How do you eco-drive a diesel ?

[tasdrouille]

Originally Posted by Piwoslaw

This may have been already discussed, but there is a thread on ecodriving at my local Peugeot forum, and someone wrote that accelerating with 80% throttle is efficient on gassers, but not diesels. Diesels should accelerate very slowly for fuel economy.
Is this true? I'm using the 80% rule on my turbodiesel and seem to be getting good FE, but maybe it could be better?

Nonsense, it doesn't have anything to do with the engine being a diesel. As for a gasser it depends if the trans is auto or manual. For a manual trans, around 90-95% load is best.

[Piwoslaw]

Thanks Tas
That's what I thought, but hearing it from someone else makes me feel smarter

[COcyclist]

Hi Piwoslaw,

The biggest difference is that diesels typically do not have a throttle plate that is choking off the air to the engine at all but wide open throttle. Gassers require a fixed ratio of air to fuel so at part throttle, the plate closes and cuts off air. This creates a vacuum that the engine has to fight against at light loads. This is why it can be more efficient to step on the gas and "shift early, shift often" with a gasser and why a "warm air intake" mod helps some cars get better mpg. WAI feeds warmed, less dense air to the engine and the throttle can be opened more to maintain the same highway speeds with less restriction and engine vacuum from the throttle plate.

My buddy has two VWs, one gas and a newer diesel. He can't understand why the old gas car makes heat in the cabin in two blocks and the diesel takes two miles and a hill before it warms up. Diesels are very efficient at idle but they suck in unrestricted volumes of frigid air while adding very little fuel. I have read that diesels can run at 50/1 air to fuel ratios. VW guys (Deezler, Tasdrouille, and myself) on this site use grill blocking to help the engine get up to temperature sooner where diesels are most efficient. Also, newer VW diesels have three additional glow plugs in the coolant stream that stay on after start-up to get the engine up to temp. I also use as tank heater to preheat the coolant. The engine starts and runs better and hopefully the glow-plugs shut off sooner and quit making a high amp draw on the alternator.

I have a Scanguage on my car and can monitor intake air temps. I do a little intercooler grill blocking in frigid temps that I can easily remove before climbing mountain passes, to feed cool air to the intercooler. As for hard acceleration, lots of guys say to drive a TDI hard for best mileage. However, I have gotten my best tanks by driving under light load on the Scanguage after the engine is warmed up. That said, the occasional "Italian tune-up" doesn't seem to destroy tank mpg.

[nj1266]

Well I have a 2010 Golf TDI. I just bought the car and I am on my first fuel tank. I have pulsed and glid with my S2000 gasser and was able to improve gas mileage from an average of 25-26 mpg to an average of 31-32 mpg. I have noted the following differences between the gasser S2000 and the TDI Golf:

1. The Scangauge II does not display TPS on the TDI but does so on the S2000. I do not know if this is a 2010 model thing or it is a TDI thing. It does make sense not to get a TPS signal since there is no throttle plate on a TDI. With the S2000 I used to pulse to 70-80% TPS (not load). With the TDI I pulse to about 80 LOAD. With the S2000 I accelerate quickly and that does not have a lot of impact on FE. With the TDI I accelerate slower, becuase quick acceleration has a big impact on FE.

2. Pulsing and Gliding with a gasser seems to produce a higher rate of return on FE than P&Ging with the TDI. Keep in mind that this is my first tank with the TDI so I do not have a lot of data to compare. I want to eventually try a full tank w/o P&G in the TDI vs. a full tank with P&G.

3. The FE on the TDI is simply amazing. I got 55.7 mpg per the on board display in one trip from work. I have 530 miles on the current tank and I still have 1/3 of a tank to go. I should easily hit more than 600 miles on this tank. The engine is still green and I am told that FE improves as the TDI hit 20-30K miles. My S2000 was running on empty once I hit 330-350 on a tank of gas.

[Piwoslaw]

Congrats on your new TDi and on the great milage, nj1266
Try not to P&G for 2-3 tanks so that you know what your baseline is, and then go all out!! I'm sure that you could get an 800mi tank with small aerohelp.

[modmonster]

my peugeot 106 seems to have a hot air intake as stock. it sucks it from the radiator. also i noticed that the fast idle temperature adjustment has been moved/fixed/broken by the previous owner. the fast idle temperature sensor now just terminates in the engine bay and not inside the engine block. this may be a good thing becauseits not wasteing fuel on startup to get cabin heat quicker. i fancy an adjustable grill block soon.

[mcbota]

I own an Audi A4 diesel, 96 KW, and being new here I am very interested which are the best methods to increase fuel, hypermiling especially in city. I use to downhill on my trip to work in the morning, when the car is not warm. Which is the best method to coast: in gear or neutral? It is worthy to put something in fron of the radiator, even in the spring-summer time?

[COcyclist]

Originally Posted by mcbota

I own an Audi A4 diesel, 96 KW, and being new here I am very interested which are the best methods to increase fuel, hypermiling especially in city. I use to downhill on my trip to work in the morning, when the car is not warm. Which is the best method to coast: in gear or neutral?

It depends on whether you need to use the brakes or if you can coast onto a flat stretch. If you would be using the brakes, use engine braking as much as you can. The VW/Audis use no fuel during engine braking. If you can coast then coast in neutral (I leave the engine on) and get 400 mpg U.S. while coasting at highway speeds. If the hill is steep enough I may alternate between the two.

Originally Posted by mcbota

It is worthy to put something in front of the radiator, even in the spring-summer time?

Yes. I have had the upper grill blocked year round since I bought the car. There seems to be more than enough cooling airflow from the lower grills.

In the city I accelerate fairly briskly to get up to speed and coast in neutral. At 30 mph the VW coasts forever and hardly loses momentum. Keep your tire pressure to the maximum.

[mcbota]

Many thanks for the answers, COcyclist! The downhill is pretty strong, with some corners and crossroad so I have to use the brake for some moments.
I am glad that I have found you and I hope I can learn a lot from the people from here. Also I am thinking if is worthy to change the wheels, in this moment I have 215/55/16 and I want to change with 195/65/15, but I am not sure how much I will gain!

[user removed]

http://ecomodder.com/forum/showthrea...-2l-18235.html

member vekke's thread with videos. He is Finnish (Finland) one of my favortie places and people, if it just wasn't so COLD.

regards
Mech