B9 engine comparison S4/5 vs RS5 (dyno)

[hayasa]

Was really interested in how these two engines compare. 2.9L twin turbo vs. 3.0L twin scroll single turbo. For those who want to geek out over engine dyno graphs:

S4/5 dyno


RS5 dyno




S4/5 engine



RS5 engine

[Foxbat]

All that turbo lag... :(

[hayasa]

All that turbo lag... :(

Yeah, that twin-scroll give peak torque 500 rpm sooner, but the twin turbos more than make up for it by giving you 100 more peak hp (and 75 more torque across the powerband.) Both seem to putter out around 5000 rpm, though.

[Jet Jockey]

I'll take the 2.9L twin turbo please.

[B8_Jim]

[Jet Jockey]

Beat me to it!

Those are most likely numbers from a MAHA dyno too.

[RudyH]

All that turbo lag... :(

but it will smack you in the back when it kicks in...add an ECU tune and it will remind me of the good ol' days of the B5 S4 (K04'd)

[hayasa]

So is it just raw boost that is pushing that 2.9 twin-turbo to all that extra power? I'd think that the twin turbos would help with spool (but obviously not as much as a twin scroll) and efficiency since they can be sized better, but an extra 100 hp? The engines are *basically* the same, right, aside from probably better internals on the 2.9? They look essentially the same, have roughly the same displacement, and rev to roughly the same RPM. The 2.9 has an air-to-water intercooler but that shouldn't make that much of a difference unless the boost is much higher in the 2.9. Maybe the 3.0 is seriously de-tuned?

[Foxbat]

I am confused about the air flow through all those components - what is that silver box on the bottom right?

[B8_Jim]

I am confused about the air flow through all those components - what is that silver box on the bottom right?

Air-Water intercooler. The 3.0TFSI cooler is air-air and has been removed in the picture above - but it can be seen here (S4 - would assume S5 is identical)

https://s7d9.scene7.com/is/image/Aud...774&fit=crop,1

[Foxbat]

That's what I suspected, but I did not see water hoses.

Thank you!

[B8_Jim]

This shows the heat-exchangers and pump, with the water lines - but it's not a very good view of the connections to the intercooler.

[JamesRS5]

Chargecoolers are great for consistent temperatures but I can't help feeling that one looks a little on the small side. My money is on a larger unit being being one of the first mods available from the tuning companies.

[DeanoC]

And this is why i doubt i will be replacing my B8.5 RS4 with the B9. more torque but only available over a 3k rpm band and runs out at 5k. Mine has 90-100% of its torque avaiable from 3-8.5k rpm.

Only replacement for displacement is revs and its a 2.9 revving to 6.5k or a 4.2 reviving to 8.5.....

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[superswiss]

And this is why i doubt i will be replacing my B8.5 RS4 with the B9. more torque but only available over a 3k rpm band and runs out at 5k. Mine has 90-100% of its torque avaiable from 3-8.5k rpm.

Only replacement for displacement is revs and its a 2.9 revving to 6.5k or a 4.2 reviving to 8.5.....

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Unfortunately, the age of high revving NA engines is all but gone for some emotive low volume vehicles such as the R8. The required CO2/km average emissions on the books are driving the downsizing and what few people are talking about, the downspeeding of engines. It's all about high torque, low revs in the name of fuel efficiency. The only way to achieve what the EU and others have agreed to in the Kyoto protocol is taller gearing to keep the average revs low. Low revs means less fuel burned, means less CO2 emitted. It won't be long until we see engines making peak torque from 800-1500 rpm. The 4000-4500 rpm redline of diesel engines is what's coming to petrol engines. The age of exciting sounding engines is over as sad as it is.

[DeanoC]

Unfortunately, the age of high revving NA engines is all but gone for some emotive low volume vehicles such as the R8. The required CO2/km average emissions on the books are driving the downsizing and what few people are talking about, the downspeeding of engines. It's all about high torque, low revs in the name of fuel efficiency. The only way to achieve what the EU and others have agreed to in the Kyoto protocol is taller gearing to keep the average revs low. Low revs means less fuel burned, means less CO2 emitted. It won't be long until we see engines making peak torque from 800-1500 rpm. The 4000-4500 rpm redline of diesel engines is what's coming to petrol engines. The age of exciting sounding engines is over as sad as it is.

Exactly right. Lets all drive RS badged Audi's in the same way we do a 2.0 TDI.

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[shoe3k]

All that turbo lag... :(

What? That isn't lag. The 2.9L is literally making similar power down low and continues building TQ where the 3.0L plateaus. Putting a huge turbo on a tiny 1.4L 4 banger that makes no power until 5500rpm is what "real" lag is.

[wahpao]

I hope the days of problematic Audi motors is over. Knock on wood.

[Hy Octane]

done with turbos.. Too much heat cooking components (esp in hot climates) due to cooling issues and variables in performance due to outside temps and fuel quality as well as maintenance costs.. I'll stick with my Supercharger..

[audiBoon]

The torque on these cars is so disappointing (mine too, 2013). But, then again, it's not meant to be a torque monster.

[JamesRS5]

I don't see how 600nm of torque would be disappointing?

What's your daily ride, the space shuttle?

[audiBoon]

I don't see how 600nm of torque would be disappointing?

What's your daily ride, the space shuttle?

Nope, you're totally right. The nm to ft-lbs conversion in my brain went wonky. 440ft-lbs is good. Apologies. That being said, my v8 is still a dog off the line in Denver.

[chrissurfr]

I don't see how 600nm of torque would be disappointing?

What's your daily ride, the space shuttle?

ahahahhahaahahahahahaha

[01northernS4]

done with turbos.. Too much heat cooking components (esp in hot climates) due to cooling issues and variables in performance due to outside temps and fuel quality as well as maintenance costs.. I'll stick with my Supercharger..

+1

[Quattttttttttro]

And this is why i doubt i will be replacing my B8.5 RS4 with the B9. more torque but only available over a 3k rpm band and runs out at 5k. Mine has 90-100% of its torque avaiable from 3-8.5k rpm.

Only replacement for displacement is revs and its a 2.9 revving to 6.5k or a 4.2 reviving to 8.5.....

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Right there with you. We also have the better looking generation. I think I'll hold off for the B9.5 and see what that will be all about

done with turbos.. Too much heat cooking components (esp in hot climates) due to cooling issues and variables in performance due to outside temps and fuel quality as well as maintenance costs.. I'll stick with my Supercharger..

Agreed.
Never was and never be a fan of turbo's. Not only because of the things you mentioned, but the non-existent exhaust sound. Or should I say artificial speaker sound.

[DeanoC]

Right there with you. We also have the better looking generation. I think I'll hold off for the B9.5 and see what that will be all about

This was proven to me in the real world this weekend. I borrowed this f rype R which has a massive 250nm more torque and 100 more horsepower but it doesn't feel as quick. There is no build of surge in the revs - it just flicks between 4 and 6k in every gear which is boring.

I know it's faster and that is apparent when you look at the speedo rather than the road but it doesnt feel it and i buy a car for how it feels.

Sounds epic though 😈



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[DinB]

This was proven to me in the real world this weekend. I borrowed this f rype R which has a massive 250nm more torque and 100 more horsepower but it doesn't feel as quick. There is no build of surge in the revs - it just flicks between 4 and 6k in every gear which is boring.

I know it's faster and that is apparent when you look at the speedo rather than the road but it doesnt feel it and i buy a car for how it feels.

Sounds epic though 😈



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Why are there Audi Rings on that Jag?

[DeanoC]

Why are there Audi Rings on that Jag?

Because i was on a weekend driving trip with a load of RS owners and i felt like the odd one out.

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[superswiss]

There is no build of surge in the revs - it just flicks between 4 and 6k in every gear which is boring.

I know it's faster and that is apparent when you look at the speedo rather than the road but it doesnt feel it and i buy a car for how it feels.

+1... That's exactly my biggest disappointment with all these new FI engines. They are great if all you wanna do is put the transmission in automatic and then mash the throttle with no regard to where you are in the powerband. Car will surge forward with no finesse or skill required. What makes the old RS5 so interesting IMO is the fact that it takes some finesse to drive it fast. Sure you can put it in S and it mostly keeps the engine in the powerband, but again... boring! The real enjoyment is driving up a windy mountain road in manual mode and play with that crisp responsive powertrain.