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Super Unleaded....!???

nhenson

Well-known member
Joined
27 May 2013
Messages
85
Quick one?

Do all members run their 997s on Super Unleaded, ie Shell Nitro, BP ultimate etc...?

I read somewhere that the timing self adjusts if the lower octane fuel was used...????
 
Its a thoroughbred animal, it needs feeding top notch food else it'll run like a donkey :lol:
 
I agree, and only ask as last night I found myself driving past three supermarket filling stations to get to a Shell garage. It was touch and go as the range calculator and Sat Nav kept disagreeing as to wether we had enough fuel to get there...!!!

We did, but was just wondering if I was panda-ing to my ODC ways once more...!
 
I run mine on Tescos Momentum, 99 octane and pretty cheap, as an emergency measure I carry a tin of octane booster in case I can only get 'the cheap stuff'
Heres a link to some very reasonably priced and a good octane booster

http://www.ebay.co.uk/itm/250967639966?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649

They claim more MPG, I have noticed whenever I use 118 octane it seems to last a lot longer than is expected (considering the car is on 100% throttle when im using it) I might try a fill up with 'normal' unleaded and a half bottle then full bottle of this and see what difference if any it makes, anothe rgood product is Power Pour, your motor simply WILL NOT detonate with this stuff, £15 a bottle or £10 if you buy a case.
 
The engine management system adjusts for the lower ocatne rating of 95RON so in that situation where you were low, running on 95RON would have done no harm to the engine. The handbook for my 996 Turbo does say to use Super Unleaded 98RON. I'd be surprised if it is different for a 997.

You may need to see a doctor if the OCD and Porsche Paranoia symptoms become worse.
 
Its a thoroughbred animal, it needs feeding top notch food else it'll run like a donkey

I'll just elaborate on my answer...

I always use high octane fuel, however there have been occasions when Ive been stuck and had to use the cheap stuff. I put as little as possible in to get me home and to my regular garage, then fill up with normal stuff.

I like the idea of carrying octane booster so I'll probably do that now.

Also I'm getting 32MPG on my twice weekly commute (180 miles all clear motorway) which is in general above what most people on here achieve, I've not tried normal fuel but I think high octane usage has something to do with that figure.

And yes, I do drive like Miss Daisy's chauffeur !
 
I doubt the Porsche centre's use high octane stuff for the cars :puh:
 
The guy I got the car from said it was very sensitive to cheap fuel and that it took a while to grt back to full performance after filling up with super again, as soon as I fit the standalone ecu I can switch maps for whatever octane fuel im using.
 
You CAN run on 95, but don't.

As we are talking 997, the 997.2 DFI really hates 95 (the 997.1 less so)

But the manual and fuel flap say 98 RON, and for good reason.

Not only do you lose power, but that cheaper fuel is used quicker.

The engine will run hotter too on 95 RON, and that is not good for all sorts of longevity, thermal stress and reliability reasons.

Expect to lose about 30BHP and a load of torque if you use 95 RON fuel on a Turbo (less so on an NA, but still more than 10 BHP).

95 RON will also result in increased consumption at a steady speed - by up to 2-3mpg (so an easy 10%).

So a real false economy to fill with the cheap stuff.

The DME can "learn" the fuel grade (and atmospheric fuelling effects), so if you are planning on using a higher grade than in the last tankful, do a reset for immediate effect (rather than waiting for up to half a tank to passive reset).

DME reset is via key, Throttle Body reset is via key

Reset via key requires turning the key to ignition "1" (the position when all the lights are on on the dash) and leaving it for 60+ secs (DO NOT TOUCH THE THROTTLE PEDAL), then switch off for 10+ secs and you should be able to hear a few clicks and whirs from the engine bay as it recalibrates the adaption values.

Adaption must be performed when ambient temps are > 10°C
 
GT4 - thanks for a comprehensive response. I have a 996 Turbo with X50 and use Super Unleaded. Question is, is Super Unleaded the same octane rating and basic detergents that are required whether it is from Sainsbury Supermarket or from BP Ultimate, Shell V-Power Nitro etc?

I appreciate the brands such as Shell market themselves on extra detergents and additive that clean the engine and injectors as we drive, but is the Sainsbury Supermarket stuff really that bad as to avoid - given that it is 98 RON? Bit like generic medicines - generic atorvastatin is as good as Pfizers Lipitor global brand because there is a Standard of manufacture to bemet and manufacturing sites are inspected to ensure the generic meets the standard of the brand. The difference is thaat the generic is £3/month versus Pfizers global brand at £30/month. Hence the NHS drives the usage of generics.

Does the car industry accept 98 RON from Supermarket does not harm the engine and is the same as Shell V-Power? If so then Shell V-Power is charging a premium for some detergents in theirs that are not in the Supermarket product? And anyway, Supermarkets buy their fuel from the big refineries of Shell and BP anyway?

Value your thoughts and advice on this topic please.
 
I can tell you that Sunoco race fuels are no longer used in a couple of the bike classes as they were found to be nothing more than supermarket fuels with a few additives thrown in :eek:
 
The RON weight is what you are buying.

Any discussions into snazzy detergents or how often Tesco put diesel/water/baked beans into their petrol storage tanks is entirely separate.

Identical RON will provide identical power (where an engine has been tuned to accept that grade)

The RON grade is a legalling binding commodity specification (with reference to gasoline delivery)

If you buy a 40.0% supermarket value vodka, it will get you just a drunk, just as quickly as Grey Goose.

You might get a different headache the next day, mind!
 
Interesting analogy with the Vodka GT4. If it says 40% w/v or v/v or 70 degree proof then an own brand has to meet that specification. Of course the own brand is not their own make, it has been put into a bottle I suggest by a major distillery.

I use Shell V-Power sometimes in the hope that an occasional tankful will help to keep injectors etc clean with their additives. BVut without eveidence, I am of the view it is just marketing hype. I have been in the medical and pharmaceutical field all of my life and am always sceptical of any of these claims by Shell or others because the one thing they do not have to do which a regulated industry such as pharmaceuticals have to do is provide compelling double-blind placebo-controlled studies in large populations across dimesions of efficacy, safety and tolerability. Hence my cynicism about these marketing claims.

Rest of the time I just use Super Unleaded from wherever or whichever supermarket I can get it from. If anyone knows of any studies with statitically significant methodology about these claims by Shell etc. then I am keen to scrutineer the claims - I have been used to doctors pulling apart clinical trial data and have become an expert at
spotting real data from marketing hype.
 
Ive always found a bit of Toluene does the trick now and again, as well as boosting the octane massively.
 
GT4 said:
You CAN run on 95, but don't.

As we are talking 997, the 997.2 DFI really hates 95 (the 997.1 less so)

Interesting.

I run mine on super unleaded because that is what Porsche specify, usually BP or Shell but I'm not obsessive about it. On the odd occasion where I find myself needing fuel and the garage I pull into doesn't carry super, I don't worry about putting a third to half a tank of straight unleaded in there.

Why third to a half? Semi rational explanation would be that it gives me some range, but with the 5-10 litres of super still in the tank, doesn't completely dilute the blend down to 95, and means I will top back up and raise the average again before very long. Or maybe its just irrational.

To be honest I personally have never really noticed an objectively measurable difference, in performance or on the temperature dials, under normal driving conditions. Can't speak to consumption, I don't monitor it that carefully. So I'd say run it on the good stuff, but don't be so dogmatic that you play Russian Roulette over whether you can get to the next Shell garage before being stranded on the side of the road.
 

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