Disagree. It can be very simple.

chatgpt suggests that the B10 A5Q is heavier at 1855kg vs 1645kg for the A4Q 2024. If true, that would be a good starter.

 

Yes the US-spec car has engine start-stop. I experienced it on my test drive. Not as jarring starting the engine as the start-stop on the 2018 A4. About the same as the mild hybrid system on the B9.5. Audi made improvements here without the complexity as the new A3 has the smoother start-stop function as well.

 

As I already said earlier in this thread: "and a 10% increase in weight"

 

I would really hope people aren't resorting to chat GPT for stuff like this. ChatGPT for example wouldn't know the curb weight of the US-market A5 (or whatever the hell an "A5Q" is) is notably lower than the EU-spec A5 due to the lack of a 48V mild hybrid system.

 

The figures BlakeV quotes will be very close.

The North American region B10 A5 sedan is using what was the B9 quattro 45 high output version of the EA888. The most equivalent EU-spec, which is more accurately a global spec, is a transition from what was the B9 quattro 40 version of the EA888 - the TFSI quattro 150 kW S tronic. There is no weight difference between the 40 TFSI and 45 TFSI quattro versions in terms of engine and drivetrain.

The B9 A5 Sportback 40 TFSI quattro (a better comparison than the lighter A4 sedan) in base EU spec weighs 1660kg. The equivalent B10 A5 sedan weighs 1825kg. That is almost entirely due to the B10 platform. Note EU-spec weights are base model - smallest wheels, manual seats, no panoramic roof, tiny sound system, etc etc. US cars have higher levels of equipment, so always weigh more. Don't know Canadian equipment levels. Regardless, B9 to B10 is a large increase in size and weight. B10 is very close to the C8 A6.

There is no 48V MH system on the EA888 in the B10. Audi have just released a high output version, likely the new EA888 Evo 5, but that is only present in PHEV form, with one version outputting a total of 290hp, the other 360hp. I doubt they will bring these PHEV versions to the US. The only global B10 A5 models using 48V MH+ are the TDI versions and the S5.

As suggested by SMac and others above, the increase in weight over the larger B10, built on the new PPC platform optimised for hybrid drive, will be the reason that Audi has increased the EPA fuel consumption figure. Noting that the EPA don't calculate the numbers, manufacturers self-certify. I also agree with Smac that the differences being discussed here are all pretty minor. They are relevant to manufacturers in terms of meeting Euro 6e and upcoming Euro 7 emissions and fleet average CO2 contributions. And in Europe onerous and ongong taxation in most markets related to CO2 contributions/fuel consumption (these are the same thing). Which is why almost all high performance global vehicles are moving to hybrid drive.

In terms of efficiency, BMW do seem to hold a small advantage with ICE over Audi and Mercedes, although this is engine dependant. So BMW the best choice if that is the prerequisite.

 

The 1825 kg is "with driver". The "without driver" weight for the FU is 1750 kg (3858 lbs). Without driver is more akin to US curb weight. But I believe the DIN "without driver" weight is also sans fuel. US curb is all fluids present. That's almost 100 lbs of gas. Audi USA specs the A5 sedan curb as 4090 lbs, but lists it as 4156 lbs in the EPA app. I suspect the remaining difference is standard equipment on the US models; US curb requires inclusion of any optional equipment present on at least 1/3 of the vehicles. Guessing that glass roof is not as light as some thin sheet metal, if the glass panels in my B8 panoramic are any indication.

All the B10 2.0 TFSI are evo5. There are simply the different power class variants. The b-cycle engine is power class 1 [PC1] (b-cycle 2.0 replaced the standard 1.8 at this tier starting with the B9), the standard engine is power class 2 [PC2], the S3/TTS got the power class 3 [PC3]. A4/A5 never got PC3, instead getting the heavier V6. Kind of sucks, but whatever. For the evo5 in the FU, the PC1 b-cycle is 110kW and 150kW (same as evo4, and up from Gen3 b-cycle's 110 and 140), the PC2 is 200kW (up from evo4's 195 and Gen3 evo's 185). I was surprised to see the FU PHEV are using 185kW detuned PC2 rather than the more economical PC1. FU PHEV adding over 700 lbs to the vehicle, pretty much spot on as expected.

The shorthand in the parts catalog for the model variants is A4Q for A4 quattro, vs A4 for A4 FWD and A4AR for A4 allroad (but only for B8; for B9, it was just in A4Q). But there is no A5Q. A5CO is the coupe/sportback catalog, A5CA is the cabriolet. But only for B8 and B9. For B10, it's A5A for the avant and A5L for the limousine (sedan). Not sure why they split it.