How to tune for economy.

[obi_waynne]

We have an old thread on tuning a car for economy but I thought we would start a new one and get the benefit from our newer members.

What tips do you have for economy tuning?

Here are my top tips.
Tire tread and compound makes a big difference as do tyre pressures.
Run the engine a little hotter, a higher temp thermostat will do this.
Small advance on the timing will generally make an engine run more efficiently.
Bigger spark plug gap will also make a bit of a difference to both power and economy.
In large V6 & V8 engines a flow, polish and port can often give better economy.
(Finally one for HDI) Put a Diesel engine in the car. - in reality this is much more hassel than it is worth.

Now its over to you guys to add to this and discuss the pros and cons of these suggestions.

 

[turbonutter69]

Loose all uneccessary weight including passengers.

 

[pgarner]

block of a small section of the radiator off. this will allow the engine to heat up quicker and run slightly hotter.
remove any ducting to the air filter, this will allow warmer air into the engine. ECU will pick up on this and reduce the fuel comsumtion

 

[HDi fun]

Driving style makes the biggest difference of all.

 

[Munday]

Reduce airflow restrictions in the inlet to a minimum

Skim the head for an increased CR

Port and polish cyl head

Design a under tray for front/rear to help smooth airflow under the car

Use the thinnest oil as recommended by your manufacturer

Get wheel alignment checked

Service regularly (fuel, air, oil filters etc)

And in ref to driving style its best to use wider throttle openings and low revs rather than higher revs and less throttle openings.

 

[HDi fun]

Reduce airflow restrictions in the inlet to a minimum

Skim the head for an increased CR

Port and polish cyl head

Design a under tray for front/rear to help smooth airflow under the car

Use the thinnest oil as recommended by your manufacturer

Get wheel alignment checked

Service regularly (fuel, air, oil filters etc)

And in ref to driving style its best to use wider throttle openings and low revs rather than higher revs and less throttle openings.

With naturally aspirated conventional petrol engines yes. Mitsubishi GDi ones won't respond to this driving technique.

Diesels don't have throttles at all so keeping revs down will help. Again though, don't labour the car at 650rpm, for example.

 

[turbonutter69]

But driving style is not a form of tuning. It's technique.

 

[herb]

why would anybody tune for economy?? if i wanted economy i would choose a gwizz or equivalent!!
but if i wanted economy and performance i would choose a td of some sort

 

[turbonutter69]

why would anybody tune for economy?? if i wanted economy i would choose a gwizz or equivalent!!
but if i wanted economy and performance i would choose a td of some sort

Economy and performance don't mix.

 

[herb]

Economy and performance don't mix.

oh god hdi has got to me :amazed:
but using his car as an example they do mix

 

[turbonutter69]

oh god hdi has got to me :amazed:
but using his car as an example they do mix

Not really. I bet if HDi nailed it every where it would loose quite abit of MPG.

 

[herb]

Not really. I bet if HDi nailed it every where it would loose quite abit of MPG.

very true but he would still return better mpg than me in my car with only the occasional foot down

 

[turbonutter69]

very true but he would still return better mpg than me in my car with only the occasional foot down

But thats the point of owning a petrol.

 

[herb]

But thats the point of owning a petrol.

tbh no owning a petrol and wanting to up the performance the main aim isnt to lower the mpg (which you are suggesting from that statement) the main aim is to get the best from the car and if you can keep decent mpg that is an added bonus!!! :amuse:

 

[HDi fun]

I don't drive like your typical driver who's in pursuit of maximum fuel economy. OK - I don't nail it everywhere but I really don't need to do so either.

My 38-40mpg average (over tens of thousands of miles) is achieved in spite of the fact that I rarely see a day go by where I don't hit 85+mph.

Diesel is a good way to get the economy of a carefully driven 1.6 petrol car with the midrange shove and flexibility of that offered by a 3.0 petrol V6 car.

There are other things to consider: diesel costs more than petrol, and the engines need more frequent, more prescriptive and more expensive servicing.

If economy is your only goal and you're willing to drive in a mercenary fashion then diesel won't help you much. Buy a tiny 1.6 or 1.4 petrol engine and change up at 1500rpm. You'll save money, possibly, but by the time you get to your destination inflation will have halved the value of the fuel remaining in your tank.

If you are loaded with cash then sure, a BMW 540i will deliver all the performance you want, with a premium to pay at the pumps with the 15mpg you'll likely achieve.

If you like to get on with your driving, want easy access to deep seams of midrange overtaking shove, and want to make swift progress without the noise that a modest 4 cylinder petrol engine will make whilst doing so then a decent common rail diesel is absolutely the way to go.

A sympathetic remap will realise even more torque than you imagine possible; at worst your fuel usage will remain the same.

Manufacturers, even now, detune their diesel models to make room in the range for the petrol equivalents.

The biggests proponents of petrol engined models over any diesel are the elderly drivers who still think that diesel means slow and noisy.

Not that any of 'em will bother test driving a diesel to see whether that's still the case.

 

[turbonutter69]

tbh no owning a petrol and wanting to up the performance the main aim isnt to lower the mpg (which you are suggesting from that statement) the main aim is to get the best from the car and if you can keep decent mpg that is an added bonus!!! :amuse:

I know the aim isn't to lower consumption. My point being is that if you want performance then you shouldn't be worrying about MPG.

 

[HDi fun]

My point is that if you want performance then you should not ignore diesel.

 

[herb]

I know the aim isn't to lower consumption. My point being is that if you want performance then you shouldn't be worrying about MPG.

this is true but if you could have performance and good mpg would you??????

 

[herb]

My point is that if you want performance and fuel economy then you should not ignore tractors.

edited for you mate :amuse:

 

[Sid447]

Good read,

about cooling systems here (to help ensure better efficiency and economy).......

http://www.grapeaperacing.com/tech/coolingsystems.pdf

 

[HDi fun]

Quote:
Originally Posted by HDi fun
My point is that if you want performance and fuel economy then you should not ignore tractors.

edited for you mate :amuse:

Thankyou - kind sir

 

[CitizenErazed]

perhaps I'm just being ignorant here but... LPG conversion?

 

[herb]

perhaps I'm just being ignorant here but... LPG conversion?

the lpg van i had for quite a while
there was no difference at all that i could tell between the petrol and the gas the only real difference is the price and no congestion charge in london

 

[CitizenErazed]

but surely your financial economy comes with LPG being so cheap, so you wouldn't need to keep MPG so high because you will still be paying less then petrol cars

 

[MasterAuron]

If you want pure performance, you shouldn't consider a diesel. Simples. The good thing about modern TDI's is that they offer a very very good compromise. That's what's hard to ignore.

You have to remember turbocharged petrol cars can also offer very reasonable economy off-boost, especially small-engined ones. This is aided by the fact petrol is cheaper than diesel.