Dyno-sheets

[Vdub]

Because of the trashed-topic from Special Sauce..

Here 4 Dyno-results from our Dyno..

13353
Original RS6 4.2 BiTurbo

13352
JDEngineering Stage 1 RS6 4.2 BiTurbo

13354
Another JDEngineering Stage 1 RS6 4.2 BiTurbo


13355
Above a compare-sheet between org and tuned.

The red line is Wheel HorsePower, the Blue line is Engine Power(calculated due drivetrain-loss-test), green is Engine Torque in NM(NM/1,35=Foot pound torque)

[lswing]

Your stock dyno hp numbers are way to high from anything I've ever seen, what type of dyno? Regardless these are just computer calculations from a machine. While your dt loss is closer to ~10%, all reports until now have been around ~20-30% here.

It really depends on what Audi used to calculate the 450bhp to begin with. Your calculated bhp is a bit higher than stock, but still close which is good, but I highly question that whp calculation. What calibration methods do you use to confirm accurate whp numbers?

Of course this could be never ending as they are just calculations in the end, best for referencing tuning and modifying the car from base numbers on the same dyno.

Thanks for posting the clear charts, interesting!

[Vdub]

This is a Superflow AutoDyn 880 AWD, as i wrote in another topic.. here in the EU we have 10 different engines in a Golf, from 1.2TSI to 3.2FSI(R32) and from 1.2TDI to 2.0TDI 170bhp(gtd) we have much cars to compare.
The Dyno loss-test is measured/with 3000rpm, both the Dyno and the Car will be set on 3000rpm, so accellerate to 3000rpm set it on cruisecontrol or hold foot steady, press 'hold' rpm on dyno and the dyno knows what 3000rpm is.
Then you do a accelerate test to max rpm and let the car roll out to <1000rpm, in this cycle the Dyno measures the loss the drivetrain generates.

The difference between EHP and WHP is re-calculated everytime with every new car(-run)

Here is a sheet from my S6:
13356

The sheet displays 2 lines, but the difference between EHP(338) and WHP(280) is 58HP on 19 inch, 255/35/19

Her one from our Leon 2L TFSI:
13357

Org was the engine spec 185BHP, tuned 263EHP and 233WHP, so a difference of 30HP for a FWD on 17 inch.

[Vdub]

At the moment my friend is building a new engine, that engine will be dyno-tested on a engine-dyno, after we will fit it in the car we will also test it on our Dyno, so we can see if the calculated engine power on the rolling-road is the same /nearby the Engine-dyno.

[ttboost]

At the moment my friend is building a new engine, that engine will be dyno-tested on a engine-dyno, after we will fit it in the car we will also test it on our Dyno, so we can see if the calculated engine power on the rolling-road is the same /nearby the Engine-dyno.

Great, this is EXACTLY what everyone has been waiting for (at least I have). TRUE driveline loss. I've also built and tuned a LOT of cars, and I have to say, there is NO WAY you only have a 10% driveline loss with an automatic AWD car. Maybe I will eat my words..but not likely...

[4everRS]

The ONLY way anyone can say what EHP is, would be by taking the engine out of the car, and running it on an engine dyno. Anything else is just guessing. Wether it's guessing by a human or by a computer.

My car did 342 on a dynojet stock. Running healthy, judging by several engine parameters including lambda voltage, air/fuel ratio, timing, boost pressure, ect.

Different chassis dynos cannot be compared to each other, as the software programming is different between manufacturers, and some are even adjustable by the end user.

[ttboost]

The ONLY way anyone can say what EHP is, would be by taking the engine out of the car, and running it on an engine dyno. Anything else is just guessing. Wether it's guessing by a human or by a computer.

My car did 342 on a dynojet stock. Running healthy, judging by several engine parameters including lambda voltage, air/fuel ratio, timing, boost pressure, ect.

Different chassis dynos cannot be compared to each other, as the software programming is different between manufacturers, and some are even adjustable by the end user.



Which is exactly why the above (post #4) will help. They will engine dyno an engine, THEN put it in a chassis and dyno for WHP.

[yokust]

I can tell you that something is off with your dyno numbers.

Knowing superflow dynos, you dyno readings are going to be based off how much weight load you put against the rollers.

If you put too much or too little your numbers will be WAY WAY off in either direction.

I can tell you that I have ran 4 differnet bone stock RS6's, 2 of which were mine, on a superflow dyno make about 330-350whp.

These are known drivetrain loss numbers for msot VW/Audi vehicles, that have been calculated by companies with engine and chassis dynos

FWD manual is 11-12%
FWD DSG 13-16%
AWD manual is 18-20%
AWD Auto is 28-30%

I dont know what the FWD auto is(dont honestly care), and dont know the new AWD DSG Audi S-tronic stuff, because I dont think anyone has done that yet with them that publishes anything

[lswing]

yokust, thanks! Your numbers are just what I've calculated off of whp stock numbers compared to bhp 450 stated by Audi.

Vdub, have you read much about your dyno type reading high? The whp calculation seems off by a good amount, very "customer friendly":)

[hahnmgh63]

http://www.modified.com/tech/modp-1005-drivetrain-power-loss/viewall.html

http://rusubaru.com/drivetrain-loss/

Doing an internet search their are thousands of hits you get on drivetrain losses through Dyno's. Here is they rough guide from Audiworld

■FWD: 10-15% loss;
■RWD: 10-18% loss;
■AWD: 17-25% loss.

[JCviggen]

Great, this is EXACTLY what everyone has been waiting for (at least I have). TRUE driveline loss. I've also built and tuned a LOT of cars, and I have to say, there is NO WAY you only have a 10% driveline loss with an automatic AWD car. Maybe I will eat my words..but not likely...

There is no true driveline loss. It varies enormously depending on rpm (so if you make peak power earlier or later that will vary the loss considerably) and tire speed (gear).

That's why loss curves are not flat but rising with rpm and speed. A run in 3rd will have higher whp than 4th which will have higher whp than 5th (engine power staying equal)....the gears and diffs don't get any less efficient in this case you're just wasting more power on tire friction.

[ttboost]

There is no true driveline loss. It varies enormously depending on rpm (so if you make peak power earlier or later that will vary the loss considerably) and tire speed (gear).

That's why loss curves are not flat but rising with rpm and speed. A run in 3rd will have higher whp than 4th which will have higher whp than 5th (engine power staying equal)....the gears and diffs don't get any less efficient in this case you're just wasting more power on tire friction.


Rerspectfully disagree, or maybe we are saying the same thing, but you first say there is NO driveline loss, then you say it VARIES? Your engine makes the same power, regardless of any gear you are in. However, the gearing will dictate the illusion of more or less "power". And for the record, a dynomometer measures wheel torque and then calculates wheel HP. I agree that driveline loss is consistant for any certain drivetrain, HOWEVER, I think it ALSO increases a little as HP increases, because of drag, rolling resistance, etc...

[JCviggen]

Rerspectfully disagree, or maybe we are saying the same thing, but you first say there is NO driveline loss, then you say it VARIES?

I said there is no "true" driveline loss in the way you are suggesting that there is a magic percentage number that you can apply to every RS6 from then on. Of course there is loss, but the "I made xxx whp so that means I have xxx bhp because loss percentage is X" thing will never be remotely accurate unless by accident.


Your engine makes the same power, regardless of any gear you are in

Absolutely, but if you are on a rolling dyno you will see very different wheel horsepower numbers because you are not measuring it at the engine but effectively at the tires. If you are measuring it without wheels but at the hubs instead then you are getting a truer picture and power will not be influenced much by what gear you are in (assuming the gear isn't so short you don't see full load)
The gearing itself isn't what makes the difference, it's all about tire speed which is the result of gearing.


And for the record, a dynomometer measures wheel torque and then calculates wheel HP. I agree that driveline loss is consistant for any certain drivetrain, HOWEVER, I think it ALSO increases a little as HP increases, because of drag, rolling resistance, etc...

A dynamometer measures torque and calculates power, at least if you're not talking about a dynojet. That one actually calculates power directly (and needs a spark pickup for rpm to be able to calculate torque from that)

Any dyno that measuresat the tires is calculating TOTAL losses, most of which are the tires themselves.

If you've ever seen a MAHA graph you know what I'm talking about. The green line at the bottom is "loss". Note that loss in this case is directly linked to speed. Some of all that loss is actually in the transmission and diffs, but most of it isn't. Tire friction is by far the biggest component.
See example here: http://img153.imageshack.us/img153/116/imag0727.jpg

So let's say you have 2 different remaps for the RS6. One which blows its load in a torque mountain right off the bat, and another one which makes peak power closer to redline. Because the first one is making power 1500 to 2000rpm earlier in the run, it will do it at a lower tire speed where friction losses are considerably less.
If both of them have a peak power number of say 500bhp....torque mountain (and cliff) remap will give a considerably higher "whp" number. When I say considerably, 1500rpm difference is probably worth 50 whp right there. This imperfect method of measuring power at the tires has the implied side effect that a large number of variables can create big swings in the end result. When I say many variables... tire speed, tire compound, tire width, tire and roller temperature, tire pressure, tire load...

Tire speed is directly linked to rpm so when a different car has a differently shaped power curve any fixed percentage loss from another car is already not applicable...even if all the other conditions were identical.

I can even use my own car as an example. Stock map made peak power at the very very end of the run. 522/396 bhp/whp. After the higher boost map went in, 546/441. I gained 45whp while only gaining 24 bhp. Peak power was only 600rpm earlier. 30 mins between these 2 runs. Obviously my driveline didn't suddenly have less real loss. In any case the percentage of total loss will continue to drop when you crank up the power. Loss does not scale at all with power so a 450bhp stocker has a higher PERCENTAGE loss than a 550bhp one. In terms of total loss in absolute HP numbers it would be almost identical however.
http://www.greenringer.net/various/mrc/RSdyno.JPG

[lswing]

Great detailed info! And by your numbers, looks like dt loss is 19% and 24%, putting your numbers right in with the common thought.

I specifically tuned my car for the boost to climb linear instead of spiking early, much nicer drive and better on the trans. Basically just lowered expected boost a few pounds, and the ko4's still reach a high psi, just takes more time.

[yokust]

There is no true driveline loss. It varies enormously depending on rpm (so if you make peak power earlier or later that will vary the loss considerably) and tire speed (gear).

That's why loss curves are not flat but rising with rpm and speed. A run in 3rd will have higher whp than 4th which will have higher whp than 5th (engine power staying equal)....the gears and diffs don't get any less efficient in this case you're just wasting more power on tire friction.



Ahh there for sure is a true drivetrain loss.

Clutches, torque convertor, gear friction, are all TRUE drivetrain loss.

An engine dyno graph has the same peaks and curves as a chassis dyno.

An engine does not have the same effiecency at 2000rpm as it does 8000rpm

[yokust]

I said there is no "true" driveline loss in the way you are suggesting that there is a magic percentage number that you can apply to every RS6 from then on. Of course there is loss, but the "I made xxx whp so that means I have xxx bhp because loss percentage is X" thing will never be remotely accurate unless by accident.


And yes there are many companies that have calculated loss between each transmission.

But sure these 'loss' numbers are based on a fully correct functioning system. IF you have a weak converter, clutches, extra play in bearings and gear mesh of course you will get more loss than a correct one

[JCviggen]

Ahh there for sure is a true drivetrain loss.

Clutches, torque convertor, gear friction, are all TRUE drivetrain loss.

An engine dyno graph has the same peaks and curves as a chassis dyno.

An engine does not have the same effiecency at 2000rpm as it does 8000rpm


Of course there is a true loss figure on every car. But the suggestion was that one could find out this number and then apply it to other cars' results - from a chassis dyno so usually measured at the wheels. That is flawed and will never be remotely accurate.

What I meant is - there is NO single percentage value that you can apply to whp numbers to get an accurate bhp estimate. It does not exist because whp figures are always contaminated by irrelevant data.

Loss can never be a fixed percentage either because it does not scale with power. At best you could take an average absolute number but it would vary from dyno to dyno. Single rollers would have a smaller number than dual rollers etc.

[ttboost]

What I meant is - there is NO single percentage value that you can apply to whp numbers to get an accurate bhp estimate. It does not exist because whp figures are always contaminated by irrelevant data.

Did you dyno your engine on an engine dyno? How do you know it makes 546BHP? Have you ever put it on a chassis dyno? How did you do this math? Did your tuner tell you it had 546BHP? How does he know? WHP is the only number that means ANYTHING.
I am not trying to be antagonistic, just trying to understand your logic. Maybe it's not coming through in print?

[blmlozz]

this is all way too much information. Can I go back to being innocient and ignorant?


Did you dyno your engine on an engine dyno? How do you know it makes 546BHP? Have you ever put it on a chassis dyno? How did you do this math? Did your tuner tell you it had 546BHP? How does he know? WHP is the only number that means ANYTHING.
I am not trying to be antagonistic, just trying to understand your logic. Maybe it's not coming through in print?
I only understood the tire stuff.. this is applicable in the same way that Audi is generous with their speed limiters. IE you can do 170 in most of their higher tier cars on fresh tires because they engineer the 155 limiter to kick in on worn tires.

Since we're measuring power at the wheels, they effectively become an additional gear, and tires themselves are highly variable.

[ttboost]

Well yes..there are many variables to a chassis dyno. The dyno itself, vehicle parts including engine power, (or lack thereof),transmission, clutch (manual or auto), driveline slop, tires spinning, air flow, ambient temperature, etc...

As we all know, a dyno is a tool for tuning..which means improving wheel power, run after run, from the starting point. What that number is is really irrelevant, although we all use it as a comparison tool....sometimes against other cars on other dynos..so again, not really relevant. Fun..yes..relevant...no.

I just never understood why people claim BHP (crank) numbers when they have never had their engine on an engine dyno? Are people tuning their cars, doing some math and advertising a BHP number? If you have never had your car on a chassis dyno, or dyno'd your engine, you really have no idea what it makes.

I realize that some people just buy a tune from someone, who says it it a "520BHP tune". But unless you check it, how do you know?

[DiabloChad]

Just ran approx 350/350 on a dynojet. Bone stock. Two runs back to back yielded the same result.

[ttboost]

Sounds about right. On equally good running cars in the fairly same ambient conditions, Dynojets seem to read 40-60whp higher than Mustang dynos. Not scientific and not "be all end all", but all in all, pretty close to judge...

[blmlozz]

just never understood why people claim BHP (crank) numbers when they have never had their engine on an engine dyno? Are people tuning their cars, doing some math and advertising a BHP number? If you have never had your car on a chassis dyno, or dyno'd your engine, you really have no idea what it makes.
For most people, Yes, thats exactly what they're doing(as I used to to it)
The answer as to why is simple
Ignorance.

I frequently hear all kinds of misinformation and utter garbage anytime i go to any sort of auto event, I realize I'm not the last word and a giant wikipedia of knowledge myself, but some of the stuff i hear is truly astonishing.

Theres nothing complicated about this. People hear someone else say x car has approximately x drivetrain loss, they dyno their car and apply their whp times 1.xx DTL and obtain their crank whp figure.

in JC's case he's obtaining his figure from a calculation based on the rolling resistance of the drivetrain and tires, and on the dyno you essentially run the car to peak rpm and then wait for the car to roll to a stop, higher loss vehicles will have more friction and slow down more quickly, cars with less drivetrain loss will roll longer.

if you've ever tried to push a quattro B5 and then a fwd B5 you'll understand the concept

as to whether this actually is accurate i couldn't say, but at face value at least, it would appear that it could be used to get pretty close.

[MaxRS6]

Mine cranks about 1 juziliobeileinuium of hp at the crank. I know this as I put it on an exact 2.3 degree sloped hill of finely cut bermuda grass and spun until hitting bedrock. We all know redneck math translates hp at the crank via time lapse to hit bedrock multiplied by ego multiplier divided by earth's rotational temperature frictional loss dependent on moon phase.

I think that about dumbs it down so anyone can understand it.

[blmlozz]

Uhh.. You forgot to add beer to the power of four at the redneck to bedrock function in your equation


gawd..

[MaxRS6]

^Jeeezzzz <face palm>...I always forgit that there part of it..Never was good at rithmitic. Thanks for the correction

[JCviggen]

Did you dyno your engine on an engine dyno? How do you know it makes 546BHP? Have you ever put it on a chassis dyno? How did you do this math? Did your tuner tell you it had 546BHP? How does he know?

I take the 546 number with a grain of salt, it's a guesstimate done on a load dyno with coastdown losses. But the math works out pretty well, it's probably not off more than 10bhp which in the chassis dyno world is pretty good.


WHP is the only number that means ANYTHING.

The great American automotive fallacy...
Put the same car on different dynos and you will get wildly different WHP numbers. WHP is hardly a reliable yardstick when you can't compare it to anything, just about every car manufacturer on the planet specs in BHP. Because the engine's output is the only thing you can realistically specify.
Swap your wheels to a bigger size or use different tires and your whp number will change. Pump up your tires to the max before heading off to the dyno and you'll see more pleasant numbers as well.
A good load dyno like a MAHA (used by quite a few german car manufacturers btw) will give you the same BHP figure even if you change wheels, change tire pressure or whatever.

The WHP and loss figures will differ, but the coastdown losses are measured accurately enough to get back to the same BHP number. When I say reliable, it's a pretty close approximation based on stock production cars' numbers. One thing a chassis dyno can never measure directly is the actual driveline loss. But in reality those losses are much more consistent and easier to predict by the software. Put in the type of gearbox and number of driven wheels and it will take into account a certain amount of predicted trans loss. The overall amount of transmission loss is also relatively small so even 80 or 85% accuracy in this area will get you a BHP figure that is within a single digits margin of error compared to an engine dyno bench. That should be good enough for most of us.

WHP in theory would be more "real life" considering you are measuring what is actually making it to the ground. In practice the variables are so huge that you can only really use it to compare a car "before & after" on the same dyno under the same conditions. That's the case for ALL dyno's anyway, whether they give you bhp or whp.

To compare 2 cars on the same dyno measuring in whp you would still need to calculate the average amount of power within a limited rpm band to know which one should be faster in real life. You can artificially inflate the whp number by moving your power band to lower revs, but that could hurt the car's performance in a real life scenario.

Bottom line here is not that BHP is the perfect way to compare, but that the BHP number holds a bit more information about how the engine is performing. The irrelevant data from the wheels and tires has been stripped from the result. At least on real dynos with coastdown measurement, there are many others that give a BHP number by a simple percentage calculation which is of course BS. In those cases WHP really is all you need to look at.

Finally, just because the print says WHP doesn't mean you are seeing raw data. Dynojets in particular don't give you the real WHP at all.




I am not trying to be antagonistic, just trying to understand your logic. Maybe it's not coming through in print?

Totally understand, it's just an enjoyable technical discussion as far as I'm concerned. Dyno numbers are a pet peeve of mine I suppose. English isn't my first language nor do I live in an English speaking country so bear with me.

The reason I am commenting on the unreliability of WHP numbers is simply that it was stated at the beginning of this topic that measuring one of our engines directly would give us a great insight into our real true transmission loss figures.
It will do no such thing. It will tell us something about the OP's car in particular and about the dyno he originally measured it on. Nothing more, nothing less. Whatever his loss will work out at precisely will not be accurate for any of our cars except by chance.

And if anyone feels compelled to calculate BHP from wheel numbers, they should always add a number of hp rather than multiplying a percentage. In any case, those who want to know their BHP have only 2 viable options.
First is the inconvenient engine dyno thing, second is putting it on a MAHA or similar dyno. The proposed 3rd method of calculating bhp from whp using "known" loss figures will have a much, much larger margin of error making it for practical purposes a futile attempt.

[blmlozz]

Totally understand, it's just an enjoyable technical discussion as far as I'm concerned. Dyno numbers are a pet peeve of mine I suppose. English isn't my first language nor do I live in an English speaking country so bear with me.
You speak perfect english(within Internet tolerances) as far as I'm concerned. I would have never known if you had not mentioned it.

[lswing]

You speak perfect english(within Internet tolerances) as far as I'm concerned. I would have never known if you had not mentioned it.

Your grammer is better than many Americans posting on forums:) Thanks for the input!

I always just did the engine hp estimate for kicks/general idea of where the car has improved since stock. Plus chatting with most folks, they only want to know engine power. I changed my sig to whp, so it's official:) Numbers from a Mustang dyno, calibrated well i believe, 80 degree day with big fans, lots of factors.

As long as the Millenium Falcon can hit warp speed I'm happy!

[Jimmy Joe]

JCvigguen, I have always been fascinated by the technical aspects on the very broad field of the automobile, and it´s really awesome to hear someone like you who has mastery on automotive subjects. It,s not the first time I have followed you on this forum, and I think you are a very welcome adittion from which we lurkers can learn ssomething. Congratulations!

[hahnmgh63]

JCviggen, I think what was meant is that WHP from a Chassis Dyno is about the only available tool any of us can use, but yes to be more accurate we all need to use the same Dyno which is not possible, too many manufacturers. But some, as many in the East Coast group of the U.S. did a "Dyno Day" so they could get a bunch of cars together to make comparisions on the same Dyno under the same conditions.
As for Manufacturers data, I think that can be taken with a grain of salt as Porsche for one has been known for years to under rate their HP numbers, and now it seems Audi has been under rating their numbers. Some manufacturers have been known to over rate their numbers to get bragging rights. So we do wish that all manufacturers were honest with the Engine BHP numbers but once again we have seen that it is not true. I think the "Dyno Days" are the best way for us to make before and after comparisons, but anyone posting Dyno numbers need to post the type of Dyno used as some are known to be Optimistic (Dynojet) and some are known to be conservative (Mustang).

[JSRS6]

Speaking of which, I think I want to set up another one in the spring, I'm thinking sometime in April. Same bat time, same bat channel.

[ttboost]

JCviggen, I think what was meant is that WHP from a Chassis Dyno is about the only available tool any of us can use, but yes to be more accurate we all need to use the same Dyno which is not possible, too many manufacturers. But some, as many in the East Coast group of the U.S. did a "Dyno Day" so they could get a bunch of cars together to make comparisions on the same Dyno under the same conditions.
As for Manufacturers data, I think that can be taken with a grain of salt as Porsche for one has been known for years to under rate their HP numbers, and now it seems Audi has been under rating their numbers. Some manufacturers have been known to over rate their numbers to get bragging rights. So we do wish that all manufacturers were honest with the Engine BHP numbers but once again we have seen that it is not true. I think the "Dyno Days" are the best way for us to make before and after comparisons, but anyone posting Dyno numbers need to post the type of Dyno used as some are known to be Optimistic (Dynojet) and some are known to be conservative (Mustang).



Well said..and probably what we all tried to say..albeit miserably...

[MaxRS6]

^I think that is exactly how I described the calculation...;0

[JCviggen]

JCviggen, I think what was meant is that WHP from a Chassis Dyno is about the only available tool any of us can use, but yes to be more accurate we all need to use the same Dyno which is not possible, too many manufacturers. But some, as many in the East Coast group of the U.S. did a "Dyno Day" so they could get a bunch of cars together to make comparisions on the same Dyno under the same conditions.

Of course that's the best way to compare cars, to put them on the same dyno on the same day. But it's not really connected to core of the "drivetrain loss" discussion. As I pointed out earlier, a different remap on the exact same car can cause considerable differences in total losses at peak power (by moving the peak to a different rpm point)
I've always found dyno days to be great fun, but it's only that :)



As for Manufacturers data, I think that can be taken with a grain of salt as Porsche for one has been known for years to under rate their HP numbers, and now it seems Audi has been under rating their numbers. Some manufacturers have been known to over rate their numbers to get bragging rights. So we do wish that all manufacturers were honest with the Engine BHP numbers but once again we have seen that it is not true. I think the "Dyno Days" are the best way for us to make before and after comparisons, but anyone posting Dyno numbers need to post the type of Dyno used as some are known to be Optimistic (Dynojet) and some are known to be conservative (Mustang).

Rule of thumb with manufacturer ratings is that FI engines tend to make their rating or slightly over. NA ones usually fall short (with a few mostly American exceptions) but perhaps the main reason of that might be simply that NA engines suffer more from the typical dyno environment with insufficient airflow.
In any case, we tend to know what a typical car X is supposed to perform like. Only if you're the first person in history to dyno a particular car will things be a bit muddy with regards to the BHP you should be seeing. It's still the best yardstick for judging how well any upgrades have worked.

I would say once again that the biggest problem with the "wheel horsepower" standard comes from the fact that total loss between engine and road surface rises very very quickly at high tire speeds. Even 200 or 300 rpm in 4th gear can make a 10whp difference in the measurement when the engine is putting out the same power and the car is performing the same. So while staying on the same car, it is possible to gain a good amount of power at the wheels whilst not gaining any performance. Coastdown loss measurement would remove the illusion of having gained actual power in such a scenario.