Why does the TT A8L barely make more HP than the Mustang GT?

"TDogg" (needamiata) 06/28/2016 at 21:05 • Filed to: A8L, Mustang, Engines

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For reference, the A8L comes with a twin turbo 4.0L V8, making 450HP. The Mustang GT is naturally aspirated 5.0L V8, making 435HP. Why the minimal HP difference? Is it just the displacement difference or is there more to it? Because a twin turbo 5.0L supposedly makes 700+ HP.

PanchoVilleneuve ST > TDogg 06/28/2016 at 21:14

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So it doesn’t get too far away from the dealership before the window motors or something fails because, you know, Audi.

nFamousCJ - Keeper of Stringbean, Gengars and a Deezul > TDogg 06/28/2016 at 21:15

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I ask the same about the 3.8l v6 Gen Coupe making 350hp but the 335i and it’s TT 3.5l only produces 300.

djmt1 > TDogg 06/28/2016 at 21:15

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Because Audi want people to spend more money on the S8. Keep in mind that engine is everywhere in the VW group so you’re spoiled for choice if you want more power from the TT 4.0.

BugEyedBimmer - back in the Saddle Dakota Leather > TDogg 06/28/2016 at 21:18

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A) Audi chronically underrates their cars. IIRC, this engine acuallg puts out over 470hp. Also, peep the torque. The A8 has a LOT more, and makes it a LOT lower in the powerband. The coyote is a revver, the 4.0T is a stump puller.

Shankems > TDogg 06/28/2016 at 21:19

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No one is DD’ing an putting 20k miles a year on that 700 HP Coyote.

The torque curve on the A8 most likely puts a stock Coyote to shame.

TheHondaBro > TDogg 06/28/2016 at 21:20

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Because Audi wants the engine to last.

Supreme Chancellor and Glorious Leader SaveTheIntegras > TDogg 06/28/2016 at 21:24

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It’s not meant to be a murder weapon

dogisbadob > TDogg 06/28/2016 at 21:28

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Audis often don’t make any power :p

spanfucker retire bitch > TDogg 06/28/2016 at 21:28

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Because you’re meant to be driven around in the A8L. You don’t need a gorillion horsepower.

Because the S8 exists (which can only be had as the S8 Plus in the U.S.) and makes over 600HP for those who want to brag.

wacopalypsenow > BugEyedBimmer - back in the Saddle Dakota Leather 06/28/2016 at 21:33

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From my understanding all German manufacturers underrate supposedly. German horses must be stronger then American horses...ect. ect.

BugEyedBimmer - back in the Saddle Dakota Leather > wacopalypsenow 06/28/2016 at 21:35

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I think it’s a difference of philosophies. When it comes to cars, German manufacturers are very much with the speak softly and carry a big stick. American car companies just wanna pull out and measure.

Rico > nFamousCJ - Keeper of Stringbean, Gengars and a Deezul 06/28/2016 at 21:38

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335i only has a 3.0L TT. Dynos put it at around 320-330 hp but only around 300 hp at the wheels.

sm70- why not Duesenberg? > TDogg 06/28/2016 at 21:44

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It’s tuned to only make that much. There’s a version with that engine that makes over 600 horsepower; it’s the S8.

Opposite Locksmith > nFamousCJ - Keeper of Stringbean, Gengars and a Deezul 06/28/2016 at 21:51

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335 is a 3 liter

Saracen > TDogg 06/28/2016 at 21:58

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Why do you assume that a twin turbo V8 should automatically be boosted to within an inch of its life?

You’re comparing apples to oranges here. I could just as well say that “the Koenigsegg Agera R makes 1350hp from 5 liters...WTF Mustang?!”

nFamousCJ - Keeper of Stringbean, Gengars and a Deezul > Opposite Locksmith 06/28/2016 at 22:06

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Really? Then what the hell is the 5 for? What about the 328? Is that a 2.8 or a 2 liter? Or is it all lies?

AMGtech - now with more recalls! > TDogg 06/28/2016 at 22:06

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Three reasons that I know of.

1. “Pay wall.” Meaning if you want more power step up a trim level.

2. Reliability. Less boost theoretically equals longer engine life and lower cost of repairs.

3. Emissions/economy. Less power means less emissions and higher fuel economy, typically.

nFamousCJ - Keeper of Stringbean, Gengars and a Deezul > Opposite Locksmith 06/28/2016 at 22:07

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Really? Then what the hell is the 5 for? What about the 328? Is that a 2.8 or a 2 liter? Or is it all lies?

Opposite Locksmith > nFamousCJ - Keeper of Stringbean, Gengars and a Deezul 06/28/2016 at 22:25

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All lies.

Carbon Fiber Sasquatch > BugEyedBimmer - back in the Saddle Dakota Leather 06/28/2016 at 22:43

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Danimalk - Drives a Slow Car Fast > nFamousCJ - Keeper of Stringbean, Gengars and a Deezul 06/28/2016 at 23:15

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BMW has been lying to you for a long time.

Best not look too close at Mercedes Benz either...

Danimalk - Drives a Slow Car Fast > BugEyedBimmer - back in the Saddle Dakota Leather 06/28/2016 at 23:19

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“...speak softly and carry a big stick...”

But don’t they put 2Ls in their 128s and 3.0L in their 335s. Sounds the other way to me.

NavyNole > Rico 06/29/2016 at 07:08

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And actually, after the first couple of years, they went to the twin-scroll single turbo setup they have now, so not even TT. So you have a rev-to-the sky Hyundai motor built for peak horsepower, vs a hugely underrated luxury performance engine tuned farther towards the refinement end of the scale than all out horsepower. Throttle response, low-end torque, smoothness, etc. are all vastly better than the 3.8L Hyundai motor. Exact same thing applies to the Audi 4.0TT vs the Coyote 5.0; completely different tuning for a completely different purpose. The raw, peak HP number is not the single point of focus with the Audi engine like it mostly is with the Mustang.

bhtooefr > TDogg 06/29/2016 at 09:20

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2016 A8 4.0T: 450 hp @ 5300 RPM, 444 lb-ft @ 1500 RPM

2017 Mustang 5.0: 435 hp @ 6500 RPM, 400 lb-ft @ 4250 RPM

It’s worth noting that the formula for converting torque to hp at a specific RPM is hp = lb-ft torque * RPM / 5252 - so the reverse is lb-ft torque = hp / (RPM / 5252).

So, at 5300 RPM, the 4.0T is producing the same torque at redline that it’s producing at 1500 RPM (there’s some rounding/conversion errors I think, so you’ll actually get 446 lb-ft doing that math, which is obviously wrong, seeing as the peak’s 444 at 1500).

Conversely, at 6500 RPM, the Mustang’s 5.0 is producing 351 lb-ft - it’s already coming off of its flat torque curve. Ballparking a number, I’d guess that at 5300 RPM, the Mustang 5.0 is producing somewhere around 375 hp or so.

You could also look at it from the direction of, what if the Audi could maintain its torque curve up to 6500 RPM? Then, it’d have 550 hp.

Another way to look at it is to look at a lower-revving (although also lower-octane, which will reduce available torque across the board, and therefore power) application of the 5.0, in the F-150. 385 hp @ 5750, 387 lb-ft @ 3850. It still revs higher than the Audi engine, but it illustrates the point well.

tl;dr: The Audi engine doesn’t rev as high - it doesn’t even rev as high as the truck applications of the Ford 5.0.