regular or premium?

[tjbick]

I have a 84 944. I was filling up the other day and my gas filler flap has a sticker saying 91 RON. I have always filled up with regular which is 87 RON. I want opinions from all of you experts if the extra money from premium is worth it on a non-turbo 944?

[krystar]

91 RON is regular 87 octane in the US

[962porsche]

by all rights you should use what octane rating they tell you to use .
how ever fuel has changed so much from 1984 that you can run a lower grade octane rating than what is stated as long as you are not getting any detonation / pre ignition .
the higher the octane rating the slower and cooler the burn of the fuel giving more or a complete burn in the combustion chamber .
i run reguler in the two 944 loaner track cars i have and have been doing so for years now with no problems .
octane does not give a motor any more power ! or i should say is if you only need say 87 octane then running a higher rating will not give you more power . to much octane is just as bad as not having enough . you need to match the burn of the fuel to what the motor is called for .
i could get into the hold thing of forced induction and why you would want a higher octane for that but it still comes down to the same thing .
i see people at the track filling there cars with high octane leaded fuel when there is just no need . little do they know they are waisting there money and doing damage to there cars .
if your running a cat on your car it clogs them up because lead does not burn . also any sencer will also get coated with lead over time .
i should make this more clear ! i'm not talking about pump fuels what i'm talking about is using very high octane race fuel in a street motor .

in the usa we use AKI and not RON . so if it states 85 AKI then it's 90 RON . 91 AKI = 95 RON .

[9FF]

87 is fine for our cars. It's not so much the octane of the gas or the viscosity of the oil but the fuel & oil quality that is more important. I like to use gas with Tecron additives and oil with high zddp content.

[John_AZ]

OR..If you prefer to understand gasoline by reading a Pelican Technical Article:

Pelican Technical Bulletin: All About Gasoline

I use "regular" in both cars and the '88 has a more HP.

John

[JAXTURBO]

Originally Posted by 9FF

87 is fine for our cars. It's not so much the octane of the gas or the viscosity of the oil but the fuel & oil quality that is more important. I like to use gas with Tecron additives and oil with high zddp content.

I agree. Even though Chevron fuels are becoming harder to find, I use it when ever I find it. However, I do supplement other brands with the Techron additive. As for oil... Mobil 1

[Gawernator]

87 US octane is what you need. Unless you have a Wilks chip etc enabled then you should be using premium or you'll get pinging.

[Chunkerz]

I use premium because my chip calls for it. I've read if you race the car or drive like a lunitick (not sure if I spelled that right) and keep your foot in it 90% of the time, then a higher octane rating is recommended. I read that on Rennlist, so I'm not sure if that's 100% true

Sent from my Galaxy Nexus using Tapatalk 2

[Gawernator]

Lunatic and 87 octane is what the owner's manual recommends.

[cauzomb]

I'm in US/Cali with an 83...

Been using regular 87 from random stations with a dose of techron and on occassion, a couple or three gallons of chevron 89 with techron inbetween.

[black_falcon]

I've tried 87 a few times in my stock n/a and felt my car didn't idle or run as nice. Premium is such a small premium that for how little I drive the car, I'm willing to pay it.

[MDH]

I run premium because it is the only fuel I can find in N.E. Wisconsin that does not have ethanol.........
I will not run ethanol in my older vehicles.

[mueller944s2]

I run 93 in my S2, its got a chip. And I only run non-ethanol when I can. I rarely use ethanol garbage

[VirginiaF1]

Originally Posted by black_falcon

I've tried 87 a few times in my stock n/a and felt my car didn't idle or run as nice. Premium is such a small premium that for how little I drive the car, I'm willing to pay it.

Same here in the '88...
Compared several half tanks of Shell 87 with half-tanks of Shell 93.
With 240,000+ miles, there is no doubt that MY (YMMV) Porsche handles better with Premium fuel.

At Idle, Low RPM Pulls, High RPM runs, AirCon on, AirCon off, Summer, Winter, Spring and Fall... 93 indeed makes a diff in my old girl.

Good thread..

[Guest765]

Originally Posted by VirginiaF1

Same here in the '88...
Compared several half tanks of Shell 87 with half-tanks of Shell 93.
With 240,000+ miles, there is no doubt that MY (YMMV) Porsche handles better with Premium fuel.

At Idle, Low RPM Pulls, High RPM runs, AirCon on, AirCon off, Summer, Winter, Spring and Fall... 93 indeed makes a diff in my old girl.

Good thread..

If the car does not have a knock sensor and can't adjust timing to take advantage of the higher octane then this is a waste of money, and won't make a bit of difference unless your engine is in such poor shape that it is detonating all over. Fact.

This refers to cars without a chip of course.

[VirginiaF1]

Originally Posted by fwayfarer

If the car does not have a knock sensor and can't adjust timing to take advantage of the higher octane then this is a waste of money, and won't make a bit of difference unless your engine is in such poor shape that it is detonating all over. Fact.

IIRC, 8-valve n/a's lacked knock sensors, I'll take solace in the 93 octane making my engine much more responsive/smoother. Engine is all original at 240k+...
Peace

[Chunkerz]

Originally Posted by MDH

I will not run ethanol in my older vehicles.

Why not?

[Gawernator]

Seems like most of this Cali gas is at least 10% ethanol.

[Guest765]

Originally Posted by VirginiaF1

IIRC, 8-valve n/a's lacked knock sensors, I'll take solace in the 93 octane making my engine much more responsive/smoother. Engine is all original at 240k+...
Peace

On the off chance this isn't a great example of confirmation bias ;if this is really making a noticable difference your engine is basically shot.

[Guest765]

Originally Posted by Chunkerz

Why not?

"Some people" think alcohol somehow rots old gas lines. I don't get it either. Just like the octane issue - some people just don't know what they're talking about and that's how you get rumors like the one old guy told me , "never fill gas in a Cadillac at Sunoco they have mercury in their gasssssss it will destroy your car!

I guess he meant methanol, which is still wrong as its ethanol not methanol in the gas...