First (and only) tank of 87 octane fuel test is complete. I know I said I was going to do 2 tankfuls, but as I eluded to in the podcasts and the lasts posts comments, results were less than favorable.
Roxy ran WAY too rough. The shudder at idle didn’t go away altogether, but it did reduce. The biggest downfall? Loss of power. I don’t have that much to start with (about 108 according to my last dyno run) so I need all I can get. I know the computer is supposed to surpress any knocking and pinging, but it takes a little bit for it to learn the new fuel. Really bad pinging happened within the first 50-70 miles when starting from a stop.
On the plus side, mileage was right on track for what I should have gotten. 31.9 mpg out of the last tank. I might have lost maybe 2 mpg. Maybe?
So, instead I will try midgrade (89 octane here in SoCal). Still going to save about $.10 per gallon and hopefully Roxy will run better.
So, I am here to highly recommend AGAINST running 87 octane gas in your MINI. Trust me.
I will keep you posted about the midgrade stuff.
I’m thinking of switching to Mid-grade here in Maryland. Thats 87 octane. But with my mods I think the extra octane is needed. I have intake, pulley and exhaust on the way.
I also wonder if changing the ecu to the lower octane will help? By using MTH or another ecu tuning.
I do not recommend going to the 87 octane. Really. You’re MINI won’t be happy. There will be a HUGE power drop off that will erase all of your mods! BTW, get the exhaust installed yet?
If midgrade is 87, what’s regular?
I’m not sure if an ECU re-map would help. Always worth a shot, but I’m always weary of those kinds of things myself. I would hate to cook my ECU and have to replace it.