best fuel & octane to use for CIS??
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Hi all,
Am wondering if any of you know which common fuel retailer (Mobil, Exxon, Texaco, etc..) tends to have the least amount of alcohol??
I know that these CIS engines need execellent fuel pressure and tend to resist pockets of moisture and alcohol inside the lines..
With today's ethanol ingredients and higher octane fuels..am curious if any of you have found one manufacturer's fuel to suit your engines - better than other's???
As Bill Gregory has pointed out before that Porsche has recommended certain oil brands and grades -- have they ever done so for fuel companies and octanes??
Thanks for any thoughts..
Maurice
'80 SC Coupe
Am wondering if any of you know which common fuel retailer (Mobil, Exxon, Texaco, etc..) tends to have the least amount of alcohol??
I know that these CIS engines need execellent fuel pressure and tend to resist pockets of moisture and alcohol inside the lines..
With today's ethanol ingredients and higher octane fuels..am curious if any of you have found one manufacturer's fuel to suit your engines - better than other's???
As Bill Gregory has pointed out before that Porsche has recommended certain oil brands and grades -- have they ever done so for fuel companies and octanes??
Thanks for any thoughts..
Maurice
'80 SC Coupe
#2
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Checking the 82SC book I have here, it says to use 87 octane (R+M/2) or 91 RON in Europe. As an aside, I do use premium when I go to the track, to minimize detonation at higher engine temperatures and conditions driving on the track.
You need to check regionally what blend your local gases are, and may need to query each gas manufacturer to understand what, if any, is the % of alchohol. For example, here in Connecticut MBTE is the primary oxygenate added to the gasoline, so alchohol % isn't as relevant as a 10% ethanol blend elsewhere.
I don't recall seeing a Porsche list of preferred gasoline, although BMW has been at the forefront for many years with gas testing.
You need to check regionally what blend your local gases are, and may need to query each gas manufacturer to understand what, if any, is the % of alchohol. For example, here in Connecticut MBTE is the primary oxygenate added to the gasoline, so alchohol % isn't as relevant as a 10% ethanol blend elsewhere.
I don't recall seeing a Porsche list of preferred gasoline, although BMW has been at the forefront for many years with gas testing.
#3
RL Technical Advisor
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[quote]Originally posted by Perkins:
<strong>Hi all,
Am wondering if any of you know which common fuel retailer (Mobil, Exxon, Texaco, etc..) tends to have the least amount of alcohol??
I know that these CIS engines need execellent fuel pressure and tend to resist pockets of moisture and alcohol inside the lines..
With today's ethanol ingredients and higher octane fuels..am curious if any of you have found one manufacturer's fuel to suit your engines - better than other's???
As Bill Gregory has pointed out before that Porsche has recommended certain oil brands and grades -- have they ever done so for fuel companies and octanes??
Thanks for any thoughts..
Maurice
'80 SC Coupe</strong><hr></blockquote>
Hi Maurice:
I hope you'll allow me to offer my opinion on this, as well.
Porsche's fuel recommendations were written several years ago and even with the low compression ratio your cars has, CIS Porsches run VERY lean and as a result, run rather high cylinder head temperatures. USA fuels are rather marginal and inconsistent, compared to Europe which has far more stringent octane testing and compliance.
For this and other reasons, I've recommended using premium fuels in all air-cooled Porsches which do experience wider ranges of operating temperatures than other cars. Its good insurance against detonation that you will never hear over that noisy engine,...
Each and every fuel manufacturer has different blends of oxygenates by season and when the EPA mandates a cleaner fuel during Winter months. Many cities use Ethanol instead of MTBE from Oct 1 until March 1 when the potential for smog is at its peak. According to Federal law, one cannot label a fuel as gasoline if it contains more than 10% alchohol, so expect that blend as normal except in areas of the Midwest which offer a 15% Ethanol blend called "Gasohol".
CIS cars & Ethanol do not do well together and one must be very diligent about preventing the accumulation of moisture in the tank, fuel distributor and other components. Keep the tank very full, change that fuel filter often (twice yearly), and use Techron religiously; the Bosch Fuel distributor is very expensive to replace.
If your cars sits much during the Winter, then put some fuel stabilizer like "Stabil" in the gas and start & run it every few weeks to get it warm.
Hope this helps,
<strong>Hi all,
Am wondering if any of you know which common fuel retailer (Mobil, Exxon, Texaco, etc..) tends to have the least amount of alcohol??
I know that these CIS engines need execellent fuel pressure and tend to resist pockets of moisture and alcohol inside the lines..
With today's ethanol ingredients and higher octane fuels..am curious if any of you have found one manufacturer's fuel to suit your engines - better than other's???
As Bill Gregory has pointed out before that Porsche has recommended certain oil brands and grades -- have they ever done so for fuel companies and octanes??
Thanks for any thoughts..
Maurice
'80 SC Coupe</strong><hr></blockquote>
Hi Maurice:
I hope you'll allow me to offer my opinion on this, as well.
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Porsche's fuel recommendations were written several years ago and even with the low compression ratio your cars has, CIS Porsches run VERY lean and as a result, run rather high cylinder head temperatures. USA fuels are rather marginal and inconsistent, compared to Europe which has far more stringent octane testing and compliance.
For this and other reasons, I've recommended using premium fuels in all air-cooled Porsches which do experience wider ranges of operating temperatures than other cars. Its good insurance against detonation that you will never hear over that noisy engine,...
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Each and every fuel manufacturer has different blends of oxygenates by season and when the EPA mandates a cleaner fuel during Winter months. Many cities use Ethanol instead of MTBE from Oct 1 until March 1 when the potential for smog is at its peak. According to Federal law, one cannot label a fuel as gasoline if it contains more than 10% alchohol, so expect that blend as normal except in areas of the Midwest which offer a 15% Ethanol blend called "Gasohol".
CIS cars & Ethanol do not do well together and one must be very diligent about preventing the accumulation of moisture in the tank, fuel distributor and other components. Keep the tank very full, change that fuel filter often (twice yearly), and use Techron religiously; the Bosch Fuel distributor is very expensive to replace.
If your cars sits much during the Winter, then put some fuel stabilizer like "Stabil" in the gas and start & run it every few weeks to get it warm.
Hope this helps,
#5
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The reason I try to run Chevron gasoline is because it has Techron in it and I know Porsche recommends it,can't hurt and I all ways run premium.Good luck....... <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />