Improving. 1000 miles on the clock and 41.2mpg against an indicated 39.6mpg, so the actual mpg is improving but the computer mpg isn’t.
Have just changed oil and filter (foul job on a Mk3) for Mobil Super 3000 Ford spec stuff.
Mines a 2.0l, so i know it don’t count here, but got 41.5 mpg, not hanging about for the full tank mostly on dual carriageways and motorways for the last tank, with the roof down, I put this down to it being very warm? usually get about 35mpg
Yes, the car warms up much quicker (so only runs rich for a couple of minutes at the start of the trip) and the air is thinner, so less drag at high speeds. Using the aircon hammers fuel consumption worse than having the roof down IME.
How do you manage to get 41 ?-i get a constant 29.3 across the board - i do ‘use’ it when i can -but i am no racer - cheers terry
Short trips? Stop-start traffic?
Brakes dragging or handbreak not fully releasing? Flat tyres? I don’t know, but 40mpg seems to be pretty achievable.
I’m getting 40-42 mpg and often race up to the speed limit. I use cheap and nasty supermarket fuel too…
Shouldn’t really, but will depend on speed. Air con isn’t going to affect fuel consumption differently at different speeds (percentage wise it probably makes less difference as speeds go up), but worse aerodynamics from having the roof down will make an ever bigger difference as speeds increase.
However suspect even with the roof up the MX5 aerodynamics are pretty poor. Being small helps but not enough to make up for the shape.
All the best
Keith
Soem rough maths based on the small difference in max speeds suggests that the power required to overcome extra drag with the roof (and windows) lowered might be an extra 10%, so maybe 2.5kW at 70mph. This is about the same as power taken by the air conditioning compressor, or at least in the same ball park.
The aircon wins if it’s not too hot because the compressor will switch itself on and off as required. However, when it’s 30 degrees outside (as it was this week), the compressor is running all the time and struggling to keep up.
A mere 40.3mpg from the last tank (indicated 39.8). Suggest it was one of those petrol pumps that cuts off later.
My 2008 2.0 Sport I am lucky to get 25mpg… Its averaging about 24.
What fuel are you all using, particularly 2ltr owners, just normal unleaded or the more expensive super, V -plus or what ever they call it nowadays?
It currently has a tank of Esso Supreme 97 in it - indicated 41.3mpg and nearly empty, so probably about 42mpg when I come to fill it up. That’s better than the Yaris 1.5 T Sport I once had - and the MX-5 isn’t even run in yet. Not daring to rev it above 4500rpm yet - I’m increasing that by 500rpm every 500 miles so soon I’ll be able to do 70 in 3rd again.
My dad and I took his '98 1.8 mk2 around scotland last year, 1700+ miles and averaged 42mpg. Thats better than my 1.6 focus. Did notice that on long motorway runs that drops to 38mpg but still not bad. That was fully loaded car with one large lad and me dad in the car
The car is definitely running in now - much more free-revving. Last tank was 41.4 brim-brim. Current tank is currently indicating 44.4 on the OBC, which always under-reads slightly. That was the very definition of “mixed driving” - a trip to Stourhead and back, about 110 miles involving A-roads, B-roads, some 70mph stuff on the A303 and the usual snarl-up that is Devizes town centre. Short trips are the killer.
To put it into perspective, that’s about the same mpg as my old 1993 1.3 Micra would have managed over the same sort of route. Similar engine technology (16v multipoint FI) but 300kg lighter, 13" 70-profile tyres, no power steering, and about 40bhp less. The MX-5 is therefore quite impressively efficient.
Last two tankfuls (run almost completely empty) were 42.7mpg each. Esso first time, BP next. And it’s getting revved to 5750rpm now, when I want to get it going. No short trips.
It’s settled down to 42.5mpg +/- 0.5mpg for the last five tankfuls. I do pretty much the same drive every week, a 150 mile round trip from Swindon to Northampton in off-peak conditions with fast and slow A-roads (A43, A34 and A420). Revving it harder now that it’s run in (I take it to the redline) hasn’t hurt mpg, nor has fitting the Nokian WR A3 winter tyres. I suppose the 16" wheels and taller profile compensate for any extra drag from the winter tread pattern.
I have tried it on various premium unleaded fuels (I know premium fuels won’t give any more power in a NA engine but at least they have more detergents in them and the company pays me more than enough mileage allowance to cover it). No discernible difference between BP Ultimate, Esso Supreme or Tesco Momentum (the latter used in desperation - I try and avoid Tesco as they’ve had more than one contaiminated fuel incident). Haven’t used V-Power since the car finished running in so will try a tank of that next.
Probably the last post on this as it’s getting so tedious but the last tank (Tesco Momentum 99) was 42.4mpg. I only mention it because it was a totally different mileage; Northampton to Swindon in a stiff headwind but then a trip down to Selsey Bill, several trips into and out of Chichester and beyond, a bit of off-roading (no, really - we took the wrong entrance into Petworth House and got mixed up with the local Hunt traffic…winter tyres work just fine on mud!) and then a thrash back up the A27/M27/A34/M4 to home. 399.7 miles, with the fuel light on for the last 30, and just over 42 litres to refill.
In summary, if you can avoid short trips, illegal speeds and frequent congestion you should get over 40mpg. Mileage improves by about 2mpg (5%) as the engine loosens up, which takes about 1500-2000 miles if you run it in according to best practice - wide throttle at low revs to give high cylinder pressures without actually lugging it.
Air con typically takes 6 to 7 ho on start up and reduces to 3 to 4 hp on maintenance mode.
Clearly this has a greater impact at lower speeds as the air con power parasitic is greater as a percentage of the power used to drive the car .