Best Petrol

bacon

bacon

Well-Known Member
I've just bought a Mazda RX8 and within 4 days had some engine problems. I took it back to the dealer and he said that the problem was that I was using cheap fuel (Tesco Momentum 99).

I'm confused 'cos I would have though that Momentum 99 would be better than BP Ultimate 97. Searching about the topic I've found nothing conclusive but I did see one post saying that Momentum 99 is octane boosted by being partly bioethanol (Search for "boost" on this page) and some say that the supermarkets don't put as much effort into avoiding contamination with water and between the different fuels (petrol/diesel) (last post on that same page).

In people's opinions, what is the best fuel to buy? Esso, BP, Shell, one of the smaller brands or one of the supermarket brands?
 
Tingham

Tingham

In Cryo Sleep
You could have asked me!

Hull University Motoring Journalist and Section Chief for 2 years!.

Petrol is NOT just Petrol. But I actually suspect that may not be the problem.

Obviously go for the highest octane you can, I would Suggest BP or Shell, in Particular BP Ultimate 97.

The other thing that you need to know, and I suspect you probs do is this:

Mazda Rx8's use a Wankel Rotary Engine. 1.3l Capacity, 200bhp, if im right.
This uses a lot, and i mean ALOT of oil. So check that your oil is full.
Also check that your oil is correct, you can do this my ether phoning a mazda dealership, or taking a sample down to your local independent.

Dont buy an audi. You will look like either a photocopier salesman called Steve dressed in clothes from burton's on his way to the gym, or someone in a white tracksuit on his way to smack some bitches.

Im fairly sure your not either. Check the Oil, Dont buy Supermarket Petrol
 
bacon

bacon

Well-Known Member
Tingham said:
Mazda Rx8's use a Wankel Rotary Engine. 1.3l Capacity, 200bhp, if im right.
This uses a lot, and i mean ALOT of oil. So check that your oil is full.
Also check that your oil is correct, you can do this my ether phoning a mazda dealership, or taking a sample down to your local independent.
Click to expand...

Yeah, 231 bhp. I checked the oil just before taking it back to the dealer and it's just below the max mark on the dipstick. No idea if it's the right oil though. I believe Mazda recommend 5W20 fully mineral but not many places seem to sell it (according to Google).

I topped up with BP Ultimate 97 on Friday at South Mimms (expensive place) and it seems to be running fine. Is BP Ultimate 97 better than Shell V-Power (99 according to the leaflet I've got here)?
 
Xylak

Xylak

New Member
Another thing to remember about Wankel engines is they do not like very short periods of running. You should always warm up a little before each journey and allow to cool after a long run. Even just driving off/back on to a driveway can cause problems if you don't allow it to warm up.
 
bacon

bacon

Well-Known Member
Xylak said:
Another thing to remember about Wankel engines is they do not like very short periods of running. You should always warm up a little before each journey and allow to cool after a long run. Even just driving off/back on to a driveway can cause problems if you don't allow it to warm up.
Click to expand...

Yep, had that one when I first drove it. Stalled at a petrol station, ran it for 20 seconds to back up to the pump and it flooded.
Needs to get to the middle of the temp gauge before stopping.

It's also annoying when you start it then realise you've forgotten something because even with 2 keys, you can't lock the car while it's running.
 
eMP3Danie

eMP3Danie

In Cryo Sleep
BP Ultimate 97 always used to enter my tank.. I wasn't paying for this though.. its what fuel cards are meant for...

How ever my Dodge Nitro loved Shell Diesel Extra... though it was poor on the a-b roads.

bacon said:
It's also annoying when you start it then realise you've forgotten something because even with 2 keys, you can't lock the car while it's running.
Click to expand...

That's a good thing! you wouldn't believe how many times I've been called out because someone was warming up their car and locked them selves out
 
bacon

bacon

Well-Known Member
OK, so someone else has suggested using regular petrol most of the time and then getting a tank of premium every 4 or 5 fill-ups.
 
Pwnstar

Pwnstar

Member
The dealer is talking shit.

Commerically available petrol will NOT damage your engine, otherwise it wouldn't be comerically available.

The fatc you're using a higher octane means you're actually putting better than your average petrol through the car. (I used to then i sacked it off when my tank went over £100 a pop...)

On a seperate note. You'll struggle to find anydifference between 95 and 99 octanes driving that car on roads. It's pushing the lower boundaries of a sports car at ~200bhp and unless you're thrashing it around at the red line on a track you won't find any difference.

Signed
A fellow rice rocket owner (Nissan 350Z)
 
Spicypixel

Spicypixel

New Member
Pwnstar said:
The dealer is talking shit.

Commerically available petrol will NOT damage your engine, otherwise it wouldn't be comerically available.

The fatc you're using a higher octane means you're actually putting better thna your average petrol through the car. (I used to then i sacked it off when my tank went over £100 a pop...)

On a seperate note. You'll struggle to find anydifference between 95 and 99 octanes driving that car on roads. It's pushing the lower boundaries of a sports car at ~200 and unless you're thrashing it around at the red line on a track you won't find any difference.

Signed
A fellow rice rocket owner (Nissan 350Z)
Click to expand...

This is actually pretty much spot on, the difference in anti knocking from the octane won't really make a difference unless you're always in the high end of the rev counter. Drive smart drive safe drive yourself mad.
 
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