Tesco 99RON fuel - tested

[alexb]

Alexb,

They have it in Dereham !!!! Why not Norwich !! Bizarre.

Gareth

Hi mate,

Apparently the Hall Rd store took out their Super Unleaded underground tanks a while back, don\'t know about Blue Boar lane, aren\'t they refurbing the place at the moment? Maybe once the petrol station opens up it\'ll sell it. Would be better for me as only 2 mins up the road!

Cheers,
Alex

[Jodypamplin]

If anybody watched Fifth Gear last night, they did a test on petrols - supermarket 95 vs bp ultimate vs optimax. on a new tuned scooby optimax performance figures were quite a bit better than the bp, and obviously the supermarket 95 did not have a shot. would have been interesting to see what tesco 99 would do against them. personally i have gone back to optimax - my local is now 96ppl so not really a massive saving going to tesco, and i\'d rather buy the tried and tested good stuff.  :p

[Jono FD3]

Jodypamlin....
Any idea what the difference in figures were? did they do a power output if so was there any difference?

Reason I ask is I did a rolin road day the weekend and I used super plus instead of optimax. I find with optimax my car for some reason overboosts = 1bar   :3gears-lh but on the super plus it ran standard 0.8bar :xconfused ? better for my slipping clutch mind :cheers !!

Jono

[Jodypamplin]

just call me mooseman  :cool

yeah sure, if I can remember rightly:

supermarket - 235

bp ultimate - 245

optimax - 258

there or there abouts i think, it was that kind of difference. personally i find bp the worst - lose about 25 miles a tank on the optimax and its more expensive. i\'d go with tescos any day if optimax was not around, which did happen not so long ago when i could not find 97 petrol for 4 days ...

[gsb876]

Was the idea of filling up with optimax not down to it using minerals that help keep internals cleaner ? As well as higher RON rating ?

[Bobfish]

Does anyone have any concrete evidence its better? I.e knock sensor readings, power readings, intake temp readings, EGT readings?

When your talking fuels and how the car runs, its not just how smooth the car drives...you have to look at EGTs, boost pressure, knock readings etc.  This car is mapped to run 100RON fuel, and i wouldnt chance putting anything less in it (Even though its more than optimax) without proven results and safety testings...

[gsb876]

Does anyone have any concrete evidence its better? I.e knock sensor readings, power readings, intake temp readings, EGT readings?

When your talking fuels and how the car runs, its not just how smooth the car drives...you have to look at EGTs, boost pressure, knock readings etc.  This car is mapped to run 100RON fuel, and i wouldnt chance putting anything less in it (Even though its more than optimax) without proven results and safety testings...

In truth Bob if you get the car mapped to run Optimax it will be cool, other than that i watched 5th gear\'s review on optimax / bp ultimate / normal unleaded and the result very briefly was that tuned high performance cars react much better to optimax than the other two.

Something like (Impreza tested) 19 more bhp made on optimax as can run the engine harder more safely on optimax ron

[Bobfish]

thats my point, as standard these cars ARENT mapped to run optimax.  And tuned high performance cars do react better to optimax, but if mapped for it would react better to 100 ron fuel.

You can run the engine harder and more safely on optimax, but this is my point - you dont know how hard you can run in in normal road conditions until you do some damage.  Some high octane fuels are refined to be high octane fuels, others are standard petrol with an additive to up the octane.  This settles over time and does not mix properly with the fuel...in any case - id rather have a high quality proven fuel that a standard fuel with an additive to make it higher performance.

[gsb876]

Understand what you are saying Bob,

I had my car mapped on optimax by Pip thus it should be fine running hard on optimax as thats what its geared for ?

Sometimes if i am doing a long steady run on the m-way i will fill with super unleaded and drive conservatively as i know it will be fine, but 95% of the time we have optimax in the tank.

[Bobfish]

Gearing has no effect on what fuel you use.

The lower the RON fuel you use, the more prone you are to detonation. In a rotary this sounds a bit like walking through some woods in summer (Dried leaves and sticks breaking under your feet)


The higher the RON Fuel you use, the slower the burn and the more heat generated.  When you start to use race fuels you actually have to be careful about very high octant level fuels because these can still be burning when exiting the exhaust ports and can toast your turbos if your still using them.

Using lower RON fuel is fine on long smoooth runs, but i wouldnt do it without some kind of aftermarket knock sensor.

[Ricco_04]

I read on here that higher rated RON fuels burn cooler  :confused: Which is it?  :confused:  :confused:  :confused:

As I generally pootle around I may as well just use the normal 95 stuff (Uk Car) if this is true and have the cooler temps?  I have been using Optispax cause I thought it ran cooler, was cleaner for the engine and to gard against detonation?

I\'m not trying to cause an argument, I am genuinely confused and want to know!  

[Bobfish]

Higher octane burns hotter and more slowly, lower octane burns cooler and more quickly.  Add quick burning fuel to a boost/advanced engine timing situation and you have detonation.

Detonation is basically the fuel exploding rather than burning.  This is detonation.  Higher octane fuel burns more slowly so does not "explode" in this way, but it burns hotter.

read this:

http://member.rivernet.com.au/btaylor/BMWText/technical/FuelOctane.html

[Ricco_04]

Thanks Bobfish - just having a read now!  :wave

[Ricco_04]

Without being too much of a swat - interesting  :p

According to that link, if you are detonating then use a higher RON rated fuel otherwise it\'s a waste of money.  And as for cleaning they say "virtually all detergent packages are alike in all fuels within a given gas companies line these days."

I am using Optispax purely cause I thought it would benefit the carbon issue and also for det protection.  I have no mods and being standard UK car I guess I should just use 95RON and save 6p per liter when I fill up (£4.56)

Mmmmmmm  :rollin

[Bobfish]

well its up to you if you want to take the chance!

No matter what the cars designed for (100 RON, 80 RON, blah blah) using a higher octane fuel is ALWAYS going to help stop detonation.  I would use it purely for that reason alone. Just think - its what, 3p per mile for that extra safeguard...