93 octane gas only?

[porscheracer]

Originally Posted by pteam

Does the boxster / S require 93 octane gas only?

This is a damn ass thread... especially from a guy who owns a yellow Lambo and Ferraris. Pteam for Poseur Team?

Although, lately I see a lot of LAMBOS driving around Chelsea NY. Hmmm...Not like theirs anything wrong with that!

[CJ_Boxster]

Originally Posted by porscheracer

This is a damn ass thread... especially from a guy who owns a yellow Lambo and Ferraris. Pteam for Poseur Team?

Although, lately I see a lot of LAMBOS driving around Chelsea NY. Hmmm...Not like theirs anything wrong with that!

Did you run out of Vagisil???

Originally Posted by CJ_Boxster

Did you run out of Vagisil???

HAHAHAHHA, LOL

[trube78]

A gallon of gas whether high test or regular has the same amount of energy. The engine of your Boxster will convert the chemical energy of the gas to mechanical energy to move the car. Porsche designs its engines under the assumption you will use 93 or 91 Octane and sets ignition timing to ensure there is no knocking and the car gets the max power and fuel economy for the expected Octane. When you use lower Octane fuel the car will have a tendency to knock so the knock sensor will sense the beginning of engine knock and tell the ECU to adjust (retard) timing to protect the engine. Eventually if you consistently run low test the ECU will automatically assume there is something unusual and either automatically retard timing or spit out an error code (according to some Porsche Gurus the ECU will adjust after about 25 to 30 hours but I have never seen it in writing.) That assumes all of the protective features work proberly. If not, for example if you go full throttle and there is no early indication of knock you could knock before timing is retarded and harm your engine.

Since the car will frequently have retarded timing while running 87 Octane, it will not be operating at peak efficiency and thus produce less power and worst Gas Mileage. Cars that are designed for regular will see no improvement by using high test. However, many chip tuners get their best results by programming for 93 Octane vice the 93 or 91 octane spec called premium in various states and recommended by Porsche.

ATB.
Tom

[MikeinLA]

I don't think I've run into higher than 91 octane. Is there a station that routinely sells 93 octane as their premium? I ran into 100 octane racecar gas once, but it was 5 bucks a gallon. Ouch!

Mike

[spark00]

Originally Posted by MikeinLA

I don't think I've run into higher than 91 octane. Is there a station that routinely sells 93 octane as their premium? I ran into 100 octane racecar gas once, but it was 5 bucks a gallon. Ouch!

Mike

come to east coast and see 93s. well, i think it all depends on which state you are in but in VA/DC/MD you have choice of 87, 89, or 93 and no option for 91. i think i saw 91 in Ontario and NJ.

i think i read somewhere that there are 2 methods of calculating the octane rating. maybe 91 served in CA is same as 93 served in DC area?

[trube78]

It varies by state or locale. 93 Octane is available on the east coast, 91 is the max in many states. You will also see different maximums in Mountain areas. So ... yes it is available but probably not in your area. However, unless your Boxster has been chipped, the factory ECU is tuned for both 91 and 93 Octane U.S. gasoline. It should provide optimum power and torque with either. Increasing Octane to 95 without reprogramming the ECU probably won't buy you anything either. The ECU will be unable to advance the timing to take advantage of the higher Octane. Although I suppose you could burn hotter plugs which may get you something.
ATB,
Tom

[porscheracer]

Originally Posted by CJ_Boxster

Did you run out of Vagisil???

are you asking me if i want some of your extra stash? no thanks bro i am not gay. not like theres anything wrong with that.

[Brucelee]

Octane threads go nowhere.

Kind of like Oil threads.

[OldBlevins]

Quote:
"Octane threads go nowhere.

Kind of like Oil threads."


Interesting, though, for us Newbs. I was always under the impression higher octane gas was yielded more power. Now I know better.

[JackG]

Originally Posted by OldBlevins

Interesting, though, for us Newbs. I was always under the impression higher octane gas was yielded more power. Now I know better.

Higher octane gas doesn't yield more power, but it does allow you to develop more power by running more spark advance, more boost, higher compression, ect.

In a modern computerized engine that is designed and tuned to take advantage of high octane gas, you do develop more power automatically when using the correct, higher octane gas.

In an engine optimized to burn 87, you don't make or lose HP by using 93. You just pay more money.

[JackG]

Originally Posted by Brucelee

Octane threads go nowhere.

Kind of like Oil threads.

Or global warming threads.

[Dohertycm]

I dont put anything but premium 91 or 93 in my boxster.

I have never put regular in it.

However, when I am towing my cars I put premium in my truck, it eliminates the knock and the motor becomes more efficient. If I run mid grade instead of regular I get better gas mileage. I am assuming that is because of a more efficient burn.

It all depends on what the car was tuned for and what it is rated for. My friends Dodge pickup CANNOT run anything but regular because it will burn out the O2 sensors.

[CJ_Boxster]

Originally Posted by porscheracer

are you asking me if i want some of your extra stash? no thanks bro i am not gay. not like theres anything wrong with that.

LOL got me.... but im not gay either, not that there is anything wrong with being gay.

[pteam]

Originally Posted by porscheracer

This is a damn ass thread... especially from a guy who owns a yellow Lambo and Ferraris. Pteam for Poseur Team?

hmm I just noticed this reply porscheracer, thats a pretty F'ed up reply. If you notice all I did was ask "Does the boxster / S require 93 octane gas only?" because I havnt owned a boxster in about 6 years and that was a non - S version. Especially since my girlfiend is driving it everyday right now I need to make sure that the proper gas is going into the car.

Maybe CJ Boxster was on the right path about you when he asked if you forgot your Vagisil???

[Peer]

JackG wrote:
> In an engine optimized to burn 87, you don't make or lose HP by
> using 93. You just pay more money.

Well, actually the best matching octane/timing would be a compression that's just on the limit to ping. However, since pinging is bad for the engine, the manufacturers are usually exaggerating the recommended octane rating just to be on the safe side.

-- peer

[trube78]

For high compression high reving engines, advancing timing just before ping occurs is great for steady state driving on the flats. Anti knock sensors are inserted to ensure there are no instances where knock actually occurs in the transients although the use of High Octane gas ensures a reasonable engineering margin of safety. Continuing to retard timing to prevent knock will adversely affect both power and MPG. For many cars the computer will log instances where the anti knock sensor retards timing. Dealer Repair shop use it for troubleshooting to see if there is an engine management problem. In BMWs if there is consistent indications of knock onset without an accompanying engine problem they will assume low octane fuel is used (BMW also logs over-rev situations on their cars and has used the data in warranty claims in the past.) I do not know what the new Porsche computer logs but it does log more than they did in the past. Under current EPA rules and automotive engineering standards. Exagerating Octane requirements in order to squeeze additional performance is prohibited. The Mazda RX-8 performance was downgraded due to engineering sleigh of hand by mazda. When independent testing was conducted, the output was downgraded and Mazda had to compensate their new RX-8 owners. My personnel experience with high octane/high performance engines. Expect a decrease of about 10% in gas mileage and similar HP decrease from using regular vice the recommended premium gas. So you will loose in the end plus possibly put your engine's long-term life at risk during hard acceleration. while my 'test" were not scientific other folks experience concurs.

ATB,
Tom

[Peer]

trube78 wrote:
> Expect a decrease of about 10% in gas mileage and similar HP decrease from
> using regular vice the recommended premium gas.

A ping-free engine will not gain any power by increasing the octane rate.

-- peer

[JackG]

Originally Posted by Peer

trube78 wrote:
> Expect a decrease of about 10% in gas mileage and similar HP decrease from
> using regular vice the recommended premium gas.

A ping-free engine will not gain any power by increasing the octane rate.

-- peer

You're missing the point. If an engine is designed to use, and benefit, from 93, it will most definitely lose power when using 87. The engine management computer will detect pinging, and will retard timing, enrich the fuel mixture, etc. to stop the ping. It will be ping-free, but will be down on power and will use more fuel on 87.

Running 93 will gain you power in this case.

[clickman]

So I'm trying to understand what octane rating I really need here in the great white north:

My manual says:

1. "Your engine is designed to provide optimum performance and fuel economy using unleaded premiuim fuel with an octane rating of 98 RON (93 CLC or AKI).

Porsche also recognizes that these fuels may not always be available. Be assured that your vehicle will operate properly on unleaded premium fuels with octane numbers of at least 95 RON (90 CLC or AKI), since the engine's "Electronic Oktane knock control" will adapt the ignition timing, if necessary."

2. On the fuel filler door of my Box it says "Minimum octane RON+MON/2 = 93"

Some quick net research tells me that AKI (Anti Knock Index) is the same as (R+M)/2.

Therefore the manual and the fuel filler door don't agree, and I'm left wondering if I really can run 91 or 92 instead of the much pricier and rarer 94 I'm currently using.

It sounds some of you are running 91 without any issues, but I'd like to know if that's more universally the case before I switch.

And I'm also curious if USA cars have the same label on the fuel filler door that I have.