Mazda RX8 Real world MPG

[lilwashu]

I had two RX-8s over a period of three years (one of them was almost new) and super unleaded (note: premium unleaded = 95RON in the UK) made sod all difference to anything.

[otolith]

fernandofan2008 said:

They didnt know it? Funny how mine has the Mazda sticker on the fuel cap saying 'premium unleaded only'. Clearly Mazda didnt know what they were doing then, eh? Premium unleaded gives better MPG, smoother through the revs and overall better performance from the engine. Dont believe me? I dont care. many owners have found a noticeable difference in all of the above. All you need to do is go on the owners forum and countless owners will tell you premium petroleum gives MUCH better results than standard petroleum.

Right now, many of us are trying Nitro+ and getting slightly better MPG than the standard Vpower. Which is much, much better than standard 95 RON. Might want to go back and rebuy one of these and test it yourself and see how wrong you are, and also how the car has much more to give than standard petroleum.

high octane is a much safer petrol for the car, as it has more resistance to detonation which as you know, is prevelant in high compression engines. Also additives in the premium fuel assist with reducing carbon build up.

Please note this from the owners manual;



Note reccomended fuel 96RON+. 91MON/95RON can be used in emergencies but will reduce performance. Seems like you didnt read the manual and didnt experience its full potential :P

Edited by fernandofan2008 on Thursday 6th June 19:47

Edited by fernandofan2008 on Thursday 6th June 19:49

Edited by fernandofan2008 on Thursday 6th June 19:49

That looks suspiciously like a US manual. For UK cars, see page 14 of the brochure.

http://www.bc-mazda.co.uk/pdfs/MazdaRX-8_Brochure_...

This was Mazda UK's position when I bought one back in 2006. I'm pretty sure I would have noticed if the handbook said otherwise, I'm the sort of car geek who actually reads handbooks.

This was all done to death on the UK owners club forum back before all the kiddies arrived.

[moribund]

I averaged around 22mpg in mine, but I was proud to completely empty a full tank (around 9mpg) during a track day at Croft

One bonus of such poor economy is I was fully acclimatised to large fuel bills before moving to the 4.6 V8 I have now, and I actually feel quite pleased with myself when I get 23mpg from a tank!

[The Flying Ox]

otolith said:

That looks suspiciously like a US manual. For UK cars, see page 14 of the brochure.

http://www.bc-mazda.co.uk/pdfs/MazdaRX-8_Brochure_...

This was Mazda UK's position when I bought one back in 2006. I'm pretty sure I would have noticed if the handbook said otherwise, I'm the sort of car geek who actually reads handbooks.

This was all done to death on the UK owners club forum back before all the kiddies arrived.

I'm not 100% convinced that the 2009 R3 manual outlines Mazda's position in 2006. I know it's nitpicking, and I'm a massive rotary fan so not trying to be a cock, but is the 2009 manual just a rehash of the earlier ones?

[otolith]

The Flying Ox said:

I'm not 100% convinced that the 2009 R3 manual outlines Mazda's position in 2006. I know it's nitpicking, and I'm a massive rotary fan so not trying to be a cock, but is the 2009 manual just a rehash of the earlier ones?

Brochure for phase 1 car, page 29.

http://www.mazda.co.uk/assets/uk/usedcars/brochure...

[fernandofan2008]

otolith said:

That looks suspiciously like a US manual. For UK cars, see page 14 of the brochure.

http://www.bc-mazda.co.uk/pdfs/MazdaRX-8_Brochure_...

This was Mazda UK's position when I bought one back in 2006. I'm pretty sure I would have noticed if the handbook said otherwise, I'm the sort of car geek who actually reads handbooks.

This was all done to death on the UK owners club forum back before all the kiddies arrived.

Seems the kiddies know more then. Countless websites confirm it requires premium/high octane. When I go to my car Ill scour the owners handbook and find the page where it says, use premium and take a snap to show you.

[otolith]

Premium = 95 RON.
Super = 97 RON.

[otolith]

http://www.nolanoils.co.uk/unleaded.php

link said:

Premium Unleaded is suitable for use in all petrol (spark ignition) engined vehicles where the vehicle manufacturer recommends the use of unleaded petrol with a Research Octane Number of 95 (RON 95).

http://www.nolanoils.co.uk/super_unleaded.php

link said:

Super Unleaded Petrol was introduced for use in petrol (spark ignition) engined vehicles where there is a requirement for a high-octane unleaded fuel. This grade exceeds the octane levels of Premium Unleaded Petrol and is equal to the octane level for both Lead Replacement Petrol (LRP) and (the now obsolete) 4* Leaded Petrol.

[ChrisC85]

Ok guys, I've tried a number of fuel additives ... no super serious improvement. Was still doing 150 miles on a tank :/

So I went all out, because I bought the car relatively cheap I went for a full racing exhaust, filters change, sparks, uprated coils, leads etc. and a remap Now I've got the car back, sounds like a beast (if you like that sort of sports sound), has a lot more torque in the midrange, I can do a burnout easily and I just did 175 miles on a tank ... driving like a maniac round town

So to conclude, I think it was a broken cat (lambda maybe?) + old sparks / coils. Now I have buckets more power and fuel eco seems to be back to normal. Also fuel additives didn't help me much with my problem.

To touch on GT86 a bit ... after doing the exhaust and the remap GT86 doesn't hold a candle to RX8, not even in the same ballpark the only advantage it has is better fuel eco, but who cares about fuel eco that much running a street fighter performance car (I've been running against remapped 310 break S3 and ... I almost stood a chance ) haha. Anyway really happy with my ride atm.

[Andy30241]

Chris where did you get your RX-8 remapped?? I'm struggling to find anyone to do mine. I'm looking into a Turbo now for mine??

[otolith]

These guys have been offering a remap for ages now;

http://www.pettitracing.co.uk/pettit_racing_mazda_...

[Andy30241]

otolith said:

These guys have been offering a remap for ages now;

http://www.pettitracing.co.uk/pettit_racing_mazda_...

Thanks buddy :-)

[wolves_wanderer]

Group B in Deeside also do a remap, they have dyno graphs on the website and seem pretty well thought of.

[ChrisC85]

otolith said:

These guys have been offering a remap for ages now;

http://www.pettitracing.co.uk/pettit_racing_mazda_...

I used those guys no dyno but happy with effects. I've done a small vid over the weekend https://www.youtube.com/watch?v=XpdMLvuPwC8&fe...

[Lione1 Richie]

I know the RON debate seems to be largely settled now but if you feel that putting in premium fuel aids your cars performance and mpg then please continue buying it.

From my personal experience of owning two RX-8's over a number of years I can say I ran them on 95 RON for the duration of ownership and never experienced any issues what so ever.

In response to the OP's original question, over the life of both of mine I averaged 23 mpg. This was a 10 mile commute in town each morning and weekend enjoyment drives and trackdays thrown in.

If you are worried about mpg I'd suggest this is perhaps not the vehicle for you. It is a superb handling vehicle but it can be frustrating to own and maintain in my experience (which will differ from others.)

All the best with your decision.

[WarrenG]

I'm in the same place as many - If I drive 5 miles each way to work I get 15mpg. If I go further, just nipping about and generally enjoying the car, I get 18ish. When I go further and make it into the next county at a steady motorway pace - 22mpg.
I think my exhaust is puffing a little at the front, probably the front end of the cat - so I'll do that and see what varies.

Specifically though - Mine was rebuilt at Haywards, and to keep their warranty safe - they specify the oil - 10w40 or 15w40! the fuel - only 95RON and NO additives. This departs from Mazda's spec for the car, but then Haywards have been racing rotaries all the way from Cosmo to Rx8 and are highly respected in their field and prized by the Owners club of one of very few specialists trusted to look after your Rex.

[Varn]

Ozone said:

sherman said:

The car has a 50 litre tank and that equates to around 22mpg

Mine had a 60 litre tank and i usually got 200 - 230 miles from it with mixed road driving.

I'm pretty sure '03s-'08s have 60 litre tanks, and the R3s have 65 litre tanks (both excluding the filler pipe).

I've found if you drive efficently 300 miles to a 60 litre tank is not difficult. However, I'm current only using mine at weekends so never get above 15 mpg.

Waste of time using anything higher than premium unleaded (95).

Edited by Varn on Wednesday 4th December 10:27

[4PPLEP1E]

Got anywhere from 10-15 around town and 26 motorway, with an average of about 18-19.

Was usually on the lower side of things. :/

[TREMAiNE]

Tend to average 16 around town and 20 on the m-way...

So 18 average.

That is driving pretty sensibly too.

[princegary]

I must be breaking the norm or laws of physics then as my 8 around town gets around 20. On a run when I first collected it I did over 225 miles from £50 in fuel snd still showed 1/4 tank left with no fuel light on. On a run, measured from brimming the tank it works out around 30mpg.