mambodoc

My 09 C4S PDK Launch model has around 14,200 mi...bought new on 28 nov 09with 35 mi. I'm alwys in a quandry as to driving around town which... comprises most of my driving...in regular or sport mode. Noted the other day that while accelerating up a siginificant grade of a bridge, I though I heard pinging from the motor. Since then on regular acceleration in normal mode, Ive noted it numerous times. Doesn't seem to happen in sport mode or if it is happening, I'm not hearing it. I thought the engineering marvel thet this car is, that I shouldn't be experiencing this. Use Hess 93 premiun exclusively, and there is not a hint of pinging when throttling up an onramp with kickdown etc...in normal mode. What's the scoop? Thanks everyone! I would thing one should be able to drive around in whichever mode desired without any problems.

mambodoc

I suspect its a dealer/warramty adjustment issue...just wondering if others have experienced this and other preferences in driving PDK normal or sport. Anything I can do different?

ADias

What is Hess 93? I suggest you stick with Chevron, Shell, or Union 76 for better gas.

Edgy01

I get knocking all the time with the 91 octane stuff in California.

MUSSBERGER

Hess is a well respected brand on the east coast. I would have the dealer take a look.

mambodoc

Ditto...Hess is a major east coast brand...93 = octane.

BostonDuce

Just a SWAG, but maybe a trace of carbon build up from low speed driving, or some ethanol issue.

Sounds like it happens when the engine in under load in a high gear (i.e. not in sport mode or @ kick down where the RPM level would be higher).

Before you suffer the inconvenience of a dealer suntan, or throw money at it try the following cheap fixes.

Try something like Techron or Seafoam, go out for an "italian tune-up" and then change your oil afterwards.

If you're in a 10% Ethanol area, try some marine Sta-Bil.

BD

mambodoc

Thanks Boston...It does happen at higher gears ( at least higher than what I think it should be considering the speed ) under moderate load...not at higher RPMs. Will try the fix...An Italian Tune Up, I take it, is Techron in & light'em up...am due to change oil in 800 mi. Thanks! Dealer has been good to date, I'll look into the frequency of this type of complaint. Ethanol is 10% here. I thought I'd get more response here?! O well. Thanks All!

Macster

BostonDuce has it right. Even though I drive 30 miles one way to work -- most of it highway miles -- I notice when I take a car out for a longer drive after an hour or two at highway speeds the engine just runs better. And by the time I hit the CA/AZ border the car's engine is just purring and ready to roar.

I would not advise overdoing the Techron thing but a bottle maybe 2 as per directions and used just before an oil change can work wonders. Might be a once a year thing if that often. Depends upon how you drive and how much you drive.

Keep feeding the engine premium name brand gas and buy from a busy station to get the freshest gasoline. Premium gas goes "off" quickly.

Sincerely,

Macster.

Kuhan

FYI, the gas you buy at the pump, no matter which brand, is essentially the same. It's the additives which are brand specific. Supermarket brand gas comes from the same place that V-Power and Chevron with Techron come from - just will a little something added...

Some companies sell you the additives separately (e.g. Chevron sells Techron separately) and you can buy the gas at Kroger and add the Techron yourself should you wish.

LlBr

Regarding gas octane level? AFAIK, The engine is NOT supposed to ping even if you're in some little country next to nowhere and can only get the lowest octane gas.

Macster

Tests have found differences measureable differences between major brand premium gas and discount brands. Tests even found differences between fresh gasoline and stale gasoline so it pays to buy from a busy station which is almost always the station selling gas for less than its neighboring stations.

Up to a point gasoline is gasoline but a major brand of gasoline based on my experience burns better. Not hotter, better. When I run my 02 Boxster on discount gasoline -- sometimes I get lazy and stop at the most convenient station vs. seeking out a name brand station -- the check engine light comes on -- converter worn out -- but when I clear the error code and fill up with Shell V-Power -- for instance -- the check engine light stays off and I drive the car the same way almost every day.

(Sometimes when I fill up with Shell the station is running a special on premium and the actual price charged is 5 cents less than price posted on the signs by the station entrance, even the price posted on the pump octane selection window.)

The Techron you buy over the counter is not the same per se as what comes in the gasoline. The OTC stuff is higher strength and my feeling is it is not for constant use.

Generally I avoid gas additives, preferring to buy a good brand of gas that helps keep engine deposits down vs. trying to undo thousands of miles of deposit build up with a Techron treatment.

One can run whatever gasoline he wants in the car, as long as he stays with the proper octane rating specified by the owners manual but a constant diet of discount gasoline especially in the new 997 DFI engines I think a big mistake.

Given how little some of these cars get driven the few pennies saved -- and this savings at the pump likely lost to higher fuel consumption -- it makes no sense to run a low detergent cheap blend of gasoline.

Sincerely,

Macster.

Macster

That's not accurate. IIRC the owners manual states gasoline octane rating should be above a certain level for best performance. One can use a lower octane gasoline in a pinch but the engine controller can only adapt so much.

87 octane is not approved for use in these cars.

Run a crappy 87 octane in an engine that has been fed a diet of crappy high octane gas and the engine almost certainly will ping.

These engines have extremely high compression -- high compression one of the most cost effective ways to extract high performance from an engine -- and feeding these engines anything but the best gasoline -- though shopping for it on sale -- is just crazy.

Sincerely,

Macster.

Edgy01

Are you suggesting that the 91 octane fuel is not 91 octane? Because there are certain times that I get knocking and I use the best gas that California offers.

todd.

Hess is crap, it's not Top Tier gasoline. The only time I used Hess 93 was the only time I ever heard pinging in my truck, which I use to tow horses with. I exclusively use Shell 93 octane, or another Top Tier gas when Shell is not available. Like you ADias, when I lived in California I used Chevron & Shell.
http://www.toptiergas.com/retailers.html