So it IS OK to run 87 in a NA? Cause me and the Bonnie are heading up through the mountains this summer.

L27'* and L36'* are designed to run on 87.

KTHNX.

no you dont have to... thats why we have map sensors and such run what you want

When I went out west last spring 91 wasn't an option. 90 was usually the highest. You are pretty much f'ed for modding a */C car if you live in the rockies. :(

uhhh.....no that is inaccurate info....91 is the minimum you should ever run in a SC 3800...its been said many times before in this topic and other topics before

Muscle, your opinion may be as you say, but our experience and by DESIGN and FUNCTION dictate otherwise. Even the manufacturer agrees.

You're welcome to destroy your car in time, but I won't. And I have news for you. The MAP sensor in a 92-95 SSEi serves no purpose other than a boost gauge indication.

Willwren, is 90 safe? I know that in states like CO, UT, WY and other western states it is very HARD to find 91. Most are 90 octane. What is the reason for the drop in octane at high altitudes? Is it cause the slight change of oxygen would cause a rich condition?

If 90 is the highest octane available to you, use it. And in my opinion, don't bother trying to bring your octane up with bottles of octane boost off the shelf at a parts store. Whenever you're on the road in an SSEi, you'll want to use 93-95 octane if possible. Anything more than that is overkill, and may adversely affect your mileage (I'm assuming you're running mostly-stock parts here... 95 may even be more than necessary for a stock L67). If those octanes are not available, use the next-highest rating you can find.

Another alternative might be to keep some toluene in your trunk for mixing on the road, in order to modify the 90 octane up to 92-93. But that'* another thread.......

Correct. Most over the counter octane boosters will only raise you one point. POINT ONE. From 90 to 90.1 octane.

I disagree. 91 minimum. My 93SSEi running a Gen3 Supercharger and 2.2" pulley runs fine every day on 92 octane. In the heat at the dragstrip, I have to run higher octane. 95 seems to be the sweet spot for performance, but the car runs just fine on 92.

The trunk isn't really a good place for highly combustible chemicals. Keep it in the kitchen next to the stove, or as close to the pilot light in your furnace as possible.

Toluene is dangerous. Both to your home, your paint, and CAN be to your engine, so do your research first. I use it, but won't be for much longer. I have an excellent local source for 100 octane unleaded. One of the highest rated race fuels around. About a mile away.