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steve
07-18-2003, 01:04 AM
I HAVE A 99 COBRA WITH THE BASIC BOLT- ONS. IT'S ABOUT 302HP @ THE WHEEL AND 293RWT. I notice on real hot days, especially like now (summertime) the car doesn't seem quite as powerful as it does during other times of the year. IT feels like it loses a little hp when it's warmed up on a really hot humid day. It's still really strong, but I NOTICE a little drop in power. IT HAS A CHIP , SO THE IGNITION IS ADVANCED A LITTLE BIT. I TRIED ADDING 2-3GALLONS OF 100 OCTANE RACING GAS AND IT SEEMED TO HELP A LITTLE BIT. THE CAR RUNS VERY COOL. IT JUST SEEMS LIKE DURING THE WINTER IT RUNS MORE POWERFUL THAN DURING THE HOT HUMID SUMMER. OTHER THAN THAT THE CAR RUNS GREAT. I KNOW WHEN IT'S HOTTER OUT THE FUEL CHARGE ISN'T AS DENSE AS IT IS WHEN IT'S COLDER AND THAT ADDS TO A DROP IN POWER. LET ME KNOW IF YOU GUYS OR GIRLS NOTICE THE SAME THING. THANX, SWB.::thumbsup:

tcrews
07-18-2003, 08:11 AM
Yep, that's the way it is.....and it is a noticable difference. The 100octane fuel you are adding isn't helping at all so I suggest saving your money and not doing that. Fuel (octane) doesn't make power and in fact higher octane gas burns slower, less violently (less engergy) than lower octane gas. High octane is only to prevent detonation. Your overall goal is to run the LOWEST octane gas you can without detonation/pinging.

The main reason you have more power in colder weather is because the air is denser and you get more air molecules in a given space. More air in, more air out = more power. Hot days the air is less dense so you have less air coming in which creates a loss in power.

laserred
08-08-2003, 12:13 AM
Hi. I have noticed this in my 98 too. And running 100 in it during hot days only makes my car run hotter. I have noticed in my particular car that on good cool days the high octane ( 100 ) runs really well. Anyway, it is better to run 93 for me. It is the all around better gas for my car.