Improving MPG / Fuel economy.

red reading

red reading

Active Member
getting the car mapped will make the biggest differance to mpg, i had 39mpg on my old spec when crusing at 70 to germany...................... what alot of you lads are forgetting is that good mpg show's good engine efficency as well as power, my parasitic losses are less too as the car has a straight cut transmission and final drive. also try running higher tyre pressures for less rolling resistance.
 
PobodY

PobodY

Moderators
Staff member
So in your opinion, the straight-cut gearset is the best way to reduce transmission losses (over changing the gear oil for example)?

The tyre pressure is also a good suggestion.
 
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skiddusmarkus

Active Member
KieranEG6 said:
Jeez Ill say it again Im really not concerned about making the car have great MPG and of course I know there are things you can do to help that will just reduce the perforance of the car.

I just though it would be a good topic for people to input usefull things they have found that will help. Its not like its a dumb question that gets asked every day.

Whats with all the sarcastic reply's :evil:
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You asked a question that's been asked before(so searchable).People are still answering helpfully but you don't seem to like them?

The best thing you can do is learn to drive more efficiently-this will help you with every car you drive forever more.I used to teach this at work and I guarentee you I could get more mpg out of your car than you could yourself and then show you how to do it.The next best thing is a remap.
 
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PobodY

PobodY

Moderators
Staff member
Ironically this was on the episode of Top Gear repeated on Dave this morning (the Audi V8 diesel from May 2004). - To improve MPG: reduce engine revs; reduce weight; reduce drag; and turn-off unnecessary electrics etc.

I think Jeremy managed to almost double the fuel efficiency by not exceeding 1,200rpm (not really an option in a turbocharged petrol car; it's probably something more like 3,500rpm), and by turning-off everything that wasn't actually required to drive (so no stereo, no heater unless the windows were fogged, etc). His calculation was a saving of £600 per year.
They also said "don't carry around excess weight... if you see two hitch hikers; leave the fat one.", and "you see people driving around with those sheds on their roof? That will cost you an extra £10.50 in fuel to do the same journey; you'd save money by just buying it when you got there."
Finally; "You'll save money, but you'll always be late."

That's pretty-much what has already been said in this thread; and exactly the same advice you'd get if you google "improve mpg".
 
KieranEG6

KieranEG6

Member
red reading said:
getting the car mapped will make the biggest differance to mpg, i had 39mpg on my old spec when crusing at 70 to germany...................... what alot of you lads are forgetting is that good mpg show's good engine efficency as well as power, my parasitic losses are less too as the car has a straight cut transmission and final drive. also try running higher tyre pressures for less rolling resistance.
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Thanks for the input. Just the kind of thing I was hoping to see.

I think most of you missunderstood my initial question. I started the thread because I kept seeing poeple slate the MPG of the GTiR's and when I searched it I could only find people fixing faults that caused excesive fuel consumption nobody generalising things that will help on GTiR's. I myself dont realy a problem with my MPG as im yet to get mine on the road. Have owned 300hp STi's and 200sx's so know how bad these types of cars can be and how much your driving makes a difference.

It was literaly just a conversational topic for people to input what different things they have found that helps all in one place. As every car has different flaws in different areas.
 
PobodY

PobodY

Moderators
Staff member
PobodY said:
A remap will also improve the fuel efficiency; you can lean the map out for low RPM on the highway, there's not much in the way of engine load so the risk is pretty small. - I'm sure Ed has done this when mapping Nistune for some of his customers.
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That was one of the first things I said; it is definitely a topic that has been covered before. :doh:

Most of the threads I've read aren't slating the MPG, they're saying "I'm using a lot more fuel at the moment, so something is wrong; I'd like to find and fix it."
 
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paz

Active Member
I knew someone who ran lpg in a 200sx with a limiter at something like 3000rpm. Whenever he wanted to have fun he switched it back to petrol.

Didn't know him that well, so don't know the specifics of how it worked, but I guess in theory it's possible - I never knew until that point you could safely run LPG on turbo cars.
 
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warpspeed

warpspeed

Well-Known Member
the only real problem you'll come across running lpg on an r is space, because of the rear diff etc it's very difficult to find space to fit the lpg tank without filling up the boot.
I am building my r to run standalone liquid injection lpg and i'm altering the rear seat area and the areas above either side of the diff so i can fit 2 tanks lengthways but another option that i have used on a fwd sunny gti is to cut and remake the boot floor to accept a tank inside (iirc it was about 80ltr water capacity) and fit a side exit exhaust

lpg is definately the way ahead if you want performance with around half price running costs but it needs to be done properly really as there's no point running an lpg system alongside the original fuel system due to the reasons mentioned above and also the extra weight (the lpg tank is heavier although the lpg is around half the weight of petrol by volume)
 
bensmith907

bensmith907

New Member
A very valid question I reckon and one I regularly ask myself so not quite a pointless thread. I recently changed my wheels back to standard ones just to run me to and from work. I have filled up twice since the change and both times I have noticed an increase from 350kms per tank to 400kms. Not bad I reckon especially as I'm not wearing out more expencive tyres doing so (although I have had the piss ripped out of me for having 14"rims lol)

I also reckon the underside of the car must have a massive drag factor was it just the GTIs that had a tray underneath (I seem to remember it says to remove one for an engine cx) coud this not be fitted the gtir with some modification?

I would be interested to see how economical ed could get an engine if he was just aiming for fuel effiency and not power.

(Same again I'm not massivly worried about how much £€$ I put into the tank as its what I bought myself into but also I'm not ignorant enough not to know that cheaper is better)
 
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skiddusmarkus

Active Member
Well I trained people in vauxhall movano vans with huge drag due to a massive frontal area and they averaged 18-20mpg at the start of the day and 40mpg by the end of it.No amount of aerodynamics, mapping, weight reduction etc is going to give gains like that.

Concentrate on your driving style, it's free.If you do a training cours eyou will get the money back many times over.
 
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