From everything that I understand all of the fuel this summer will be a 10% methanol blend rather than the addadive package that we have been used to in the past. How much will this change the air/ fuel ratio and how will this effect people that have supercharged applications?? Any thaughts from Mike Troyer will be appreciated!!!

 

i know in the winter- here in westmoreland cty i get better mpg with citgo 93 versus 93 sunoco-in summer time i use ultra 94 and that gives me best mpg-phil in -IRWIN

 

The only way to know the effect is to test the A/F's - that cannot be guessed at.

Yes, "gasohol" does change the stoich point from about 14.64:1 to roughly 14.2:1 - and the O2 sensors will switch at that different point automatically.

But as to any potential changes in A/F's, the only way to really know is to test them, as always. For owner like you Chuck, we have always recommended going with the LM-1 unit so that you can do your own A/F's any time you like, on any fuel (as long as it's unleaded & no nitromethane, etc of course!) at any time, and thus *know* instantly what's going on - it's either that or a trip to a dyno to get them properly tested.

All else being equal, the results should be a slight leaning of the A/F - and I mean a coupla-few tenths of a point, generally speaking - but for supercharged engines like yours, running higher boost & all your other mods (and that's a *very* neat truck Chuck has, for those who don't know it), I do recommend testing the A/F's to see just what really happens.

I hope that brief info helps, & good luck, Chuck!

 

Thanks for taking time for the reply Mike. I will do some data loging when the time comes and post results. My tune is safe on the rich side so a few tenths of a point will be a help in a way, but I will do some runs when I am able and see what changes do happen and maybe a new tune will be in order to maxamize the set-up, as I am not planning any large changes in the near future. Thanks again, Mike, for taking time out of you're busy schedule for the reply.

 

Hi Chuck,

You are more than welcome - it's been a delight to work with you over the years, as you are so detail-oriented and do whatever it takes to make sure *everything* is dead right on the money, and that is always a joy for us.

I also appreciate all the other people you have helped out, as over time we have gotten a number of calls from people saying things like "I've been talking to Chuck for a year (or 2 years, etc.), and finally decided to get the tuning & mechanical configuration right." Kudo's my friend, & continued fun and good luck!