1.4Tdi, 80bhp MPG?

[MikeThelm]

I've been averageing around 51mpg on runs of around 15 miles of local lanes with some town work. I try to drive economicaly but don't hang about . On longer, motorway journeys, it goes up to around 56mpg using cruise control at around 70mph.

 

I'd just like to know how this compares with others. Has anyone used Redex additive or similar and does it make any difference?

[freelanderman]

Your fuel consumtion very much matches what I am getting, can manage 60 mpg on longer runs but keeping speed at 65, shove it much over 70 and it struggles to do 50 mpg

[MikeThelm]

Thanks for that. I suppose that I expected a bit more as I was getting around 50mpg from my 1.9tdi Passat estate that had 240,000 on the clock.

[keystonedriving]

Over 75k miles I have averaged 52.4 mpg.  That is, in part, because of the lack of flat ground around here.  I do tend to cruise at about 60-62 on motorways and dual carriageways, that improves the figures no end.  On the A30 in Cornwall at that speed I can average about 60mpg, if I set the cruise to 70 then I'll get about 50mpg.

 

I got 54 from a 1.9 SDi Polo (173k miles) and about 53 from a 1.9 SDi Fabia (135k miles).  The Roomster isn't the most aerodynamic beast and that seems to make a big difference.  Round town it can be pretty good if you drive gently.  I did a run from Woodford Green round the North Circular and down through Richmond to the M3, leaving at about 1730 on a busy Sunday evening.  The trip computer was saying 69.7 mpg as I got onto the M3 (but headed south fairly quickly once the speed went up).

 

It sounds to me like you're in the ballpark.

[MikeThelm]

Thanks for that. It's good to know that I'm getting about the same as others. I do very little motorway driving but it's useful to know that the mid 60's are better than the low 70's.

[Robjon]

I get similar figures from my 1.9TDI, with 63-65MPH producing best fuel consumption.

If I take it above 70MPH, consumption increases noticeably.

 

When compared with other cars, I am happy to accept my Roomy's lesser aerodynamics as a consequence of its greater headroom and cargo capacity.

[MikeThelm]

Roomy has so much going for it, a few MPG is a very small price to pay. :clap:

Edited 7 August, 2014 by MikeThelm

[capnjack]

In three years I have averaged 57.8 mpg, travelling 59,000 miles. 'Saintly' behaviour will get me 63+ over a tank-full, the worst I've seen was 52 (included 400 miles of the A1, the less said, the better!) About 5000 miles per year are on this road and I usually try to keep below an indicated 70, the remainder being travelled with economy as the target. I find the Roomster's grip helps... 

I guess this doesn't help you much but if I were you, I'd be disappointed. The 1.6 may be better suited.

[tamiyaandy]

Its much the same in the fabia, Do 70mph and i see 55mpg, Drop down to 60mph and it jumps up to 68-70mpg.

 

I think the 1.4 is a great little engine, if i try real hard i have squeezed 83.3mpg on a 30 mile b-Road plod. :clap:

[RichardatWakefield]

Hello Mike,

I've experienced the 3-cylinder 1.4tdi PD in a Mk1 Fabia hatch, and now its bigger 4-cylinder PD brother in a Roomster, the Fabia felt very flat below 2000rpm, I had the cat core removed which brought the (older-type wastegated) turbo in a bit sooner, then used Millers Oil and Fuel Additive, then got it re-mapped; listed at 75bhp, actual 79bhp, and 99.9bhp re-mapped, was able to average 76.5mpg all summer (it's fairly flat where I live) but was very vibratory pulling hard at lowish revs once mapped.

 

Roomster has unaltered cat, comes fitted with newer Variable Vane turbo, Millers oil and additive, standard paper air filter, just been re-mapped, list was 105bhp, actual 117bhp , now it's shall we say sufficient, mpg has varied from 56/57ish autumn/winter soon after purchase, but now with handbrake cables replaced, better tyres (Goodyear Efficient Grip Performance), stiffer front console bushes and re-tracked correctly, and re-mapped, well I poddled across to Blyton last Sunday into a blustery headwind and averaged 68mpg, and eked 73mpg on the return leg (with tail-wind), that was  just myself.  Touring the Northumberland coast in late June two-up, some days showed 70mpg.

 

That's doing the full economy driving routine, coasting downhill bits and up motorway exit slips, switching off at tedious traffic lights (but not straight after fast bits).  And yes the big back-end favours moderate speeds.

 

So I would certainly recommend better oil and a good (diesel-specific) fuel additive, will usually release several more mpg, and the Roomster remappers (Darkside Developments) got me to remove the Green Cotton air filter and fit a bog-standard paper-element type, as they say the oil on the re-usable aftermarket filters contaminates the wire of the MassAirFlow sensor (MAF), indeed I'm awaiting an aerosol of MAF wire cleaner to (hopefully) smooth idle-speed running in town.

Being only 2-valves per cylinder engines, they're quite rough, but durable.

Good luck!

Richard

[MikeThelm]

Thanks Richard. Some useful tips though I'll probably not go the remapping route but the paper air filter and good quality oil sounds about right. I've always liked to change the oil at 5000miles which may not be necesary with modern synthetics but I'm sure it can't hurt.. I have noticed the roughness and lack of grunt at low revs, she's much happier above 1500rpm.

Cheers, Mike.

[tamiyaandy]

These engines are a little rough below 1500rpm, partly down to being a 3-cylinder.

But saying that, mine was greatly improved by a clean air filter, and cleaning the MAF sensor, it's much better around idle speed, and pulls very cleanly.

[grafitti]

On long runs I have gotten 73mpg average off the onboard computer, and cross checking against fill ups and odometer it's within 1 or 2 mpg of actual.

Obviously the slab rear doesn't do any favors, and 50-55 seems to be the highest I can go before consumption drops into the mid 60s.

At 80 my average drops to 57mpg