MPG - I DON\'T believe it!!!!!!!!!!!

[Ianmcurtis]

Seriously folks, I am amazed with this

Old sexy 8\'s best mpg ever was about 25 when I first got her and took it easy driving back from Durham, motorway cruising. After that any where between 18/22 mpg.

Just filled up new sexy 8 (1/2 tank ish used so far) 206 miles since filled up for Pod. 31.89 ltr\'s = 29.39 mpg  :yes . Obviously still running in (max 4/5000 rpm)but I expected a new motor to guzzle fuel.

Suffice to say I AM IN SHOCK  :yes

[iaint]

If it\'s a new car then maybe it\'s got a new ECU update in place?  Others who have a service and update may see an improvement.  Or conversely it may just be the running in driving that\'s doing it - I got close to 30 mpg running my FD in a few years ago which is >10 better than normal...

[BlueAdept]

Well, I recently followed my cousin back when he came to collect a car after just passing his test... doing a gentle 65-70 all the way, I made 320 miles on a 52 litre tank. and I recon that\'s  just over 30mpg... so there is an economical way to drive these cars.... although I prefer the other way..

[peterch]

I reckon I got 30mpg on my fd when I tried driving it without the turbos kicking in. But it is so much more fun driving it properly, that is the trouble.

[ilovemyrx8]

Seriously folks, I am amazed with this

Old sexy 8\'s best mpg ever was about 25 when I first got her and took it easy driving back from Durham, motorway cruising. After that any where between 18/22 mpg.

Just filled up new sexy 8 (1/2 tank ish used so far) 206 miles since filled up for Pod. 31.89 ltr\'s = 29.39 mpg  :yes . Obviously still running in (max 4/5000 rpm)but I expected a new motor to guzzle fuel.

Suffice to say I AM IN SHOCK  :yes

The new 8\'s have been much improved, I know they had to do a few mods to the fuel tank and they also upgraded the ecu which is also suppose to reduce to amount of oil being used also?? (we\'ll soon see)

[Spectre26]

holy pOOp!!!  How on earth u get those kinda figures... Think u got your new 53xy 8 not long after i got my 8 and yet the best i can ever manage so far was like 270miles from a full tank, and that was mainly motorway driving which was around 4k rpm, never exceeding 5K rpm.

Wonder what i am doing wrong in my driving...

[BlueAdept]

To get the best economy, you have to drive below 3750 RPM.... so no faster than 70.

[Spectre26]

To get the best economy, you have to drive below 3750 RPM.... so no faster than 70.

K will give that a go.

[Ianmcurtis]

holy pOOp!!!  How on earth u get those kinda figures... Think u got your new 53xy 8 not long after i got my 8 and yet the best i can ever manage so far was like 270miles from a full tank, and that was mainly motorway driving which was around 4k rpm, never exceeding 5K rpm.

Wonder what i am doing wrong in my driving...

Paul, the best tank range I got from old sexy was 280 but that included mostly m/way cruisin\' and odd bits of .... u know :evillaugh .

TBH I\'ve found it VERY hard not reving much over 5000 in any gear - and 5000 in 6th \'aint 70. I\'ve got to put it down to simply keeping the revs down but it\'s still hard to believe almost 30 mpg, like I\'ve said my first steady m/way drive in old sexy, which had about 1000 miles on the clock, got around 25 mpg.

As you say, you only got your 8 a couple of weeks b4 I got mine - can you recall your mpg during running in?

Ian.

[Spectre26]

Yeah i think my MPG during run in was at best 270miles on a full tank. But that could just be my driving. Might have been able to gain more miles if i had followed what James had said, ie, keepin strictly to 3750 rpm.

I really had no idea on what was the best way to squeeze the economy out of a rotary so i just drove it at the same economic method i did in my previous piston engined car. Which as i now know is a lil different.

Right now that 270 is indeed my best MPG as i\'m still desperately tryin 2 get over the whole hi-reving addiction :p As u said its very hard to drive the car sensiably. As today was testiment to, when i "smoked" a local chav in croyden when he tried to undertake me on a dual caridge way. Just dropped it into 3rd n pulled those rotors to a comfortable 7k, leaving his fart cannon (old model) astra standing. N he did try his best to undertake me, i could tell by the all mighty loud farting sounds comming from beyond the passenger seat. I did feel very childish immidiately after it all. So i moved over to the inside lane n waved him on past me. Feeling that i had made my point to him:)

I know this was a reckless and childish way to behave on a public road n looking back i am ashamed at my behavior :mad: But at the time like most childish acts.. it was FUN!!!!! :evillaugh

[zevans]

Chaps, orbist over on rx8ownersclub has written a tremendous article for the latest club mag, based on experimentation with a laptop plugged into the PCM and driving up and down flat bits of road at different speeds...

The gist of it agrees with what I guessed from reasoning about the way the engine and gearing are put together in this car (I\'ve had over 300miles once or twice following these principles...) and I\'m sure I\'ve posted on this before here, try a search...

6th doesn\'t do load. Do not use unless flat and constant speed, or on a decline. If you need more than 10% throttle in 6th, change down otherwise you\'re just wasting fuel. This means using 5th (and even 4th) on uphills on the motorway, fr\'instance all the big hills in Staffs.

Keep between 3k and around 5k - engine not efficient until at least 3k - more injectors cut in over 5500 revs, so 3-5 is the inbetween sweet spot. This means using 2nd in town a lot more than you would naturally do, and means staying in 2nd unless you\'re really sure you\'re going to be at a constant 30mph for a while.

Better to use a fair bit of throttle to achieve your chosen speed, then box change into your chosen cruising gear. Don\'t be afraid of a 2nd to 6th gear change in the right circumstances, for instance, overtake tractor, get back to 50mph, plonk into 6th. Or similarly, 6th to 3rd if approaching a large uphill on an A-road, for instance.

Don\'t labour the engine - if you need full throttle to make reasonable progress, change down a gear or two. Half throttle at 5000 is better than full throttle at 3000.

Basically, use the revs, it\'s geared to do that!

[Ianmcurtis]

So, what sort of mpg were you getting Zack, assuming you used the methods described? Cheers,

Ian.

[zevans]

I was tooling up and down to Northants for a time earlier in the year and had 280 miles out of a tank once or twice. "A tank" means something in high-50s litres depending on what mood the warning light is in, so let\'s say it\'s 55 - that comes out at 28mpg.

However the days when I set off at 0530 and had empty M6 toll road to play on it went down to more like 20, I expect due to, um, aero drag. (Lots of drag at 69.9 mph as we all know.)

Days I went over the pass (hills, overtaking) and got stuck in Tintwhistle (lots of idling) it was usually a shade over 20mpg still because the mway stretches made up for it.

[Spectre26]

Just done my best MPG yet. Went to peterborough this weekend and filled my tank right up then started the trip meter. Once i reached th other end i filled up again to get the figure of the ammount of fuel i had burnt. then settled down o churn out the figures like so

145 miles travelled using 24.5 litres, so that makes 22.41MPG.

But then something dawned on me... are we working in US gallons or UK gallons? For the record i worked mine out in US gallons.

The ride i took was 80% motorway, so constant speed stuff trying out what zevans said, the other 20% was a stint weaving thru central london.. so lots of up and down shifts. Therefore i think it fair to say a much better MPG could have been reached if i didnt do the section thru London. Maybe able to push 25MPG or more? :rolleyes:

[Ianmcurtis]

^ Cheers Zack & Paul. TBH I do believe my first mpg were a fluke! 20 - 24 mpg here I come (again) :-) OR :-( depending on how I feel while refueling!!