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

B8 S4
#1

I’ve blasted this all over the internet as it seems RS5 data is few and far between. I’m a data driven person, and I know many of you are, so I’d love getting my hands on more data. Anyways here’s what we gathered from our RS5, completely stock, a few days old. BTW, I’m not here to sell anything, just share data where I’d expect to see the most interested people.

Here’s my post from RS5 forums:

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.

#2

Good stuff thanks for sharing.

What’s an rs4 do on that dyno? (Carbon clean of course.)

#3

Good question. I really need to compare my notes to get the conditions of all the cars, and the environmental data, but the graph below is from all 6MT vehicles (except the RS5 DSG). I’m pretty sure all were clean and healthy. It would be best if they were all brand new, dynoed back to back for the best accuracy in the same conditions, but that will never happen anywhere.

One thing I should say though, the RS5 was SPOT ON run after run. The first two were lower, but that’s likely because something wasn’t up to temp/adapted/whatever but the following 4 runs were dead on top of eachother. The RS4 on the other hand was never like that if I recall correctly.

Big graph:

http://www.goapr.com/news/wp-content/uploads/2012/08/42fsi-compare.png

#4

Interesting. So it’ll be a mid-12 second car, assuming it’ll be in the ballpark of a stage II s4 on pump gas or a little slower even.

Tuning potential has to be pretty slim without adding the supercharger. I’d have to assume that’s why you guys have one, because the NA tuning potential must be pretty slim. But still, can’t be too many customers, no? I’d be surprised you’d spend much time on this one.

#5

But hey, now that you’re here, post us a TVS1900 dyno…or a 1650 retrofit…or whatever it is you’re planning for our cars.

#6

fingers crossed for a 1900 for both

any chance you can grab a picture of the exhaust manifolds? are they tri y like the rs4, or did that have to change with the motor being moved back?

#7

Tuning potential slim???

Come on. Same day my rs4 went 13.1 @ 106 , a jhm rs4 went 12.2 @ 112 with tune exhaust and clutch (and beat 81bear in his stage two +HFC+ exhaust +lw wheels b8) All pump gas.

There is huge upside on these cars. You forced induction guys keep forgetting that for some reason.

That stock vs modded rs4 gap is the same as the stage two vs stock b8 gap (which is also about six tenths and 6 mph.)

There are bone stock rs5 quarter mile times at 12.4 12.5 @ 110 112 already.

#8

You’d figure it would be the R1900 as the kit could be adopted to span a number of vehicles B8 S4, S5, RS4, RS5, S6, S7, and even the R8. Well, that’s if it fits the S4! ;D

#9

For me, the gap was 1.4 seconds and 10 mph, mind you I have only gone to the track with race gas.

I dunno. I agree with tuning potential with something like the c63, where the bar was set pretty low from the factory and just getting the car near 100 hp/L with a tune and long-tube headers has gotten people deep in the 11s.

But the new 4.2L motor is already pretty tuned from the factory, sorta like the B18C was for the honda guys back in the day, over 100 hp/L. VE gains to get the torque up are hard to find. The honda guys only found significant power through ridiculous CR pistons, some at 13-14:1, and ridiculous RPMs and cam profiles, several spinning past 10,000 rpm. Dig through the Honda-tech site, you’ll see some crazy builds, but none of them really of beneficial on the street - maybe some info there for you NA guys though.

#10

I want to get this out here too. What do you think of my analysis and estimation of drivetrain loss below:

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

http://www.goapr.com/news/wp-content/uploads/2012/08/s4.png

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.

http://www.goapr.com/news/wp-content/uploads/2012/08/rs5.png

And here are the two crank figures overlaid.

http://www.goapr.com/news/wp-content/uploads/2012/08/rs5-vs-s4.png

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

Thoughts? Discuss!

#11

Jspazz

Come on…your ‘stock’ time was horrendous at 13.5, and was run in the summer in horrendous DA. You can’t compare that to ice cold conditions when you went low 12s. Further, you were on race gas.

If you want, let’s use my extreme heat time last month when we met at Cayuga to compare to the JHM car. I ran 13.3 @ 104 on 94 on my first pass. He ran 12.2 @ 112.45. How about the Rs4 in Florida that went 12.2 @ 112 with no tune at all.

Not a very valid comparison, you have to admit. For the record, the fastest stock B8 S4 time at Cayuga that I have seen on teh various sites was 13.0 @ 106 in the heat. We all know that it can go quicker, but let’s use that as it beiinefficientficientits you. Then to compare a tuned car stage II or equivalent (REVO 1 93), turbobaby ran 12.3 @ 113 with his REVO tune, LW Wheels and exhaust. So 7 mph and 7 mph. He was the car who ran 13.0 @ 106, fittingly. DSG.

I like having this discussion with FI OR DIE guys. It’s better in person because they seem almost like they think you’re making it up, it goes against their embedded mindset so much that a NA car can make big gains with simple bolt ons.

#12

ARIN - I like it! Very interesting to see.

APR’s budget is really a good thing to take advantage of. No other tuner is out there buying brand new cars and doing stock baseline research for us. I appreciate it, for one.

#13

Saki, I don’t disagree with you, but I think we can all agree a B8 RS4/5 will only be a match at best, on average, for a stage I B8 S4 side-by-side, and likely get walked by a stage II - I am saying “on average”.

If Arin was to plot a dyno from their various tuned B8 S4s on there, well we all know what that would look like compared to the RS5.

Arin, you are basically showing that Audi doesn’t try to compensate for DTL for any higher revving car, and of course DTL grows exponentially, thus accounting for how they end up with overachieving low-revving cars like the S4, and underachieving high-rev cars like the RS5. Basicially a 40 HP spread at redline, or more like 50 HP considering the B8 peak at stock achieves at even lower RPM.

This is why I always try to change the subject to 1/4 mile results…:slight_smile: Us B8s are always a surprise at the strip compared to the 500+ hp crowd of unsuspecting stock C63s and CTS-Vs at the track.

#14

I thought this was fairly interesting. This is a stage 1 v1.0 B8 S4 6MT that’s advertised on our website, wheel, vs RS5, stock, DSG, wheel.

http://www.goapr.com/news/wp-content/uploads/2012/08/s4-s1-vs-rs5-wheel.png

I also played around and overlaid a 100 octane winter S4 2+ v2.0 run and, oh my lord. :wink:

#15

[quote=“Arin,post:14,topic:3637”]
Post it Arin!

#16

http://www.goapr.com/news/wp-content/uploads/2012/08/100.png

;D

#17

jspazz, I think you’re getting a little too B8 S4 proud. Comparing dyno results only ‘proves’ that ink sticks to paper. We all know that what happens on the road can be drastically different. Just ask the GIAC tuned + exhaust B8 S4 who I beat repeatedly in my bone stock RS4 when we all went to the strip. Sounds like you’re suffering from short term memory loss! Remember…that car supposedly should dyno 402 whp if you trust Austin@GIAC. My car might dyno 320 whp or so. So what gives? What of your dyno dominance now?

Anyway, try to keep this thread about the 4.2 FSI RS5, rather than your 3.0T on race gas. Not sure anyone really cares to compare that…other than a few B8 owners trying to show that their car is ‘better’ than an RS5.

We all know that once a proper sized supercharger (TVS1900 is small potatoes for the 4.2 FSI high revving motor) is attached to the RS4/RS5, it will make the 3.0T it’s permabitch :D. Still waiting for one of your 3.0T superstars to trap 125 mph on pump gas. Has that happened yet? Did I just miss it?

#18

Lol not a fair comparison (stage 2+ car in the winter on race gas dynoed vs a stock car dynoed on pump in the summer) but it is interesting to see the huge gap on paper.

I would expect a lot out of the RS5 from aftermarket mods. Stock vs tune and exhaust RS4 is around a 1 sec 1/4 mile difference, so if the same applies to the RS5 you would have it running mid-high 11s with a tune and exhaust… That’s what I want to see ;D

What are the engine differences between the RS4 and the RS5?

EDIT: Google search…

"Stephan Reil, R&D chief in charge of all Audi RS and R models, explains:
The engine for the RS5 was practically developed from scratch. It develops more power and torque than the outgoing unit, yet it uses twenty percent less fuel. Although the redline was pushed up to 8500 rpm, maximum torque, an identical 317 lb-ft is now available between a less hectic 4000 and 6000 rpm. Engineering highlights include a two-mode intake manifold with tumble blades, variable intake and exhaust timing, and a multimode exhaust system. To trim parasitic losses, Audi reduced piston friction, lightened the DOHC valvetrain, and fitted a variable-output oil pump. A regenerative braking system increases alternator output during deceleration and reduces its output during normal driving. "

This reminds me of the boss 302 vs regular gt. Not much HP difference on paper, same or less torque even, but the engine changes allow for greatly improved stock performance, and aftermarket potential.

#19

[quote]Lol not a fair comparison
[/quote]
For sure, which is why I’ll only really post it in the B8 S4 forum.

#20

Hey Sak, you know me, dynos are tricky, I always like to settle it at the 1/4 - read my post again…

Don’t forget everyone you are posting on the B8 S4 forum guys, so I have every right to compare.

Sak, the GIAC car you beat was running 12.9 - hardly representative, you can compare to Skid here too, on APR S2V2 not even running 12s, but even he will admit he’s not getting the most out of the car.

NA cars will never get the gains on race gas that FI cars get. You can ignore it, say it’s cheating, but I’m a tank away from that at all times, I always have some 110 in my garage. Why would I go all the way to the track, all this prep, to run slower when it’s so easy to fill? I’d consider that artificially limiting myself to settle some silly internet dispute of who is faster on the street…well, I’d just rather be faster, period.

Arin, what do you expect a race gas tune on the new RS5 to look like? maybe 40 hp gain? I’m assuming the whole reason for the RS5 at your shop is to put a TVS1900 on it…tell us…