Can we use 89 octane with NO problems

The company I work for will only reimburse as of today for 89 octane. So either I pay for my own fuel, or look for a new job, or use 89 and hope for no issues whatsoever

I saw an article a few months ago - I don't remember where - that discussed this with a Porsche engineer. Basically, he said that they have to make their cars to run on available fuel all over the world. And that there is no problem running on a lower octane. It just won't be as peppy. Maybe someone can find the article and repost is. It started because of a discussion on different retailers, and whether there was really a difference in fuel by manufacturer.

the ECU in a 996 will automatically retard ignition to prevent premature detonation, so i think you don't have anything to worry about except a loss of power.

How quickly are the adjustments made? Is the octane read more or less instantaneously, or does it average it over some period of time? If you go from a tank of 89 octane to 95 octane, is there a period where the ignition is not timed optimally?

The car's computer will retard the spark advance whenever detonation is indicated. So it is instantaneous whenever premature detonation occurs. Much unlike viagra which requires advance planning, so I've been told.

I think there is a range wherein it can compensate. If I remember correctly, it is ideal at 93, but wiil retard to accomodate down to 91 octane. 89 is beyond it's range. Why not just use the premium gas but charge your company the regular gas price per gallon?

I can't find any higher than 91 in San Diego county. If any of you know of a station with 91+ let me know. I am not interested for daily use but it would nice to give her a treat every now and then.

Not sure if this is updated. I used the place in Huntington Beach. http://www.osbornauto.com/racing/100locations.htm SYMA, they won't just pay the normal price for 89 and let you pay the difference?

We use this Wright Fuel Express Fleet card. I never see the bill. So if I put Premium in at say $2.00 a gal. when the 89 or mid is say $1.90 and I put 15 gallons in, how would I reimburse them the $1.50 ?? My company probably won't do it just due to the paperwork.

Island Boy: Cosby Oil at 6225 Fairmont has Sunoco 100 unleaded at a pump. You can also get it from them in 5 gallon cans. You can get a fleet card from Cosby Oil at cosbyoil.com and access the pump 7/24. If you get there during business hours M-F they'll gas you with a VISA/MC/AMEX card, but it's more expensive than using the fleet card. 5 gallons of 100 and 10 of 91 puts the tank octane at about 94. With the fleet card 100 is about $4.50/gal. My impression is the car runs a llittle stronger with the octane at 93-94 vs. 91, but I don't have any objective data.

SYMA --- Find a friendly station and see if they won't ring you up inside at the counter at the lower rate and just pay them the difference in cash. This might be difficult in these days of integrated point of sale and inventory, but every once in awhile I still run into a station that doesn't have all of the new-fangled electronics. As a reference, I run nothing but premium. The PAG delivery guy was extremely adamant about not using less than (our equivalent) premium. But just as has been previously stated, the ecu will compensate to some degree. fwiw..... Jeff

You don't need another dummy receipt - just use the one you get for premium gas but simply add and circle another lower amount reflecting the octane 89 price. Granted that companies can try to do whatever they want until corrected by the law, reimbursements for travel expenses fall under the federal IRS codes. So unless your company is allowing you to expense gas out of the goodness of their hearts, coming out of profits and not going into their pool of legal business expeditures because your job category ordinarily qualfies for no travel per diem reimbursements, they can't dictate reimbursement by what grade gas you use. The IRS currently sets personal vehicle use reimbursement as 37.5 cents per travelled mile in excess of your normal daily commute. If your car is company leased, then reimbursement is based on gasoline used. I'm assuming your p-car isn't company leased. Now that would be a great company Assuming it's just too much bureaucracy to question why the 37.5 cent rate per mile isn't being used, why not ask your company to simply reimburse you for the portion of gas up to the number of gallons you buy based on octane 89 and you'll eat the cost of the difference to premium? You don't even need to dummy up another receipt - just buy premium gas, turn in that receipt, but write and circle another lower cost basis which is what you calculate the same gallons based on octane 89 would be. Point out to your company that when receipts are provided to the IRS to prove businness expenses or to auditors doing a review, no IRS code says you can't claim a lower expense than what is on the receipt. You just can't claim higher.

Thanks Lomcevak, At $4.50/gal. I'm not too eager to run over there but I'm sure I'll go try it out at some point.