Can i use regular gas in my 97 28 with 113k miles. Iv e been using 94 octane gas and i get like 15 mpg mostly city driving. I dont race or anything but I dont want it detonating like crazy. I want to save a little money if I can. Do you think a mid grade would be ok and maybe use premium once in a while? Well, what do you say?

 

Wouldn't bother with crap gas. LT-1's aren't low compression engines, play it safe and use premium 92 octane or higher.

 

If you have the stock programming you can run 87 octane.
The PCM and knock sensor will adjust the timing and give you 10% less power.
If you have the HPP or mail order tuning then you won't be able to run regular without pinging.

 

the guy i bought my car from said he tried 89 once and from the way it ran he said he would never do it again. dont have any personal experiance though.

 

I ran a couple of tanks of 89 with the HPP3 power tuning and didn't notice any difference.
Running 87 with the HPP3 made it ping but when it had the stock tuning it adjusted for the lower octane.
I've always run 93 though especially now with the S/C.

 

If you spend $2 a tank extra for premium, your saving less then $10 a month if you drive 60 miles daily. Find another way to save money, that's not very practical. The LT1 is a high compression engine, and its better not to risk detonation then to save some miniscule amount of money.

 

The iron head LT1 is 10:1 and setup to run 87 octane, I even had pcmforless do me a tune for the cam with 87 octane, mostly for winter, but it worked so well I ended up running it all year. Aluminum allows more compression and your motor is only 10.4:1, so if you really want I would think a tuner could set it up for you, but that would cost too much for it to be worthwhile. It worked OK for me because I use an OBD1 swap pcm with unlimited updates so the 87 octane tune was free. So while you could certainly do it, it is not going to be worth it because of the cost of tuning OBD2.