So, I have been seeing a number of threads about the new Diesel offered in the Cayenne. I have been doing some basic searching as I wanted to learn more about this new offering in the Cayenne line. It appears that 2013 is the first year it is offered, and it also appears that there is a V-6 and V-8? I say that with a question as it is confusing. Hoping someone can clear some of this up.

Funny what you get when you do a Google Image Search words "Porsche Diesel"

Who is the original Designer of this Diesel going into the Cayenne? Example, the Ford Diesel is an International design, The Dodge Diesel is a Cummings Design, at least until Next Year.

Is the Porsche Diesel a common rail design, or one like the International that used Hydraulically assisted Electronic actuated injectors. I know it isn't an old mechanical design where spring pressure is overcome by a high pressure pump, but wanted to learn more details related to the technology.

One think I learned with the newer Electronic Diesel's, Prepare to change various pressure and temperature sensors from time to time. They fail and get all clogged from various emission features on the Electronic Diesels.

I know I couldn't afford a new one, but maybe in a few years, they will be in my price range.

 

There are two Cayenne diesels. The Cayenne diesel that you see worldwide, which is basically an Audi V6 tdi slightly modified by Porsche. There is in Europe, the Cayenne diesel S, which is also based on an Audi V8 diesel.

For NAFTA purposes, we only get the V6 turbo diesel. I believe it uses a common rail design. It is really not new since it has been introduced in Europe beginning with the current Cayenne design. It was introduced in the U.S. in 2013. So far, if you read the VW Toureg tdi and Audi Q7 tdi forums, you'll find that it is quite a reliable engine.

 

As already noted, the V8 is only in Europe at this time. I did see a rumor that we might get the Diesel S in the next model (not the pending refresh, but the replacement for the 958), but who knows.

To add to what was said not only has the motor been in Europe for some time, but the V6 TDI has also been in use for a pretty long time in the rest of the VAG offerings for even longer. It's had some tweaks and changes (most notably the DPF system), but my understanding is that it still pretty much a nice strong almost 10 year old motor.

I still love mine and it puts a smile on my face every time I drive it. All that low end torque belies it's lack of horse power (compared to the other Cayenne motors) and gives you a nice kick when you use the gas.

Mine just got repainted and I looked into getting the tractor logo to put on the rear, but damn it's pricey!

This is something that will be interesting to see. So far the 958s with any motor haven't taken the nose dive the 955s and 957s did, but they also haven't been plagued with "common" problems like those (even if they were more internet noise than really common). Diesels in general have also historically held their value well even in the US compared to their gas counter parts.

 

It is in fact a common rail (turbo) diesel, and the injectors are piezo-electric; hence computer controlled. Not sure where you picked up that info, but I've never heard/read about clogging issues with these things. Third-generation common rail diesels now feature piezoelectric injectors for increased precision, with fuel pressures up to 3,000 bar (300 MPa; 44,000 psi). And the do that several times per second. So it would seem pretty hard to clog once you get up in that territory. Besides, the ECU notifies the driver immediately (with a fault code) if an injector begins to operate outside design parameters. Whereas 1st and 2nd generation injectors - like spark plugs - would be changed en mass - 3rd generation injectors are typically replaced individually.

Turbo boost pressure is controlled by the ECU as well. The turbocharger turbine has electronically variable vanes, the angles of which are controlled by the ECU (relative to driver input). It makes a single turbo act like a twin-turbo, but without out the physical bulk of an separate turbocharger. Good thing too, it's already pretty crowded up by that firewall.

I actually saw one of those original Porsche tractors by the way. I was stationed in Germany for 4 years, and did a lot of clay pigeon shooting. During one shoot outside Munich (Hattenhofen), I walked past a faded little red tractor in the weeds behind a shed. On the cowl were the faded but still readable Porsche emblems. It was one of those days you wished you had a camera along.

//greg//

 

Nothing wrong with that "old" technology...I had 2 MB 300Ds with over 700K cumulative miles. I replaced the injectors when they got noisy every 10K miles or so for about $15/ea. And I replaced a couple water pumps. Aside from oil & filters, I didn't spend $500 on those engines in ten years. I doubt that the "new" tech diesels will come anywhere near the reliability/longevity of the venerable low tech smudge pots. We have a Jetta TDI about to go off warranty next month, and I'm debating its future...the 18,000 (!) PSI fuel pressure doesn't give me warm & fuzzies for the long term.

 

I didn't say the injectors will clog. What I said is that the various Pressure and Temperature sensors will. ALL Cayenne Diesel Owners will have an experience in the near future that will cause them to get stuck on the side of the road, one of the Pressure or Temp Sensors that help control the computer will foul. All the Diesel Truck owners started learning this over the last decade after Electronic Diesels were introduced. Oh, not to mention the EGR valve issue on the Volkswagen Diesel... We may want to learn where and how accessible the EGR valve is on the CD top clean it before it fails.


This Porsche Diesel is starting to sound more and more like the International 6.0L in my Ford truck. Note, Ford went to twin staged turbo's in their 6.4 design to minimize turbo lag. It will still be there even with the variable vain.


I didn't say there was. I also have two old Hino Diesels in my boat I take care of. Very reliable.

There is and was much to learn about when caring for a Diesel. I look forward to seeing the future posts, not because of the failures, but because of the repairs we will discover together.

Last Note. In 2004, when my 6.0 was new, the Ford Dealer had a new Engine program for me every time I brought the truck in for service. Each program would change the characteristics of the engine performance. I believe we may expect the same form Porsche as the engineers fine tune this Motor.

 

From a purely mechanical sense, you're correct. But you're not considering diesel torque and the programmable transmission. This engine idles at ~800 rpm, and is already developing max torque by 1750. Unlike the V8 Cayenne, this transmission always starts out in 1st gear. Between the 6.4:1 gear ratio and the high engine torque, turbo lag isn't noticeable in the least. At 60 mph in 8th, engine is turning 1600 rpm. Accelerate to pass, it drops to 7th, and is right back in the max torque range. At 75 mph, you're at 2000 - car doesn't even feel a need to drop to 7th.

That's in stock form. I subsequently installed a diesel tuning box, bumping the stock 240 hp/406 torque and 0-60 time of 7.2 seconds to (an advertised) 305/515. I say "advertised" because I don't have access to a dyno to verify the numbers. But I can tell you that 0-60 times are in the low sixes. Turbo lag in imperceptible.

This engine/transmission combo has been on US roads since 2012, and ROW since 2009. I belong to 5 Cayenne (diesel) forums. If fuel clogging and/or turbo lag was an issue, I think I'd have read/heard about it already. Underestimating this engine/transmission combo impresses no one but yourself.

//greg//

 

If the Cayenne had been available with the V8 diesel in the US I would have bought it instead of my GTS.

"Audi-designed 4.1, strengthened to 382 hp and 627 lb-ft of torque"

http://www.caranddriver.com/reviews/...t-drive-review

 

Hmm.

https://rennlist.com/forums/porsche-...pressions.html