pslewis

Gutted ......

I pride myself on my MPG ..... usually hovers around 35mpg

I have used Sainsburys 97RON for years ........

Thought I would try Tesco 99RON in the last tankful - filled it to the brim as it was 94p ........

I reckon I have dropped to 18-22mpg!!!

Now either the Pikeys are nicking it .... or Tesco 99RON is CRAP for your MPG figures!!

NOT HAPPY!!!!!!

Pete

ru'

Surely using 99 ron in a car you drive is like using a sledgehammer to cracka wallnut?


Seriously though, that's cronic! Are you sure you've got your figures right? (mainly your original mpg ones; it sounds about right now!)

pslewis

No, really, I have got 30 - 38 mpg quite easily since about 30,000miles.

I got about 25mpg up until 30,000miles then it just sky-rocketed up to the 30's

I will put another tankful through and check again - but it doesn't look good for Tesco 99RON and me!

Pete

ru'

I've only just been able to get it round here, so still on my first tank full. mpg seems about the same; I'm on around 150 miles and I'll be filling up again soon (150 - 230 miles for 3/4 tank is about right for me).


Maybe you should use fully synthetic oil? Just remember to change it correctly!

Be interesting to see if your next tank full does the same thing.

Mica Blue

You're not the only one, Pete..

http://bbs.scoobynet.co.uk/showthrea...ht=tesco+99%2A

pslewis

Interesting points ref. the cold .....

Pete

WRXewl

iTrader: (1)

I would love to get 22mpg, I used 97 super and got 17.5mpg and with Optimax its about 20mpg. That is town driving with some heavy right foot moments on A roads mind

E

Houghton

iTrader: (1)

Have you replaced the MAF at last then Pete? Sounds like the fuelling's about right now Time to fit a KnockLink and check things are OK

C2forWRX

might have had something to do with the extra cold temp this week. causes your mpg to drop

edited because i just realised you have tagged onto the colness thing...

pslewis

Nowt wrong with the MAF!!

And no CockLink is getting anywhere near my car!!!

Pete

Houghton

iTrader: (1)

Bugger! Thought you'd seen the light at last

sgcooby

Im pretty sure a slightly different fuel cant have that much input in to the mpg figures 97-99 ron and mpg drops by 10-15 mpg. LoL, rubbish. The test of fuels on 5th gear showed slight differences in performance and that was between 95-98 ron and again it was only slight differences so i would imaging the mpg figures would follow a similar trend. Maybe you were free wheeling down hill on the first tank and when you had to come home it was then obviously up hill all the way. 35mpg!!!! i couldnt imagine ever being able to achieve that figure and i drive very carefully around town. Maybe your calculator is broken.

JohnD

iTrader: (5)

As long as it's not the big red one!

JohnD

pslewis

Personally, I cannot see how it can happen ............. but I can clearly see the gauge moving!

I cannot smell petrol, so no leaks.

I am an Engineer and cannot really explain it - the ECU will meter the same amount of fuel for each throttle position and temperature and load ......... so, I can only imagine that I have to squeeze the accelerator more with Tesco 99RON (which doesn't really make sense!) Or, of course, the Cold weather has a drastic effect!?

The reason for the improved MPGs noticed on Super Petrol over NUL is because you can get the same performance for a lighter throttle position (thats basically the reason)

So, I am utterly confused

Pete

Houghton

iTrader: (1)

How do you calculate your MPG? People on here seem to do it by different methods. Personally I fill the tank to brimming and then re-fill xxx miles later. Then work out the miles from the litres/gallons used.

FWIW I have found that using the nozzle cut off as an indication of a full tank isn't consistent as the delivery rates vary considerably across forecourts and even pumps.

I have a hell of a job to fill my tank at the Tesco's at Cheshunt, for instance and need to apply very light pressure on the trigger or it cuts off immediately.

pslewis

Light comes on

I put petrol in

Zero milometer

Light comes on

Look at mileage

Check sales receipt and see how much was bought

Calculate mpg (in my head normally as I drive along)

It has been roughly 30mpg around town ...... 35-40mpg on a 100+ mile run

Now, it 'appears' to be about 18mpg it could actually be as low as 14mpg but I am awaiting the light to pop on, then I will know for sure.

Whatever ................... something is happening - I can drive 10 miles and the gauge has dropped!! thats never happened before!

Pete

sgcooby

**** me. 40mpg now. Do you have a sail attached to your car?? I will have to try this. Ill drive at 56mph next time i pop down to Edinburgh and i bet i dont get 40mpg. I would love to know if anyone else has achieved these somewhat unbelievable figures in their cars. They must have broke the mould when they made your car.

pslewis

Seriously, when I drive along the M1/A1 up to Middlesbrough, 38mpg is easy.

My brake pads and discs are still original at 63500miles .... I am actually getting concerned over this as it appears to be well over the 'normal' - I suspect that changing them will be difficult as they haven't been disturbed in 5 1/2 years.

The 2nd set of tyres are showing signs of wear ... so, I'm not a complete freak!!

Pete

AndyTurbo

I dont think ive ever seen 30mpg even when i drive like a grandad! Optimax or tesco 99ron makes no difference to me. Changed my MAF and O2 sensor this week as MAF was packing up. I'll see if the MPG increases.

pslewis

What alerted you to the MAF packing up?

Pete

DarkStar66

I've been using Tesco's 99RON for a couple of months now and haven't noticed any significant drop in range which is about 250 miles per tank full.

Pete, have you noticed a slight whistling noise since you've used Tesco's 99? It's the noise of the turbo starting to spin and can cause a drop in MPG.

Seriously, I've heard that it takes the fueling routines in the engine's CPU a while to adjust to the new octane rating.

Jza

In the MX-5?

Jza

pslewis

Errrrr no ....

Pete

AC-scoobie

It's not all about RON, it's the monkey sperm Shell use in Optimax that makes it so good.

Chachi

Correct me if I wrong ... I'm sure a lot of people will!

I understood that octane rating was more to do with the stability of the mix under compression. Subaru engines are higher compression than your run of the mill shopping trolley so require a higher octane fuel to stop detonation. (Knock links a plenty). the actual power of the fuel is from the chemical blend that composes it - or as AC-scoobie says so well "it's the monkey sperm Shell use in Optimax that makes it so good"

Just because Tesco Super is 99Ron doesn't make it better.

I'm probably full of sh#te but I'm sure I read it somewhere! I'll see if I can dig it up.

<edit>

Aha!

http://en.wikipedia.org/wiki/Octane_rating

told you!

</edit>

Mjb1957

I have to agree with sgcooby , my WRX 05 is lucky not to see the petrol station every other day . My belief is the car is to be driven , i rarely get 25mpg let alone 30-38 mpg .

GrahamG

i'm not being funny pete... but do you every boot it? Because i know you can get good MPG out of any car... i get 55-60 out of my 1.1 106 (the work horse!) but then i drive it like a nun and never take it over 55/60

I thought the impreza was meant to be pushed now and then??

G.

Houghton

iTrader: (1)

Don't tell him that

Don't listen to him Pete, you'll never sell the car with sweaty hand prints all over the boot lid.

Pete's next thread will be 'How to get 100+ MPG from your Impreza'

SiDHEaD

Pete stick NUL in, i used to get 35mpg+ with that and less on SUL!

AndyTurbo

Pete, the first sign i had that my MAF was going was that I was getting a bad eratic Idle. The revs were fluctuating between 200 and 1100 RPM and it cut out once at a junction. It drove fine though. I got about 280miles to a tank last saturday going down the M6 to birmingham and back.