Not bad for a 5 litre v8

[kieron1977]

29.6 mpg over nearly 300 Miles.

[Farqui]

Hi Kieron, good figures there for a big thumper.  

What were the driving conditions?

Did you drive it like you stole it or poooooootle?

[NemesisUK]

Almost managed the same from my 5.5ltr supercharged AMG, 27.5mpg over 280 miles. Motorway to and 'B' roads round the Lake District..

[Mark G]

I once saw a similar figure on the day I drove the car back from the dealers when I bought it, and that was it, I just struggle to achieve more than 27-28 on a run.

Driving style and speed obviously.

[kieron1977]

This was from calais heading towards loire valley. Mostly toll roads so going around 80mpg And no traffic. 

My daily drive is into west london so my average is around 19mpg over the 3.5 years i owned the car. 

[Big Rat]

 Big Rat 😉

 

[NemesisUK]

Looking good there BR 

[Big Rat]

@kieron1977 matey @Rusty Crobar gets this MPG, mind you the Police were behind him 😂

Big Rat

[Guest]

Lincs to Manchester. ECO mode all the way sticking to speed limits ish. So 75 indicated max. Pretty boring but I was interested to see if it really works. It really does. Get about 18-24 driving around here at weekends. 

 

Sent from my STV100-4 using Tapatalk

 

 

[Linas.P]

3 hours ago, Comedian said:

Lincs to Manchester. ECO mode all the way sticking to speed limits ish. So 75 indicated max. Pretty boring but I was interested to see if it really works. It really does. Get about 18-24 driving around here at weekends. 

 

Sent from my STV100-4 using Tapatalk

 

 

yeah but RC-F switches to Atkinson cycle when cursing... hence the difference

 

[Guest]

Yep, clever stuff. Rarely mentioned in car reviews.

 

Sent from my STV100-4 using Tapatalk

 

 

[Mark G]

2 hours ago, Linas.P said:

yeah but RC-F switches to Atkinson cycle when cursing... hence the difference

 

It doesn't matter how it does it, the fact that it can achieve it with no loss in performance is great.

 

[Linas.P]

3 minutes ago, Mark G said:

It doesn't matter how it does it, the fact that it can achieve it with no loss in performance is great.

My point was that even though on the paper RC-F and IS-F seems to be pretty much the same when it comes to engine (that is obviously if you ignore the part where it states Atkinson cycle), but that is not the case. Engine does loose power while in Atkinson cycle... the achievement is that 5L sports coupe can switch between cycles whilst driving - quite neat. 

[Mark G]

19 minutes ago, Linas.P said:

My point was that even though on the paper RC-F and IS-F seems to be pretty much the same when it comes to engine (that is obviously if you ignore the part where it states Atkinson cycle), but that is not the case. Engine does loose power while in Atkinson cycle... the achievement is that 5L sports coupe can switch between cycles whilst driving - quite neat. 

To anyone that knows the engines they are clearly not the same. as you say the RCF switches to the Atkinson Cycle when required, technically there is no loss in power, when the engine needs to produce power it does so, hence near identical BHP, Torque and performance figures as the ISF, what I am saying is, I don't care how it achieves such great MPG, I would just be grateful that it did.

[Flytvr]

20 hours ago, Mark G said:

I once saw a similar figure on the day I drove the car back from the dealers when I bought it, and that was it, I just struggle to achieve more than 27-28 on a run.

Driving style and speed obviously.

So, I'm not surprised by this 

[dougie175]

On 10/08/2017 at 10:49 AM, NemesisUK said:

Almost managed the same from my 5.5ltr supercharged AMG, 27.5mpg over 280 miles. Motorway to and 'B' roads round the Lake District..

Thats quite impressive the way most people drive around here really doesn't allow for good fuel economy! Too many holiday makers who don't know the roads and brake every time a car comes the other way

[Defratos]

On 8/10/2017 at 3:31 PM, Big Rat said:

 Big Rat 😉

 

My thought exactly 

[MNMJ]

Yep, the RC-F is much more economical than the IS-F. And has 54bhp more (depending on whose figures you believe). Yet another reason to change.

And, no, I'm not trying to big up the RC-F to sell you mine; I'm keeping it at least two more years

[FTBBCVoodoo]

On 10/08/2017 at 10:36 AM, kieron1977 said:

29.6 mpg over nearly 300 Miles.

I see your 29.6 and lower you...  14..5 over 170 miles exactly.  Literally been 170 miles of town driving. 

Took this just before restarting after filling up.  Was showing a 9 mile dte

[emjay82]

Never realised the ISF had a mpg computer thingy, my 2008 gauge looks like this..... 

 

[C.B]

How accurate is the MPG calculation on these cars?

As I understand it the car has a 65 lite (14 gallon imperial) tank and so to be getting 30mpg you would need to achieve 420 miles to the full tank. Is anyone getting anything near that??

Looking on fuelly there is pretty much no one getting above 20mpg out of 34 registered owners.

I have fallen into the trap of believing the lying b*stard computer myself thinking I was getting 32mpg on my current S5 till I did the maths and realised its actually 23mpg.

I am pretty keen on switching to a facelift ISF but dont want to drop any lower than my current 23mpg really

[kieron1977]

Hi C.B 

Yes 65 litre tank but around 12 of those litres are once you hit the reserve mark. 

I try fill up when my range says around 15 miles left and i only manage to fill around 53 litres until the tank is full. 

I live sw london And drive into kensington most days so traffic is not great And i average around 19mpg according to the trip computer. I get about 220 per tank (or per 53 litres) if you want to work that out to real world figures. 

[C.B]

220 Miles for 53 litres (11.6 gallons) is pretty much bang on 19mpg

[Nick W858]

I normally get around 300 miles between fill ups, the fuel gauge warning light is a bit pessimistic in my experience, computer says I have averaged 25.2 mpg since I bought the car and this matches up with my own revised/calculations.

[Terry Barr]

I checked mine over 1800 miles and got 26.5 mpg. A bit of driving around Ilford, a trip up to Old Buckenham and a trip to Ireland which did include a fair bit around Dublin as well as basicly covering the country East toe West and South to North. Included hold ups on the M25 and M1 as you would expect.