Long time reader first time posting. I am defintely going to upgrade cars in about a year (I have a 07' 2.0T A4 with APR93) to either a B8 S4, TDI (assuming that it comes to the U.S. soon) or a 335xi (even though I can't stand BMW's interior). The question is, what do you think are the pros and cons mainly between the upcoming S4 and 3.0 TDI S-Line. Pricing for a 3.0 TDI S-line with an ECU upgrade down the road should still be a good 10K cheaper than an S4, and will be close to 300hp. What do you guys think are some of the things I should consider when trying to choose between the two??
What are some of the downsides to diesel, (I am not familiar with diesels at all)performance, weight, compared to bi-turbo, etc. I live in the metro detroit area and diesel fuel is about 3.59 right now compared to about 3.22 for premium just to give you some info.

As for price of fuel, Diesel has more heat content per gallon than gss, so in terms of the power it makes, it is cheaper...and you get this return in the much higher fuel milage.

The Diesel, turbocharged, also has a much greater torque output, which is acceleration ability, for a given displacement.

The biggest advantage of Diesel vs. gas engine is the economy of the Diesel under low load conditions, such as cruise. There is no throttle on a Diesel engine. It is pumping the full volume of air at all times. The only thing that changes is the amount of fuel injected. The Diesel is a highly variable fuel/air mixture process. More power? Inject more fuel. Less power? Less fuel, much less fuel.

In contrast, gasoline or Otto cycle engine runs a throttle plate, because it needs to run a very narrow fuel/air range somewhere between 15:1 and 11.5:1. At low loads the gasoline engine must burn more fuel than a Diesel or it will get too hot inside and/or it will missfire.

With the modern Diesel, the traditional disadvantages, noise, smell, weight and high initial cost have all be successfully reduced to the point that the advantages of higher torque and 15% to 25% fuel cost savings are very attractive.

Also, although Diesels have less rated horsepower, their torque is much higher, and acceleration times can be and often are comparable.

The S4 will probably accelerate 10-15% faster going flat out, but the Diesel will always provide some 15-20% better fuel economy, and probably higher under cruise conditions.

Hope this helps, but drive them to see what you prefer. I am going Diesel, having driven them in Germany. They are quick enough!

==m==
Mike

Or at least here in Los Angeles, it's about 10-30 cents more than premium.

The present market differential btw. the cost of the fuels (.20 to .25 cents) (Premium gas vs. Diesel) is quickly over come given the diesel's efficiency. One of the members over at www.tdiclub.com has posted an elegantly simple MPG vs. Cost per gallon formula of the two fuels. I'll look for it and edit this post. The bottom line is diesel rules the $ cost per mile argument.

Make my Audi B8 Avant a 3.0TDI.

do you think that the 10k or so price gap between the tdi a4 and s4 will be worth it? What options do you think the S4 will have standard over the tdi s-line? if any. I am just trying to justify why I would spend another 10k for two cars that seem to be so close (if you chip the tdi). Thanks for all the help.

Your question and interest is a tough call given the mounting speculation on future products.
However, you may be onto something ... and it's called diesel; Drive the torque....

Like anything, if people are trying to recover the cost of the higher priced engine, don't even bother.

It's like people buying a hybrid thinking they're saving money when in fact they don't break even until MUCH MUCH later.

So looking at diesels, I say look at the environmental impact and the fact that you get a lot lot lot more mileage out of a tank of diesel vs gas but with a lot of torque which is very attractive.

I'd like to get a 3.0TDI when the next A4 comes out but if it's going to be priced around a 3.2L I may have to go with the 2.0T unfortunately. Unless my company stocks (US) takes off and the Canadian dollar tanks :)

replace the wheels, susp, and brakes anyway. Hoping Stasis will offer some sort of Signature package after a year or so. I'm going to wait a little for the TDI's to get here to see what issues there are. Yeah, they have been running them in Europe for a while, but that doesn't mean they won't have US spec issues. The one reason I want TDI...mileage per tank. Both my wifes and mine commute are at least 60mi round trip every day so the great mileage of the TDI will be nice. 2.0TDI for her (Tiguan I hope), A4 TDI DSG(I hope) Avant for me! Throw an MTM chip in there and the power and torque are good enough for me. I have a 2.7T B5S4 and don't need or want that 400hp anymore.

Let's say you have a 15 gallon fuel tank.

Fuel is:
$3.10/Gallon 93 octane
$3.40/Gallon Diesel

You Fill up the tank and it cost you:
$46.50 for 93 Gasoline
$51.00 for Diesel

You get approx:
26 MPG for the Gasoline
40 MPG for the Diesel


With those numbers, you will yeild 210 more miles in that tank of diesel compared to the Gasoline engine. That equates to 8.08 more gallons of Gasoline compared to the Diesel. Or more aptly, $25.04 for the additional Gasoline.

So, you have to ask yourself. Is the additional .30 a gallon worth it? You're damn right it is.

been dreaming about a quattro diesel in the US. This will be my perfect car. I owned a Citroen ZX and an Alfa Romeo 145 both turbo diesel in Argentina before I moved to the US. Loved them both. I could even live with a 2.0 TDI, but I hope i can afford the 3.0 TDI.
cheers, juan

I didn't do the math, as you did. I simply proposed the notion. Thanks for the break-down.

Drove the Peugeout 407 this summer from Provence to Burgundy at 130 km/h with my family aboard. This is a Camry sized car but has a 1.6 turbo-diesel and a simple five speed. We were doing 4.8 litres per 100/km which I believe works out to over 40mpg. almost 45. In town traffic this car still got about 36-8 mpg. It was no hot rod but wasnt too slow either. About like a four cyl Camry. 130 km/h is over 80 mph. This car was sooooo efficient. A 3.0 TDI A4 wont be this high in the mileage but will be solidly in the 30s and will be perfectly suited to driving here in the US with stellar 0-60 performance with tons of torque off the line and for loafing along the interstate at 70. Audi USA: get that car over here and sign me up.

Check out the site http://www.fueleconomy.gov , maybe you've seen it. The site allows the side by side comparison of many vehicles.
My family's MY06.5 VW 1.9TDI/DSG Jetta is about a year old now and has covered 24k + miles in total, most of which are city use. (a 80 mi. daily school commute. 2 x40 mi round trips) The average MPG for this commute stands at 36.3MPG. Try that in a 15-18MPG SUV..

Now, if Audi of America would hurry up with their TDI availability; make mine a A4 Avant Sport w/DSG.

The 3.0L TDI is already available on the B7 A4 where I am and the price is exactly the same as the 3.2L V6, so I doubt that the B8 will go up.

Maybe they will do things differently in the US.

as diesel normally commands a higher entry price for the car...It's much improved fuel economy will pay dividends over time as will it's lower servicing costs...

Instead compare it to the 3.2 petrol V6...Then you will see how diesel makes a lot more sense...

I hate that truck clacking sound...

Typically the V6 would have a few extra options not available on the 2.0T.

And I won't be surprised if the TDI MSRP ends up being uncomfortably close to the B8 S4 base MSRP

The audible character of the Jetta (VW/Audi 1.9PD TDI) diesel motor is very un-truck like, as it's fairly quiet. Never the "truck clacking sound" of past diesels. And from the interior perspective, the vibration/sound is the same or better to the VW gas motor.

Those that have heard the new VW/Audi 2.0TDI common rail motor say its remarkably quiet. That even with the engine hood open, you must study the sound to determine if it's the diesel version Jetta. That's substantially quiet. Gotta luv that neu common rail injection! Quiet is also true of the A4 Avant 3.0TDI (common rail injection) that a family relative owns.

IF the price of entry plus the higher cost of filling up with diesel ends up topping the cost-savings of the better mileage. Which it doesn't appear to do at this early point.

in durability, gas mileage and torque.
They will be expensive, diesels typically go for much more than their petrol counterparts. I think they will be top of the line as the TDI has a built-in audience in the USA. They will buy no matter the price.

But at least this is another viable option for people other than the stupid hybrid marketing that is out there suckering people in believing that they are going to get awesome mileage when in fact, the improvements aren't even close.

I watched a You Tube vid of a new A6 2.0 TDI (European) and that thing was pretty rough (from the outside) but it may be deceiving with the camcorder mic?

I still wonder if Audi will have enough 3.0's to go around when you consider it'll be in the Q's and most likely in the A5 & A6?

If the S4 and the tdi are the two cars that I am trying to decide between than I WILL consider them as competitors. They both have something to offer and it makes for an interesting debate, NOT the 3.2 and tdi 3.0, thats not even worth talking about.

in order to get them out there to begin to change the perception of diesels in the united states.

I wouldn't be surprised if Audi offered on heck of a lease deal as incentive to get as many TDI's out there for people to flash around as possible.

With all this talk and rhetoric lately of fuel savings and "going green" this is the best option for Audi in order to turn the most heads their direction...

But kudos to you for your interest in the TDi...

Typically from a cost and performance point of view the 3.2 petrol and 3.0 TDi are natural rivals...

Seems I've read a recent MB USA announcement where MB plans to only lease the E series sedan Bluetec; no sales. Maybe that Lease only strategy was solely in California? It's a large market CA...

I'd suppose this is how rumors are started - (I'd swear I read/heard this MB lease thing somewhere, WSJ, Autoweek, MSNBC, etc.)

Additionaly, I think you're right, production of these TDI motors is going to ramp up in a BIG way if North America takes off. AoA should be so lucky to have a product back log. Feast or famine.

sell their diesel. I predict it will go for sticker and be in short supply.

I'm saying that they are going to want the first wave to get out there as soon as possible to start the movement.

We here on audiworld are not their main demographic. They are going to be trying to go after the MB/BMW/Caddy/Volvo/etc drivers that don't really know much about Audi.

This new TDI is the perfect opportunity to bring something new and exciting to them, but they're going to need a little something to help them make the leap into an audi.

4 year 100k miles lease on TDi Passats and Jettas a few years ago. Something like that. It was tailored to long-distance drivers and spoke to the durability and long-legs of the TDi engines. They could certainly do something innovative like this to wave the flag.

I have a suspicion that the TDi will be HUGE for the first 1-2 years, but may taper off a bit afterward, as all of us waiting for a diesel get ours and they have to sell afterward to the unindoctrinated. Can't wait for mine.

Let MTM breathe on the 3.0TDI, that and possibly the brakes. Make that, brakes first, the MTM 3.0 magic second.

Read an article a month or so back about alt fuels, and they mentioned used diesels were priced several thousand more compared to the gas engine car. One example was the E-320, where a 3 year old diesel cost up to 5K more than the gas counterpart as a used car. Granted this is Mercedes, with a much longer diesel production history, but I think this will hold true as long as the Audi engine does not have any fatal flaws.

Look at the VW lineup. If you were to look for an 06 Jetta TDI (sold new up to this summer), you'd be hard pressed to find one under $20K used. The last generation B5-based Passat TDI is hard to find used, for good reason. Owners hold on to them for a long time. (Just like manual S4 Avants).

So adding in the higher retained value, plus the better mileage, a diesel is a great proposition for someone that keeps a car longer than just a couple of years. I want my TDI as a manual tranny Avant. Perhaps not as a replacement for the S4, but as a companion piece.

Just my $0.02.

It would be interesting to see how well the VW TDI's have been doing compared to the 2.0t? If you can't sell a TDI Golf or Passat, how can you sell one in an Audi? I think in America, the hybrid fascination has put the diesel option in the background for most buyers wanting high fuel economy.

But luxury car buyers don't really care about 50 mpg do they? I still think it will take gas prices to go over $4/gal and a lot more publicity here for there to be a sizable market for luxury diesel cars. I know many here on this forum love the performance of the 3.0 TDI (Euro dudes) but in the US, diesels just aren't seen as a performance option, especially by those dropping $40K+ for luxury sedans. A few grand a year saved on fuel expense is a drop in the bucket compared to the overall cost (including insurance and repairs).

Now, just look at all the gas guzzling luxury SUV's on the road. To me, that's the perfect market right now for the diesel in the US, but we only see the diesel in the biggest SUV's like the Ford Excursion. All the marketing is pushing towards hybrids in these boats. Maybe if the Toureg and Q7 3.0 TDI's take off and get great reviews in the US press, there will be a growing seed of demand here.

Just my $.02

except it won't be here for 2+ years and my B7 lease is up in 5 months.......

I'm all over the place as for my next car:

Phaeton, A8/S8 (D2), S6 Avant, allroad, (all used, of course)

New: 9-3 Sportcombi XWD, 535Xi SportWagon

Tiguan? (probably too small)

import a 6MT C5 (diesel) Avant from Deutschland?
hmmmmmmmmmmmmmmm

or maybe just f-it for next spring and summer, drive the V8, get a convertible of some sort, and worry about a responsible car next fall/winter (2008-9)

I know you just can't "ramp-up" overnight. Do you build more capacity for a potential and unproven US demand?

Well I took an S5 for a drive the other day, gorgeous!!!!! Made a point down shifting all the time when I came up to a stop sign or red light, the sound, oh, it sounds a bit better than the RS4 at lower RPM.

Comparing it to the B6 S4 I test drove a while ago, the S5 felt so much lighter up front through the corners and with little body lean. Wonder how much the B8 S4 will feel like since it uses the same platform but slightly larger.

Well, it seems like diesel fuel is sky high price wise here in michigan. It is making me wonder if the additional likely cost of having diesel may be just enough to make it not worth buying. Here 91 octane is around $2.93 and diesel is normally around $3.59. That is a 23.5% differece. (normally 55-70 cents more)On top of the fact that not every gas station has diesel. Hopefully the diesel gets better than 23.5% mpg over the standard 3.2L or even the the B8 S4. Makes me think...

Diesel from what I recall used to be fairly cheap compared to regular unleaded, but I don't understand the economics on why diesel is much more nowadays.

Or is it because refineries have to do make "cleaner" diesel now?

IIRC, diesel and heating oil share many processes, so in the winter, the proportion of diesel coming out of a refinery is lower to accomodate the demand for heating oil. That causes diesel prices to go up in the winter.

Here in Alabama, there is no shortage of diesel filling stations due to a large number of farm vehicles and work trucks that run on the stuff. But I have noticed that diesel prices in the summer can go almost as low as regular, while in the winter (such as right now) it can be even more expensive than premium.

So how about my 3.0TDI Avant 6MT, Audi?