Gas?, what kind to use. Options

[flipb]

cast of sordid weenies.

I have nothing to add to this thread except that somebody should use this as the name of their band.

[Madswede]

MTBE (not MBTE) poisoned the water because the tanks leaked. The tanks shouldn't leak. MTBE was only a small percentage of gas, which is not exactly mothers milk in its own right, having the known carcinogen benzene, among others. Wells in the LA area continue to be closed due to other solvents that are worse. To the extent that MTBE renders gas more soluble in water is also true of its replacement, ethanol, which has its own bogus rationale and cast of sordid weenies.

To continue this interesting (to me, anyway) sidebar conversation, MTBE is one of the most water-soluble components in gasoline (if not the most soluble component), though it doesn't make any of the other components of gasoline any more or less water-soluble. It's because of this that it actually can be thought of as a pretty good indicator of "trouble ahead" when it starts being found in groundwater, though MTBE itself is not a carcinogen and is relatively non-toxic.

Other components that are much less water-soluble but far more carcinogenic are toluene and benzene. They are spilled from the same gasoline spill, and are more slowly following behind in the same plume that the MTBE was at the vanguard. So in a way, MTBE could be used as an advance indicator of a problem, and I wonder at the logic of removing it completely from fuels. Removing MTBE entirely, at least in my opinion using the logic I just stated, might be penny-wise but pound-foolish if there is not another advance indicator of the plume spread such that we could stop it before the real bad actors (toluene and benzene) reach groundwater. But it seems that decision has already been made.

Of course, all of that discussion is about the relative risks of spilling too much gasoline which is besides the point when one is talking about engine performance. I think most places in the US add ethanol these days, though it could become more cost-effective to just add iso-octane itself (still much more expensive than MTBE) or even ETBE (ethyl tert-butyl ether) as they do in Europe (as I just read). Incidentally, I wonder how many engines out there really need higher octane fuels or is it all just a big marketing scheme? (IMG:style_emoticons/default/dry.gif) I certainly don't see much need for high-octane fuels in n/a motors at the altitudes I live in (same goes for all of us in the Rocky Mtns), almost regardless of compression ratio.

- Nelson

[IronHillRestorations]

Always use the LOWEST octane you can without pinging.

This is probably 180* from what you may think: Higher octane fuel is better for my car, it's the good stuff and costs more, so it has to be better right?

The lower octane fuel has fewer additives, which results in a cleaner burn and less carbon build up in the combustion chamber.

"High Test" or high octane fuel has more additives to make it burn slower, and these add to carbon build up on the cylinder head and top of the piston. Extra carbon build up raises the compression and causes pinging and starts the whole vicious cycle.

Techron is a good product for cleaning the combustion chamber. There is also a whole line of products from BG Petroleum designed to help remove carbon deposits.

[Cap'n Krusty]

I don't like ARCO for a number of reasons, some philosophical, some because of their additive package. A former big weenie at ARCO was on the Air Resources Board and suckered the state into using MBTE, that wonderful additive that poisons our water systems and happened to be under an ARCO patent. We're gonna be paying for that for about a thousand years ..................

The Cap'n

MTBE (not MBTE) poisoned the water because the tanks leaked. The tanks shouldn't leak. MTBE was only a small percentage of gas, which is not exactly mothers milk in its own right, having the known carcinogen benzene, among others. Wells in the LA area continue to be closed due to other solvents that are worse. To the extent that MTBE renders gas more soluble in water is also true of its replacement, ethanol, which has its own bogus rationale and cast of sordid weenies.

Hey, it was dark and my fingers couldn't see ............... The biggest problem with MTBE is it aggressively seeks out water. While some wells and industrial sites are most assuredly closed for other solvents, we actively made sure that, wherever gasoline was sold, dispensed, spilled when filling a chainsaw or lawnmower, or anything else, or leaked out of ANYTHING, it was headed for the nearest water. And we did it on purpose. Everywhere. Off road bikes, snowmobiles, personal watercraft, the aforementioned lawnmowers and chainsaws, all spread it to every corner of the state.

The Cap'n

[realred914]

GAS???? yeah I have some, want to smell it? pull my finger (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/hissyfit.gif) (IMG:style_emoticons/default/piratenanner.gif)

[Tom_T]

To answer the original question, 87 octane regular gas is perfectly fine for a stock 1.7 914.

91 RON is not the same as 91 AKI. You guys that think your stock 914 needs premium fuel in the US simply because the sticker on your car says 91 RON, really need to read about gasoline octane ratings, past and present, US and Europe. DOn't take my word for it. Just keep wasting your money.

Difference between RON and AKI

Because of the 8 to 10 point difference noted above, the octane rating shown in the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. See the table in the following section for a comparison.

Not to nit-pick, but it's MTBE and not MBTE isn't it?

Thanx Gint - I forgot about that factor!

By 73 MY CA was requiring all cars to run on unleaded 87 octane - remember the different pumps with the smaller nozzle to differentiate & not allow you to put "old gas" in your car? There was also a change to the rating system in the USA about that time which showed a lower rating than for the old 60's & earlier system, per my Dad who was a Petro-Chemist in his first career.

So the 4-5+ lower AKI/USA octane rating on87 equals or betters the 97 RON. Also IIRC for the 2.0L's the GA was a bit lower 7.6:1 compression ratio, while the Euro heads were the 8.0:1 on the GB motors, & therefore turned out 100 hp vs. 95 in the GA's.

So I suppose the 87/Regular is fine for my 73 2.0 also, unless it starts pinging/knocking with the current products, and even then I'd first check out the octane enhancer additives etc. for older cars first, before buying higher grade gas. I did run 87 unleaded during 80-85 in it with no problems.

[Tom_T]

MTBE (not MBTE) poisoned the water because the tanks leaked. The tanks shouldn't leak. MTBE was only a small percentage of gas, which is not exactly mothers milk in its own right, having the known carcinogen benzene, among others. Wells in the LA area continue to be closed due to other solvents that are worse. To the extent that MTBE renders gas more soluble in water is also true of its replacement, ethanol, which has its own bogus rationale and cast of sordid weenies.

To continue this interesting (to me, anyway) sidebar conversation, MTBE is one of the most water-soluble components in gasoline (if not the most soluble component), though it doesn't make any of the other components of gasoline any more or less water-soluble. It's because of this that it actually can be thought of as a pretty good indicator of "trouble ahead" when it starts being found in groundwater, though MTBE itself is not a carcinogen and is relatively non-toxic.

Other components that are much less water-soluble but far more carcinogenic are toluene and benzene. They are spilled from the same gasoline spill, and are more slowly following behind in the same plume that the MTBE was at the vanguard. So in a way, MTBE could be used as an advance indicator of a problem, and I wonder at the logic of removing it completely from fuels. Removing MTBE entirely, at least in my opinion using the logic I just stated, might be penny-wise but pound-foolish if there is not another advance indicator of the plume spread such that we could stop it before the real bad actors (toluene and benzene) reach groundwater. But it seems that decision has already been made.

Of course, all of that discussion is about the relative risks of spilling too much gasoline which is besides the point when one is talking about engine performance. I think most places in the US add ethanol these days, though it could become more cost-effective to just add iso-octane itself (still much more expensive than MTBE) or even ETBE (ethyl tert-butyl ether) as they do in Europe (as I just read). Incidentally, I wonder how many engines out there really need higher octane fuels or is it all just a big marketing scheme? (IMG:style_emoticons/default/dry.gif) I certainly don't see much need for high-octane fuels in n/a motors at the altitudes I live in (same goes for all of us in the Rocky Mtns), almost regardless of compression ratio.

- Nelson

Nelson, good info.

However, while MTBE is not as bad as the others, the jury is still out on its health risks - esp. in the water supply, which is 80% groundwater here in my town - Orange, CA. In Brownfields Redevelopments in which I've been involved, we still need to remediate for it per EPA in order to get site clearances for redevelopment, but it's tenacious in the way it quickly passes through the soil & spreads so quickly, that it's like herding cats/chickens according to our remediation engineers.

As for keeping it as a marker, the problem is - & was known by ARCO from the start - that it eats at the rubber (both natural & synthetic) so that fuel lines, gaskets, seals & grommets, etc. are prone to early failure, and therefore results in more surface spills from vehicles on the roads & off-road. As I stated earlier, I've had to reseal the 88 Westy's gas tank 3-4 x during the time which CA used MTBE additives.

[Tom_T]

GAS???? yeah I have some, want to smell it? pull my finger (IMG:style_emoticons/default/piratenanner.gif) (IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/lol-2.gif) (IMG:style_emoticons/default/av-943.gif) (IMG:style_emoticons/default/hissyfit.gif) (IMG:style_emoticons/default/piratenanner.gif)

(IMG:style_emoticons/default/icon8.gif) .... don't try that near an open flame or spark! (IMG:style_emoticons/default/laugh.gif)

[SGB]

As a registered Environmental Engineer, water resources and superfund investigation/ risk assessment specialist, Registered asshole (see pole), and authentic old coot, I will state that MTBE failed.
It leaks more easily than gasoline, implying that OK systems are bad, so needed cleanup $ go to false failures.(there is a 2 feet deep plume of petroleum under Phil PA. over 1 foot of petroleum product cover 100s of square miles of groundwater in southern Cali -these are much greater sources than some gas station leaking MTBE. Oh, and then there is NJ...). It eats distribution system (big industrial and individual engine) components. It MAY be carcenogenic, so it is considerd so by EPA risk assessment processes. MTBE was another "science will save us, so we don't have to act responsibly!" delusion, foistered on us codependant users. Bad objective, bad execition, and manipulation of a willing public. I'm glad it got stopped. They are still trying all kinds of chemical, physical, and biological "fixes". Some may work. But some may provide employment for the next gen of Enviro Engineers.

[914 shifter]

gas,grass, or ass no free rides (IMG:style_emoticons/default/smile.gif) (IMG:style_emoticons/default/av-943.gif)

[underthetire]

I actually had a discussion with a state inspector on the different fuels. In his opinion, there was not enough of the "fuel system cleaners" per tank to make much/any difference. He said to buy the cheaper stuff and run a bottle every few months of good FI cleaner. Now, I do see about 1-2 MPG less in my Jeep if I run Safeway gas vs a little better quality, but Safeway is all I have next to home.

[realred914]

What if youre running dual webber would that change the ball game? Or Still use 87.

To expand upon the Cap'n and my earlier post...

Octane is a detonation/pining prevention. Detonation/pinging are related to engine compression which is set when the motor is built and doesn't change (slight simplification). Nothing you bolt on (carbs, FI, exhaust, chrome engine tin, etc) is going to change the compression ratio, except a turbo or supercharger.

detonation is also related to temperature of combustion chamber (run to hot and it happens) and too much advance with cuase pinging. higher octane can help reduce these effects and allow hotter temps and more timing advance.

[realred914]

I actually had a discussion with a state inspector on the different fuels. In his opinion, there was not enough of the "fuel system cleaners" per tank to make much/any difference. He said to buy the cheaper stuff and run a bottle every few months of good FI cleaner. Now, I do see about 1-2 MPG less in my Jeep if I run Safeway gas vs a little better quality, but Safeway is all I have next to home.

That's not so bad, you can't eat gas, 'least you wont starve. (IMG:style_emoticons/default/chowtime.gif) (IMG:style_emoticons/default/chowtime.gif) (IMG:style_emoticons/default/chowtime.gif) (IMG:style_emoticons/default/chowtime.gif)

[oldschool]

I actually had a discussion with a state inspector on the different fuels. In his opinion, there was not enough of the "fuel system cleaners" per tank to make much/any difference. He said to buy the cheaper stuff and run a bottle every few months of good FI cleaner. Now, I do see about 1-2 MPG less in my Jeep if I run Safeway gas vs a little better quality, but Safeway is all I have next to home.

Safeway? that was a super market back in the day.

[black73]

The Porsche 914 Workshop Manual (group 0 1.2-1/2) states:
required octane rating: 98 Oct. (premium fuel)

...so if today's octane ratings are 10-11 points off from the old method, does that mean that today's 87 octane is equivalent to 1970 era premium (98 octane) and that the old school high compression engines should run 87 octane?? (IMG:style_emoticons/default/confused24.gif)
(IMG:style_emoticons/default/popcorn[1].gif)

[john grier]

I have not really read this thread.
But I am not going to put ethahol in my 914 unless I am somewhere
that I cannot find alcohol free gas.
Case in point.
I was running the alcohol gas in my 94 4 runner.
It kept loseing power.
After about 2 years I put real gas in it and the power doubled.
Or so it seemed.
After that I only use real gas.
John

[underthetire]

I actually had a discussion with a state inspector on the different fuels. In his opinion, there was not enough of the "fuel system cleaners" per tank to make much/any difference. He said to buy the cheaper stuff and run a bottle every few months of good FI cleaner. Now, I do see about 1-2 MPG less in my Jeep if I run Safeway gas vs a little better quality, but Safeway is all I have next to home.

Safeway? that was a super market back in the day.

Still is...

[Krieger]

Safeway is The most common supermarket in N Cal

[Tom_T]

The Porsche 914 Workshop Manual (group 0 1.2-1/2) states:
required octane rating: 98 Oct. (premium fuel)

...so if today's octane ratings are 10-11 points off from the old method, does that mean that today's 87 octane is equivalent to 1970 era premium (98 octane) and that the old school high compression engines should run 87 octane?? (IMG:style_emoticons/default/confused24.gif)
(IMG:style_emoticons/default/popcorn[1].gif)

Gary, that's probably for the early & higher compression non-USA motors. Also note on the next page or so that the 914-6 is listed at 98 octane premium.

The stickers on the pass. front wheel house next to the tank is 91 RON, which as Gint pointed out earlier, equals the 0ld 1970's 87 Regular. Also gasoline formulations were different then, different USA vs. Europe, as compared to now.

For those worrying about +/-10% Ethanol as a smog control additive, most testing I've heard about says that it's not detrimental to performance until it reaches 15-20% for non-Ethanol engineered motors (such as the Chevy dual-fuel ethanol models out today). What caused the poor performance in the 4Runner above was more likely a higher % &/or a bad blend (refiners have been known to cheat on octane, especially smaller ones & independent dealers).

[Zardozz]

I run the 91 but I'm also running about 10#s of boost (IMG:style_emoticons/default/smile.gif)

I could prolly push that to 14#s if I ran the 104.