City Driver, Consider A6 TDI vs. 3.0T Plus Stage1/2, Advice Requested

[oopsy]

I've recently decided to buy an A6 and have been reading as much as I can on these forums, thanks for the insights. I'm eyeing 2015 or 2016 Prestige for my daily driver to replace my 15 year old Prius. I'm very much looking forward to the upgrade and I plan to keep the car for at least 5 years if not longer. I live close to work and my trip each way is about 3 miles (all city), although in about 2 years, my commute will be about 15mi each way (mostly highway). My estimated annual mileage is going to be like 4k/year in the next 2 years. I'm looking for some insight about a 3.0TDI vs. 3.0T plus tuning.

Initially, I thought it was a no brainer for me to get the TDI because of the fuel economy, less times at the pump, and torque advantage for my city driving, but it was appropriately pointed out to me (in a different thread) that I likely wont be enjoying a lot of that on my short trips to work. I understood that I may in fact have a harder time with the longevity and efficiency of the diesel if I dont get running for longer trips and get the engine temperature up which takes about as long as my commute. I also live in a place where I have to drive-way park (but it is in the deep south, so winters are benign but it would be a colder start than inside). Bummer, but I get it. I'm aware that for such short commutes, an electric car like a Tesla would be ideal, but there's not a practical setup for me to do that in terms of charging etc.

That said, I just test drove a TDI (Premium Plus) and a 3.0T (Prestige) back to back a few days ago, and I was blown away by the torque on the TDI. It was incredible--I found myself really enjoying the low end power on the TDI and found that it suited my driving pattern really nicely. I dont see myself using the high RPM passing HP on the way very often for the 3.0T, but definitely accelerating in the city and on backroads far more often. It's hard to see myself going back to the 3.0T having experienced that much torque and fun on the TDI after the back to back drive. It's all a huge upgrade, but the TDI was loads of fun. In terms of fuel economy, it's not the highest priority, the 3.0T is sufficient although obviously the TDI is preferable (with longer commutes in the future).

So the questions for the group:

• With my generally short trips in mind, does it make sense to avoid the TDI? I worry about the longevity of the engine and mucking it up without consistently get it up to temperature, but dont know anything about this, so wanted to get further input if this should be avoided.

• Given this hesitation, I've been reading through the forums and learned about the tuning options. I'm starting to consider getting a 3.0T and doing a stage 1 or straight to stage 2 modification to get the torque into the 400s. Again the torque is what I found most fun, the HP advantage of the 3.0T less so (but certainly awesome, and I imagine moreso with the tune). If I do this, would I void any warranty on or increase the risk of engine damage/failure (I plan on keeping for a long time)? My impression is that MPG is roughly the same for a comparable intensity of driving with the tune, please correct me if I'm wrong. It seems like the power would be relatively comparable, but I am unsure if it would similarly be in the low end of RPM like the TDI (for my city driving). The major upside here is that it's 100x easier to find a Prestige 3.0T than the TDI. In fact, the 3.0T Prestige that I test-drove was fantastic (Prestige, Black Optic, Sport, 20", etc, 2016, 50k miles, ~28k+fees asking) although seemed a touch overpriced.

• Finally, if there are significant drawbacks to modifying the 3.0T and the TDI is less suitable for my city driving patterns, I was considering caving and buying a stock S6 (2015/2016 or so), but honestly it's a lot of car for what I do. It takes my purchase price from mid to high 20s into mid to high 30s. The hit in MPG is also suboptimal, but not the end of the world since my annual mileage is low. It's doable, but not what I had in mind up front. It's hard for me to imagine having a V8T for such a short commute, but here I am considering it.

Thanks in advance for your consideration and input, and apologies if these are unsophisticated questions, just keep in mind that I' coming from a Prius...

[paul-g]

my 2 cents...you've enjoyed the mileage on your prius so you like the economy of that. i'd buy the TDI an you'll enjoy great mileage sill and will be a major step up in power from what you have now. with a 2016 A6 tdi getting 25 city 38 highway and I think you can better that if your drive nice

[eurolover23]

I would get the 3.0T.

You’re commute is way to short for a diesel. Unless you delete the DPF.


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[Audisthesia]

I'd get a tdi for a commuter car. Diesel has incredible low end torque... That's why it's frequently used in towing applications. There are even tunes for TDI engines as well. I've had two and love them. My commute is only 10 miles, never had any issues with DPF. But I'm sure someone has. VAG cars you can always find reports of things happening. I had a 12 Passat TDI... Had some adblue tank system failure.. Dealer had never even heard of it. I asked on vw forums, couldn't find a single person who had the same failure I got. It's sort of like people reporting blown turbos on the 4.OTT... A small percentage of total owners even reporting, and not even half of those had the issue.

[Cayo71]

Get the TDi if it gives you what you want/like, most likely it will have the extended emissions warranty due to the Dieselgate. That warranty will cover not only the emissions system but also almost anything in the engine long block, something that you won’t have on the gasser 3.0T due to age and mileage of your potential candidates. If you have issues with the DPF they will cover it. After the warranty runs out you just delete the DPF and you will be good to go. That’s the rationale I used when I purchased my TDi last year.

[Valpo A7]

What year did the CREC motor come out? If the year you are looking at is before the CREC motor then you will have problems eventually with carbon build up on the 3.0 because of the direct injection. The motor will never be up to temp on your commute for a long enough time to help mitigate the build up. All 3.0t direct port injection motors will eventually have carbon build up, by running the engine long enough at operating temps you can help keep it at bay.

My 2012 was last carbon cleaned around 105,000 miles and now I am at 205,000 miles and when I scoped the intake runners they looked fair, not great but not bad. Before Covid it saw a daily commute of 63 miles each way to work at highway speeds. This helped keep the build up at bay.

[daytona rs7]

probably gonna get hate for this...but look more into the tesla. or maybe a plug-in hybrid.
My neighbor has a plug in hybrid X5, that he charges outside. seems like he had an exterior GFCI outlet installed next to his driveway specifically for this. im sure a similar setup can be done for a Tesla.

youll have all the torques youll need.

the only problem is need to pony up more money [than a used TDI] for Model S. or settle on a Model X/Y with bad panel gaps and faux wood and duct tape holding parts together.

on a similar topic, my wife used to drive 4k a year. since covid she is on track to average about 1k/year. and it looks to be that way indefinitely as she has been told she will most likely be working from home forever. when her current lease is up im considering to get a Tesla for her, since she never drive far enough to run out of electric.

[oopsy]

Thanks for the commentary thus far. Just to address a few things raised above
--RE MPG: My current Prius is an accident of circumstance and not a statement re: utilization. I'm not married to the fuel economy of the TDI although certainly appreciate it if it pans out in some regard for me.
--I understand nothing of what ValpoA7 said regarding CERC motor, etc. Sorry that's way over my head.
--RE: DPF, I looked up DPF deletion on the forums and online and I think I understand the general principle, but my impression was that this was not legal and would be a chore to find someone to do. Aside from that, what's the downside of doing this for the car's function/reliability, anything? I looked it up and confirmed that in my state, diesels dont have to have emission testing.
--RE: Tesla. I was actually hoping to ride out my Prius for another 2 years and get a Tesla once the flux in my job settled out (in limbo pending contract renewal), and then get a Model S, but I can't justify that cost now with the ambiguity. Anyways, that plans not going to pan out. Model 3 seemed small for my needs, but maybe will reconsider.

To emphasize an outstanding question, what's the downside of getting a 3.0T and doing stage1/2 on it? Does that void warranty or accelerate hardware failure? Can it capture the low-end torque of the TDI?

[Cayo71]

Any performance modifications that requires a new ECU program will flag TD1. That doesn’t mean that if you AC fails they won’t cover it under warranty but any power train issue you have they will most likely deny warranty due to the performance mod.

[Audisthesia]

You're not going to get low end torque in a gasser like a diesel puts out. Its not really fair to even compare the two, apples and oranges.

This guy gives a really good explanation of the engineering behind why diesel always has the torque... https://www.youtube.com/watch?v=D6YmAecTolQ

[IbisA7TDI]

TDI - barely commute now...but typically have a 50 mile roundtrip for work. But, did it for the torque as well and absolutely no regrets :)

[A665]

I'd buy the TDI and not worry so much. The low-end torque is tremendous, as you know, and the fuel economy is as well. If the longevity is so concerning, I'd just plan to run it longer after work or during weekends. :)

My family of four traveled to Scotland last summer. We rented a Kia Sportage diesel, which accepted all four of us (adults) and our luggage nicely. We drove just over 600 miles during our 10-day stay, driving through Glasgow and other cities plus miles and miles of countryside through the Highlands and elsewhere, yet barely consumed 2/3 of the fuel. The accelaration from a stop and the overall throttle response was great. Made me look into diesels for my next car. I probably would have bought one if I hadn't found such a great deal on the 3.0T I'm driving now. It's apples to oranges to a degree, comparing a Kia Sportage to an A6, I know, but you get the idea.

[ramses333]

I'm on my 3rd TDI and the 3.0TDI torque is so much fun. I do 160kms roundtrip commute (98% highway) with 1000kms+ per tank. I see why you like it.

But with your short city commute, I'm afraid you won't even see the benefit in fuel savings and more of the common engine troubles these cars are known to have. These cars are highway cars and short commutes tend to affect the longevity of the engine and emissions system (though covered under the extended warranty). At that distance, your DPF will never have enough time to run a full Regen cycle which which clog it up. DPF is covered under warranty but I doubt you want your car to spend all that time at the dealer even if it's free.

If you want the TDI, I'd suggest doing a DPF delete once out of warranty to avoid issue.

If I had your commute, I'd definitely get the gasser (probably S7/S6 ) for the fun.

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[Alabama]

To emphasize an outstanding question, what's the downside of getting a 3.0T and doing stage1/2 on it? Does that void warranty or accelerate hardware failure? Can it capture the low-end torque of the TDI?

Trust these other guys for engineering comments. If you get a 2015/2016 model, likely the warranty will be mostly or all over so maybe not really a concern, especially for a clean car that these guys can give pointers on what to check. Probably also a minor point, but consider if you have access to good quality diesel at a good price. For example, Costco in Louisville KY sells diesel for only 12 cents/gal more than their price for 87 octane, but no Costco diesel in Georgia. Good luck, doubt you'll go wrong either way.

[christianb5s4]

Personally, the diesel as others mentioned will not like the short commute over a long-term period. The CREC 3.0T in the 2016+ C7.5 is a big improvement especially in the fuel economy and reliability department. I have no issues beating the quoted city MPG figure of the TDI with my car.

You will definitely feel the torque of the TDI, but in any situation the 3.0T is significantly quicker.

[oopsy]

Thanks for everyone's input and help. I learned so much! First, when I initially looked, I didn't know that the A7 had moved on to 3 seats in the back, I assumed it was still just 2 seats as it was in the earlier days when it came out. That was a revelation b/c I love the swoop. Next, I thought a lot about TDI vs. TFSI, and I ended up giving the 3.0 TFSI another try and liked it a lot, albeit in a different way. I basically decided that I would get whatever I could find in terms of my colors/options of interest, I found a 2016 A7 3.0TFSI Premium Plus, 50k miles, black on black, with black optic package, cold weather, s line +sports, and a nice tint on it. I jumped on it and brought it home today!

Will be digging through the forums to figure out next moves, chiefly car play and whatever else you may advise! I'm going to give it a little bit of time and then will consider advance tuning to stage 2.

All of that to say, thank you all for your help and insight, and RIP to my Prius.