Super Unleaded....!???

Techron Super Concentrate

Does anybody have a view about these fuel additives such as Techron Concentrate? Are they all they are hyped up to be - cleaning injectors etc.?

Mercedes Benz's reply when I asked about my E-Class 220 Diesel is that MB do not recommend any additive and that for new cars it can invalidate hte warranty.

What about a 10 year 996 Turbo? Would it benefit from this being added once a year into a tank of petrol?

Having come from the world of Jap performance cars into the loving arms of German high-performance I can say in my experience that I've never noticed a jot of difference between fuels of the same rating.
Even in highly stressed turbo's I've never been able to discern any difference between Shell/Tesco etc.

I did however own a rather raggedy L registration Cavalier SRI (Redtop with porous head and everything! I was a poor student!!)
The first time I rebuilt it, previous owner had done 50k in it, engine was horrific.
Second time I'd been running it on 95 ron for ~15k and it was once again, filthy.

Third time I'd done another 20k or so but on V-Power back in the day and it was still spotless.
Could have been a fluke but I would put some weight behind the idea of there being additives and detergents in the fuel.

I still don't think it makes a jot of difference to the performance but perhaps there is some weight in the cleaning claims?

HarryH said:

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)

Click to expand...

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.

Click to expand...

They will all run on 95 RON.

The "hating" it bit is where the engineered fuel stratification will not kick in - ie the engine's key feature is turned off.

A lot of "super" unleaded petrol is rated at 97 RON e.g BP. It says to use 98 on the inside of my fuel cap (997.2).

There's no real difference performance-wise between petrol of the same rating but I use Shell (98 RON) whenever I can because it just seems to work well.

One thing I will say is there's been a fair amount of negative feedback on Shell's new V-power Nitro.

I've stopped using it for the time being as my car (M3) was hunting at tickover (especially from cold). I have replaced it with Tesco 99 and the car has been perfect. I even went back to Shell and the same thing occurred so back to Tesco I went.

Apparently it's something to do with the cleaning chemicals in the fuel... :?:

GT4 said:

The "hating" it bit is where the engineered fuel stratification will not kick in - ie the engine's key feature is turned off.

Click to expand...

WHOOSH!!
Ah... the all too familiar sound of a technical GT4 post going straight over my head. Takes a man to admit when he's hopelessly out of his depth.

:worship: :coat:

Formula Shell all over again!!

I've filled it with V-power nitro for the last month and have to say haven't had any issues; but might try using the Tesco stuff for a while for comparison.

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)

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

Click to expand...

dude is there anything you don't know about these cars!!!!

I don't know your current mileage.

GT4 said:

I don't know your current mileage yet.

Click to expand...

Fixed it for you.

I deliberately chose a moving target, so I can never really know it in any real sense.

If I had said VIN for example, then "yet" would have applied (although that is a bit stalkerish)

GT4 said:

I deliberately chose a moving target, so I can never really know it in any real sense.

If I had said VIN for example, then "yet" would have applied (although that is a bit stalkerish)

Click to expand...

Drat foiled again!

Though I wouldn't be surprised if you had a note of all the VIN's plugged into the decoders and the user names of the entrant.

Sadly I have lost my access to HPI and live PIWIS, which allowed me to clock someone's number plate, get the VIN, get the full factory build spec and then tell them the part number for the optional footwell lights for their model year they had fitted inside!

Great party trick! :bandit:

I'm glad a fuel thread has popped up, as I have found some interesting facts recently regarding my 996T and it's fuel habits.

My car has always been run on Super unleaded during my custody, I would never run on 95 unless forced to by circumstance . As a day job, I regularly test fuels back to back for power, torque and brake specific fuel consumption (a measure of a fuels specific power output vs weight. We measure in Lbs/hp/hour with our engine dyno, after entering the measured specific gravity of the fuel).

We regularly see Tesco Momentum 99 coming out on top in these tests. The fuel burns clean, exhaust systems run grey right through ( a sign of good burning) and the engines are not sooty when stripped. A slightly better fuel is a race fuel, 100 RON made by Elf, called Atol. This is used as a general baseline fuel due to it's stability and repeatability. Momentum 99 nigh on matches this lab fuel in all respects.

We have yet to test VPower Nitro, other than to dyno engines on it, but not strip them to check cleanliness etc. However, in my 996Turbo during the recent hot weather, the performance on this fuel was not at all good. The car was getting slower and slower as the learn maps retarded the ignition. One full tank of Tesco later, my power is returning in dollops, despite ambients of above 28 degrees.

So, for me it is a given which fuel I personally use. I have absolutely no connection whatsoever to any fuel company, I'm merely offering my findings to the forum. For clarity here, the bulk of the engines tested were Japanese 600-1000 four cylinder race bikes, ranging in compression ratio from 12.8:1 to 14.9:1. I'm very aware that we don't drive 14-17000 rpm engines, but my own findings appear to back the bike figures up. The output of the bikes represents 227 hp/ litre at the gearbox sprocket, so they are fairly well developed engines. One more finding, on VPower Nitro, my OIL consumption rose! Food for thought....

Hope this helps some of you guys....if you haven't fallen asleep yet!