I like to get people opinions on the injector cleaner - I have used it on my previous cars, and wanted to find out if Porsche has any recommendations ? In the past I used it about once or twice a year - to be honest I wish I had access to a dyno - so many questions that we have here could be helped with a dyno results.

If you use good quality premium unleaded in the Cayman, you shouldn't have any problems as most gas today has a good amount of cleaners already in it. Having said that though, using a good injector cleaner once or twice a year is what I do and won't harm a thing.......so why not! I don't fall for those injector cleanings offered by dealers (even though they are a good process) if there isn't any problems with the car......its just easy money for them.

Are those of you who own Porschenow using the highest octane fuel available? I have forgotten what the owners manual recommends. And do you have any preferences as to what kind of gas, Mobil, Chevron, Shell etc?


Thanks Russ




Edited by - RussK on 12/19/2005 07:58:56 AM

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The max we can get here is 94 - I have used that on my BMW and was very happy with it - will use it on my Cayman.

The Cayman Owners' Manual rec for the US is 93 (an avg of RON & MON ratings which may differ from ROW ratings). That's generally the rating of our premium grades except, I believe in CA where the gas sucks. [img]/fckeditor/editor/images/smiley/MWPX/regular_smile.gif[/img]

As for injection cleaners, for years I've poured a can of additive in my tank so that it's burned prior to every oil change. I've used Techron in the past, but switched to Lubo Moly's Ventil Sauber (valve cleaner) &amp; Jectron (injector cleaner). According to several P car mechanics whose advice I value, it makes a difference., but who knows for sure? I figure it's cheap insurance - assuming it works!!!!<span class="specials">[/quote]

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Dan

In the owners manual it says, 'use unleaded premium fuel 98 RON (93 CLC or AKI), what the heck is RON CLC and AKI stand for? The highest we can get here is 92.

Aloha Russ

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Hey Russ,
From what I've read on the PCA teck site (at pca.org) these designations are basically differtent ways of saying the same things (like mm and inches). We have 91 octane gas in CA for the most part, where I've seen as high as 94 on the east coast. The computers read the octane of your gas and adjust accordingly so your 92 octane will be fine. Higher ocatne unleaded can be found at select stations and at the racetracks, but the engines are optimized for 93, and going to a higher than 93 octane with a normally aspirated engine will generally not get you more horsepower. Using higher than 93 octane in a turbocharged car can make a big difference because the computers control the variable boost and timing. I've seen a big difference using 96 and 100 octane racing unleaded in my turbo.

Brad

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21-year PCA Member
PCA DE Instructor

Brad,

I appreciate your thoughts, you have been helpful as usual.

Aloha Russ

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Russ
The 'octane number' is a measure of a fuel's anti-knock (or pre-ignition) characteristics. Pre-ignition or 'pinging' is when the fuel mixture detonates from a source other than the sparkplug &amp; is both bad for performance &amp; for the engine. The higher the octane number the more resistent fuel is to detonate before it's ignited by the sparkplug.

Higher compression engines like the Cayman's require a more knock resistent (higher octane) fuel to prevent pinging. If a lower octane fuel is used, the engine's computer will 'hear' pinging at a very early stage &amp; compensate to avoid damage, but generally at the expense of power output. So, using lower octane gas will reduce power, but as beez said, using a higher octane than 93 in your Cayman will not achieve any gain.

There are different accepted standards used to measure the anti-knocking characteristics of gas. The octane number you see at US pumps is the average of two such octane numbers; the Research Octane Number (RON) and the Motor Octane Number (MON). This average number is sometimes referred to as the Anti Knock Index ('AKI') or the US Cost of Living Council method ('CLC'). The RON and MON numbers are determined by American Society for Testing and Materials ('ASTM') laboratory tests. Thus, US octane numbers are described as, e.g., 93 AKI or 93 CLC. The equivalent RON number in other countries would be 98.

The RON method determines low speed and low load knock characteristics whicle the MON method tests high speed, high load, high temperature conditions such as exist during periods of high speed power accelerations, hill climbing, or any period of high power output. The MON method results in a higher octane number &amp; is the more relevant value for racing.

Maybe more than you asked, but ... . [img]/fckeditor/editor/images/smiley/MWPX/beer1.gif[/img]

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Dan

Dan,

I am always amazed at the amount of information that is available here at this site. I really appreciate you taking the time to enlighten me.

Mahalo Russ

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Dan's explaination is also another reason to be wary of chip mods. There is no free lunch and most require a higher octane fuel. One needs to ask some pointed questions about those requirements before buying into the concept (including what octane gas is available to me).