What grade of gas do you use.

[Brent Lineker]

I have a 75 model with the webers and SSI's and 73 RS exhaust but pretty well everthing else stock,8.5 compression.Is premium fuel really necessary or would 89 or 90 octane be high enough.Premium up here in the Pacific North west is 92 and super is 94.Thanks....

[azasadny]

Premium (93 octane) in my '74 with Webers. my mechanic recommended it after we switched the CIS over to carbs.

[gassy]

93 in my '70

[Danimal16]

93 in my 71 with Zeniths.

Not to highjack the thread but what is the compatability of the 76 union 100 octane racing fuel with Porsche engines?

[Superman]

Higher octane simply protects against detonation. So.....I use it in all the engines I care about.

[porschefool]

Super. It's all I've ever used in any of my Porsches...928,914, and the lowly 924. It would make me feel like a bad father to put anything less in my SC!

[cgarr]

You should use the lowest octane you can, only high enough to protect against detonation.

[75blkcarrera]

93 Why take a chance!!! Use the cheep stuff in everything else. If you are pinching$$$ have an extra salad for lunch and put the $$ in the tank.

[Amail]

The way I've answered this question in the past is use the lowest octane you can that doesn't cause your car to ping. Higher octane means a slower burn rate. If your engine is designed to run on 87 octane, use 87. The only thing you do by using a higher grade is cause it to burn fuel less efficiently, perhaps to the detriment of your mileage.

It doesn't hurt to use the highest octane, but if your engine doesn't need it, it certainly doesn't help.

Smart people, please chime in and tell me if I've got this right.

[Dan in Pasadena]

Premium - which in California is only 91 octane - in my stock 127,000 mile, unrebuilt '76 2.7 which leaks oil but runs like a scalded dog.

[TroyGT]

I used 89 prior to my Steve Wong chip... no probs, great mileage. Steve recommends 91 while on the performance chip... so that's what I run now.

-Troy

[81 911 SC]

87 in my 911 with PMO. 87 was all that was needed when the car had CIS as well. Running super is a waste of money IMO.

[Jadams1]

87 octane, 1980 ROW 911SC's have low compression is 8.6:1.

[Rot 911]

I am waiting for someone to give a reason why you couldn't use 87 octane in an engine with a 8.5:1 compression ration. Should run just fine.

[tangerine911S]

I use 87. With a CR of 8.5, i dont think anything higher is neccessary.

[Phantom911]

I use 93 on my 82. I have a 9.8 CR.

[Thrasher]

Originally posted by Kurt V
I am waiting for someone to give a reason why you couldn't use 87 octane in an engine with a 8.5:1 compression ration. Should run just fine.

Kurt, are you implying that irrespective of Steve Wong's requirement to run 93 if my chip is mapped for it, that the CR limits the need in any case to the factory-recommended 87?

I thought you got "Wonged" recently and would've switched to 93 at that time, too?

[Brent Lineker]

I don't have the owners manual in front of me,IIRC it states using fuel with a rating of 92 RON which is typically translates to our octane rating of 89.I will try on my next fill up using the mid grade fuel (89).and see how it runs.I have been keeping a log of fuel mileage since I got the car a couple of months ago and will continue with the different grade of fuel.This is not about penny pinching,this is about using the fuel it was designed to use.Thanks for all of the replys.....

[FenderGuy]

I use 91 here in Az and I get crappy mileage seems every 4 days $15 goes into the tank...Fuel lines, fuel filter, accum and mixture have all been changed and still the gas mileage is down

[RoninLB]

i use 87 w/8.5:1 & 2.7RS dizzy. Initial is 10deg, total is 35deg.


gas is crappy enough without adding more additives than needed.

i also get slightly better mileage.

I've also run 100+F deserts with no problem.


i think if the issue makes you nervious use high test.