[GuardsRedCoupe]

I've read most of the chip discussion that has taken place on this board. I still have a couple questions. Please, no comparisons between chips in performance, price, or otherwise.



Where can the chips be purchased? I see the ProMAX icon on the right. Where can the Speed 6 chip be purchased?



Is it worth it to chip my car if I want to use 87 octane fuel, or are the performance gains only valid with higher octane fuels?



This question also pertains to the stock chip - Does the DME prevent acceleration above the redline? So if I floor the accelerator with a stock chip, will it only run up to 6.5k RPM?



Thanks!

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[flash]

YOU CANNOT SAFELY USE 87 OCTANE FUEL!!! this does not matter what chip you use, INCLUDING stock - do not do this!



this car requires a MINIMUM of 90 octane (RON + MON/2) - check your owner's manual



all of the aftermarket chips were developed on higher octane fuels - however, they will safely run on 91 octane, and that is what we tested on



all of the aftermarket chips raise the redline, but to varying degrees, depending on the chip - see the article in 9 Magazine, and just about any of the threads about chips for those details



the racer x chip can be purchased at www.speed-6.com

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[RPM]

When you hit the redline with a stock chip your fuel will cut out.

Trust me, you will know when it happens.

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[GuardsRedCoupe]

Thanks for the info, Bob.



So, as I understand it, if I floor my accelerator, the DME will not allow the RPM's to go above the red line, whatever my chip happens to set my red line at. - Is this understanding correct?



[color="red"]EDIT[/color]: OK, RPM, that answers my question. Now that I know that, I may try it some time. <img src="/forum/images/smilies/968/biggrin.gif" class="smilie" alt="" />

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[flash]

no worries - i didn't mean to sound harsh, but that could easily end up costing you a ton of money to fix if things went wrong



if you are running hot, and you have been running 87 octane, you may have found part of your problem - lower octane fuel will cause detonation, which results in heat

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[bob blackwell]

The knock sensors and the computer will prevent any detonation with our 968, just as they will with any other modern automobile. The 87 Octane will result in the computer retarding the timing to prevent detonation/pinging and will give less performance than higher octane will. Good luck, Bob Blackwell.

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[flash]

while i agree that modern cars have devices like this to accommodate a wider range of fuels, and that's great, but they still have to live within the laws and principles of the internal combustion engine - i'd hesitate to say they would stop ANY detonation - i'm certain there are limits to how far back it can pull the things back to accommodate the lower octane - there are physical limits and minimums with an 11:1 engine, no matter what controls they add



the car was designed to run on 95 octane (RON+MON/2) and pulls things back on anything lower than that - the book says 90 is the minimum - if i were to guess, i'd say that was about as low as the system is set up to handle - i had to stick 89 in it in texas when i was bringing my car back from cleveland - it was ugly



also, this presumes the knock sensors are working

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[rustech]

[quote name='bob blackwell' date='Aug 11 2005, 12:00 PM']The knock sensors and the computer will prevent any detonation with our 968, just as they will with any other modern automobile.  The 87 Octane will result in the computer retarding the timing to prevent detonation/pinging and will give less performance than higher octane will. Good luck, Bob Blackwell.

[right][post="8629"]<{POST_SNAPBACK}>[/post][/right][/quote]



I believe the question is, can the DME retard the timing enough to compensate for 87oct? Correct me if I'm wrong, but I don't think it can.

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[968 Cab]

ahh... the debate rages on... read on



http://www.caranddriver.com/article.asp?se...2&page_number=1



http://www.caranddriver.com/article.asp?se...article_id=3604



http://hotrod.com/techarticles/72498/



In a real pinch, you can go lower than 91, but take a risk as everyone noted and you will suffer with poor performance. But the price differential is not that great anyway - so stick to name brand 91+ (recent spate of off-brand gas damage to new cars in this area). So stick to "top tier" gas @ http://www.toptiergas.com/



TOP TIER Gasoline Retailers:



QuikTrip

Chevron

Conoco

Phillips

76

Shell

Entec Stations

MFA Oil Company



My beater '90 Jeep runs fine on 87 and that's all it gets. The Porsches are driven less frequently and dine on 92 octane - the turbo gets 94 almost all the time.



Oh, apparently if you live in Denver, you can get away with lower octane fuel due to the lower density at higher altitudes.

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[GuardsRedCoupe]

For all interested, here's the official word on octane from the Owner's Manual. Quoted verbatim from page 4:

[color="black"]Fuel octane rating[/color]

Your engine is designed to provide optimum performance and fuel economy using unleaded premium fuel with an octane rating of 98 RON (93 CLC or AKI). Porsche therefore recommends the use of these fuels in your vehicle.



Porsche also recognizes that these fuels may not always be available.  Be assured that your vehicle will operate properly on unleaded premium fuels with octane numbers of at least 95 RON (90 CLC or AKI), since the engine’s “Electronic Octane™ knock control” will adapt the ignition timing, if necessary.

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[flash]

not so much a debate - my jeep also runs fine on 87 - that's because the compression ratio is much lower - for an 11:1 engine to run right, no matter what anti-knock devices, there is a minimum octane rating requirement - lower compression engines require lower octane ratings



and just for clarity, CLC and AKI are the same as RON+MON/2, as it is displayed here in california



gotta look into the denver thing - gonna be there next week - was wondering what the deal would be with fuel there

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