91 tune with 87

[Bwoodkid]

If I run the 91 tune, then can only find 87 ( like up in the mountains). Can I run 87 with an octain booster? I want the 91 to tow my 6K lb travel trailer.

[06MonteSS]

no.. octane boosters only add about .3 octane.. so would make 87 octane be 87.3...

if you only get 87/89 octane, then install the 87 octane tune.

[techntrek]

I bought this tuner for the same reason (6k camper) and just went through an 8000 mile trip over the Rockies in July. After a lot of testing I found my best combo was the 87 tune with high octane when towing (87 octane when commuting). That eliminated the worry about getting at least 91 octane gas and I did only have 87 or 89 as an option multiple times at altitude. I got my best mpgs that way (towing and commuting), compared to the stock, mpg and Diablo tunes. When you are at 8000 feet the limiting factor is the available oxygen so the higher-octane tune made no difference up the long slogs. What made the most difference was putting the highest octane gas into it.

The best thing you can do for towing over the Rockies is to have a turbo or supercharger, and my next tow vehicle will have one or the other.

See my thread about fan settings and towing, which was the biggest reason I bought the tuner.