nice to see 'before' and 'after' but I would have liked to see some results that were for a longer period of time, not just a 5 sec. pull.

[jgun81]

I heard someone saying that rs6 does not really have

450HP. I haven't brought my car to dyno, so i coudln't disagree

with him since I didn't know...hopefully it's not true.

[Bauer]

At the motor it does.....at the wheels...not so much. :cheers:

[GmbHouse]

Same as this, minus the video.

http://www.rs6.com/forum/showthread.php?s=&threadid=2500

[Marcus Frost]

Excellent post. 520hp and 532tq. God damn, this RS6 is one tempting car!

I look forward to seeing continued development... next stage is some nice downpipes and full exhaust systems.

-m

[Nordschleife]

Guys

I'm sure AWE Tuning has published this information in all good faith. However there are a number of problems with the figures as published:

Firstly, there is the matter of the RS6's actual horsepower, as jgun81 pointed out.

Let me clarify matters, the RS6 has 450 DIN bhp, which is equivalent to 443.655 SAE bhp. DIN is a (German) metric measurement, SAE is an American measurement, nearly the same, but not quite.

Examining the dyno printout we see torque being measured in Pound Feet (lb ft), never mind that the printout shows Ft-Lbs, which is neither an Imperial, American or Metric measure, but we understand what they mean, its just a rather casual way of expressing torque.

Now, if you look at the bottom of the printout, you will see that a factor of 1.29 has been used to convert back from wheel hp (whp) to brake or crank horsepower (bhp).
Lets do the maths:
Stock Brake Horsepower - 443.655 bhp SAE
Measured Wheel Horsepower - 349.7 whp SAE
Correction factor is 443.655 / 349.7 = 1.2687

To understand what is happening, for the Stock Brake Horsepower of 443.655 bhp SAE, let us substitute 450 bhp DIN, and recalculate:

Tuner's Correction factor is 450 / 349.7 = 1.2858

Not coincidentally, this value rounds to 1.29

Which is the value printed on the bottom of the printout, and used, as we shall see, to calculate the Brake or "crank" horse power, after tuning.

I have examined the printout, and I cannot see anywhere any corrections for temperature, humidity, altitude or atmospheric pressure, which should be made in order to correctly calculate the conversion factor from measured stock whp to stock bhp, so this is another cautionary issue to bear in mind when examining the quality of the data.

With the above information as a background, we can look at the claimed performance increase as a result of rechipping the car.

Measured whp - 404.1 whp SAE
Calculated bhp - 404.1 * 1.29 = 521.289 or 520 "Tuner" horsepower

Using the correction figure we calculated above, the relevant figure is:

Calculated bhp - 404.1 * 1.2687 = 512.68 bhp SAE

So I'm not saying that AWE have deliberately set out to mislead people, but I just find their calculations sloppy.

So take all tuners' claims with a pinch of salt, caveat emptor guys!

R+C

[Marcus Frost]

Originally posted by Nordschleife
Guys

I'm sure AWE Tuning has published this information in all good faith. However there are a number of problems with the figures as published:

Firstly, there is the matter of the RS6's actual horsepower, as jgun81 pointed out.

Let me clarify matters, the RS6 has 450 DIN bhp, which is equivalent to 443.655 SAE bhp. DIN is a (German) metric measurement, SAE is an American measurement, nearly the same, but not quite.

Examining the dyno printout we see torque being measured in Pound Feet (lb ft), never mind that the printout shows Ft-Lbs, which is neither an Imperial, American or Metric measure, but we understand what they mean, its just a rather casual way of expressing torque.

Now, if you look at the bottom of the printout, you will see that a factor of 1.29 has been used to convert back from wheel hp (whp) to brake or crank horsepower (bhp).
Lets do the maths:
Stock Brake Horsepower - 443.655 bhp SAE
Measured Wheel Horsepower - 349.7 whp SAE
Correction factor is 443.655 / 349.7 = 1.2687

To understand what is happening, for the Stock Brake Horsepower of 443.655 bhp SAE, let us substitute 450 bhp DIN, and recalculate:

Tuner's Correction factor is 450 / 349.7 = 1.2858

Not coincidentally, this value rounds to 1.29

Which is the value printed on the bottom of the printout, and used, as we shall see, to calculate the Brake or "crank" horse power, after tuning.

I have examined the printout, and I cannot see anywhere any corrections for temperature, humidity, altitude or atmospheric pressure, which should be made in order to correctly calculate the conversion factor from measured stock whp to stock bhp, so this is another cautionary issue to bear in mind when examining the quality of the data.

With the above information as a background, we can look at the claimed performance increase as a result of rechipping the car.

Measured whp - 404.1 whp SAE
Calculated bhp - 404.1 * 1.29 = 521.289 or 520 "Tuner" horsepower

Using the correction figure we calculated above, the relevant figure is:

Calculated bhp - 404.1 * 1.2687 = 512.68 bhp SAE

So I'm not saying that AWE have deliberately set out to mislead people, but I just find their calculations sloppy.

So take all tuners' claims with a pinch of salt, caveat emptor guys!

R+C

Nord,

The US-Spec RS6 is rated at 450bhp in all of the American literature I have seen, including in multiple places on Audi's website, which leads me to believe it is an SAE calculation, not a DIN one. I have never seen a manufacturer use a DIN hp calculation for a USA car.

Audi may rate the car as 450DIN and 450SAE, when in fact it's maybe 461hp DIN and 450hp SAE - and just for the sake of marketing they simplify it and use the lower SAE rating. It seems to be common practice for a number of manufacturers, from Audi to Chevrolet to Toyota. You are making assumptions and criticizing AWE's calculations without properly examining all the possible variables, which I think is erroneous on your part.

Also, the things you mentioned such as altitude, temperature, etc are what we refer to as a correction factor. Not all dynosheets display this on the printout. Dynojets do, but mustang dyno's do not - but that doesn't mean it isn't taking those variables into account - it just means it isn't being printed on the sheet. I am not an expert with Mustang dynos, but I do recall them taking into account correction factors differently than dynojets. On dynojet printouts you will usually see the word "corrected" horsepower when you are viewing the corrected horsepower that factors in conditions, and "actual" for actual horsepower.

AWE is using Audi's published US-specs for the car to get their 1.29 figure - which is 450bhp SAE. I don't think it's sloppy or anything of the sort... as a matter of fact it's the best way to do this calculation since using Audi's figures is less speculation than coming up with your own - such as you are.

-m

[Nordschleife]

Marcus
You don't understand, I'm not coming up with 'my own figures', I am producing the actual figures, from the car's design specification.
Unless you can come up with a statement from Audi that the US RS6 produces 450 BHP SAE, which is equivalent to 456 BHP DIN, I stand by what I say. I'm not concerned that the brochures, and such like say SAE, these are produced my marketing people who have an agenda which differs from engineers.
The Audi Germany site rates the RS6 at 331 kW.

Now to convert from kW to SAE bhp

331 / 0.7457 = 443.878 bhp SAE


For your information, some responsible US automotive magazines restate the European (DIN) horsepower, for example the better end of the press quotes the Ferrari 360 Modena at 355 bhp rather than 360.
As far as the missing correction is concerned, do the maths for yourself, there is no environmental correction applied.

Let me quote from an American viewpoint:

From the Horse's...
Manufacturers cause most of the problems in that there are several standards by which they rate their cars when new. Without knowing exactly how much difference there is from one standard to another, it's easy to get into the mentality that "horsepower is horsepower" (mathematically, it is always the same, after all) without taking into consideration the circumstances under which it was measured.

SAE Net Horspower
In 1972, American manufacturers phased in SAE net horsepower. This is the standard on which current American ratings are based. This rating is measured at the flywheel, on an engine dyno, but the engine is tested with all accessories installed, including a full exhaust system, all pumps, the alternator, the starter, and emissions controls. Both SAE net and SAE gross horsepower test procedures are documented in Society of Automotive Engineers standard J1349. Because SAE net is so common, this is the standard we will use to compare all others.

SAE Gross Horsepower
This is the old process that American manufacturers used as a guide for rating their cars. It was in place until 1971. SAE gross also measures horsepower at the flywheel, but with no accessories to bog it down. This is the bare engine with nothing but the absolute essentials attached to it; little more than a carb, fuel pump, oil pump, and water pump. Because the test equipment on the engine is not the same as in SAE net, it is impossible to provide a mathematical calculation between SAE net and SAE gross. As a general rule, however, SAE net tends to be approximately 80% of the value of SAE gross. SAE J245 and J1995 define this measurement.

DIN Horsepower
This is a standard, DIN 70020, for measuring horsepower that very closely matches SAE net. The conditions of the test vary slightly, but the required equipment on the engine and the point of measurement (flywheel) remains the same. Because the test conditions are so similar, it is safe to divide DIN horsepower by 1.0139 to arrive at SAE net. This value is so close to equal that for all but the most technical purposes DIN and SAE net are interchangeable.

Brake Horsepower
Often road test magazines will list horsepower as "bhp". This is just another way to talk about SAE net horsepower.

Kilowatts
Kilowatts, or kW, is not a different way of measuring engine power; it's just a different unit of measure. Countries that use kilowatts instead of horsepower typically use a rating system very close to SAE net horsepower (usually DIN). To convert kW to SAE net hp, divide the kW value by 0.7457.

Advertised Horsepower
Surprise! Those horsepower numbers presented in advertising and brochures aren't always accurate. Though manufacturers are supposed to base their horsepower ratings on SAE net standards, they are not completely beholden to it. They often fudge the numbers. Ford and Mazda both recently got in trouble with the Mustang Cobra and the MX-5 Miata, respectively, when they delivered a car that had less horsepower than what they advertised. Ford ended up doing considerable warranty work to bring the numbers up where they belonged, and Mazda re-rated their car and offered to buy back any offended customers' cars. General Motors regularly underrates their engines, most notably the GM LS1 5.7L engine as installed in the F-body (Camaro and Firebird) cars. Mechanically almost identical to the engines installed in the Y-body car (Corvette), the engine mysteriously "lost" 40 advertised horsepower in the F-body chassis. Although this technically is as fraudulent as selling a car with less than the advertised horsepower, no one seems to complain when they get a car with more horsepower than what appears on the spec sheet.



Perjhaps now you will understand what I am talking about.

R+C

[Erik]

Originally posted by Marcus Frost
I have never seen a manufacturer use a DIN hp calculation for a USA car.

Read this!

http://waw.wardsauto.com/ar/auto_jaguar_comes_clean/

"Some ratings for the '03 S-Type R were published without disclaimers — and DIN ratings yield sexier numbers."

[Nordschleife]

Originally posted by Erik
Read this!

http://waw.wardsauto.com/ar/auto_jaguar_comes_clean/

"Some ratings for the '03 S-Type R were published without disclaimers — and DIN ratings yield sexier numbers."

and of course, Audi would never do that, would they?

[Audihead]

Mazda just got nailed not to long ago as well. They said the RX-8 had 247hp but people found out it only has 238hp. Now they are forced to either buy back the car or cough up $500 bones to make people happy. There should only be one standard for the world, then make it standard or metric.
:s4addict: -Bimmerhead

[Erik]

Originally posted by Bimmerhead
There should only be one standard for the world, then make it standard or metric.

And only one language... :rolleyes:

[Marcus Frost]

Originally posted by Nordschleife
HP/Dyno Lesson

Nord,

I appreciate the lesson but I've been around more dyno's than I care to recall. My Supra has made close to 50 dyno passes on Dynojet 248s and Mustang Dyno's alike. I don't need an explination between the different types of horsepower, as I am quite aware of that.

If Audi is stating DIN hp in their US literature instead of SAE, shame on them. The fact remains you cannot prove that either way. All car hp ratings usually have a # of discrepency due to manufacturing tolerances. For instance, my Supra is rated at 320hp according to US-literature but makes roughly 300-310rwhp in stock form - and this is common place. Some make 300, others make 310. We could discuss the reasons for this ad nauseum.

My point remains that you are criticizing AWE as being sloppy when all they are doing is using Audi's figures. They are going on what's published, not speculation that they are incorrect. It's wrong of you to say they are being sloppy when they are using published figures. If you want to criticize their numbers, criticize Audi for mispublishing them - not AWE for using them.

-m

[gmbh6]

Originally posted by Bimmerhead
Mazda just got nailed not to long ago as well. They said the RX-8 had 247hp but people found out it only has 238hp. Now they are forced to either buy back the car or cough up $500 bones to make people happy...

okay let's all go to our dealer this week and ask for $5000 bones back. :bang:

[360M]

Originally posted by Nordschleife

For your information, some responsible US automotive magazines restate the European (DIN) horsepower, for example the better end of the press quotes the Ferrari 360 Modena at 355 bhp rather than 360.

Ummm....the 360 Modena has 400 bhp. I should know, it's sitting in my garage. I can also say that after 4000 miles, it has broken in nicely and feels even faster than when I bought it last year.

[Bauer]

by the way 360M...I really enjoy the style of 360....It very pleasing to the eye...not to mention the sound of the motor:cheers:

I know off topic but what the hell

[360M]

Thanks Bauer. Apparently not everyone thinks the same though. Someone keyed the rear quarter panel and the estimate to repair it is $6k!

RS6 content: This type of unwanted attention is making me consider purchasing an RS6.

[Erik]

Originally posted by 360M
RS6 content: This type of unwanted attention is making me consider purchasing an RS6.

You can discuss Ferrari 360 hunting with Nordschleife and RS6-Thomas :addict: :D :incar:

[Bauer]

360M.....I am very sorry to hear that....jealous insecure JA's really suck...someone keyed the hood of my S8...luckly my detailer was able to buff it out since it wasnt to deep. Have you driven an RS6 yet?

[gmbh6]

Originally posted by 360M
...RS6 content: This type of unwanted attention is making me consider purchasing an RS6...
I agree. It's always a better idea to "upgrade" whenever possible. ;)

[360M]

Originally posted by Bauer
360M.....I am very sorry to hear that....jealous insecure JA's really suck...someone keyed the hood of my S8...luckly my detailer was able to buff it out since it wasnt to deep. Have you driven an RS6 yet?

Yes, I drove one a few weeks ago. It handles similar to my A6 4.2 which has completely modified suspension, but obviously has a lot more power. I am waiting for prices to come down a bit and I'm planning to buy a Mugello.