Octane Gas Question

[mllevin1]

After 22 years had to replace the fuel pump on '89. Going forwards, anyone use a higher octane than 93 to keep things running well, or try any fuel additives to keep the lines clean?
Thanks

[Rot 911]

91 octane is all you need if you have the stock chip. Higher octane won't improve performance. Use a bottle of techron with the appropriate amount of gasoline every now and then to keep the injectors cleam.

[mllevin1]

Car has a newer chip @ 10 years old so I have been using 94 from Sunoco

[Craig T]

Unless you're running higher than 9:5.1 compression, and have the timing to handle it, octane higher than 93 will NOT give you any benefit. +1 on the occasional Techron additive to keep things clean.

[spuggy]

Originally Posted by mllevin1

anyone use a higher octane than 93 to keep things running well

Waste of time using higher octane than specified; more expensive, actually burns slower than motor designed for, no extra power.

Just use what the motor is set up for, IMHO.

or try any fuel additives to keep the lines clean?
Thanks

I personally avoid miracle additives in a bottle....Slick 50 never fixed (nor even made any noticeable difference) to my gearbox whine on my beater 30 years ago, so I've never trusted any since..

I think Chevron already uses Techron in all their grades, I tend to use their gas quite a lot.

The only advantage to the "premium" gas might be the additive package. I believe that some brands may put more cleaners in the "premium" package than the others.

I understand that there are now Federal standards for additives to gas; the advertising blurb on the pump says that Chevron already exceeded Federal standards with Techron when those standards were introduced, but the other gas suppliers had to up their additive pack to meet them - there were stories a few years about Chevron being trucked in to the motor city (where it's not available) for fuel economy and emissions testing because auto manufacturers got better test results with it.

Dunno, I was already happy with/using their gas...

But probably the best thing you can do for pretty much any Porsche, is using the gas up/the car regularly; take it for a good, long run as frequently as possible.

Every one I've ever owned or driven seemed to run way better around town for a week or so after running them for 4-6 hours (or ideally more) on a long trip.

That's probably even more important with ethanol-blended fuels; don't let that sit in the tank unused.

[BE911SC]

So spuggy, to piggy-back on your advice, is Sta-Bil part of your fuel regimen in the winter months?

[spuggy]

Originally Posted by BE911SC

So spuggy, to piggy-back on your advice, is Sta-Bil part of your fuel regimen in the winter months?

Stabil is a no-brainer for the genset and lawn equipment, I think.

I don't put it in the 911 because it's my daily-driver - and with the gas mileage a CIS 930/60 motor gets (especially on surface streets), there really isn't any fuel getting old in there...

[ivangene]

he forgot to mention ---- plus the way he utilizes his gas pedal

but like Andy, I dont use anything but fresh gas - nearly drive the car everyday - poor poor dirty car - with a happy happy owner

[db_cooper]

I use Marvel Mystery Oil (MMO) in the fuel (4oz per 10 gallons) of all my older machines, including the 911.

Our cars were not designed with ethanol in mind. It is a very dry non-lubricating fluid. It is also corrosive and attacks aluminum and some plastics/rubber.

The MMO seems to provide some lubrication to the fuel pump and pressure/damper regulators. I don't have fuel line problems too.

The other problem with ethanol is it evaporates quickly and is hygroscopic with H2O. Any water in your fuel tank will be dissolved into the fuel and when the engine is shut down...the trace amount of fuel in the fuel injector tip, due to the very warm environment, will evaporate the ethanol and leave the H2O behind..and rust the injector tip.

I think MMO helps protect against that problem too. It leaves a little lube behind in the injector tip.

Sorry, I don't have any data points. I do have a 1974 Laverda, 1986 911 and 1991 Vanagon that are very reliable using the MMO. It seems to work

[spuggy]

Originally Posted by ivangene

he forgot to mention ---- plus the way he utilizes his gas pedal

Some years of the owner's manual advised you must run a turbo, once it's hot, full boost to red-line at least once EVERY time you drive it to ensure the continued correct operation of the wastegate.

Just a conscientious owner over here...

[tmsautoart]

The good stuff....if you need it:

[kidrock]

my car tends to like ethanol-free brands. Somebody posted this link here before. Drink up!!!

Ethanol-free gas stations in the U.S. and Canada

[Rod Schneider]

Well, my 66 911 just loves the occasional tank of 100LL avgas--it keeps the fuel system clean and doesn't mind long periods of inactivity.

[A horse with no name]

Hi Rod... Be careful with it as it is a dry fuel. I am an aviator and with the piston motors we have to manually run richer settings. I also have a
pro Street machine - And yes it is good for a couple blasts down the strip but only for very high compression motors. An octane booster from Chevron is an easier way to go about it if you need higher octane. The best for drag racing is true 'racing' fuel- pricey.
if you want to use it I would suggest that you put a 1/2 quart of transmission oil into a full tank so as to put some oil into the system.

Like an earlier post stated...If it the engine is not a very high compression motor you will get no real benefits. It i though good for a storage fuel as it has shelve life of a

good three years.

cheers

[Rod Schneider]

No worries on the avgas--it usually ends up being about a 50/50 mix with premium unleaded. The first time I tried some, about 3/4 of a tank, I noticed an improvement in the way the car ran and the inside of the carbs are noticeably cleaner. I don't think I've ever had 100% avgas in the tank.

[Busta Rib]

Originally Posted by spuggy

Waste of time using higher octane than specified; more expensive, actually burns slower than motor designed for, no extra power.

Just use what the motor is set up for, IMHO.

What Spuggy said. A lot of people don't know the difference between RON (octane standard the rest of the world uses) and AKI, what we use in the US. According to Wikipedia: "Because of the 8 to 10 point difference noted above, the octane rating shown in Canada and 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."

A 91-92 RON equals 87 AKI. Read more about it here: Octane rating - Wikipedia, the free encyclopedia

I always run 87 (Regular) and have had zero issues. And I save a lot more money over 91 (Super).

[winders]

I have been told by multiple fuel engineers that octane and burn speed are not directly related. Look here:

https://docs.google.com/viewer?a=v&q=cache:Ww4_hRh83_kJ:www.rockettbrand.com/techsupport/documents/TechBulletins/FlameSpeedOctaneAndHpRelationships.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESjnaOjr-pjMULX0MuACmOgw5QqnlXv12PjT5dmGqVn6586O7q1AgnNs3z3 olDg3bKr5IvnzRywwDWQxybf30UCV1_ey1RONDZaw_ifc5YIpJ NC84GugBD72SpWB5WlwvxXIKhpZ&sig=AHIEtbQBPy_kD8ViFLta2LFiW2a2F7Szxw

Scott

[McLaren-TAG]

Given the discussion, what's the purpose then for Steve Wong selling his chips in a 91 or 93 octane configuration?

[Craig T]

Originally Posted by McLaren-TAG

Given the discussion, what's the purpose then for Steve Wong selling his chips in a 91 or 93 octane configuration?

SW, please correct me if I'm wrong, but I believe Steve Wong can safely advance the timing a small amount with 93 octane. I'm sure there is a fuel mixture component as well.

91/93 vs. 100 is a big difference. You can not effectively take advantage of the 100 unless you're getting above the 9:8.1 compression range.

I have a 3.4L, 10:5.1, with GE-60 cams and 46mm PMO's. When I run 100 octane gas, it REALLY wakes her up! However, in my V3 race car with a stock 3.2, I couldn't tell the difference, and it didn't affect my lap times at all. I did run a mix of 91 and 100 most of the time, but only because I was told it helps the motor run a little cooler, and cleaner???

[Bob Kontak]

Originally Posted by winders

I have been told by multiple fuel engineers that octane and burn speed are not directly related. Look here:

https://docs.google.com/viewer?a=v&q=cache:Ww4_hRh83_kJ:www.rockettbrand.com/techsupport/documents/TechBulletins/FlameSpeedOctaneAndHpRelationships.pdf+&hl=en&gl=us&pid=bl&srcid=ADGEESjnaOjr-pjMULX0MuACmOgw5QqnlXv12PjT5dmGqVn6586O7q1AgnNs3z3 olDg3bKr5IvnzRywwDWQxybf30UCV1_ey1RONDZaw_ifc5YIpJ NC84GugBD72SpWB5WlwvxXIKhpZ&sig=AHIEtbQBPy_kD8ViFLta2LFiW2a2F7Szxw

Scott

+1. Resistance to detonation - not burn speed.

Octane is not how fast a fuel burns