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Trying To Get The Best Fuel Economy- What Have I Missed?

ausdrift

By ausdrift,
in General Maintenance

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ausdrift Experienced

ausdrift

Posted
Posted

OK, so I'm aware this is an age old discussion, but I'm trying to get better fuel economy from my R33 and wonder what I'm missing here.

Firstly, engine mods are - full exhaust, Blitz panel filter

I was getting around 330kms/tank and decided this was pretty poor. I then replaced the O2 sensor on the assumption that it should have been old enough to be not working at its prime. This gained me only about 30 extra kms/tank.

Now at 360kms/ tank I have recently added a bigger dump pipe and metal cat, making it a full modified exhaust which has not really changed things (that's not why I installed them, though).

The AFM I would have cleaned about 10,000kms ago and I would have thrown in a can of quality injector cleaner for good measure about 5000kms ago, so while I will do these again soon I don't expect much/any change. Spark plugs are around 12,000?kms old, and would have been platinum/iridium?

So the big questions are

1- What OEM parts should I change/maintain to bring fuel economy back up to what it would have been designed to give me?

2- What else can I do to improve this?

Thanks

Victory Mentor

Victory

Posted
Posted

When you say 330 km to a tank how many litres of fuel are you using to fill it up?

To compare fuel economy you need to be talking about litres per 100 km so you can compare apples to apples.

Your driving style and the break up of city and highway driving also impacts fuel economy.

In my R33 GTR the best I can expect is about 15 litres / 100 km and this quickly drops to around 22 or 23 if you give it a bit.

Trex Grand Master

Trex

Posted
Posted

coolant temp sensor, afm, plugs. Tyres. The list goes on. But this has been covered about a million times, with the same results and replies. Don't boost it hard, stay under 3g rpm and youll get roughly 11/100 - 450-480k per 50L

V28VX37 Veteran

V28VX37

Posted
Posted

Yep 'kms per tank' is not a reliable measure, you'll want to work out l/100km, preferably over time. All you need to do is fill up full each time and take note of the odometer.

There's some useful comparison figures in this thread: http://www.skylinesaustralia.com/forums/topic/436056-fuel-economy-for-250rwkw/ - I'm getting anywhere between 10 and 16 l/100km depending on type and style of driving (~260 rwkw).

Ben C34 Grand Master

Ben C34

Posted
Posted

True, my kms/tank isn't exactly a scientific measure, but that's ok as its just a quide to see what differences I can get.

How would replacing a water temp sensor change anything?

because if it is faulty the ecu could think its cold and run the car richer than required. Obviously refering to the one for the ecu, not the one for the gauge.

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ausdrift Experienced

ausdrift

Posted
  • Author
Posted

How would one know if the coolant sensor is defective? is there a test or check for this?

Also I checked hypermiling; that's pretty anal stuff, so I think ill just drive as I usually do (which is fairly gentle anyway). I just don't want to guzzle unnecessary fuel when i choose to own a I6T engines car that's 18 years old.

Ben C34 Grand Master

Ben C34

Posted
Posted

How would one know if the coolant sensor is defective? is there a test or check for this?

.

Check its resistance againts the specifications (probably in service manual) in water at known temperatures, or check using a consult cable and some software what is being read by the ecu at operating temp.

Ben C34 Grand Master

Ben C34

Posted
Posted

if you don't have access to either service manual and/or a multimeter just unplug it and see if your economy changes

If you dont have a multi meter, buy one.

no service manual, google :)

Ben C34 Grand Master

Ben C34

Posted
Posted

you'll be surprised some people can't even use a multimeter and have no farking idea.

It is crazy, seeing as how EVERYTHING is on the internet.

We should all be geniuses!

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