BP Ultimate Octane 102!! £11/Gallon

[Dan F]

Originally Posted by Ross9

I never used to notice ANY difference whatsoever in the Rover with higher octane levels. I just used Higher octane fuel for safety's sake due to the AFR of 12.5-12.9 it ran just in case it had any det on event days etc.

Hi Ross.

Is 12.5 - 12.9 unsafe then?
I thought that was just about spot on as far as open loop WOT AFR goes if you want decent performance?

Cheers,
Dan.

[Ross9]

Yeah Dan it is, anything over 13.0 is a bit risky so I just kept it under that, as standard the MEMS management on the Rover aimed for 10.5 AFR at 14.5 psi (fuel cut level) which was just ridiculous and wasted so much power but then it was protecting the chocolate internals by doing this, better safe than sorry though hence the optimax, at the end of the day, whether your car gains power from higher octane or not, the higher octane fuels tend to be better quality fuels as well imo, you could see where the fuel had been cleaning as it went when the head was stripped down for example.

If it were to get that bit hotter than normal at an event etc then having the extra octane was for peace of mind as well as I said, it might well have been det free at an AFR of 12.8 say up here in Scotland while doing short in gear runs with the wide band on the road, but it would be more prone to det in a different circumstance, say flat out in 5th on the top end run at TOTB on a much hotter day. The set up of the car varies the AFR as well.

While I ran a mid to high 12's AFR, the boost levels werent that high and the intercooler etc a good set up. On higher tuned cars they tend to make it richer, a guy I know has a 630 bhp R32 GTR and it runs AFR's in the mid 10's, it could be leaned out a bit but it's quick enough as it is so there's no need to push it etc and it runs a fair bit more boost, so the intake temps, boost, comp ratios etc need to be considered, I'm nothing more than an interested enthusiast when it comes to that sort of stuff though but the general concencus seems to be that to maximise power, aim for mid 12's AFR and check it isnt detting at that, while ensuring the internals are strong enough as well obviously. Sometimes running it a bit richer and puting more advance on the ignition timing gives more gains than AFR adjusting but I never delved into that with the Rover, tuners and mappers are the people to ask about which is better to sort first, ie sort the ignition map first then tune the fuel map to suit, or vice versa.

anyway, ramble over lol

Ross

[Engineer]

As I said guys chemistry is what it may be about, appreciate all the AFR quotes and agree generally with your comments, but sometimes it can be prudent to move on to new levels. Just a thought but we all know how dangerous they can be lol..

[Ross9]

Indeed I agree.

At the end of the day, AFR's, comp ratios etc etc, these are all used to get as much as possible out of the car without destroying it, however the starting point is the fuel, hence the chemistry.

If you can get a fuel that lets you run a 14.0 AFR at WOT and still keep good levels of ignition advance, then you can run it safely and make lots of power compared to using a fuel that only allows the same car running the same ignition map to have a 12.5 AFR.

So if you take your car set up for optimax say, and then were to use 102 ron BP ultimate, then you could lean your car out a bit and/or put some more advance on the ignition timing in order to make more power, but if these things arent done, then the fuel pretty much just gives a bigger safety margin, some cars to an extent will add some more ignition advance etc as they get used to the higher ron etc, depending on their software, some require remapping and setting up for the higher ron fuel. Going to daft stuff for events like 118RON Klotz fuel for example you really want to be able to adjust your fuelling and igntion via a mappable ECU.

So yes Engineer, I totally agree, the starting point should be the fuel and the chemistry of it to produce as much energy as possible and be as det resistant as possible, then have the set up of the car done to take as much advantage of it as possible.

Of course for 99% of our cars, you can take it too far with all the above, IMO if your not racing it at track or 1/4 mile days, theres no need to be shoving ever last horse out, 98 ron and a nice safe map is more than adequate for the spirited fun of a drive.

Ross

[foggyjames]

Oops, I went to hit quote, not thanks! But hey, I don't mind thanking people, even if it is by mistake

As I see it, it's engine design (specifically the combustion chamber profile) that would allow you to safely run 14.0 AFR at high load and RPM, not fuel technology. At the very least, engine design has a long way to go before we reach the limits of the fuel we have at the moment.

I see this BP fuel as giving easy access to semi-high octane fuel (110 RON is the proper looney juice though!) at a rip-off price. Avoid...

Re: running 95 octane on your Scoob Ross...I think you should be ok. All it does on a Volvo is pull the timing (and ultimately lower the boost) if it registers elevated EGT (where fitted) or ping. It'll happily do that all day long without negative effect, and (for example) our V40 2.0T is designed to do exactly that. Run it on the minimum rated fuel of 92 octane and you only lose power, not longevity.

On a final note, if you are going to push your luck re: AFRs...invest in a wideband oxygen sensor which will give you a true numeric AFR read-out in real-time...none of this £30 flashing light crap. If you're super neurotic, run EGT (exhaust gas temperature) monitoring too. Wideband AFR starts at about £100, with 52mm displays for about another £100. Ignore the rip-off UK distributors pricing. I have a friend in the US who'll sort you out for about 2/3 of the UK price.

This is what I have (and has been waiting to go in since before Christmas!)


cheers

James

[Ross9]

The ecu no longer controls the boost on the scooby so it cant reduce it.

There is also only so much an ECU can do as regards winding the timing back etc to ward off detonation, and for it to do it it first has to detect the det, meaning it has already occured briefly and done some minor damage (which can accumulate over time)

The fact is, on the type R scoobies they have a 100Ron map, and an agressive one at that so the concencsus from all corners on the associated scooby forums is to make sure it has good fuel in etc, with the ECU control the timing can only be wound back so far apparently.

Don't worry, Apexi Power FC replacement ecu is coming up to map it on UK fuel, unfortunately this also means I'll be able to run a bit more boost and get up to about 320 bhp....shame that lol.

Ross

[moynesyt5]

Hi All

I have run 102 ron fuel in my rally S70 T5 and it was very suprising how much more responsive the engine was. The turbo spooled much quicker, and the engine revved quicker.

As for BHP, who knows, but if money is no object, this is what I would run in the car, but when I used 102 ron (Carless Turbo fuel) I paid about £2.60 per litre. When the car does about 5mpg on a stage rally, it get very expensive.

Dave

[classicswede]

Originally Posted by Oli

Is this the next must have upgrade for your T4/T5/T6 or R?

Big performance claims from using this fuel, but seems you need a remap to get the best from it. As it's available in Maidstone, perhaps some comparison tests could be done at the SW Autos open day in May.

http://www.bp.com/genericsection.do?...tentId=7017179

And at £2.50/l or £11/gallon it could be viewed as a cheap upgrade for a weekend buzz, or an expensive fuel that most people won't be able to notice any difference from.

Eco friendly to boot.

Anybody tired it yet?

Oli

115 ron fuel is available at most forecourts for only 36p -45p a litre

[foggyjames]

There's always one, and it's usually Dai

cheers

James