Pinging/Chevron Premium
12-12-2002, 08:19 PM
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Pinging/Chevron Premium
A warning: My 97 993 started pinging recently. Searched the archives and discovered an interesting thread from somebody using Chevron Premium who was having the same problem. Made me think, since I also use Chevron Premium (exclusively, since it has the Techron in it). After continued pinging under acceleration with a second tank of Chevron, I decided to try Shell's premium. Seems to have eliminated the pinging. I also noticed that Shell now advertises their gas as having an additive to clean the valves (like Techron). Anyone know if it is any good?
12-12-2002, 08:37 PM
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Griffin:
I too am here in the Bay Area and have issues with Chevron "91", However, I notice it seasonally during their "oxygenation" timing, that is goin on now.
The problems with the oxynegnated gas was more noticable with my Turbo than my 993. Also, since I "chipped" my 993 with a Rennsport (Steve W.) chip it only pings briefly on extreme throttle changes, i.e. "punching" it.
Wish I could comment on Shell, but I believe that most all gasoline marketted in the SF Bay Area are currently subject to oxygenation. Long ago, I had problems with plug contamination with Shell and have shy'd away since !
If anyone has more info, please chime in !
I too am here in the Bay Area and have issues with Chevron "91", However, I notice it seasonally during their "oxygenation" timing, that is goin on now.
The problems with the oxynegnated gas was more noticable with my Turbo than my 993. Also, since I "chipped" my 993 with a Rennsport (Steve W.) chip it only pings briefly on extreme throttle changes, i.e. "punching" it.
Wish I could comment on Shell, but I believe that most all gasoline marketted in the SF Bay Area are currently subject to oxygenation. Long ago, I had problems with plug contamination with Shell and have shy'd away since !
If anyone has more info, please chime in !
12-12-2002, 08:51 PM
#3
I believe pretty much all gas has cleaning additives these days. This became necessary as the old carbureted cars died off and got replaced by fuel injected cars. The additives are necessary for the injectors, but they also clean valves. Remember when fuel injection was such a pain? This was before these additives were commonplace.
The thing is, not all additives are created equal…
Another thing that can happen is that each brand of fuel leaves its own deposits. Switching brands can help clean up the deposits left from the last brand.
Griffin, have you tried Lubro Moly Jectron and Ventil Sauber? Give them a shot, I’ll bet they’ll help.
Tom
’95 993
The thing is, not all additives are created equal…
Another thing that can happen is that each brand of fuel leaves its own deposits. Switching brands can help clean up the deposits left from the last brand.
Griffin, have you tried Lubro Moly Jectron and Ventil Sauber? Give them a shot, I’ll bet they’ll help.
Tom
’95 993
12-12-2002, 09:26 PM
#4
RL Technical Advisor
[quote]Originally posted by Griffin Brown:
<strong>A warning: My 97 993 started pinging recently. Searched the archives and discovered an interesting thread from somebody using Chevron Premium who was having the same problem. Made me think, since I also use Chevron Premium (exclusively, since it has the Techron in it). After continued pinging under acceleration with a second tank of Chevron, I decided to try Shell's premium. Seems to have eliminated the pinging. I also noticed that Shell now advertises their gas as having an additive to clean the valves (like Techron). Anyone know if it is any good?</strong><hr></blockquote>
Hi Griffin:
I cannot offer anything solid on the current chemistry of California fuels but I can tell you this.
Each and every fuel manufacturer uses different blends of oxygenates by season and when the EPA
mandates a cleaner fuel during the Winter months. Many cities use a 10% ethanol blend instead of MTBE from Oct 1 until March 1 when the potential for smog is at its peak. California's reformulated gasolines are not noted for best performance, as you might have already discovered. The ratio of RON to MON, changes each season while the average octane numbers are the same. This is why it runs differently,....
You can read more about this at <a href="http://www.rennsportsystems.com/2.html" target="_blank">Gasoline - Detonation - Twin Ignition</a>
In general, cars & ethanol do not do well together and when one uses these fuels, the mixture becomes leaner than normal and the engine's threshold of detonation goes lower. This winter blend can run rougher, make the engine feel less responsive, and contribute to some light pinging if you have some carbon buildup in the combustion chambers and piston crowns.
Short of blending some unleaded race gas, there is not much you can do aside from trying some other brands to see which one runs best for you.
<strong>A warning: My 97 993 started pinging recently. Searched the archives and discovered an interesting thread from somebody using Chevron Premium who was having the same problem. Made me think, since I also use Chevron Premium (exclusively, since it has the Techron in it). After continued pinging under acceleration with a second tank of Chevron, I decided to try Shell's premium. Seems to have eliminated the pinging. I also noticed that Shell now advertises their gas as having an additive to clean the valves (like Techron). Anyone know if it is any good?</strong><hr></blockquote>
Hi Griffin:
I cannot offer anything solid on the current chemistry of California fuels but I can tell you this.
Each and every fuel manufacturer uses different blends of oxygenates by season and when the EPA
mandates a cleaner fuel during the Winter months. Many cities use a 10% ethanol blend instead of MTBE from Oct 1 until March 1 when the potential for smog is at its peak. California's reformulated gasolines are not noted for best performance, as you might have already discovered. The ratio of RON to MON, changes each season while the average octane numbers are the same. This is why it runs differently,....
You can read more about this at <a href="http://www.rennsportsystems.com/2.html" target="_blank">Gasoline - Detonation - Twin Ignition</a>
In general, cars & ethanol do not do well together and when one uses these fuels, the mixture becomes leaner than normal and the engine's threshold of detonation goes lower. This winter blend can run rougher, make the engine feel less responsive, and contribute to some light pinging if you have some carbon buildup in the combustion chambers and piston crowns.
Short of blending some unleaded race gas, there is not much you can do aside from trying some other brands to see which one runs best for you.
12-12-2002, 09:38 PM
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I have recently noticed Union 76 stations in the SF Bay Area advertising "No MTBE". I just ran a couple of tankfuls of 76 after Chevron, and could not notice any difference.
12-13-2002, 02:55 AM
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My mechanic advised me to avoid the Chevron in my hometown (Lafayette) because supposedly they use crappy gas. I haven't gone there in 4 months, and I haven't had a check engine light in 4 months. Coincidence? 
12-13-2002, 02:53 PM
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California gas is crappy - end of story. To combat this, I add 100 octane fuel (found at a Union 76 at the corner of Foxworthy and Almaden Expressway in San Jose) to both my '89 930 3.4 and my '97 933tt. OK, so the 100 octane costs $4.299 now, but its the best thing to combat pinging.
My mix: '89 = 50%/50%
My mix: '89 = 50%/50%
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12-13-2002, 02:55 PM
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Operator error - sorry. I was trying to tab and hit "enter" instead.
In the 993tt, I mix 1/3 100 octane to 2/3 91.
Every so often I also put in a bottle of Techron (at least once a year).
Dan
In the 993tt, I mix 1/3 100 octane to 2/3 91.
Every so often I also put in a bottle of Techron (at least once a year).
Dan
