Dynoed our RS5, stock. Anyone interested in the results?

[Arin@APR]

Here's my post from the RS5 forum:

We strapped the vehicle down to our all wheel drive dynapack dynamometer to collect some data. The first two runs were lower than the last 4 which looks to be due to some adaptation that took place while the vehicle was getting fully up to temp in all areas. It was up about 5 FT-LBS on average, so I discarded the first two lower stock runs and averaged the results of the final 4 runs.

Here's what we were putting down to all 4, averaged over several runs, which were very consistent:




Now, this is to the wheels, or hubs on our dyno, so there is drivetrain loss. Audi advertises numbers from the crank, which does not include this loss. Looking through the numbers I tried overlaying our graphs over Audi's dumbed down smooth marketing graphs to see how they stacked up. I then added torque increasingly across the entire RPM range till the numbers lined up very closely with Audi's numbers.

Audi claims the following:

450 hp @ 8250 RPM
317 lb-ft. @ 4000 RPM

By adding around 2-65 ft-lbs of torque across the RPM band from 2000 to 8400 RPMs, we get a crank graph that closely resembles Audi's advertised figures:



Torque came out only slightly higher in some spots, but lower at the beginning of the dyno pulls which is not unheard of as every dyno type out there will read and load a little differently. At any rate this gets us very close to what they advertised so we'll try using this drivetrain loss calculation when analyzing other upgrades we make. We'll also reexamine the numbers after we get an RS5 on a few different dynos, including our MAHA crank calculating dyno in the APR UK facility.

[Auditude2.0T]

Good numbers. I also saw a 12.0 on the vbox 60-130 which seems on par with a Bolt on S4 with a tune. Pretty quick for stock. I'd love to see what they do with tune/exhaust/intake. Hopefully they break 400whp.

[Stereodude]

So it's got less torque than a stock B8 S4 in the midrange. If it wasn't the bypass valve opening the 3.0T in the S4 would be more powerful.

[Arin@APR]

So it's got less torque than a stock B8 S4 in the midrange. If it wasn't the bypass valve opening the 3.0T in the S4 would be more powerful.

We looked at stage 1 v1 summer numbers vs this and the torque difference was massive. The RS5 did rev higher.

[MrFunk]

So a tuned B8 S4 is going to be quicker than a stock B8 RS5?

[princeofbombay]

Yea a stage 1 s4 also might be faster to but straightline performance isnt everything. I dont think the rs5 would make that much power after mods if its still n/a..but like i said straightline isnt everything

[L0U]

rs5 is a bit of a fail. The 4.0T would have made it an upgrade from the 3.0T S5, and an M3 equal, at least. Many will be in S6's Vs rs5's i think. unless its all about the looks. beast on fuel as well.

[autoluxe]

rs5 is a bit of a fail. The 4.0T would have made it an upgrade from the 3.0T S5, and an M3 equal, at least. Many will be in S6's Vs rs5's i think. unless its all about the looks. beast on fuel as well.

+1 I have said since the beginning that this engine should have been retired after the B7 RS4 its a dinosaur for modern cars. V8TT FTW

[Jones2012s4]

Not Impressed, kind of expected though.

[Info@EuroCode]

22% DTL corrected using this dynapack. Similar drivetrain as the B8 S4.

Using conventional logic, the B8 S4 has 419BHP from the factory. The plot thickens.

[Gweezil]

I can't wait to see what a tuned 4.0T is capable of.

[joneze93tsi]

+1 I have said since the beginning that this engine should have been retired after the B7 RS4 its a dinosaur for modern cars. V8TT FTW

100% agree.

Both the RS4 & RS5 where huge let-downs on the B8 front.
RS5 or RS4 with 4.0T would have been a market dominator.

[IanVr6]

I guess we will have to wait at least 3 more years to hopefully see the 4.0T in an RS model.

[princeofbombay]

I always knew our s4's were under rated but 419 crank hp is a lil too much

[adbender]

Yea a stage 1 s4 also might be faster to but straightline performance isnt everything. I dont think the rs5 would make that much power after mods if its still n/a..but like i said straightline isnt everything

will be answering this question next month...

my buddy is taking delivery of beautiful suzuka grey rs5 any day now and we are off for a road trip/track session in mid sept with a competition package m3 too

will have a fresh v2 93 APR flash waiting for them

wish me luck...

[Arin@APR]

22% DTL corrected using this dynapack. Similar drivetrain as the B8 S4.

Using conventional logic, the B8 S4 has 419BHP from the factory. The plot thickens.

Probably not a good idea to use percentages. 350chp-360chp is more realistic.

[princeofbombay]

Well good luck

[Info@EuroCode]

Probably not a good idea to use percentages. 350chp-360chp is more realistic.

3.0T advertised at 333HP makes 327AWHP on your dyno, 4.2L advertised at 450HP makes 353AWHP on your dyno.

[Arin@APR]

3.0T advertised at 333HP makes 327AWHP on your dyno, 4.2L advertised at 450HP makes 353AWHP on your dyno.

Peak power occures much further down the rpm range on a 3.0t than it does on a 4.2l. You probably shouldn't use a single percentage for the entire run. Doing so doesn't come anywhere near close to what Audi advertises in terms of the shape of the curve. A variable dtl that gets larger towards redline is more realistic. 3.0t takes a nose dive towards redline. 4.2 doesn't. I'll graph later.

[Arin@APR]

Dave,

Here's what I was talking about.

After looking at these graphs for quite some time, comparing them to what Audi publishes and based on what other "crank" estimating dynos produce, it appears numbers should become increasing larger from wheel to crank the further you get towards redline. This seems to make sense. As RPM increases, more drivetrain loss occurs from rotating masses, frictions, drag, oil viscosities, etc within the transmission / drivetrain.

Now, the DSG s4 and the 6MT S4 both were dynoed on similar days at APR and the DSG showed less power. Yes, Redline is lower, but peak power is far before redline. It seems the DSG experienced a little more drivetrain loss, but that's just an educated guess.

The numbers are all averaged and are SAE J1349 corrected for ambient conditions. Even with correction, it seems super/turbocharged engines will not always be spot on as they have the ability to move up and down in power by simply running more boost. While the ECU tries to stay on target, I don't believe it will always be perfect with the way it was when Audi dynoed the vehicle in standard conditions (probably 0 humidity, sea level, 77F, somewhere around there). So, that said, maybe the crank S4 numbers are a little high, plus we're running 93 octane and the OEM only requires 91.

The S4 and RS5 are both quattro with DSG transmissions, so I would assume drivetrain loss is smiler. For the sake of this comparison, I'll simply use the exact same drivetrain loss I calculated for the RS5 DSG on the S4 DSG because you used a percentage above. Note, I'm not using a fixed percentage. I'm adding torque from lower RPM's to upper RPM's.

Here's what the S4 would look like. Feel free to find Audi's advertised (super smooth marketing style) graphs and you'll see the shape (especially of the HP graph) is extremely similar. Notice how power doesn't fall off towards redline and is flat? That's just like their graphs. I think I'm headed in the right direction. BTW, the green line below is drivetrain loss in HP. Meaning this is how much HP was added at each RPM to get from wheel power to crank power. ; )

B8 S4 DSG


Here's my B8 RS5 DSG Graph. Note, drivetrain loss is exactly the same for this arguments sake, but the RS5 has a higher redline, so losses keep growing and growing the further out you go. The slope of the torque loss is identical between the two engines.



And here are the two crank figures overlaid.


The S4 has a clear advantage, stock, until the upper RPMs, but with an ECU upgrade, that game changes pretty quickly.

Thoughts? Discuss!

[s4ibis]

Interesting

[salmjo1]

rs5 is a bit of a fail. The 4.0T would have made it an upgrade from the 3.0T S5, and an M3 equal, at least. Many will be in S6's Vs rs5's i think. unless its all about the looks. beast on fuel as well.

I think they should have done the RS5 as the TTRS motor with a choice of manual or DCT making 400 hp. It would have been lighter, more powerful, more torque, greener, fantastic and historic sound, all wrapped in a gorgeous body.

I said it on the RS5 forum: it's hard to want to pay for an RS5 when the S5 is just as fast and available with many more choices (drivetrain and interior bits).

[ENV²]

the RS5 is an aesthetic win but a performing fail.

I like the motor, I like the sound, but its not the correct direction. Should have been a tuned 4.0TT or the 5cyl T from the TTRS tuned, or if they really wanted to be different just supercharge that motor they used from the factory. Then it would have been well worth the sticker price or better. C'mon Audi even the M division uses turbos now.

[s4ibis]

I feel like Audi took a pass on this generation's RS models. Maybe next time they'll put some effort into it.

[helix139]

Arin-

Can you lay in the tuned S4 tq/power plots with the RS5 and stock RS4 plots?

[korben]

Can you lay in the tuned S4 tq/power plots with the RS5 and stock RS4 plots?

Would like to see this as well...

[Arin@APR]

Arin-

Can you lay in the tuned S4 tq/power plots with the RS5 and stock RS4 plots?

Here's the stuff from our website, which is still just v1.0 numbers.

[richib86]

lol

Here's the stuff from our website, which is still just v1.0 numbers.

[Arin@APR]

I'm personally excited to see how both stack up, once we, um, ahem... go a little further. ; )

[NWS4Guy]

will be answering this question next month...

my buddy is taking delivery of beautiful suzuka grey rs5 any day now and we are off for a road trip/track session in mid sept with a competition package m3 too

will have a fresh v2 93 APR flash waiting for them

wish me luck...

You won't need it, with the APR V2 you should take him pretty easily. If you have stage 2, yuo will ruin and embarass him - especially considering the cost difference in these cars, even factoring in the cost of the tune and install of these parts.

There is a Vid here on the front page where a Stasis tune + exhaust takes out a R8 V8 (same basic engine as in the RS5) and manhandles it pretty easily.

The R8 V8 spyder DSG and RS5 have almost identical weights as well, so there you go

[NWS4Guy]

I'm personally excited to see how both stack up, once we, um, ahem... go a little further. ; )

Looking to eventually try FI with this one? A little R1320 action?

[Arin@APR]

Looking to eventually try FI with this one? A little R1320 action?

Yes/No.

BTW.... B8 S4, 100, winter, 6mt, s2+ fully bolted on, at all 4 wheels - Yeahhhhh buddy!!!



;D

[richib86]

Yes/No.

same amount of room in the engine bay that you showed me at waterfest?

[Arin@APR]

same amount of room in the engine bay that you showed me at waterfest?

[richib86]

ill say it again, one at a time hahaha i need a S/C before my clock runs out and i need to get a wedding ring instead lol

[A4 Centaur]

Looks like it's time for the APR Supercharger!

[Wusty]

I can't wait to see what a tuned 4.0T is capable of.

+1!! This will be a beast. Coming from a B7 S4, I just don't know why they still have the V8 4.2 still around? It's just not that exciting. And did you see the post today of a tuned B8 S4 taking a V8 4.2 R8??!! Nuff said.

[CreoSTi]

ill say it again, one at a time hahaha i need a S/C before my clock runs out and i need to get a wedding ring instead lol

I only have a week or two left for that, and I don't think Arin will come through in time...

[ENV²]

I only have a week or two left for that, and I don't think Arin will come through in time...

ill be soon after lol

we will def need someone to step up and make a better clutch for stage 3

[NWS4Guy]

ill say it again, one at a time hahaha i need a S/C before my clock runs out and i need to get a wedding ring instead lol

You can do both, just depends on how big you wanna go on the rock