Mileage/Average/Fuel Economy(FE)

In a modern car equipped with manual transmission, computer-controlled fuel injection will stop injecting fuel while coasting in gear, as the wheels will turn the engine and all of the accessory belts.

I recently presented this same question over at a Consumer Reports forum, and the Consumer Reports staff expert stated:

"We have fuel meters that are tapped into the lines to read actual fuel consumption. Coasting in gear uses no fuel to speak of. Coasting in neutral still requires fuel to keep the engine running. The most efficient way is to come to a stop in gear for as long as possible and coast down hill in gear." [emphasis mine]

Any time you are engine braking (on a hill or approaching a stop), you are using no fuel to speak of.

If you have a Consumer Reports membership, you can view that thread here: http://dis...r-38aujohn
Post numbers 2 and 8 were the most informative. (The quote above is from post 8.)

I can't comment on the degree of relative savings (except that it must be marginal at best), only that the CR expert, with his access to specialized testing equipment, confirmed as true the theory you presented.

AND DONT COAST WITH THE CLUTCH PRESSED ITS CRAZY

I HAVE BEEN DRIVING SINCE 1969 ALL VEHICLES SMALL AND L A R G E
ONE WAS OVER 125 TONS AND IN THAT BABY ONLY A FOOL WOULD COAST
STU

Of course it uses no fuel it is the motor that is revving not the fuel
the rev counter is electrick collects an impuls from the crankshaft and will not work ONLY when you turn off the ignition
Stu

Alright then, i stand corrected if that is the case, a better and a more safer way would be by using gears and not the neutral...

That has pleased me mate !!
another good deed done by the forum
StU

Hi all ... am back after a break to see that there has been a lot of activity here.

What I had posted were some experiments, of course. They are not being posted as a recommendation for driving, per se. As part of the experimentation, besides constantly glancing down at the extra display (also an unsafe practice!), I have been tryin our various combinations of gear/brake/clutch, to see their effect on FE.

The problem is that improving FE is proving to be an elusive target, where several factors are coming into play.

As I had mentioned in the earlier post, I am still in the process of investigating the effect of either coasting in gear/neutral and the FE numbers I am getting. These results are being reported, with the caveat that these are experimental results with some info missing, like what Stu confirms, that the Renault engine does cut-off fuel, in deacceleration/downhill in gear, and exactly what data the ScanGauge is getting from the ECU and interpreting as Fuel Efficiency.

Paramount of course, is that each driver drives safely and within his/her comfort zone.

==============

Another bit of info I can report is, (confirming something Stu had mentioned earlier) that the Logan is very fuel efficient at STEADY SPEED, regardless of whether your are cruising at 60kmph or 90kmph, I am getting fairly good FE figures of 6-7 LHK (14-17Km/L). You actually only mess up the FE by accelerating. Between 90 - 110 kmph FE drops to 9-10 LKH (10-11Km/L)

=================================

Did a round trip of 340km on half a tank of petrol (26L), averaging 7.5LHK (13.3 Km/L) for the whole trip, including some amount of heavy traffic innercity driving, 6-lane expressway, national highway and country roads. Maximum speeds reached was 111kmph and tacho max of 4000rpm

hi guys ,

Whats the average mileage obtained in a DLS .. I have done 3500 KMS and im getting 15 With AC . IS it normal .....
Please share your experiences .... Im using the ordinary Diesel ... Will the turbojet..the premium diesel make any difference ,, Im checking the tyre pressure once in 8 days and maintaining it at 29PSI.

Hey i filled up by accident on Sat with Super plus .I must say the car is a lot more responsive in the lower revs .I think I will try a tankfull out on the 28th when I drive to the UK .because with my reckoning. it will be better going uphill and i will maybe get that little more out of my tank (Lets see )
Stu

You are doin well sabrish, so is your logan..
No worries
Loganize
Btw, i have recorded a drop in mileage with premium diesel. Not everyone did... So.. I guess u try and decide..

Dear All

This is my 1st posting on this forum. I own a 1.4 GLX model which is 3 weeks old and have done around 800 Kms (city + Expressway). I have calculated the milage using the method of filling the fue tank completely, running it and ten refilling it again. I am getting a average between 11.5-12 Kmpl. Is this average ok for a new car. I am keeping the RPM between 1500-2500 and max speed upto 80 kmph (on highway). 5th gear change is at around 45 kmph mark.

All inputs are welcome
Thanks

Hi and welcome !Dont change up below 2000 I would class 2000RPM as the bottom limit
Stu

With regard to diesel, 2000RPM seems to the ideal RPM to engage a higher gear. You can limit it to 2500RPM for good fuel average and decent acceleration. This is my first tank of fuel (ordinary diesel) so will have to check later for actual mileage. I decided to go for ordinary diesel after reading inputs from members. Also as Stu pointed out earlier these vehicles have been designed taking into account the variations in fuel quality available worldwide.
I release the accelerator pedal when approaching humps and let the gear (5th) add futher to the deacceleration. Only when the speed comes down to a particular level (just before vibration starts due to low speed)do I engage the 2nd gear and move. One can get familair with that threshold with experience and observation.All this happens probably within four or five seconds. Also I will engage the first gear if the hump is a nasty one or if there is an inclination just from the hump onwards. I think you could also shift to nuetral and keep moving. But you'll be depressing the clutch twice in that case, once to get to nuetral and the next to change to the appropriate gear. In the earlier case you'll be depessing the clutch a little longer but only once. In the course of day to day driving you can safely estimate the number of times the clutch usage is avoided.

Hi Loganians

I again did a milage check after second tank topping. It gave me 14.40 kmpl with AC on and using normal unleaded petrol. Looks quite decent milage.
Thanks
Yogi

I own 1.4glx. it is 7months old. i live in hyderabad. my consistent observation on milage is 10-12/liter km in city and when i go on highway it is 14-15km/liter. is there an optimum speed for each gear level?

I have 1.4 GLx, done about 7000 + KMS. On city with AC i get only 7-8 KMs and without AC i get 12 - 13.

In highways am getting 13-14 with AC.

sAuMiL wrote:

Guys,
I m having this problem now, my logan isnt givin me good mileage. Dunno wats wrong.
When i fill premium diesel, i can do a max of 520 odd kms in a fill of about 45 lts... With normal diesel, it does about 620 or so barely. I am very irritated.
I went to Milestone, Mumbai for the same. They told me to undergo a Mileage test. Idiots made me pay 250 for the test . Sadly, even they got a dissappointing 10-11 KMPL. Have to go back to them on monday probably cause the Head of Service is on training... Lesse.

After the above mentioned episode, i gave them the car for checking and correcting the problems. They seemed to connect it with the Laptop, checked and tweaked the system. Later to my surprise the mileage i got three times after that was again still 10-11 kmpl. frustrated i went there again and asked them to check it again as it didnt change much since last time. We again went for a mileage drive with them and got a dismal 10.69 KMPL.

They had a form which was filled and sent to Mahindra. I spoke to Mahindra mysef too and later they asked me to leave the car with them once again. I finally went to collect my car from the service center yesterday. We once again went for a drive and thankfully we recorded a mileage of 16.44 KMPL in city with AC on.

On asking what was done, they said they cleaned the exhaust system and airfilter. The fuel filter had already been changed just a week back during the service.

Thats a bit of an information which we all can use Saumil.
Now we know where to look for the problem just in case.......

Saumil its nice to see that your issue got resolved, well my car has done 8000kms i am getting an average or around 20kmpl i am driving without Ac and maintaining a constant speed of 60 -65 km/hr

Is it ok to trust the mileage reported by the car computer?

Is the total fuel consumed reading correct?

The best approach would be to check 'tank full' to 'tank full' i.e. fill it up completely, drive 100kms or more then fill it up completely again and check how many litres were pumped in. Do this couple of times so that you can get an average figure.

There is always a margin for error, though small, with regard to the onboard 'computer'.

Yea..
I have a DLE so dont know much about the accuracy of the trip computer but the 'proven' Tank-Tank method as rajesh just mentioned is most reliable and believed to be accurate.

For more details on the same, go to page no 1 https://mahindralogan.forumotion.com/mahindra-renault-logan-technical-f6/mileage-average-fuel-economyfe-t48.htm
of this thread. Its very simple..

I checked mine and it gives between 17kms and 19kms per liter of diesel with a/c on almost 100% of the time.

Thats a nice mileage u gettin rajesh..

Yes, its good.