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Would you buy a diesel smart?

  • No

    Votes: 14 12.6%
  • Maybe

    Votes: 24 21.6%
  • Yes

    Votes: 23 20.7%
  • Definitely

    Votes: 50 45.0%

  • Total voters
    111
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You're close (off by only 800 RPM) The VW 2.0l TDI ('10-up) redlines at 5000 RPM
Track Tested: 2011 Volkswagen Jetta TDI
Sorry, I've been out of the VW and TDI world for a few years now, so I guess I need to brush up on my info. In any case, redline on the newer TDIs is actually 5,100 RPM and I think it was 4,800 RPM on the '09 TDIs. What it was prior to that (non-CRD TDIs), I forget, though 4400 RPM seems to jump out at me. Anyway, with a 5,200 RPM redline (per Mazda's website), the new Mazda diesel still isn't an unusually high revver.

What does fascinate me about the new Mazda is that it has an unusually low CR, and it meets emissions standards without all the fancy NOx aftertreatments.
 

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Discussion Starter #124
oh I love that. diesel torque down low.
Imagine the easy pull in a diesel fortwo, casually passing someone as if you downshifted.
 

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Flashback: The 1967 Peugeot 204 Diesel wagon had a 1255 cc diesel that developed maximum power at 4900 RPM and redlined at 5100. Your trivia for the day.
 

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Discussion Starter #126
I just spent $30 on gasoline, the pure undiluted gasoline my car was designed to run on; the stuff that isn't 10% ethanol. It was going for $4.099 tonight.
while diesel is still only $3.85, goes further per gallon, and isn't hygroscopic like $3.60 Unleaded Premium.
Eventually people are going to notice. Just because no smart diesel is being announced right now doesn't mean that's set in stone. Now that the next fortwo is being pushed back for maybe half a year, that'll give them time to change that.
 

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Diesel is 70-80 cents more a gallon than regular, and 50-60 cents more than premium. I just really don't understand the whole pricing structure of fuel in the US -- seems like there is a lot of shenanigans going on!
 

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MY08 cabrio MY09 cabrio Brabus MY15 ED
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Just because no smart diesel is being announced right now doesn't mean that's set in stone. Now that the next fortwo is being pushed back for maybe half a year, that'll give them time to change that.
Sorry but it would take MB/smart longer than that just to gain EPA approval for a NEW cleanburn diesel. Then there is the additional diesel tech training and parts inventory for a niche of a niche.

The 2008 emissions standards killed the smart fortwo cdi as we (actually Canada) know it and I doubt a new version will see this side of the pond.

As for the high cost of diesel at the pump there are three main issues;
  1. The first is supply and demand. Most developed countries are using more diesel and less gasoline for each barrel of oil when compared to U.S. consumption. In addition to this foreign demand for diesel, our "over the road" transportation fleet and farm/construction equipment rely heavily on diesel.
  2. Besides supply and demand, taxes also play a significant role. The Federal Excise Tax on gasoline is 18.4 cents per gallon (cpg) and 24.4 cents per gallon (cpg) for diesel fuel. On average, as of April 2012, state and local taxes add 31.1 cents to gasoline and 30.2 cents to diesel for a total US average fuel tax of 49.5 cents (cpg) per gallon for gas and 54.6 cents per gallon (cpg) for diesel.
  3. Finally, there is the possibility that by requiring low-sulfur diesel, the refining process may have become more complex and costly?
 

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In our area right now gas prices for E10 Premium are $4.40/U.S. gal. Diesel is slightly below the cost of Premium but is known to jump all over the scale from season to season. I have seen diesel as high as 90 cents/gal. more than Premium. It's only since the latest go round of gas price jumps that diesel has dropped below the price of Premium in our area for a long time.
 

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Discussion Starter #132
At a nearby Mobil Station
Diesel $4.09
Premium $4.11
At a nearby Chevron Station
Diesel $4.09
Premium $4.19

And this isn't even ethanol-free gasoline;
it's the diluted down E10 swill.
 

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I'm speaking here as a long-term VW TDI owner. Both of the TDI diesels in my experience have been great.

BUT ...

For a car that already has low fuel consumption to begin with, in gasoline engine form, and given the extremely complex emission control systems needed on diesel engines nowadays in order to conform to emission regulations, I don't think I would bother on something as small as a smart - particularly if the gasoline engine on the upcoming model is improved.

The smart cdi is mostly reported to use 4.3-ish L/100 km. My gas engine model uses 5.8-ish L/100 km. Gasoline and diesel fuel are close to the same price in this area. So you save 1.5 litres (about $2) every 100 km. In a normal expected lifetime of the vehicle (say 200,000 km) the business case is borderline. Meanwhile ... you have a 44 horsepower vehicle that takes 20-ish sec to reach 100 km/h as opposed to a 70 hp vehicle. Doesn't work for me.

Longevity? Diesels have a reputation for it, from the past. But ... Look at the induction and fuel injection and emission control hardware.

The gasser has: 40 psi in-tank electric pump, manifold-mounted injectors, 3-way catalyst, 2 oxygen sensors.

The diesel has: 40 psi in-tank pump (same thing - no difference), high-pressure (1600 - 2000 bar) fuel pump (VW has been having trouble with these), direct injectors, variable-vane turbocharger, EGR valve, EGR cooler, intercooler, oxygen sensor, oxidizing catalyst, DPF diesel particulate filter, SCR de-NOx catalyst, AdBlue tank, AdBlue metering pump, and a bazillion other minor components and sensors to make all this magic work.

VW has been having trouble with: Turbo, high-pressure fuel pump (the Bosch CP4 injector pump is a poor design), EGR back-pressure valve, intercooler (exhaust from the low-pressure EGR system puts moisture into the intercooler, which freezes in cold weather), and the estimated life of the DPF is claimed to be 120,000 miles / 200,000 km, just in time to blow away all of your fuel savings IF nothing else has broken first.

Bottom line ... I do not want a new-technology diesel engine unless there is a serious business case for it AND a good warranty. In the case of a small car that already starts off with low consumption to begin with ... No thanks.
 

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spritmontior shows that the 450 cdi average fuel consumption is 4.14 L/100 km, and about 4.27 for the supposedly more efficient 451 cdi.

They don't use AdBlue, variable geometry turbos etc, but overall they are slightly more complicated than the 451 gasser. One way in which the cdi is simpler is the valve train (2, not 4 valves).

The high pressure pumps and injectors are basically bulletproof. The weak points are EGR for city driven cars and intercooler chafing on earlier models. The speed issue is thoroughly addressed by a Fast Eddy remap, which makes the car very responsive, close to a 451.

Diesels should not be bought by people whose typical drive is under 20 km or 12 miles. They respond very well to longer commutes and service life is well over 300K km without major repairs if that's how they're used.

The reason we didn't replace our rear-ended cdi writeoff with a brand new 451 was the fuel consumption and type of fuel they require. Our 2013 Ford Fiesta has 125 HP, is as quick as a 451 BRABUS and is cheaper to drive than a 451, with identical FE to 70 HP 451s and regular fuel. That was the main criterion for that particular car, which goes 190 km to and from UVIC every day.
 

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The cdi is also not certified to meet US EPA Tier II bin 5. It remains to be seen whether it would be possible to achieve that without AdBlue and without variable-geometry turbocharging and with older-generation fuel injection hardware. Mazda claims they'll be meeting those standards without AdBlue but their engine uses two sequential turbochargers and variable valve timing. It is very, very tough (and therefore, expensive) for diesels to meet either US EPA Tier II bin 5 or Euro 6. In small vehicles, it's hard to justify.

The pickup truck diesels have been having all sorts of headaches with emission controls and fuel injection hardware since 2007, too. And poorer fuel consumption.

The next smart is supposed to be using a newly-developed Renault 900cc engine which has some interesting design features. If they can get improved fuel consumption out of that engine (and using conventional gasser emission control hardware!), it reduces the business case for diesel even more.

Aerodynamics is the other challenge. It's tough to get a good Cd on such a short vehicle.

For myself, once the consumption gets into the 6-ish L/100 km, I stop worrying about splitting hairs. It's good enough. I got the smart because that's what I wanted.
 

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Pretty much an exercise in speculation at this point. If all the rumors are true there will be no diesel 453 in any market, probably because the gas power plant will be almost as efficient at lower fuel cost with a less complex engine arrangement. Rumors for sure but we'll know more come September. :)
 

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Yeah the diesel smart is dead for sure, which is a shame, but them's the breaks.

The 450 has a 0.37 Cd; the cdis with 135 section front tires have 0.36. Not great, not bad. I think the 451 may be similar, though it has more frontal area than a 450.

Nearly two-thirds of respondents to this poll would take a diesel if it was offered, which is interesting. Americans supposedly hate small cars and hate diesels on top of that!
 

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The cdi is also not certified to meet US EPA Tier II bin 5. It remains to be seen whether it would be possible to achieve that without AdBlue and without variable-geometry turbocharging and with older-generation fuel injection hardware. Mazda claims they'll be meeting those standards without AdBlue but their engine uses two sequential turbochargers and variable valve timing. It is very, very tough (and therefore, expensive) for diesels to meet either US EPA Tier II bin 5 or Euro 6. In small vehicles, it's hard to justify.

The pickup truck diesels have been having all sorts of headaches with emission controls and fuel injection hardware since 2007, too. And poorer fuel consumption.

The next smart is supposed to be using a newly-developed Renault 900cc engine which has some interesting design features. If they can get improved fuel consumption out of that engine (and using conventional gasser emission control hardware!), it reduces the business case for diesel even more.

Aerodynamics is the other challenge. It's tough to get a good Cd on such a short vehicle.

For myself, once the consumption gets into the 6-ish L/100 km, I stop worrying about splitting hairs. It's good enough. I got the smart because that's what I wanted.
what is the inside scoop on the 2.0 TDI in the Golf/Jetta/Passat? If I could be assured that it was dead-nuts reliable the Passat with a 2.0 TDi and a 6 speed manual is very near the top of my hit list for a new family car.
 

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2.0 TDI in Golf/Jetta is not the same engine as Passat. The Passat engine came later, and they fixed some of the issues that Golf/Jetta have.

HPFP in Golf/Jetta seem to be failing in USA at a rate of somewhere near 1% per year - that is, every year, about 1% of the fleet experiences a failure. VW has been covering these under warranty up to around 140,000 mi IF the owner makes enough noise and IF it is not a known case of gasoline in the fuel tank. This is roughly a $8,000 repair if you have to pay; i.e. if it happens beyond 140,000 mi, the car goes to the scrap heap. Whether you consider this to be an acceptable lifetime is open to question. Failure rate in Canada seems lower - our diesel fuel meets international lubricity specifications, American diesel fuel does not.

The Passat HPFP is still a Bosch CP4.1 but it is a different part number and there are known differences inside it, and the fuel system outside of the HPFP has some differences. The HPFP failure rate seems to be much better so far.

Golf/Jetta have been having issues with the intercooler freezing up in cold weather (happened to my dad) due to the moisture from the recirculated exhaust. There is a retrofit kit to sorta fix this (not 100% effective but it's a lot better) - for some reason, it is not being incorporated on the production line! Passat fixes this issue, because it uses an air-to-coolant intercooler which is thermostatically regulated so it can keep the temperature above freezing.

They've all been having issues with the EGR back-pressure flap seizing up. It's underneath the car in a location vulnerable to salt, dirt, road debris, etc. They've extended the warranty to 120,000 mi / 10 years on this part.

We already know a thing or two about the next TDI engine in the upcoming Golf 7. Liquid-cooled intercooler to solve that issue ... the EGR back-pressure flap is no longer needed and what's not there can't break ... hopefully the fuel system will incorporate the Passat improvements but all we know right now is that it still uses the infernal Bosch CP4.1 HPFP of death. If the calibration doesn't push the operating pressure to the limits then maybe it will survive. If failure rate is at Passat levels it's probably acceptable. A few Passats have had the turbo let go early in the car's life, but nothing's perfect.

So if you want a VW TDI right now, the Passat is the way to go. The trouble that I have with that car - aside from that I don't need one that big - is that it looks like the outgoing Chevrolet Impala, and if I want a car that looks like a Chevrolet Impala (which I don't), then I'll buy a Chevrolet Impala. Otherwise, hold out for the Golf 7 and hope they don't introduce any new first-model-year problems.

Or go with the soon-to-arrive Mazda 6. The fuel pump is Denso (not Bosch) and is a different internal design. If you live in the rust belt, Mazda does not have the greatest reputation in this regard ...

Keep in mind with this, the tendency for failures to be exaggerated on ALL automotive internet forums. Plenty of people have late-model TDI cars and are happy with them and have not had trouble. It's the same as it is on this forum. If you go by how the smart forum is, then we all are travelling in peril of burned exhaust valves, coolant hoses rubbing through, shifters that won't shift, etc., and yet, in reality, most of the cars don't have these problems.
 

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Much appreciated for the detailed response Gofaster. I've about got it narrowed down to the Passat (I do need/want a bigger car for trips) or a [used] Lexus GS 350 (2008-2009). I would buy the VW over an Impala even if it looks the same (similar? A bit, but I've purchased my last American car!).
 
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