Gas Shortage in ATL - Can I run Reg vs Premium

[mthomas58]

There has been no Premium available in Atlanta this week. Stations are only getting Regular, not even mid grade.

Any problem running a tank or two of regular if I have to until supply is available?

[rammstein]

I dunno for sure, but you can go to an autoparts store like a pepboys and buy some octane booster. Assuming its not a scam.

[dd74]

Originally Posted by mthomas58

There has been no Premium available in Atlanta this week. Stations are only getting Regular, not even mid grade.

Any problem running a tank or two of regular if I have to until supply is available?

In what? Your Porsche? If you do, you should probably not drive it too hard.

What's with this gas shortage anyway down there? Are other cities short on fuel, or is it just Atlanta?

[Shadetree930]

Atlanta has 'special blend' mandated for enviro reasons. Guess what? Because of that they have no gas. Mandate has been waived for interim until the Colonial pipeline and associated refineries are back to full capacity. Should be sorted out by end of next week.

[nostatic]

Depends on the car. Most modern vehicles have knock sensors that will compensate for lower octane fuel.

[pookie]

Nashville has been having the same issue. I only put in a couple gallons to get me through and then added an octance booster. I haven't been driving the car as hard either.

There wasn't a gas shortage until the media made one. Started talking about it on the radio and tv and gas lines were blocks long and it took hours to get gas.

[masraum]

Originally Posted by mthomas58

There has been no Premium available in Atlanta this week. Stations are only getting Regular, not even mid grade.

Any problem running a tank or two of regular if I have to until supply is available?

If you're talking about your '87. Well, some folks claim that they run regular all of the time in their late 3.2L cars. I never did and still wouldn't unless I really had to. If you have to then run a good quality, like Chevron, and as stated don't drive too hard (don't redline or full throttle accelerate, especially in higher gears)

Heat plays an issue too, so if it's cool, then it's probably much less of an issue. Your '87 doesn't have a knock sensor, so don't rely on that to save you.

[nostatic]

fwiw I ran 87 in my '79 without issue. On track days I made sure that I had 91 in the tank, but for regular driving I never noticed pinging, etc.

[Henry Schmidt]

If the car you are inquiring about is an 84-89 Carrera, you can adjust the ECU for lower fuel quality. There is a rheostat on the side of the ECU (a yellow knob with a triangle slot ? memory is fading) that will retard the timing about 4 degrees. It's easy to change and can be reset to normal when the fuel quality is restored.
Cheers

[mthomas58]

Yes I am talking about running regular in my 87 - Its my daily driver and is SW chipped for 93 octane fuel.

Fortunately I was able to top off at a Quick Trip on the way home from the office. Most stations are still dark (no gas). Those that have gas are posting prices for Reg and Diesel only. Lines are long at those stations reminiscent of the mid 70's.

Highly populated cities with poor air quality like Atlanta are required to use cleaner burning oxygenated fuels which is in short supply following the recent hurricanes in the gulf.

Virtually all stations were out of gas on Sunday. News was that fuel supplies should correct later in the week. Seems to be taking longer. I'll keep topping of whenever I can until the situation stabilizes.

[red-beard]

Do you have an owner's manual? What does it say?

Put in the regular and try it. Try the octane booster and see if it helps, if needed.

[DARISC]

Originally Posted by nostatic

.....I never noticed pinging, etc.

You can't always hear detonation/predetonation/pinging/knocking - that can destroy your engine - in very short order - as I found out . It wasn't a Porsche.

[Rot 911]

If it is a SW chip don't run anything less than 91 octane. Steve advances the timing on his chip and you need the higher octane. A stock U.S. 3.2 engine was designed to run on 87 octane. Says so right in your owners manual.

[speeder]

Originally Posted by nostatic

fwiw I ran 87 in my '79 without issue. On track days I made sure that I had 91 in the tank, but for regular driving I never noticed pinging, etc.

A '79 SC, which is a fantastic car, only had 8.5:1 CR IIRC. It's an 87 octane car all day long, even at the track it would not make a difference. Later ROW 911SCs and all 3.2 Carreras were premium cars, it's all about CR, nothing else.

Actually, on modern cars w/ more sophisticated ECUs it can be about something else. My dad's Lexus RX 330 states in the owners manual that it can run on 87, but for maximum performance use 93. IOW, it will adjust timing for the octane.

[GothingNC]

I think you'll be fine as long as you don't drive too hard when the temps get up.

We have a shortage of regular/mid-grade here, doesn't phase me since I've always been using 93 octane.

I have the compression bumped up to 9.8 and my VW Turbo requires premium.

[masraum]

Originally Posted by Henry Schmidt

If the car you are inquiring about is an 84-89 Carrera, you can adjust the ECU for lower fuel quality. There is a rheostat on the side of the ECU (a yellow knob with a triangle slot ? memory is fading) that will retard the timing about 4 degrees. It's easy to change and can be reset to normal when the fuel quality is restored.
Cheers

But if you want to try this, make sure you know what each setting is. IIRC, there are 6 settings of various timing and fuel richnesses. It's not necessarily as straight forward as just turning the knob one click in a specific direction.

Originally Posted by Kurt V

A stock U.S. 3.2 engine was designed to run on 87 octane. Says so right in your owners manual.

Not all of them. My old '88 said 91 was the minimum, IIRC. 3.2L cars had higher compression ratios than the 3.0L SC. The ROW 3.2L cars were 10.3:1, I can't remember if the US models were 9.3:1 or 9._:1, but it was more than the SC which is why the 3.2L cars used higher octane fuel. (I think my manual or gas door sticker said 95RON(Europe) / 91 (R+M)/2 (US Spec))

Also, in '87 I believe the cam timing and also the ECU mappings were changed from the early 3.2L cars.

"Changes in the fuel map & chip programming from October 1986, further improved the power to 217 bhp (160 kW @ 5900 rpm) for North American delivered cars..."

[Porsche-O-Phile]

Don't bother with octane booster in a bottle - that stuff is garbage and will do nothing. The best ones only raise you by about one tenth of an octane point.

You can mix fuel with either xylene or toluene to raise the octane. Do a Google search for toluene octane booster and read up about it (and yes, I've done this with excellent results in the past). There's a wealth of information out there. It allowed me to run very high boost levels on my old 951 without any pinging or other issues.

[rammstein]

Oh yeah.... I remember there was a guy who had a whole page somewhere about using toluene... you can buy it by the gallon at hardware stores. Wish I could remember the site...

[Porsche-O-Phile]

If you Google it, you'll get about 100 explanations of it. Here's a very useful one for reference:

http://www.faqs.org/faqs/autos/gasoline-faq/part1/

[MotoSook]

IIRC, my '89 Carrera manual says use 91 Pump Octane.



The FQS -Fuel Quality Switch is a small rotary switch inside the DME box, accessible via a hole in the metal DME box (about 1/2 inch diameter). If one hasn't open the box up to see it, be careful. Don't go sticking stuff into the hole or you'll be just like the kid who let his buddy drill into his ZX6 ECU.

A small tool (triangular tip) can be made from a long golf tee to insert and make adjustments.

Here are the settings:

SwitchPosition/Fuel Correction/Ignition Correction
0/0/0
1/+3.1%/0
2/+6.3%/0
3/-3.9%/0
4/0/-2.79°
5/+3.1%/-2.79°
6/+6.3%/-2.79°
7/-3.9%/-2.79°