troos

What would be the long and short term consequences of running regular gasoline in my 996? I am having serious trouble finding premium around here right now. Is there an additive I can add to regular to make it work?
Thank you.

No HTwo O

Detination is a possibility.

1999Porsche911

No long term consequences. The computer will simply pull timing and add fuel to compensate. Performance of the car will be less than it is now.

iii911ooo

Tom,

You must be in the western part of the state. Here in the Raleigh area, we don't have any problem getting premium (except for the price). Using lower octane will only reduce performance as the knock sensors will retard the timing to protect the engine. Alternatively, you could fill up with regular and add an octane booster to raise the octane level of the regular.

Randy

troos

Thanks for the replies, guys.
Bad news Randy. I'm in Durham.
(15-20 miles away to the rest of you)

Macster

consequences would be a decrease in gas mileage thus higher fuel costs, lower engine output with possible degradation of drivability, increased exhaust gas temperatures with increased wear/tear on anything in contact with exhausts gases, increase in fuel system and combustion chamber deposits.

These engines have a pretty high compression ratio partially to boost their output (and provide good throttle responses). Burning a lower octane gas on a regular basis takes away from the engine and its performance.

In a pinch, if premium in short supply, or even no supply, 87 octane better than nothing but feeding these engines a regular diet of regular is just silly.

Sincerely,

Macster.

insite

don't bother w/ octane boost; in order for it to actually make a difference, you need literally gallons of it. the 996 has knock sensor ignition and will dial back the ignition timing to preclude detonation. the car will be a bit down on power and gas consumption will go up a bit, but the engine will suffer no damage.

Palting

AFAIK, the engine management system can only compensate down to 90 octane. Below that, as in regular at 89-87, the electronics can no longer compensate and pre-detonation and consequent problems can arise.

Quote from tje manual:
"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 (90CLC or AKI) since the engine's Electronic Oktane knock control will adapt the ignition timing, if necessary."

Boosters are useless.

Best bet is to mix with 100 octane unleaded race gas. Someone here has posted the appropriate ratios to get the right octane. Not cheap, but cheaper than a new engine.

Nicolaasdb

I am filling my escalade with 87 (screw it it is a lease and the recommend premium, not demanding itlike BMW and Porsche) and never had a problem...I would put it in a delicate machine like a P engine....

htny

honestly I'd drive the 15 miles for premium once a week or every couple, I think your fuel economy will scrub and it will probably save you some cat work down the line.

Yoops Racing

geez I cant get any gas here in my area - Atlanta.....no one has any

htny

one of my employees is down in ATL (a California transplant). He recently said he had to drive for an hour in every direction looking for one with supply, and when he finally found one, he was on fumes and the line was 100+ cars long

Macster

in a way that lets the dealer know the car was not filled with proper grade of gasoline and this was a regular (no pun intended) action on your part.

This could be construed as damage just like body damage with the end result is the vehicle's residual value being lowered and you having to come up with the difference.

Also, that you posted this info here and if the dealer/lease company decided to google for any posts by you and sift through looking for indications of vehicle odometer tampering (which is quite common with leased vehicles (though I'm sure you'd never consider tampering) but instead came up this post by you admiting you fed the vehicle the wrong grade of gas, your actions if you didn't admit to them when you turn the vehicle back in could be construed as an attempt to defraud.

I am not a lawyer but you should be aware of the possible risk to you arising from your action regarding fueling your lease vehicle wtih the wrong grade of gasoline.

As lease companies deal with falling residual values they are looking to defray these or receive compensation from lease vehicle leasees.

Sincerely,

Macster.

Yoops Racing

so I got up at 6:00am this morning and found only regular - which I promptly filled up from 1/4 tank of prem (no telling when the gas supply will increase here) There is simply no Prem available here at all.

So more importantly give me a real reason not to go buy a few bottles of Octane booster. I see no one giving any reason why it will not help in these dire circumstances. What can it harm vs running w/o it?

Anyone have any real facts on this?

salayc

Doubt it. A bunch of manufacturers (including Porsche) just recently had to admit that using regular gas will not harm their cars and will not void the warranty. It was in response to a class action as I recall.