new member, oxford uk; diesel honda civic
 

Hello. Just joined, hoping to learn a lot from you chaps.

I run a 2015 honda civic tourer (wagon/ estate/ combi etc depending on where you come from).

It's a 1.6 diesel engine, 118bhp, officially rated as follows:

Urban (city/housing areas) – 67.3mpg
Extra Urban (motorways/country lanes) – 74.3mpg
Combined (a combination of the above) – 72.4mpg

This car i believe is still the Guinness record holder for lowest fuel consumption on a trip visiting all 24 continuous EU countries; 8,387 miles across the EU it achieved 100.31 miles per gallon.
http://www.autoexpress.co.uk/honda/c...0mpg-civic-run

I've not managed to get to 100mpg on mine but i'm doing my best :)

Since i got the car last year i've fitted eibach/bilstein suspension (lower about 40mm vs. stock ride height), fitted "A" rated tyres for fuel economy, had the inlet manifold cleaned, set the tracking spot on and fitted some super-light forged wheels. All of that has helped and i can now regularly see 75 mpg on my commute.

Best i've achieved is high 80's mpg but this is hard to repeat as the roads i use regularly are pretty busy. All these numbers are uk mpg - us gallons

I'm keen to learn what i can do to boost my fuel economy, both for ecological reasons and also 'cos it saves me money.

Looking at next possibly a re-map, maybe also wheel covers for improved aero, maybe grill block and some additional underfloor aero.

Anyone else on here running a diesel honda?


:thumbup:

Not got any good pics of the car, but here's a few.



https://live.staticflickr.com/7849/4...b8ea1883_k.jpgThule by Rob E, on Flickr

https://live.staticflickr.com/7805/4...84ab18f4_k.jpgUntitled by Rob E, on Flickr

with spacers fitted to put the wheels flush with the arches.

https://live.staticflickr.com/65535/...acb53537_h.jpgspacers by Rob E, on Flickr


The mk9 tourer is a model you guys don't get in the USA, this is a Swindon (UK) built car.

Nice looking vehicle. Check out the driving tips link up top for the best and quickest results. The mods list also is a great resource to start.

If these were sold in the US we wouldn't need hybrids.

ha ha yes. I looked at a bunch of hybrids before i bought this, but the small capacity diesel is more effective solution for the type of driving i do.

long distance (near) constant speed lends itself more to this sort of car i think - a hybrid would only use the battery getting up to speed then have the penalty of carrying around the additional weight of battery and elec motor for the rest of the trip.

Eco driving tips, yep been reading a lot recently. I managed 91 mpg on my trip in to work this morning ~58 miles with some coasting down hills and (safe distance) slipstreaming some trucks.

I'd love to drive one, if I could get my hands on one...beautiful machine.

Update:
I've booked for engine remap, should be mid-september i get this done.

The map runs the engine slightly leaner on part throttle (cruising) so i'm hoping to see a benefit.

Other positive of the map is it'll get me 309 ft lbs torque (418 Nm) if i need it, should make it pretty nippy i expect :)

This is a diesel, correct?
 

leaning a diesel at part throttle. It's throwing me.

I didn't know Honda made a diesel. Honda quality engineering directed at a diesel power pack sounds like a win to me.

That is a beautiful car that I wish we had here, although it is far too new for me to consider. How often do you use the cargo carrier? Would it be possible to use a tow hitch-mounted cargo box instead? I am not sure how well that would work with your hatch, but that would fill the wake, instead of increasing drag.

Also, I am sure the guys here would say the cargo box would be more aerodynamic the other way.

Has anyone boat-tailed a cargo box? :)

Hardly ever use the box tbh. Only when absolutely necessary.. it does make a difference to the economy but not a massive amount, less than you would have thought. The Thule box is a good aero design but yes i think you are right either a box tail or turning it around might be better. :)

Update: REMAP.

I've had the car re-mapped a few weeks ago - this is a very common thing for diesel drivers in the uk to do, lots of aftermarket companies offering a re-flash to give you a map that normally just focuses on adding fuel and allowing more boost (= more power).

I found a company that offered a map that also considers the efficiency on low/part throttle and aims to improve on the factory settings.

It's much smoother with the new map, general driving its a nicer car to drive. Full boost is much stronger and it picks up speed much better than before (and uses more fuel as a result) but when i'm driving eco to the max it is much easier to get higher MPG numbers than i was before.

It's now easier than it was before to get in the 70s mpg on my commute. Best i've seen was one motorway (freeway) stretch a couple of weeks ago that was constrained by traffic and speed cameras to 50mph. Over around a 20 mile stretch i got up to 100 mpg which is the best i've seen on this car. It dropped back down after this section but the trip was still 85ish mpg over 150 mile route.

Next i've got some aero tweaks i want to make; grille blocker, diffuser and wheel covers - i'll get going on those mods in the next few weeks.

:)

It looks better than the sedan. BTW have you never considered trying supplemental water injection or some dual fuel Diesel + LPG setup?

yes i've done some research but as this is my daily driver i don't have the luxury of taking this off the road to do any development work.. there don't seem to be any off-the-shelf kits for lpg into diesel and i don't want to do any damage experimenting.

i'm sure there are gains to be made with lpg - from what i've read it works in a diesel a bit like nitrous in a petrol (gas) engine - ie makes more power. i don't want a faster car but maybe could be configured somehow to give my economy gains..

So i've been doing some experimentation, just to see what's possible to achieve for mpg on this car.

Not a scientific test, but seeing how far i could travel on 1 gallon of fuel.

Method:
- re-set the "A" trip meter
- drive until the trip meter and the mpg hit the same number, so in theory this is how far i've gone on one gallon.

i managed a good early morning run earlier this week, starting with a warm engine, clear-ish roads, +8 degrees, dry, some trucks around which pretty much matched for speed, so 56-60 mph. Just one 5 minute mid-way stop/ start i had to do but otherwise a single journey.

Managed 99.3 mpg :)

https://live.staticflickr.com/65535/...0b9ee3c1_b.jpg
99.3mpg by Rob E, on Flickr

Pretty pleased with this result. It's not reflective of "real world" usage which would involve cold starts, different air temps/weather, passengers, luggage etc but as an exercise and a bit of fun..?

:)

U
 

There are some off-the-shelf dual-fuel setups, even though they're more frequently fitted to commercial vehicles.

This is an example I found on Google
https://www.lpgshop.co.uk/ac-stag-di...onversion-kit/


It doesn't actually work in a way comparable to nitro. It may eventually make more power, but it only happens because the Diesel AFR is so lean that it allows enough oxygen to burn some extra amount of fuel to be accurately burnt. And since the volatility of LPG increases the flame spread, the Diesel fuel also has a more accurate combustion which by the way leads to a better usage of its energy content.


Using LPG to partially replace the Diesel fuel instead of supplement it is the way to go, and that's exactly the strategy followed by most operators who resort to it.

It works, with LPG or CNG, but in the EU you can't just toss in some gas gear .

I asked around years ago when I still had the V50 with 1.6L PSA diesel
It's possible
But not worth the cost & effort

On lorries you're talking about far more diesel use, thus far more to substitute with CNG/LPG than on a frugal diesel passenger car

I'm going to assume by "part throttle" you simply mean you are not accelerating, because diesel engines typically do not need throttles.

I also would not expect to get better mileage "leaning" the mixture at light loads because diesels always run lean; reducing the map at light load would simply reduce power forcing the driver to apply more fuel via the accelerator.

I've had the revised map on the car for several weeks now and it's definitely using less fuel to travel at the same speeds as before - see my pic above, with a warm engine, constant speed, i have achieved up to 99mpg. No way i could get it that high previously.

My overall average is not much difference, as i'm finding it hard to avoid using the additional performance i get with the new map, but when i'm really doing my best (driving style) for mpg then it is easier to obtain high numbers, and the max i can achieve is greater than before based on my non-scientific experimentation :)

That kit that cripplerooster posted looks interesting - its 500 quid plus id want to get it professionally fitted, say another 250 ish, and it doesn't look like the kit includes a tank? Maybe it'd be somewhere near £1000 fitted? So how do i work out the pay back on that? Harder than calculating payback in a petrol/lpg conversion in that i wouldn't run solely on lpg, but mixed with the diesel..

I do 28-30k miles a year, with spend on diesel currently about £200-£250 a month.

How to work out what the savings could be with that lpg kit? Ideas?

:)

See how much diesel you can replace with LPG

Calculate
What the £ savings in unused Diesel are over 100miles
minus
What the extra LPG costs for 100 miles


You know how many miles you do/year
That gives you your savings/year

Then see what the installation would cost
Divide by the savings/year and you know when you'll start making a profit ...
Gonna be a while I'd think


LPG tanks will be cheaper (lower pressure) than CNG
You'll normally need an extra MOT after installation
Probably extra periodic tests as well under EU regulation R110

At that fairly high mileage, it might work out

Remember you'll need a fair bit of LPG to replace 1L of diesel


AGS LPG en CNG-installaties AGS DieselMix AGS DieselBlend AGS Diesel+LPG AGS Diesel+CNG AGS Dieselgas

This calculates in € , km and in L
Under dieselmix, fill in LPG price

no need to fill in tankinhoud (tank size)

brandstofverbruik per 100 km = fuel use (in L) per 100km

hoe lang = how long you want to use the car

Thanks ^ that's a good tool. (had to use google translate to get the meaning but got there in the end).

It's pretty much what i've already concluded, very similar numbers.

I could potentially save around 300-600 a year in fuel costs if i had a lpg mix, but conversion cost is 1,500 so it'll just take too long to pay back, so not economically viable.

.. still interested in the ORBIS wheels though - that would be an awesome addition on the rear of the honda. diesel hybrid ev :)

Orbis have a new product on their facebook page - exhibited at SEMA earlier in Nov. No info on their website though, and no response to question on the FB page :(

I am sure you are correct in that the engine is using less fuel for travel at the same speed, my only point was it is not likely that the map was simply "leaned". There are other measures that can be taken to make a diesel engine more efficient, like modification of injection timing and fuel injection pressure, but diesels are completely different than gasoline engines where the air-fuel ratio in controlled.

How long do you expect to keep this car? IIRC there were less-stringent traffic restrictions for vehicles fitted with those kits in some areas where the emission ratings are being used as a reason to exclude some vehicles.

another 2 yrs maybe?

currently has 120k miles, adding 30k miles a year, so in 2 yrs time i'll be up to 180k miles.. if i did lpg and it took 3 yrs to pay back it would be 210k miles before i would be in "profit".. by which time there may be other mechanical issues to consider.

I'd have gone for it if I had a 3 year break-even period
For me at then current prices, it was double that or even longer

I went all CNG later on ;)

Hi almost neighbour :)

Seems impressive I have a quite comparable vehicle (Skoda Octavia 3 Greenline Combi). Just to be sure : do you give your mpg in uk or us version?

I will be considering a remap my major concern is to preserve the reliability of the clutch/flywheel.

Hi ptitviet - sorry not been around here much recently.

my mpg calculations are all uk gallons.

i love the octavia - very nice car, i had three of them :) all vRS (two x mark 2 facelift cars then a mark 3 vRS 230) all Combis / estates. I considered a greenline but i wanted a nice interior spec (full leather, nav, heated seats etc and the green line in uk didn't allow me to that - with the honda i have a really nice interior and v enconomical car too.

RE-map: I'd seen the graph showing how my car would deliver torque after the re-map and like you yes i was concerned it would come in with such a big "thump" that it would reduce clutch life and potentially also wear the front tyres faster or cause wheelspin.. but turns out i was worrying for nothing - its fine. The car after re-map drives just like it did before, just that you have a bit more torque and power if you need, but if you drive sensibly it's no additional strain on the drive train.

:)

Not much to update on the car - i've been running on my winter wheel and tyre setup so its harder to get good mpg, looking forward to swapping back to my lightweight forged rims and low-rolling-resistance tyres in a few weeks time as the weather improves. :)

The only mod i've done recently is a simple grille block.

I bought a cheap used grill from a breakers yard, same as my car already has fitted.. i used a can of expanding foam filler (aerosol) to fill in the gaps in the grille, then covered it with some black wide vinyl tape so it is less visible.

The grille gap i'm closing up isn't massive but i wanted to see if this would have any effect (increased mpg or raise engine temps).

Before:

https://live.staticflickr.com/65535/...f1f94656_b.jpgUntitled by Rob E, on Flickr

After:

https://live.staticflickr.com/65535/...4ca96d01_b.jpgUntitled by Rob E, on Flickr


I was hoping i'd see a more rapid warm-up on cold mornings but tbh i don't notice a difference. Good news is that the general running temp of the engine does not seem to have changed - there's obviously enough cooling air still coming in through the upper grille and the two smaller side grilles.

MPG - not really done anything scientific but i'd estimate it has made a positive difference but only v minor. Still cost very little to do and being black it's hardly noticeable..

I will try now also a block (or semi block) on the upper grille, and i have some options i need to try out with wheel covers and some underfloor aero ideas too.

.

Besides a grill block.

A cardboard engine blanket would assist in getting to operating temperature sooner and keep the engine warm in between short stops.

https://ecomodder.com/forum/showthre...-em-10529.html

I use foam insulation board with foil on one side reflecting back into the engine bay. It’s fairly cheap and can be bought at a home improvement store.

A plug in engine block heater would help also.

Nice car and nice job so far... :thumbup:


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