Is Super Unleaded Needed In my Boxster?

[onomatopoeia]

Been running mine (3.2) on normal unleaded for most of the last six years. Running it on a few tankfuls in succession of 98 made no difference to the consumption and while there might have been difference in power it wasn't noticable in every day driving (which is what I use mine for), so I went back to 95.

[yellowgriff]

Stick 95 oct in it . If the engine didnt wont it a engine management light would come on, My 996TT only runs on 98 or 99 in tescos and i wouldnt run it on anything else, My wifes 987 boxster Runs 95 ron all day long with no ill effects..

[996ttalot]

On a turbo it does matter. Not sure as to significant difference for na.

On my turbo which is not standard the difference is huge in how soon knock control starts. I can run vpower to 1.35bar after which it will start to retard. Running 104 race fuel I can run 1.6 without any knock. Therefore I am using it as protection to enable running higher boost.

Btw anyway running 1.2 bar on tt or tts or x50 can do so safely on vpower - whether your map is good is a separate discussion.

[Akajak]

yellowgriff said:

Stick 95 oct in it . If the engine didnt wont it a engine management light would come on, My 996TT only runs on 98 or 99 in tescos and i wouldnt run it on anything else, My wifes 987 boxster Runs 95 ron all day long with no ill effects..

try vpower rather than tescos; see if you can tell the difference; lot of debate on some of the more technical led discussion forums on the unwelcome additives/mixture of fuel in the Tescos pumps

[Sunnysidebb]

Rotaree said:

I used to run my 02 Boxster S on ordinary fuel as advised by the dealer - on the odd occasions I put super in it there was absolutely no discernible difference. The dealer said that there might possibly be a detectable diffence if you actually tested it but on the road you would not notice anything at all - and the detergents etc are just the same. Had the car for two years, recently saw the next owner and it's still going strong so, by all means convince yourself you're doing the engine a favour, but I doubt very much that you are spending wisely!

Every one thinks if they put 99 in the tank after running the car for weeks on 95 they will suddenly feel the difference. Well you wont. On a Porsche the ECU will have adapted itself to run on 95. There should be no detonation and all would be well. Suddenly put 99 in the tank the ECU wont know you have done it. This is because of the way the ECU works. It can immediately retard ignition if it detects pinking, ( detonation) but it cant restore the ignition back to the original value instantly .This is called the "adaption values". It requires many full engine cycles to re adapt to a high octane fuel if the car has already adapted to a lower octane. You might have to run the car for weeks on 99 to gain any noticeable power improvements.
However if you have been running on 95 for weeks, fill up with 99 then reset the adaption values to the factory settings by disconnecting the battery. This restores the ECU to the factory condition. Its the ideal point at which to run a higher Octane fuel.
Should you then decide to run 95 later the ECU will re adapt to running the 95 fuel and you will probably notice a small difference as the ECU detects small detentions and pulls back ignition. As I have already said ,if you then put 99 back in you wont see the change untill the ecu adapts to the 99 fuel and that is a long process.
Frank

Edited by Sunnysidebb on Wednesday 24th November 20:00

[mikey P 500]

Run mine 2.5 boxster on 95 octane day to day (hand book recommends 98 but says 95 is ok and engine adjusts for it). Although I do put 98 or similar in for track work, (in case its any better for the engine health when driven hard or helps with slightly better mpg).

[mollytherocker]

Even though I know the difference is relativley minor, I only put Shell V Power in my 993. It just seems right.

As others have said, you will get half of the price diff back in MPG.

Summary - Performance car = Performance fuel.

MTR