Hi, I bought a 2003 Acura TL and my partner bought an 2002 Acura RSX on the same day, five weeks ago. We got a great deal and I could not be more pleased with the purchase of the TL, I have yet to ride in the RSX. Now that I have over 1,500 miles on my car I have a few questions. 1) How many miles to the gallon are you getting on average? Seems like only 20 for me around town, 24 highway. 2) The manual states Premium Unleaded for both the TL and RSX. I will always put Premium Unleaded in but has anyone tried regular unleaded? Did you notice a difference or did it do anything? My Step-Father tells me its BS and just put in regual unleaded, I am skeptical, esp. since he is cheap. 3) The A/C works very well! But when I get into the car for the first time of the day and I turn the A/C on the sound of the compressor kicking in, is noticeable. When I start the car later in the day I cannot really hear it. The RSX apparently does the same, as does a neighbors 2001 Lexus RX300. While I am not alarmed because I have checked the belts and everything, should I mention it when I go in for my 3,500 mile check-up? Anyone else notice it? Thank you in advance! Tony

Tony, Here's the skinny: Your Type-S runs a compression ratio of 10.5:1 which is considerably higher than 90% of the cars out there, though motorcycles live here regularly. This means there's more 'squeezing' than typical cars. This high compression can lead to something called pre-ignition, which sounds like a rattle when you accelerate or climb hills. While it may not sound like much, it's really a bunch of small explosions - versus a nice smooth burn - and can pit pistons, valves and seats, and even premature rod and bearing wear. In a word, . To prevent this, many engines now come with a sensor that constantly listens for the occurance, and will retard the engine spark slightly to reduce or eliminate the effect, and that robs you of some of the power that we bought these cars for to begin with. So, while the car may be able to deal with some of the effect, there is a trade off. This may start a bit of discussion among many, but my strong recommendation is, put in the good stuff. And, ever so gently, you might want to educate dear old dad that 'global statements' like always and never are usually incorrect. He may know engines, but he clearly doesn't know yours (ours). No help with the compressor clutch here, mine's pretty quiet. And I can get nearly 30mpg on the freeway when driving from San Diego to Vegas on a weekday (that route on a weekend is pretty much like rush hour in the city...) -dave diego

Dave, Thanks for the info. Premium Unleaded is all I will ever use for both the Acura's we now own! I KNEW my step-father was wrong! ! ! ! Tony

Just for your info: The dodge viper V-10 runs a 9.6:1 compression ratio. That is within the 'standard' range for cars. Premium not needed, though the 89 might help a bit. The TL-S is 10.5:1 CR. The higher up you go, the more likely it is you'll experience detonation (knocking/pinging). The sensor 'hears' this, and retards the spark a bit to minimize the effect, thus preventing pitting of the valves and cylinders. Diesel engines run without spark plugs, and run as high as 25:1, that's why they sound like they do. That's also why detonation is sometimes refered to as 'dieseling' (especially when you turn the car off - remember the 80's?). Street motorcycle engines (which I raced for years at Willow Springs and Sears Point) have lived for years at higher-than-car compression ratios, and any pit mechanic will tell you that premium, unless you can get Jet-A, is all he'll burn. We don't notice the performance difference in our cars when our engines retard the spark, because we don't (rarely) use all the engine has to offer anyway. Nevertheless, the detonation damage is a very real risk, and my investment is worth a few extra pennies of the good stuff. -dave diego

Once again, you are right. Are you an engineer or something? When I mentioned it to the mechanic (I went out for a girls' night out with his wife) he said the very same thing you did. Basically he said he was referring to the Viper and the Integra. Now that I have a "real" car...(he says) he would recommend the extra pennies and get the good stuff. Great advice once again, I think I will take the back seat and be quiet now. You're the best!

I raced motorcycles for a few years, and was an ASE cert'd mechanic for a car rental company for a few years after that. My only involvement with the auto world these days is trying to keep up with everything new. Nevertheless, the old basics still apply. Suck in air, add some gas, squeeze it a bit, a light it on fire. The air expands from the heat increase, and we're off the line and headed down the road. Just enjoy your car. Feed it well, talk nice to it, keep it clean, and always be on the lookout for a good road. -dave diego