Diesel ecomony?

[theholycow]

Heheh, I didn't even notice that it was in the wrong section. I moved it to the diesel section.

PaleMelanesian has a great description of exactly how to bump start. After reading his description, it became very easy and comfortable for me; doing it his way doesn't feel like it's ever going to damage or even wear anything any more than every day driving (less clutch wear than a common start from a stop, I suspect). I don't know how well it would work with a diesel.

Your 1st and 2nd sound similar to mine, then the rest are significantly taller. I'm in 5th by 25-30mph, though I run a lot lower RPM than you. In 5th at 70mph I'm running 3000 RPM, same as your 4th.

If I intended to keep my Rabbit for a long time I'd definitely look into getting the same transmission you have. I hate cruising at 3000rpm, there's plenty of torque for highway cruising at 2000rpm.

Oh, and it sounds like you've got the same clutch. It feels like a video game clutch, doesn't it? It doesn't feel like it's hooked up to anything.

[theholycow]

Ok, found it....

Originally Posted by PaleMelanesian

Smooth bump starts:
Do a little clutch pulse - just a quick up-down - in top gear. Don't even let it out all the way. It'll give the engine enough to start, but not enough to jolt anything.

Then, choose your gear and shift and go.

It's smoother and less strain than even the smoothest standing start.

[palemelanesian]

I'm coming back to haunt myself!

[DarbyWalters]

Some great info on http://www.tdiclub.com

1400+ miles on one tank in a Passat Diesel http://forums.tdiclub.com/showthread.php?p=268702

[theholycow]

Originally Posted by DarbyWalters

1400+ miles on one tank in a Passat Diesel http://forums.tdiclub.com/showthread.php?p=268702

Wow! Talk about great FE, and way practical too...

Nice! 58 mpg with one of these:

[dragnbaron]

Originally Posted by theholycow

Heheh, I didn't even notice that it was in the wrong section. I moved it to the diesel section.

PaleMelanesian has a great description of exactly how to bump start. After reading his description, it became very easy and comfortable for me; doing it his way doesn't feel like it's ever going to damage or even wear anything any more than every day driving (less clutch wear than a common start from a stop, I suspect). I don't know how well it would work with a diesel.

Your 1st and 2nd sound similar to mine, then the rest are significantly taller. I'm in 5th by 25-30mph, though I run a lot lower RPM than you. In 5th at 70mph I'm running 3000 RPM, same as your 4th.

If I intended to keep my Rabbit for a long time I'd definitely look into getting the same transmission you have. I hate cruising at 3000rpm, there's plenty of torque for highway cruising at 2000rpm.

Oh, and it sounds like you've got the same clutch. It feels like a video game clutch, doesn't it? It doesn't feel like it's hooked up to anything.

Thanks for moving it into the right section for me.
Ok, so for bumping i have gotten it down pretty well, and i really don't feel it at all until i hit lower speeds (25mph or less), the rest of the time i don't even realize it started back up unless i look at my guages. Yay for new quieter diesels.
Ok, so here is my RPM reading for my 'normal' NJ driving.
1st gear shifting at 20 mph about 3.2-3.4 rpm
2nd shifting at 35 with 3.3 rpm
3rd shifting at 55 to 60 (depending on traffic) around 3.5 rpm
4th i shift around 70 at 2.3 rpm or 80 at 2.6 rpm
5th at 70 is 2.1 rpm and 80 2.4 rpm.
No big difference between 4th and 5th at higher speed, but i have been shifting into 5th around 40 mph and sticking around 1.4 rpm maybe 1.2 rpm.

Just through an 8th of a tank of gas and already noticing a bit of improvement. Usually i get about 150 miles on the first quarter tank and about 100 or 120 on the next three quarter tanks. On 1/8 of a tank i'm at 120 miles (I drive alot, about 45 miles one way to work and i drive an addition 50 miles south yesterday to Trenton). So, all-in-all not bad, but we'll see, i fill up at a half tank or 1/4 tank. If i had to guestimate right now i would say i'm getting about 43 mpg, and that's with practicing bumping and a few 'slip ups' with speed because of idiot drivers and rush hour. It's hard to go slow in NJ.
Also, i have been chasing trucks in order to get a little breeze from their backside, lol. Going at 70mpg and starting at rougly a 1second spread between putting the car in neutral and just coasting i can get about 5 miles before i need to catch up and am in a 7 second spread. That's with my tires filled up to only normal psi, too, and NOT counting going uphill, only on flat road.
I've been shifting at 2k rpm or 2.3 rpm regularly. Concidering i have a total of 6rpm to work with (as opposed to the 8 in the gas counterpart) it's not bad. Uphill a regulated 2.3 rpm seems to do fine.
Speed is going to be an ongoing issue for me. Around here if the sign says 25, go 40. If it says 55, go 75. If it says 65, go 90. So i know my FE won't be as good as someone in a much more rural setting. Since i'm by the shore i also have alot of hills, so that kills it alot, too. And my driveway should be used for rock climbing.
So, i'll keep you guys updated, if i can get this thing to 50mpg i'll be thrilled, if i can get it to 60mpg highway i'll be ecstatic but that's for my next trip to Springfield Massachusetts or Dartmouth College (too bad i can't skip over Connecticut, eh?)
Any ideas with some other stuff i can do too? I'm worried about body shape changing because the car is under lien... :-/ Lightening it would be no problem. Do you think only using a half tank of gas instead of filling her up completely would add a little benefit too?

[Lug_Nut]

A grill block shouldn't obstruct the intercooler. Leave this air flow path open. You'll gain more from a colder air charge than you might from an aerodynamic standpoint.

Block heaters, like a "FrostHeater", adds all of five pounds, cuts warm-up time to zero.

"The new TDI's come with an internal block heater coil for the fuel to allow for cold weather startup by keeping the car in AC for a minute before starting."
On what planet?

Keep the rpm as low as is possible, and in as high a gear as is possible. Obviously if you need to accelerate briskly you'll have to downshift, or have already shifted lower in anticipation, but driving at 3k in 4th, when no acceleration is needed, is nowhere near as fuel efficient as using 5th at the same road speed. Best fuel mileage is going to be at about 1200~1400 rpm in 5th. If you have to drive at 30 mph because of traffic, might as well let the engine loaf too. You can be in 5th, easily, at 55 mph. There is nothing to be gained by delaying 5th until 70 unless you are at Englishtown on import night. Peak torque is about 2000 rpm. Higher than that and there is less torque, and less thermal efficiency, too. Torque at 3400 rpm is somewhere around 130 lb*ft. Guess where else torque equals about 130 lb*ft? Around 1700 rpm. Shift sooner and slow the engine down unless you need the acceleration.

"i was getting an average of 33mpg on the first engine...I had the car a month and the clutch stuck to the floor...The dealership said the tranny siezed and killed my clutch, both were replaced after fighting with them and telling them it wasn't how i drive. Second time the clutch started whinning, like a jet aircraft taking off. Took it in and the tranny again... it also destroyed my clutch and bother were replaced. I was driving in February of 06 in Vermont in the middle of a blizzard and a car ran me off the road. I rolled the car on its side but eveything checked out a-ok. Purged the brakes and was back on the road with just a little body damage. 8 months later i was driving down the road and was speeding up from a stop light my tranny siezed again, this time because my foot was on the gas when the tranny siezed the engine kept trying to turn the gears and ended up ripping 3 out of 4 motor mounts thanks to the torque. Dealer said it was because of the accident of the autobody that did the repairs (yeah right). Whatever, i got it fixed and a new engine because the ripped motor mount cracked the block. seeign as i used to work at a dealer i know how abused new cars can be."
Absolutely nothing I can say to dispute that you know abused cars.

"... (too bad i can't skip over Connecticut, eh?)" Can you understand why I avoid New Jersey and the drivers there?

[theholycow]

Originally Posted by dragnbaron

5th at 70 is 2.1 rpm and 80 2.4 rpm.

I am so jealous.

Also, i have been chasing trucks in order to get a little breeze from their backside, lol. Going at 70mpg and starting at rougly a 1second spread

If traffic allows it, you should really hang back further. A common 53' box trailer has a good draft out to 3 seconds distance. 1 second is probably dangerous, but also the air can be too turbulent at 1 second and hurt your draft. Then there's exploding tires and kicked up rocks to worry about...

i have a total of 6rpm to work with (as opposed to the 8 in the gas counterpart)

The 2.5L redlines at 6200rpm.

Speed is going to be an ongoing issue for me. Around here if the sign says 25, go 40. If it says 55, go 75. If it says 65, go 90.

It's ok. If adjusting your speed isn't an option, then you'll just have to concentrate on other strategies. With your tall gearing and decent .31 aerodynamic drag coefficient, you're well equipped to minimize losses from high speeds.

Since i'm by the shore i also have alot of hills, so that kills it alot, too.

Hills are like forced Pulse & Glide, or if you're willing to EOC (as it sounds like you are) they are great for EOCing.

(too bad i can't skip over Connecticut, eh?)

I drive through the northeastern corner of it every day, cutting across from RI to MA.

I'm worried about body shape changing because the car is under lien... :-/

My VW is leased, and I did some decent (thought ugly) grille blocking.
http://www.gassavers.org/showthread.php?t=8597
A few screwholes in the fog grilles will go unnoticed if I make a half-hearted effort to fill them before returning it. The upper grille block is held in place entirely by friction.

Lightening it would be no problem. Do you think only using a half tank of gas instead of filling her up completely would add a little benefit too?

There's a link in my sig about weight reduction. In short, I strongly doubt it will help, though any of it that you can do for free is worth a try if you want to. Diesels especially are known for not being sensitive to weight changes (witness all the testimonies from diesel pickup owners that towing a trailer weighing more than their truck has barely affected their FE).

Driving with a half tank of fuel is an idea I've always thought would be practical for cars where weight makes a big difference, except for the problem of it making you entirely unable to measure your FE.

[almightybmw]

Just one thing noted about staying out of the boost: It's a bad idea. You'll get soot buildup on the vanes which will lead to a seal failure. Be sure to once and a while get it nice and HOT to keep it clean. Not all the time, but for the amount of driving you do, at least once a week get on it.

[groar]

I'm not a TDI driver, but a diesel one. The megane is an "old" turbo diesel without direct injection (dT), while the scenic is a common rail turbo diesel with direct injection (dCi).

The megane has no FE display. The scenic has a FE display but it displays only l/100km and only over 35 km/h, so I can't know the l/h consumption when the car is idle or at slow speed. No car is EOBD (European name for OBDII) compatible (mandatory in Europe since 2004 for diesel) so my SGII doesn't work.

On both cars I closed the front grill, except the turbo intercooler (as there isn't a temperature gauge for it). We have no heat problem, but we keep a eye on the coolant temperature gauge.

Engines are very different :

• megane (1997) : comb.EPA 35.1 mpg(US), 132 ft.lbs at 2000 rpm, 95 hp at 4250 rpm, 2491 lb, 21.4 sq.ft. & Cd 0.31
• scenic (2001) : comb.EPA 39.8 mpg(US), 150 ft.lbs at 1500 rpm, 105 hp at 4000 rpm, 2844 lb, 25.3 sq.ft. & Cd 0.33

About speeds at 2000 rpm at different gears :

• megane : 10.7, 19.4, 30.2, 41.1, 52.8
• scenic : 10.3, 18.8, 29.1, 39.7, 51.0

My best tanks are 50mpg in scenic and 55mpg in megane.

Despite the scenic has its best torque at a lower rpm, I can accelerate from 1100 rpm in 5th with megane, while I can barely do it from 1250 rpm with scenic. This implies in megane I can easily shift at 1700 rpm while I have to be near 2000 rpm in scenic.

Last June I couldn't keep a steady speed at 1500 rpm in 5th in megane. I changed the diesel grade. The best grade has both better cetane and a lot of additives, noticeably cleaning additives. During first tank the engine was accepting lower rpm and after several tanks accepted to accelerate from 1250 rpm in 5th.

I changed oil and air filters on both cars recently. Oil has been changed from 10W40 (mid-synthetic) to 5W40 (fully synthetic). In megane I can now accelerate from 1100 rpm in 5th. My wife easily forgets to ecodrive, she is now at 44 mpg in scenic while she was stuck at 40 mpg before. In both cars, my butt-o-meter tells me that they have more power Because of that, I changed my driving habits and use pulse & coast (in neutral with engine on) at mid speed (40-55mph) and immediately beat my best tank (which was a summer tank with cardboard rear wheel skirts).

I do love doing pulse and coast in megane. I find it easier than in scenic, may be because megane is lighter and has better Cd and frontal area.

Shifting as low as your engine permits is great. Staying as long as possible in neutral (engine on or off as you feel comfortable) is also great. This last point is improved by overinflated tires (max sidewall of 51 in megane while at 47 in scenic 'cause it's too uncomfortable at max sidewall of 51). I just installed coroplast rear wheel skirts on megane so I hope improve even more, while freezing morning should be gone

Denis.