2.7 conversion MPG,

[cakey87]

hay, i have built a 2.7 for my e30 using the super eta bottom end and my 325i sport head, with sport throttle body, injectors and management etc,

To be honest i was expecting hideous fuel economy, like 12 to the gallon or something but from an empty tank £20 worth of fuel plus half a litre of injector cleaner i have racked up 92 miles so far and still havnt ran out, (full gerry can in boot ready)
fare enough to i havnt really given it any stick yet as im still running it in and getting all the air out the cooling system but on an average drive round country roads the mpg needle is well past the 30mpg mark,

just curious as to what other people are getting with this conversion.

[daimlerman]

Mine gives 31/33mpg,and I have seen 37/38mpg on motorway trips.

[andyp]

I had this same engine in an auto touring and I don't think it made 20mpg, so you are doing very well

[B7]

My 2.7 is better than it was as a 2.5. I'll get 33 on a run 24-25 round town with a bit of fun thrown in.

[cakey87]

fare enough, girlfriends car has broke down so im having to take her to work and back, bout 12 miles of motorway driving and another 10 miles of country roads each way and im managing about 115 miles to £20 in the wet with a little bit of tail happiness.

[FinalD]

You can't equate £xx to xxmiles as MPG. Fuel costs different amounts all over the country for starters so in some places £20 will get you 18L and others it'll get you 14L. Because of this you will not be able to correctly work out MPG.

To do it properly you need to brim the tank, reset the odo, empty the tank (by driving), brim again, record the odo reading, reset, repeat.

You can then use your odo reading and the xxL to work out a much more accurate MPG than 'I did 100 miles to £15'.

[cakey87]

to be fare i think you can work it out quite accurately around ''i did 120 miles to £20'' £20 of fuel =14 litres @ £1.41 a litre, 14 litres is just over 3 gallon so 120 / 3 = 40 and that was a complete empty tank, £20 of fuel, then running out again,

[Sanchez]

As long as you no how many litres you got for your money and you pay the same price everytime you fill up or the person in comparison pays the same price then its fine.

[Speedtouch]

A long-stroke, torquey slogger of an engine usually is better on fuel economy than a large bore, short-stroke, revvy one.

That's why the 325e and 525e (eta 2.7 engine) were designed, specifically to be economical.

It's all about the torque, that gives you the ability to waft down the road in a high gear at low revs, on a light throttle.

Most 325i's are slightly better on fuel than the 320i, for the same reason.

I've even seen 30+ mpg out of an E34 535iSE, with a 20 year old M30B35 boat anchor, on motorway runs - overall, it did about the same economy as a Land Rover Freelander I had with a 1.8 K-series, and both vehicles weighed about the same.

[BATTS91]

But are we classing a gallon as 4.5l as it should or 5L ? This is a common misconception .

[HairyScreech]

But are we classing a gallon as 4.5l as it should or 5L ? This is a common misconception .

It is? Why would anyone use 5l?

[Speedtouch]

A gallon is 4.55L.

5L just happens to be the size of most jerry cans.

[cakey87]

i was working it out to be 4.55 litres to a gallon, and to be fare i was also driving like a granny for that period as was over due for a cam belt.

[Speedtouch]

It doesn't surprise me in the least that you're seeing 30 mpg out of it.

[cakey87]

it suprised me lol, i thoguht i was guna have to save up for a diesel to use as a dfaily driver, but the mpg this gives im jsut using htis every day now, and with your chip it makes a massive difference to how it drives,

Oh, i have that other chip to send back to you aswell, cule u pm me the address again as i deleted everytihng out my inbox by accident.

[Speedtouch]

Good to hear that, Cal. PM sent.

[daimlerman]

It's all about the torque, that gives you the ability to waft down the road in a high gear at low revs, on a light throttle.

Most 325i's are slightly better on fuel than the 320i, for the same reason.

This really is the whole point.You can trade off some of the low down torque against more top-end by playing with cams,I started with a stock 325 cam which gave me almost maximum torque at 2000rpm,it was usual for me to be able to use 5th to overtake a truck travelling at the regulation 56mph just by tickling my right foot,this is what gave me the 35/38mpg.
I currently have a 323 cam,this needs a drop of at least one gear for a similar overtake,but the engine now pulls strongly to the red line,but I rarely see more than 31mpg!

Conversion factor that I use for litres/gallons is 4.54...

[Morat]

to be fare i think you can work it out quite accurately around ''i did 120 miles to £20'' £20 of fuel =14 litres @ £1.41 a litre, 14 litres is just over 3 gallon so 120 / 3 = 40 and that was a complete empty tank, £20 of fuel, then running out again,

I pay £1.34 a litre...