You don't have to run premium. I've been running 87 for the last year and haven't noticed a single difference in performance or fuel economy.

 

I think the engine is more responsive when i run premium versus regular or plus, there arent any power gains or anything, the engine just seems more "peppy". As for fuel economy, its all dependant on how you drive it, but no R/T gets what they post on the little sticker...

 

I didn't notice a difference in fuel economy when I got my AFX Race pcm and started putting 93 gas in. [&:]

 

your plymouth has the same as the dodge hp its 132 at the crank but ull get about 110-111 at the wheel

and about the fuel thing, the premium burns slower so it throws the timing off and can damage the engine. my dads pontiac said that but he put in premium in anyway and he stalled out until the tech told him it was because of the premium

 

if a car says it requires premium, you dont have to use it all the time....car companies say to use premium to get the best performance outa the engine.....you can always use regular to do everyday driving....but if you go to the track or racing then use premium for max output

 

is the r/t 2.0 L ?

 

all neons are 2.0 except the srt-4..... the r/t is just a 2.0 magnum

 

The premium requirement is because the ignition timing is more advanced. Higher octane means more resistance to spontaneous combustion (knocking, fuel ignites before spark plug does). It doesn't have to be at the track though. Heading up a good hill will do it, particularly in a lower gear (very high engine load). The PCM will retard timing when the engine starts to knock, but it can only do it so much. A little knocking every now and then isn't going to kill the engine on the spot, but it does cause damage over time.

High octane does not mean more power. It means the timing can stay more advanced, which means more power. I logged the knock signal and ignition timing with various grades of gas (including a half tank of 106 octane that made my debit card shriek) on my '95 SOHC with Mopar PCM at sea level (within 400 feet or so) when I was living in CT (so 2-3 years ago or so), just making normal trips to and from work (75 mile drive). 87 octane would cause the PCM to pull max timing (something like 22 degrees) just taking off from a light at a comfortable pace, and mild (3-5 degree) slopes on the freeway in 5th would do the same. 89/90 octane did fairly well under most circumstances. Timing was pulled, but I don't think it ever pulled more than 5 degrees because of knock. 92 octane performed flawlessly. 106 octane, as expected, was no better than the premium.