I live in the south east where there is a severe gas shortage. If you are lucky to find a station that has any, it's going to be regular. There is no premium to be found so my 08 Shelby GT is sitting in the garage with only at quarter tank of gas. Shelby says you must burn premium or you will void the warranty. What happens to the engine if you burn regular? Are there any solutions here? I heard that you can buy octane booster from Auto Zone and add this to the regular gas and you should be ok. Any thoughts or recommendations on this? Thanks. Stranded in the south east.
You might take a look at this thread on teamshelby.com: http://www.teamshelby.com/forums/index.php?showtopic=34083&hl= In it, someone who spoke with an SVT engineer about fuel grades states that the factory tune is a conservative one developed for 87 octane. Since the 5.4 L is actually a relatively low compression engine without the super charger boost kicking in, it makes some sense. If you have installed an aftermarket tune, then most of the additional horsepower probably comes from bumping the timing and mixture for premium fuel only. If it were me (and you're obviously not!), I would give a tank of 87 a try with some Torco additive ready, but I would probably take it easy on it, too, and not hammer it. The two gallons of 87 octane referred to in the post as coming from the factory, would just about get you through the initial no-boost period talked about in the Shelby Owner's Guide Supplement, after the car was loaded and unloaded, etc. If you do, be sure to listen carefully for any signs of pinging (pre-ignition knock), as I understand there are no knock sensors to help you out and prevent internal damage.
My first guess would be that the super chargers make enough racket under load to cause knock sensors to trigger. Deleting the knock sensors also makes building the maps simpler and more straightforward. There could also be issues with the aluminum heads on the iron block causing audible harmonics that the sensors don't handle well. Actually, these would all be guesses because I'm not an automotive engineer. I was also surprised that they weren't used in a new engine application like this.
Keep in mind the original post referenced a Shelby GT (4.6 liter) no supercharger. Do the 4.6 liter engines have the sensors?
Thanks for the clarification. I added a can of octane booster and filled up with regular. So far I have noticed no performance effects and I have listened very carefully for any anomalies while driving and none so far. I am treating this as a temporary situation and will baby her until i get back to premium gas. Thanks everyone.
