Always run the highest octane you can on a boosted 3800. They all have knock from the factory and the higher the octane the better for them.

 

I run 93 most of the time but skimp and get 89 sometimes to save the 20 cents a gallon. does not seem to hurt the engine at all. If you keep the supercharger boost from going up to high you just have a 8.5:1 compression v6. So 89 is acceptable. All the octane number means is the higher the number the more stable the gas. So by keeping the boost low you prevent pre-detonation.

 

Stock vs top swap only with no other mods, 20hp is probably right. Otherwise, the hp difference depends on the other mods that you have. A higher compression engine will always make more power, but it starts to become a little more dangerous, especially if done wrong.

I also only recommend the highest octane possible on a boosted engine. I do understand that you can "get away" with lower octane if you don't use the boost, but for the little that you save, it's just not worth it to me. Why have a supercharged engine and handicap yourself?

 

20/cents a gallon with 10 gallons of gas is also only 2 bucks...

 

ok thank u guys i apprecieate it and what about a shift kit??

 

Shift kits are all right to put in, you can also have the line pressures increased during the tuning process (I wouldn't do both)