It is this same experience with a Cayenne Diesel loaner that made me sell my GTS and replace it with a diesel. It's not a Cayenne, but it was a great decision. Economically, diesels make no sense given the diesel price premium over regular gas in the Northeastern US but it sure is cool when you get 600 miles out of a tank and the torque is addicting.

 

diesel is actually the same price or cheaper than regular unleaded down in atlanta now.

 

In most cases (all the VAG brands, BMW, and MB anyway) the equivalent gas motor in the same car requires premium gas rather than regular, so you really need to compare that price to the diesel cost. Additionally due to the increased MPG you can't can't compare the cost per gallon and instead need to look at the cost per mile.

If the gas motor will get you 300 miles but the diesel gets you 600 then the diesel can cost you almost double the gas before it becomes a losing proposition. That's an exaggeration for simple numbers. Based on Porsche's quoted numbers (24mpg * 26 gallons vs 29mpg * 26 gallons) the diesel is about 20% better than the base and at prices these days that equates to $0.40-0.60 that the diesel could be more expensive before you pass the break even point.

Based on a calculation I derived from my historical MPG from gas motors against their rated MPG I am comparing what I get in my CD to what I would be getting if I had gone with the VR6. Over 20k-ish miles I'm averaging between 40-50% better gas milage. Along with the milage I've been tracking the prices and when they are within a few cents of each other I'm "saving" $15-20 at each fill up. In the worst case where there was a $0.50 gap in premium's favor I still "saved" $5 each fill up.

Of course the other part of the equation which is critical is the type of driving you do. If you are always in stop/go city traffic then the new gas motors may do better for you with the stop/start functionality, but if you are towing or doing a lot of highway cruising then the diesel wins by a much bigger margin than just 20%. Everyone seems to report doing much better than VAG's quoted 29mpg when cruising at high speed and you won't get close to 18-20mpg towing 5k+ with the gas motors.

 

Plus keep in mind that services are twice as often on a diesel (5k vs 10k) in the US. That costs an extra $250 or so per year assuming you only drive 10k.

My most recent tank of gas on my S eHybrid yielded 1,016 miles (19.9 gallons used). That works out to 50 mpg. Of course that is not the norm, as I did a lot of short trips. Buy my average over 6k miles is 33.9 mpg (actual calc not MFD) with several 38 mpg tanks so far. So I am very happy with those numbers.

http://www.fuelly.com/car/porsche/ca...otpedlr/341217

 

That's nice. I don't suppose the charge has a meter on it so you can calculate out that cost too? On that 50mpg tank I'm really curious what the associated KWH was. I'm sure you'd still come out well ahead even on your average, but I'm a metrics geek and like having the full picture

Of course the other part of the eHybrid you have to consider is its premium over an identical diesel. I'd have to look it up but as I recall it was about $4k between the diesel and base when I bought mine. Based on my TCO that differs from the base (fuel savings, extra OCI, ad blue, fuel filters) it will pay off the premium when it gets to about 95k on the clock.

 

What about the costs of battery replacements if keeping the hybrid long-term? I haven't kept up with this and so know nothing. I just recall from when the Prius came out hearing pundits say that after 8-10 years it's a "paper weight" because the cost of new batteries would be greater than the value of the car.

 

Data point: I've got a brand new '15 CD loaner and I'm a convert: between the range, very good MPG, performance, usability, etc., she is a winner.

Now I'm gonna find some dirt roads in NorCal to do with the CD what I've often considered doing with my '10 C4S!

 

It's a Porsche so it will be expensive. I have two friends that both had to replace the batteries in their Prius (Priuses? Prii?) and both were over 10 years old. As I recall the batteries listed for $7k, but Toyota stepped in and comped the batteries so all they had to do was pay labor (about $1500 from what I remember).

I've heard (but no semi-direct experience) that Tesla has done the same kinda of thing.

I think right now the MFGs are going to be willing to play games like that since Hybrids are the easiest way for them to meet the Eco requirements for their fleet and they don't want that jeopardized. Once battery based cars are the norm I expect that helpfulness will start to go away as we will have less choices so complaints will have less impact.

Of course the other problem is that battery tech is in such flux right now that basing the longevity of the eHybrid's battery on that of an early Prius or even the Cayenne Hybrid is not likely to be very accurate.

 

I actually did the math for the electric on another site.. see below. But it still pencils out for me. As far as cost of the CD vs CSEH, the eHybrid is an S, so you really have to price it out fully to compare as the options vary. I was on the fence between the two so I did that when shopping. My SEH was stickered at 102k and netted out at $90k after discount and fed tax credit. The exact config on the CD was $89k after a discount (slightly lower discount given on the CD). So the Net $ difference was only $1k.

The battery is warrantied for 7 years and 8 years for the battery management system (probably longer then I will own it). The battery may be expensive, but will definitely be easy to replace as it is positioned like a spare tire just sitting under the cargo flow cover. I assume as more cars are going hybrid, the battery cost will become "more" reasonable.

Lastly - here is my math on the savings including electricity:

My average calculated mpg over the 6.2k miles I have driven since new is 33.9, which I think is awesome. I wanted to know what I saved over gas alone... so I assumed my mpg for gas only (SEH always running on the gas motor) would be 22 mpg. I used a total of 184 gallons of gas so far (6,244 miles / 33.9 mpg). If I used the 22 mpg average of not plugging in, I would have consumed 284 gallons to drive 6,244 miles, thus 100 more gallons. This would have cost me $316 at today's premium rate.

But since I consumed electricity, I wanted to factor that in. I calculated that I used 2,192 miles of electric (delta between the 22 mpg and the 33.9). That is the equivalent of 137 "tanks" of battery juice, based on my ~16 miles from each full battery charge. That would be 1184 KWH (based on 80% of the 10.8kwh tank that is useable). I pay 8.7cents per KwH, so that costs about $103. I multiplied that by 80% (since I fill up at public stations for free about 20% of the time approx). Thus my net home electricity cost was around $82. Resulting in a net savings over gas of about $230, or in my case it will be about $500 or so for a years worth of driving (about 12-15k miles).

If you are doing lots of long hwy trips, the diesel is a better option. More intercity and/or stop and go, the SEH shines.

I addition, I got a $500 rebate from my power company, not figured in the above.

 

Thanks for the numbers. I find it interesting that the diesel delta is so small, but you are correct that you need to spec it with the same options. Much like you I had to add the Tip to the old base as the 6MT was standard and not available on the diesel.

When the extra maintenance is factored in, I've been about $250-300 in the green over a year which is about 10k for me.

 

Very interesting data and observations, guys. Thanks.

 

One thing I wish I had gotten on our '14 CD is the air suspension. Roads here suck and the ride is stiffer than I thought. Having said that, we'll probably put 140k to 160 k on ours and I suspect I will be pleased not go have to repair / replace any of it in that time. OP, glad you enjoyed it. It's a true sleeper in the range.

 

Can't figure out how you guys are getting such good mileage. On long highway trips, fully loaded but with no trailer, I can't get over 28. Of course, much of the time we are in 75 zones with the cruise at 83.

 

on the by pass around Austin at 85 ( and for you folks not in Texas that is legal) I still get 28 plus.

 

I am very close to trading in my '08 Touareg V8 w air suspension. I love it, even nicer when we tow our 5,500 lb boat. The '14 CD I am looking at does not have AS. Am I really going to miss It? Thx.