Diesel or gaser for short commute?

Big Montana · **Posted:** Wed Nov 18, 2009 10:57 pm

My co-worker has asked me if he should get the new VW Golf TDI or the gasser. His drive to work every day is only two miles. He wants the TDI because it comes with better MPG and options packages. He thinks though that a short drive every day (we get cold winters her in SE Michigan) will negate the milage gains and may be bad for the engine.

I've heard the new VWs can heat the coolant AND the block, so he should be warmed up and ready to go as it can be parked in his condo garage each night and plugged in. He countered with the fact that his drive home will not have that option.

Wouldn't a diesel still be better? Does it even matter?

ATXKJ · **Posted:** Wed Nov 18, 2009 11:16 pm

2 miles????
Has he ever considered a bicycle?
How about a pure electric plug in?
or a Prius? - the engine would only turn on once a week.

in the VW case engine will never get up to temp (gas would be closer - but still not enough)
so you'll have moisture condensing in the crankcase every day - and never boiling off.

it's not going to live long and you'd never recover the additional cost of the diesel.

Diggerfreek · **Posted:** Wed Nov 18, 2009 11:25 pm

Diesel

The gasser is going to run richer and get worse fuel economy.... how ever, with the new DPF, if one does not drive it, there if the possibly of a plugged DPF...

My moms TDI Jetta has a heater element that provides heat to the cabin right away.... it's cool to have heat in the cabin before the engine heats up........

Big Montana · **Posted:** Wed Nov 18, 2009 11:31 pm

ATXKJ wrote:

2 miles????
Has he ever considered a bicycle?
How about a pure electric plug in?
or a Prius? - the engine would only turn on once a week.

in the VW case engine will never get up to temp (gas would be closer - but still not enough)
so you'll have moisture condensing in the crankcase every day - and never boiling off.

it's not going to live long and you'd never recover the additional cost of the diesel.

I bet he has, but we can get feet of snow for a few months out of the year. I don't think it would be good for his tie.

dgeist · **Posted:** Thu Nov 19, 2009 12:03 am

My initial response was to say diesel, then i second-thought and was going to say bike, but the weather there might not be good for bikes in winter, but at two miles, why not just walk? A decent pace walking would have you there in under half an hour and you'd get a pretty decent (and not terribly sweaty) workout...

I hope it's not like the ATV people we saw at the ECS that brought mini-bikes to take them across the gravel parking lot to the bathhouse of the campground instead of walking 200 feet. :shock:

Dan

Big Montana · **Posted:** Thu Nov 19, 2009 12:09 am

He is a runner and a biker, but what I am trying to figure out is if there is a better engine for this situation. Electric makes sense for sure.

But:
Wouldn't both engines be subject to the same slow warmup time?
Is the diesel really a bad idea? We're talking 7-8 years of (2) two mile commutes.

geordi · **Posted:** Thu Nov 19, 2009 12:21 am

If it is plugged in at home, then it is only half that number of "unheated" commutes, and would he do any driving on the weekends?

If he never drives more than 40 miles in a day, pure electric is the best option of all. Heck, he'd only need to plug it in twice a MONTH... Like on payday or something. Any decent amount of driving in a diesel engine will burn off the condensation (what little there would be) and a good 'Italian tuneup' every weekend or so would be more than enough to keep any exhaust gremlins at bay.

He's bound to forget where the filling stations are at however, with only needing to fill a TDI's tank once every QUARTER with the mileage they get. We should all be so lucky. On the plugging in thing, maybe he could talk to the employer and get a power cable out to the parking lot for the heater? It isn't like it draws that much juice. Even a second battery in the trunk, wired to an inverter with a timer (set to about 2 hours before he leaves work) and a battery charger that he could plug in at home each night would be an option.

But diesel is always better than gas. ALWAYS.

tjkj2002 · **Posted:** Thu Nov 19, 2009 12:37 am

geordi wrote:

But diesel is always better than gas. ALWAYS.

There you go again,guess blowing one up hasn't woke you up to reality.

On short drives a gas engine would be better,even if you "plugged" in a diesel it would never achieve the coolant temps that a unplugged gas engine would see in the same short drive.Either engine would not last long but the gas engine will longer with little use with fewer problems.Diesels are happier when warmed up and need to be fully warmed up to operate correctly where as a gas engine will actually in most cases produce more power when at a cooler engine temps but yes at a cost of using more gas.

geordi · **Posted:** Thu Nov 19, 2009 12:47 am

The coolant in a gasser would get hotter because they are much less thermally efficient. Wasting that energy just to warm coolant is stupid. The coolant heater (friction heater) would do wonders to warm the engine, and if the temp was STARTING at 100 degrees, it wouldn't need much to get to temp. But the myth of 'diesels need to be hot to be efficient' is just that - a myth. OLDER diesels might have needed that idea, but the high pressure diesels now are capable of operating just fine when cooler. The reason for needing to be hot was that the older diesels didn't have the adaptive after-start glow systems that we have now, so they wouldn't combust properly until they were hot.

Like many things, technology has advanced to fix this problem.

flman · **Posted:** Thu Nov 19, 2009 7:34 am

tjkj2002 wrote:

geordi wrote:

But diesel is always better than gas. ALWAYS.

There you go again,guess blowing one up hasn't woke you up to reality.

On short drives a gas engine would be better,even if you "plugged" in a diesel it would never achieve the coolant temps that a unplugged gas engine would see in the same short drive.Either engine would not last long but the gas engine will longer with little use with fewer problems.Diesels are happier when warmed up and need to be fully warmed up to operate correctly where as a gas engine will actually in most cases produce more power when at a cooler engine temps but yes at a cost of using more gas.

I agree, that TDI would be clattering to and from work because it would always be cold at any speed. And, you could start the gasser, and warm it up before the trip, something that is not possible with the cold blooded diesel.

UFO · **Posted:** Thu Nov 19, 2009 11:55 am

Neither is a good choice, both will rust the exhaust system. If he's dead set on driving only 2 miles, I say gasser -- they deserve the abuse.

ac5501 · **Posted:** Thu Nov 19, 2009 1:23 pm

Just my 2 cents.

your buddy:

1) Is considering a brand new vehicle
2) Commute to work is only 2 miles
3) Lives in Michigan

If it were me I would be taking a close look at a hybrid Escape/Mariner. It can't be that much more then a new Golf TDI. It would be better for the roads around here in the winter, and provide a little more functionality. I'm not that big of a Ford fan, but the last time I looked at an Escape, I would have to say I was somewhat impressed.

As for your original question, If my commute was that small, I would not get a diesel. Much as I like to promote diesel, it does not sound like that is the best option in this case.

butcher_block · **Posted:** Thu Nov 19, 2009 2:28 pm

if they would make it and i could pay for it i would be in one

i work at home but drive now and then to get supply's and to ship things

i would rather have it packed in asmall pickup but the jeep would work and the little car looks like it would be loads of fun
http://blogs.jpmagazine.com/6300906/editorials/2010-electric-jeep-wrangler/index.html

Big Montana · **Posted:** Thu Nov 19, 2009 11:39 pm

This thread has been so interesting to read. I told him that this topic is going both ways. I mentioned the electric and he said he looked into it. The claim he made was that the gas engine would be working in the short drive, not the battery. I thought that the battery handles the stop and go because of the torque. He didn't seem to think so.

bewestro · **Posted:** Thu Nov 19, 2009 11:59 pm

I'm in kinda the same situation as your co-worker.

I live in northern MI and have a 2 mile commute and a CRD. I make that trip 4 times a day (home for lunch), and it takes about 8 minutes. I try to plug it in, on a timer, if it's less than 40 or so at night. I also drive very gently. Driving is necessary because you don't always know when you're going to have to go somewhere from work, and having to walk home to get your vehicle to meet the boss or a customer across town is NOT acceptable. Most days it's not an issue, but sometimes. There is no public transportation to speak of here. Most people, however, do lots of driving besides just to work and back, and so your co-worker may find that the vehicle still gets fully warmed up on a regular basis. At 2 miles each way four times a day five days a week, I should only be accumulating 40 miles a week, but somehow it usually ends up over a hundred after errands, chores, weekend adventures, etc. I average around 7k/yr.

I know this is hard on a vehicle, but that's kinda just too bad and is something I (and your co-worker) can't do anything about. My mom only goes about a mile each way to her office, that's just how it is. However, we've never had problems because of it. While the life of the vehicle may not span as many miles as it would if you made longer trips, up here most of them rust out well before they wear out, and I think you'll find that will still be the case no matter what you choose.

Side note: ac5501 brought up the hybrid Escape. My dad has an '07, with AWD, it's really nice. It won't go into all-electric mode until the engine is fully warmed up and the battery is charged, but it usually gets about 10mpg better than my CRD under almost any circumstances except long highway runs where the difference shrinks to 5-7. (Mine sounds better though!)

Sorry for the long post, but I've wondered this same thing. I still don't know what the best answer is.

geordi · **Posted:** Fri Nov 20, 2009 12:49 am

I can speak to the Mariner / Escape hybrids also. My family owns TWO of the Mariners, and they only come with AWD.

The reason that the gas engine runs from the moment the engine is started is twofold: First, CARB are a bunch of ethanol-drinking arsewipes who should be flung into the ocean. Their stupid mandate is that a hybrid (specifically the Ford and GMs, The Prius does this but it can be taught not to) must burn gasoline when the engine is making the MOST pollution (when cold) for the sole purpose of heating the catalytic converter, to reduce the emissions when the engine isn't running a few minutes later. This is INSTEAD of just NOT RUNNING the engine until it is actually needed, when heating up the catalytic would be a byproduct of charging up the battery.

Why do they do this? It has to do with Carb being dumb, but amazingly, Ford being even dumber. They ran focus groups before the Escape / Mariners were released, and the focus groups (who I suspect were comprised entirely of highschool dropouts and drug addicts) couldn't tell when the car was ready to go... Because they didn't hear the engine running. It wasn't, the Escape WAS originally designed to not run the motor until the battery had been partially depleted, so it would be an EV FIRST, for a few miles. But these idiots couldn't figure it out, so Ford took that function away, and the CARB jumped on it and mandated that the engines HAD to run until the cat was heated up, irregardless of the battery's need (or not) for power. The design also is to ONLY use the battery from 80% charged down to 40% charged, Never above or below those capacity numbers. That is a SOFTWARE decision, so that they don't have to change the batteries within the warranty period... But they won't ever admit to how many cycles the batteries will put up with, OR the actual expected life. Just that it is more than their warranty... So good luck with that.

Head hurt yet?

The Prius (which has the 3rd or 4th generation software now, where the Mariner / Escape is the 2nd generation licensed from Toyota) can be taught to run in EV-only mode until the battery is partially discharged INSTEAD of running the gas engine for no good reason initially... By a simple mod of a switch being added to a circuit that is already wired into the car, and IIRC, it doesn't even need a code change. If there is a code change, its easy to do. The mod is supposed to only take a few minutes to install.

I understand your buddy's reasons for wanting an actual car instead of walking to work (and the 10 months of winter also make a difference) but I'm still with the same opinion: Straight EV, or a TDI of some flavor. The block heater can be wired up to a secondary battery in the trunk with a simple inverter and timer so that it is completely self-contained, and only a battery charger is connected at home to top off that battery... With that, the TDI would never know that it wasn't summer year-round, AND the car would be up to 'open loop' operating temp before he hit the end of the driveway. With even getting groceries and errands during the week, the engine would still last longer than the body, I'm sure.

Big Montana · **Posted:** Fri Nov 20, 2009 12:57 am

How do you know so much about electric? This is interesting.

I told him to look into the pre-heating systems of the VW. If the gas and diesel are the same with water once they get warm, it shouln't matter then.

geordi · **Posted:** Fri Nov 20, 2009 1:18 am

Big Montana wrote:

How do you know so much about electric? This is interesting.

I told him to look into the pre-heating systems of the VW. If the gas and diesel are the same with water once they get warm, it shouln't matter then.

Which electric? The inverter stuff, or the hybrid systems?

I work with the film and theatre industries, and we have to put lights and power-sucking accessories in all sorts of interesting places where an extension cord won't go... So you need to bring your own juice a lot. The hybrids, I've been researching them b/c I'm a geek and want to know how they are set up... And how to hack them to be full EV designs from the beginning. There is no good reason to run the engine before it is needed.

As for the VW pre heaters, they are the same as on the CRD - it's a dumb resistance heater (no circuitry, just a heater) in the engine. On the VW, it is an add-on product known as a TDIheater that slots into the coolant lines, on the CRD it's in the block in the oil. The result is the same - the block is warmed when the thing is plugged in. So if the 120v cable is plugged into a heavy-duty timer ($20 at Walmart) and the power is coming from an inverter in the trunk... It will only USE that power when the timer lets it. Set the timer for about 90 minutes or so before the commute, and the engine will be ready to go as if it had been running for 10 minutes or so.

Oh, BTW: I don't know any gassers that come factory-equipped with block heaters, unless there is some "arctic package" installed that isn't offered standard in the South. ALL our CRDs have the plug-in heater however, and the VW's (IIRC) had the heater as an option, but the aftermarket one LOOKS like a factory piece and is easy to install in a tdi.

mikey1273 · **Posted:** Fri Nov 20, 2009 1:26 am

most people got places other than work, shopping, to activities like going to a gym,going to church or visiting family during the week so chances are he will drive more than an average of 4 miles a day to heat the engine up. for this guy I would say either vw is fine if he likes the diesel get the diesel.

UFO · **Posted:** Fri Nov 20, 2009 2:07 pm

My head hurts geordi. :shock:

Diesel or gaser for short commute?

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