Dave

Motors with high compression require higher octane to avoid knocking, turbos can also fit this catagory depending on boost levels. More boost equals more compression. Some turbos have the stock boost set high enough to need more octane.

iloveporsches

If you have the ability to tune your car (such as with a turbo), then adding higher octane gas will help your power out because you can then tune it to use the higher octane rating.

Dave

I was reading that on his site last night and can't figure out why, the DME is very simple on our cars and does not adapt or adjust itself to anything, it just does what the software tells it to do.

FWIW, I use 93 octane myself, but my compression ratio is higher than stock and I prefer to err on the side of caution.

Luis de Prat

Uneducated guess: Yeah, baby!

Nothing less than Euro 98 octane in my 91 951.

adrial

All the gasolines in my area contain methanol during the winter months and all have a big sticker that says so.

UDPride

It all comes out of the same refineries. The refineries and gas companies live in an incestual relationship and buy and sell to all kinds of third parties who simply rebrand the gas. The oil refinery and oil platform business isnt exactly a business your average joe schmoe can start up with a few thousand dollars saved up in the bank so with limited options everybody gets it from the same wells.

This goes on in almost every sector of business though. Those K-Mart and Wal-Mart branded AA batteries you skip over at the store are actually built by Energizer and Eveready and so forth -- and in some cases are actually superior in terms of battery technology. Its been a long-kept secret in business that big companies will use their supplies they sell to third parties who ultimately rebrand them to do their market testing on new and improved products without having to do it under the big name brand corporate name. This way they can roll out new and better batteries to the public under a K-Mart brand, never advertise about it, receive trial feedback that indeed the batteries last longer, then sell 1/2 of that technology in the Energizers at twice the cost while all the Energizer technicians keep buying the K-Mart badged ones.

Same way with long distance phone industry. If AT&T is your provider, theres a 99.9% chance that in order to connect your phone call, you had to piggyback on Sprint or MCI fiber too to make it happen and when Sprint has a cut in the fiber, you think its an AT&T problem when your LD phone call doesnt work. And AT&T has to pay Sprint or MCI a charge to deliver that call off their fiber and who do you think ultimately pays back (and then some) AT&T for that charge for using another carriers backbone? You mista.

DerSchlechtSpecht

All Chevron grades from 87 to 93 have the same ammount of Techron. If you are not pinging on 87 then using 93 wont burn cleaner because it burns just as clean on a 9.7:1 compression ratio engine.

-Christian

FormulaOne10

All very true information about the gas stations...my Dad used to manage some fuel distribution - only a few people make gasoline and usually you are buying the same stuff. As for fuel additives, it is certainly not a marketing ploy. Additives do make a difference in the engine...you just have to decide how much you are willing to pay for those differences. You *may* not get some of the best additives if you go to an off brand station as they are usually using lower end gasoline. The best gas used to be Amoco Ultimate (performance and clean burn) however that may have changed with their merger with BP. Shell and Chevron were both a close second...so I figure any one of those three are ok. This was all from a fuel design engineer.

capndar

FormulaOne10- check PM

Porrsche

Nothing less than unleaded Euro 98 octane in my 85b 944

That´s specified for my car from Porsche.

Never tested anything else but it works fine

porschefig

i actually think my car is faster with the suggested then anything higher

M758

In driving my 2001 VW GTI for 36k miles I recorded the gas milage and station from each fill-up.

Some of my Data

Engine 1.8L 20 Valve Turbo. Stock everything.
Requires 91 premium per MFG


Miles diven 36,273 miles of recorded data (0 Miles to 36k)
After 13k miles Az went from 92 at the pumps to 91. Fuels are special summer and winter blends mandated by EPA for years
This car saw 90% daily driver duty.

Total average fuel Mileage = 30.0 MPG
90 Fill-ups total

My top 3 Gas brands

Arco = 42 fills @ 29.9 MPG Avg
Costco = 19 fills @ 30.3 MPG Avg
Cheveron = 14 fills @ 29.3 MPG Avg

All other brands were 5 or less fills so not fair to avg out.

Notice there is little difference. The biggest change was increse of 29.5 mpg or so to about 30.5 between 12000- 16000 miles.

My guess is that this was due to engine break in. Most all of my Costco gas was purchased AFTER the 16k mark as one poped up close to me home.


I have similar sheet for my 84 944 that I have been daily driving. Unfortuatly I do not yet have enough data to make strong conclusions.



In my 84 I use 87 oct and it works fine.
I use 91 in my 944 turbo and regular pump 91 in my 944 spec car. I did put in 110 leaded in my race car once and noticed NO difference at all.

Jonas Goldsmith

I know that in my S, in the owners manual it says to use 91 minimum and 93 recomended... to bad they dont' have 93 here in cali... I just use premium 91...

*Michael.*

So who has heard of Toulene? You can buy it at paint stores and it was used by Formula 1 It is good for turbo motors..... I have a link about it around here somewhere. It is one of the best Knock/Detonation stoppers..

Hawk36

I run Regular Unleaded in my NA. I ran a couple of tanks of High Octian and didn't see a difference. I agree Techron every 3000 miles and Regular Unleaded do the trick.