Diesel remap?

Hi I have a 2.0 HDI that I'm thinking of mapped for more economy been quoted £150 and told will gain 5\7 mpg. Does that sound about right?

Surely you don't remap for economy? I've had my 330d remapped and it does about the same fuel economy.

I had my Alfa GT diesel remapped for economy (no point in going for more power - if I want to go quickly, I take the Coupe)

Along with an EGR blank and a Terraclean, I have raised my tank average from 44 to 49 - in fact the worst tank mpg I've had since the remap is almost exactly the same as my BEST tank mpg prior - fairly conclusive evidence, I'd say

Fuelly record - remap & Terraclean done in Feb 2014

TBH, it has more power too - its difficult to remap and NOT get more power, as torque is usually enhanced

Let me know the exact model and I can quote for your various options (max power, pure economy or a "blended" map giving a bit of both)

Yeah, a sensible remap on any car can improve fuel economy. The remap irons out the cliches in power delivery and means you don't have to drive the car as hard, therefore saving fuel. My mates Fabia vRS was mapped from 130 to 170bhp and he still gets 55+mpg.

My VIS Coupe is better on fuel since the remap by Flea. Got 40mpg on a run the other day And 34mpg on the motorway in France, and I wasn't driving slow either.

Nigel, I'm interested - same engine as yours, I think, in a 1.9 JTD Multijet 150 Bravo, 2008. Looking for economy, not power.

Yes - same engine - mine's a 2008 Alfa GT 1.9 16v - 150bhp

FWIW, when I REALLY tried for a good mpg figure (by cruising at 55-60 and slipstreaming the HGVs), I managed 64mpg for a 60-mile commute

As well as a remap, you should also have a read up about Terraclean - sounds terribly like a snake-oil product, but it really does work

We can do both at Motormech

Normal commute, cruise control on the motorways and DCs at a touch under seventy and not particularly trying hard on the A roads, with a guaranteed traffic jam twice a day on a 65 mile each way commute (43-35mph average!) gives me an indicated 52-55mpg - more in winter which I think is down to the tyres, not the different fuel. A longer run helps, too.

Though there is one section of gentle A-road in which I can achieve better than 80mpg tootling along... it all disappears when I get to the DC, though.

Just passed 120,000 miles this weekend.

Do you find that the consumption is significantly affected by rain on the road, or strong winds? Can be 5-10% worse for me in bad weather.

At last! - Someone who agrees....

My mpg seems to drop by a noticeable amount in wet weather. There's always the chance that this is because there's more traffic (parents driving kids to school, or driving to work instead of cycliing)

My average speed on my daily commute was usually under 30mph - I've never beaten 40mph average

Something to try - don't use the cruise control - I found it worsened the mpg, so the only time I ever use it is through a few miles of average speed camera. Normally the traffic is simply too heavy to use it

How accurate is your fuel consumption meter? Mine used to be out by 2-3mpg, but since the remap, its accurate to within 1mpg

The meter reads about 5% low, I think. I make a point of never doing it properly with an adding machine, but it makes an interesting internal discussion on a Friday afternoon when I'm trying to decide whether I can get back to my usual filling station (which is on a slope and gives me thirty miles extra range!)

I conclude that the diesel is using so little fuel that even small changes in road friction are a significant change to the overall energy requirement; all that water the tyres are moving, or a headwind, are effective at slowing you down. Traffic is pretty constant for me irrespective of weather; I go against the flow for most of the time.

I can beat the cruise control, but not by much on my commute.

I find I have to constantly feather the throttle on the family boo. I can easly average +10mpg on the wife so around 52 average. Thats 65 ish on fast roads and doing my own thing, lots of pre planning round abouts, retards in front and traffic lights!

Am I now to understand that a 190 quid map will see me hit 60 mpg???

Nigel, can I ask if you get the diesel black soot plumes after your map?

I think 60mpg average from 52 is unlikely, but I'd be surprised if it didn't beat 55mpg, and maybe even 57. Remember you're looking at a £100 Terraclean treatment as well - in my case (160,000 miles on the clock) it made a couple of mpg difference

Yes, but less than it used to. Remember that the Alfa GT doesn't have a DPF, so you'll always get smoke when planting the throttle, especially after a prolonged period of very light throttle

Cool, my boo is only on 60k so not sure how much difference a clean wouldmake but it would be good to get a map - do you do it in house?

We have a tuner that writes the maps, but we upload them to your ECU on our premises in central Birmingham

He means central too. Get ready for a trip to the Bull Ring !

Unfortunately not. If you just had it remapped then there's a basis for comparison, but blanking the EGR and doing whatever a terraclean is, you've altered the parameters of the test.

For those wishing to JUST get a few more MPG, try bunging in a couple of bottles of Forte lubricants. But the offset of the cost of the additive will be much more than the savings at the pump from gained MPG.

There was no "test" - I made it absolutely clear that my 5mpg improvement has come about by virtue of three modifications (or two if you count the EGR deletion as part of the remap process) - I have no idea how much gain was attributable to each of the mods, I just know the net effect

The two mods weren't done at exactly the same time, but they were done on the same tank of fuel, so I never got chance to measure the effects of each in turn.

However, I can categorically say that the remap made the car much smoother and definitely more powerful / torquey. The Terraclean treatment refined it even further, with a noticeable improvement in throttle response and general engine refinement

FWIW, I also use Millers diesel additive, which I've done since about August last year - it made about 1.5 - 2mpg difference, which considering each treatment costs about £1.30, is well worth it (2mpg over a 13 gallon tank is about 25 miles, or £3.00 saving). However, I've been using this before and after the mods, so it doesn't alter the results of the remap / Terraclean

Fair enough Nigel, but telling people that they can get a map for 'economy' has to be substantiated with evidence. Especially if you're selling it as a service.

Hi Nigel , interested in this for my BMW 530d m sport, with DPF
Probably blended is best, mind you I'm not sure if I should tinker with it at all - it's given me 200,000 with no major bills 😎 PM me details please
Cj

Also Nigel can you confirm that the price for DPF removed, Performance Remap, DPF Delete and EGR Delete £320+vat would be the same for my BMW and if you guys can do it?

Thanks again

Modern diesels really are a revelation for the modern motorist. Ultra clean, and great torque/mpg make it a winning combination. They also map up incredibly well, almost to the point where you can equal or better the output of the next engine size, so worth considering when looking at which model to buy!

As for fuel economy, well it's not so straight forward as it does rely almost exclusively on driving style. Diesels are quite different to petrol engines in that it really is all about the fuel i.e. injected quantity, and start of injection. In order to achieve better economy we need to increase torque at low rpms where higher gearing can be used effectively. Increasing torque increases the flexibility of the engine allowing a higher gear to be used under many more conditions without the need to drop a gear or rev the engine harder.

So how do we achieve more torque? Well it's quite simple, we MUST inject more fuel! For a diesel, more fuel means more power. However, it has to be done correctly for two main reasons 1. Smoke 2. EGTs. Too much fuel and the smoke will become very apparent! It will also elevate EGTs considerably, the exact opposite to petrol engines, with the biggest concern being turbo failure. The way to combat this conundrum is with boost! More airflow will clean up the smoke and reduce EGTs thus allowing us to increase power cleanly and safely. Now all this can be done to achieve maximum torque and power across the full rpm range i.e. up to circa 4500rpm, or we can simply concentrate on the peak torque area of 1500-2500rpm. This is where most people will utilise the engine, and if driven correctly you will see some small gains in mpg. If using the torque for maximum performance (aka fun!) your mpg will go down.

I tune a lot of diesels, and generally most owners will see a small increase in mpg after they calm down from the massive increase in thrust! My own Volvo XC90 D5 saw 4mpg increase, mainly because it's a big heavy car and the extra torque really benefits the gearing. I am going to tweak it a little further for a little more around 2000rpm. I very rarely rev that engine, it's just not that type of car! On the flipside, I have a Seat Ibiza PD130 in at the minute which is receiving one of my special hybrid turbo upgrades. Aiming for 220bhp from this little rocket with circa 350lbs/ft, now that will rev hard all the way to 4500rpm!!!

Its just a shame a diesel.sounds like a, errr, diesel!

Interesting to read more fuel and more air means better economy.

TBH, once you're driving a decent, modern diesel, it sounds just fine (in fact even in my leggy Alfa GT 1.9, you can't really hear the engine at motorway cruising speeds - it just thrums along at about 2000rpm)

Yes, its horribly tractor-like when you're on the outside of the car, especially in warm weather (no idea why - just seems to sound more clattery)

However, I had to do a 250 mile round trip to Oxford and back today - set the cruise control at an indicated 75mph on the M40 / M42 and took it modestly easy - returned 53mpg - can't really complain

REALLY modern diesels will do even better than that - 60+ mpg would be the norm for a near-new Merc, BMW or Audi oil-burner on the same trip

There's one huge bonus to driving a diesel as the everyday hack - the performance of the Coupe feels epic when I get to drive it

I know they aren't so.bad when driven, I drive a modern (more modern than your 1.9) most weeks, but i also have a 20vt and a v12 jag in the same breath. I couldnt careless about a diesel, you cant beat a v12 jag - ever. Not for torque, power or smoothness, maybe on mpg though!

Despite my long and varied motoring history, I've never driven a V12 - I can only imagine it is a revelation after coarse four-pots

I've been following this thread with interest, as for the first time in my extremely varied car history i find myself considering a diesel. Are they still really only more economical over long journeys, or has that changed with the modern machines?

On the Big_Muzzie tangent:
My dad owned a BMW 750i for a few years, 5.3l V12 made for a very smooth and refined machine and the sound of it firing up was almost orgasmic, but i preferred my Lexus 4.0l V8 for every day driving. It didn't beg me to press the throttle quite so hard or often. Never had the pleasure of driving a Jag V12 yet, but i have a huge soft spot for Jags so i suspect that day will come soon.

Agreed. Even the 156 5 cylinder diesel is very loud at idle, but as soon as you're moving it's just smoothness and turbo whistle with a 5 pot rumble
Certainly effortless. I still prefer the sound and feel of petrol of course, but I think both serve different purposes now due to the +20mpg difference. I'm not including small petrol engines here as they don't usually fall into the long distance/cruiser/GT car category.

The best diesel I had was a V6 twin turbo Jaguar S type. Even on idle, it has the faint sound of a V6 petrol. When you started moving, you could barely hear it!

The jag v12 is supposedly the smoothest engine ever designed and built, I can believe it too. You can sit a glass of water on top of a bank and it hardly ripples.
Cant say ive ever experienced a diesel that delivers smooth power, ive also never heard one that doesnt sound like a bag of spanners on initial start up. The percussion of compression is unavoidable, its part of what they are. The cars can be quiet inside but from outside its a bit naff, which is why convertible diesels confuse me. The noise and diesel fumes in a drop top? Why?

I was a passenger in a Merc CLS diesel, which was VERY impressive and I'm told that the V8 diesel in the latest Range Rovers is fantastic

Wouldn't mind seeing how the 5-litre V10 diesels are like in the Phaeton and Tuaraeg and I'd love to drive the V12 Audi diesel (Q7, I believe and possibly a diesel R8?) - 500bhp and about 740lb-ft - must be monstrous

I would assume they are very similar to their petrol cousins except the noise is different, the LM diesels are freakish when hooning round at 200 mph, the sound is "missing".

I love the sound of petrol engines as much as anyone. Had a burn in my mates TVR Chimera 4.5 over the weekend. The shove and noise was addictive.

But I do like the raw "agricultural" grunt of a diesel. I think it must be childhood memories of driving my grandads old grey Ferguson tractor. It's more about pulling power and low down shove, and the modern turbo diesels give thrilling power from 2,000 rpm.

The Volvo 5 cyl and Fiat/Alfa 5 cyls and any of the V6, V8 V10 diesels sound great in grunty power "I can pull a 747" sort of way.

I even like the massive thumping sound of an old diesel locomotive.

As usual, there are divided opinions, but you can like both petrol and diesels. They just do different jobs. A modern diesel usually makes a better motorway car than a petrol due to reving lower.. .and better mpg.