Premium or Regular Gasoline?
 

What would be better in a 1998 Saturn SC 5-speed, premium or regular or mid grade gasoline?

87 regular -- the engines are tuned to run on it (as far as I know)

Okay because I've been looking it up and some people say premium but I was talking to a friend of mine, who worked for Saturn before they went out of business, and he said regular is best but I just wanted to check and see what you guys thought about it.

Regular

I agree -- regular is the way to go for 99% of the S-cars out there.

Now, if you have "highly modified" the original engine, there is a possibility you may need something more ....

......regular......

All I ever bought is regular. Seems to run fine.

Any engine can be >tuned< to run on just about anything.
A computer controlled engine re-tunes itself every time it is started. And part of that retuning process is to find out what the limits of the tuning have to be based on the fuel used at the time it is running.
Which pretty much says given today's mechanical design criteria they will run on just about anything that comes out of a gasoline pump and will try to run on diesel but probably will not like it very much.
However if you want maximum performance from your engine use premium. The engine will tune itself to provide all that it can with that fuel.
With 87 octane the limit is detonation or pinging. When that is sensed it will de-tune to limit the detonation or pinging.
I run mid grade on my 94 sc2. As to 87? I use it as a weed killer or parts cleaner. As you can tell from the answers here, pick the one you want to use, it is your car.

I ran 91 for 30 days when my ION was new. Kept a log of every mile and gal of gas. Took it to Firebird four times. Then switched to 87 and did the same thing. Average mpg stayed the same, went down the 1/4 mile with the same average of 16.2 Changed to a Fujita cold air intake and it runs 15.9's in the 1/4 mile with a best of 15.883 and 15.884.

Now I know this was not done under lab conditions, yet I gave it an over the counter real world shot.

I put in the cheap stuff.

Interesting data points there, RJ. Thanks for the effort and the results.

I keep thinking about adding CAI, but it appears to be kinda like chasing your tail. The stock inlet is non-metallic, so there's little (if any) transfer of heat from the engine. Most (if not all) CAI's I've seen are metallic, and I wonder how much heat is picked up by that pipe laying so close to the engine. Now if someone designed a CAI with a non-metallic inlet, seems to me that the gain might even be better than noted above ...