50 MPG city and 60 MPG highway diesel? Bring it on!! - PeachParts Mercedes-Benz Forum

braverichard · #1 05-29-2005, 11:17 AM

So the yet to be released E320 CDI with the new 224HP / 376ft-lbs of torque 3.2L DOHC 24V V6 engine is supposed to get just over 40mpg in straight highway cruising and about 30 mpg in city-only driving and about 35 mpg in combined city and highway driving (all consumer reports estimates). We all know now that the modern diesels are clean and refined, and can deliver as much or even more power than equivalent V6 gasoline engines while running 30 - 40% more efficiently. Well, all that is old news now. Bring on the new news!

What I want to see done is a Mercedes C-Class or E-Class or even the smaller Volkswagens with a small turbocharged and intercooled diesel engine and with as much technology tacked onto the engine to make it more efficient while remaining just an internal combustion engine. I mean stuff like variable valve timing on exhaust and intake valves, DOHC, 4 valves per cylinder, efficient transmission with an effective overdrive gear, etc. A four cylinder engine will do that won't be scary fast but will have enough low end torque for merging around in city driving. Basically what I want to see done is a diesel engine that will not produce the fastest car, but will have neat mileage ratings from EPA: 50mpg/60mpg city/highway ratings. Add on the particulate filter which will reduce soot and NOx emissions with no significant increase in the price of manufacturing the engines and the hybrid car can be sent to the grave early!

The Honda Civic HX has a 1.7 liter gasoline engine that can easily get 45 mpg on the highway. For a gasoline engine that's great. Can you imagine what a small, efficient modern diesel engine made more for efficiency than power can achieve in terms of mpg? At an efficiency rate that's 30% better than that of the Honda 1.7 liter engine, that would come out to nearly 59 mpg. This is definitely possible!!

I know a lot of people who won't mind purchasing a compact car that gets such high mileage without a $3,000 price premium and without having to worry about if the hybrid technology will hold up over time. Unfortunately according to automakers such people are very few to justify the development of such a car. Add on the fact that we live in a horsepower-crazy world and it definitely won't happen. For now, that previledge will be for the Europeans only.

rg2098 · #2 05-29-2005, 11:43 AM

Realistially the Toyota Prius (pronounced piece-of...) gets identical mileage to the VW Jetta Diesel. But the Jetta's engine is tough and has been out for years. Thats what convinced my math teacher on getting the diesel.

Old300D · #3 05-29-2005, 11:53 AM

Yes, a hybrid with a diesel engine would kick the crap out of a Prius.

#4 05-29-2005, 12:47 PM

Quote:

Originally Posted by Old300D

Yes, a hybrid with a diesel engine would kick the crap out of a Prius.

This was discussed elsewhere on the forum and the general issue with hybrid diesel is that the diesel engine never gets up to an effecient operating temperature in the hybrid situation because it is constantly turning on and off.

As far as "technology" goes...VW experimentally turbocharged one of their VW Rabbit Diesels (the 1.6L) back in the late 70's and were easily breaking the 50mpg mark. I think the figures were something like mid 60's for highway and high 50's for city. Averaged out to about 60+/- mpg. They of course never sold this however the "technology" and concept has been around for ages since then. Why they never realised a TDI until later, who knows. Maybe they wanted to do more testing.
All I know was, it was super effecient as compared to almost any car in that day. I am sure it helps that the VW Rabbit is a rather light automobile. But still, very interesting information.

My source, chiltons diesel guide 1979 (or some year around there....one of the first few years that they released the 300SD (w116). That book had extremely high praise of that automobile.

Cannot imagine why.

Dana B. · #5 05-29-2005, 03:03 PM

Seems like old news. My VW TDI gets nearly 50 in city/highway driving ('00 ALH model), with better economy and power after a recently chipped ECU. The new pumpe deuse injection models get somewhat less.

The Euro VW Lupo TDI gets between 70 and 80 mpg, but one U.S. reviewer criticized its quirky tranny: http://www.usatoday.com/money/consumer/autos/mareview/mauto497.htm

Brad123D · #6 05-29-2005, 03:13 PM

Quote:

Originally Posted by Brandon314159

My source, chiltons diesel guide 1979 (or some year around there....one of the first few years that they released the 300SD (w116). That book had extremely high praise of that automobile.

Cannot imagine why.

The "Chiltons Guide to Diesel cars and trucks" is a great little book. (1983 is what mine says.) It's the book that "converted" me to diesel. Any diesel lover should have it in their library.

I remember reading about a car that Wilcap of CA built years ago that got 80 mpg +. I think it was a Mazda body with a small Perkins diesel engine mated to it. Computers and super expensive parts(TDI inj. pump @ $3000 plus etc.) aren't required to get great mileage.

Old300D · #7 05-29-2005, 03:16 PM

Quote:

Originally Posted by Brandon314159

This was discussed elsewhere on the forum and the general issue with hybrid diesel is that the diesel engine never gets up to an effecient operating temperature in the hybrid situation because it is constantly turning on and off.

That depends on the design. Diesels are fundamentally more efficient.

invol · #8 05-29-2005, 06:08 PM

Quote:

Originally Posted by Dana B.

The Euro VW Lupo TDI gets between 70 and 80 mpg, but one U.S. reviewer criticized its quirky tranny: http://www.usatoday.com/money/consumer/autos/mareview/mauto497.htm

Someone will always find things wrong with any car that is ever produced. He doesn't like the tranny because it is geared for fuel economy. Boo-hoo. The car is designed to be as fuel efficient as possible, so there are comprimises that are going to be made, as with any other vehicle. I could also gripe that all of my luggage doesn't fit in the new Ferrari, or that I can't drive my big-ass Excursion more than 150 miles before taking out a loan at the gas station. Does that make either of these vehicles pieces of shyte? I think not. Some cars are just designed for a particular purpose, and people just have to realise that and deal with it.
I personally would love to buy a Lupo if they offered them here in the States. Not only for the fuel economy, but for the sheer fact that the Lupo looks like what the Rabbit SHOULD have evolved into (i.e. small, lightweight, easily tossable car), not the big and heavy (3,000+ lbs.) Golf that exists now.

braverichard · #9 05-29-2005, 09:11 PM

Quote:

Originally Posted by Dana B.

Seems like old news. My VW TDI gets nearly 50 in city/highway driving ('00 ALH model), with better economy and power after a recently chipped ECU. The new pumpe deuse injection models get somewhat less.

Well your TDI still produces some black smoke upon heavy acceleration, pollutes much more than a hybrid, is slower than, say, the Prius and is expensive. Not to say you're car is bad, but my proposal is for the creation of a very cheap, very efficient diesel engine with all the current technologies that make today's diesel engines as refined as their gasoline counterparts. If the car can be made to be at least as fast as a smiliar hybrid while delivery similar or better fuel economy and low emissions and also be nicely priced without the $3,000 or so premium that plagues hybrids, then the industry will begin to think twice about all the hybrid noise.

Ara T. · #10 05-29-2005, 09:48 PM

The prius, faster than a TDI? The TDI produces much better torque and about what, 20 more horsepower? I'm not sure of either ones' curb weights though.

braverichard · #11 05-29-2005, 10:06 PM

According to Car and Driver's road test results, the Prius does 0-60 in 11.2 seconds, while the TDI does it in 11.3 seconds. It is a small difference that's probably negligible and could have been caused by a variety of factors, so I suppose we can consider the cars equally in that regard. I am aware that a 0-60 time isn't the all in all measure of acceleration, but it is the most universally used.

BodhiBenz1987 · #12 05-29-2005, 10:17 PM

Quote:

Originally Posted by Brandon314159

As far as "technology" goes...VW experimentally turbocharged one of their VW Rabbit Diesels (the 1.6L) back in the late 70's and were easily breaking the 50mpg mark. I think the figures were something like mid 60's for highway and high 50's for city. Averaged out to about 60+/- mpg. They of course never sold this however the "technology" and concept has been around for ages since then. Why they never realised a TDI until later, who knows. Maybe they wanted to do more testing.
All I know was, it was super effecient as compared to almost any car in that day. I am sure it helps that the VW Rabbit is a rather light automobile. But still, very interesting information.

From what I understand, the early VW diesels were of notably poor quality in terms of longevity and problems. I have seen them referenced (along with early diesel Olds) as among the reasons diesel passenger cars got a bad name in this country. I don't know much beyond that. Would be interesting to research.

Brad123D · #13 05-30-2005, 12:50 AM

Quote:

Originally Posted by BodhiBenz1987

From what I understand, the early VW diesels were of notably poor quality in terms of longevity and problems. I have seen them referenced (along with early diesel Olds) as among the reasons diesel passenger cars got a bad name in this country. I don't know much beyond that. Would be interesting to research.

I have a 1981 Jetta and love it, but what you say here is very true. Timing belts, Head gaskets, Heads, engine mounts, etc. can be a problem, but If one is willing to work at it these cars can be kept running. Fuel mileage from the high 30's to as high as 55 mpg is possible. An old Benz is a much more durable car though.

#14 05-30-2005, 04:56 AM

Quote:

Originally Posted by Brad123D

I have a 1981 Jetta and love it, but what you say here is very true. Timing belts, Head gaskets, Heads, engine mounts, etc. can be a problem, but If one is willing to work at it these cars can be kept running. Fuel mileage from the high 30's to as high as 55 mpg is possible. An old Benz is a much more durable car though.

Is your 81 jetta a TDI or naturally aspirated.

t walgamuth · #15 05-30-2005, 11:50 AM

i would think that the issue of the diesel not warming up could be fairly easily solved. i think there must be other reasons for the mfgrs not doing the diesel hybrid. i think that i read that mb is working on one.