Results 1 to 9 of 9

Thread: How do YOU tune for dual fuel setups

  1. #1
    Advanced Tuner angrygoat's Avatar
    Join Date
    Oct 2008
    Location
    New Baltimore, MI
    Posts
    358

    How do YOU tune for dual fuel setups

    Im curious what everyone's technique is for dealing with two fuels of different stoich value whether it be meth injection or a mix of 93 and race gas. Thanks
    Joe
    2006 M6 GTO
    APS TT
    10.76@131

    "The goal of tuning is for the tune to run well enough you dont need any corrective mechanisms"

  2. #2
    Tuner in Training Ironmancan's Avatar
    Join Date
    May 2008
    Location
    Jacksonville NC
    Posts
    43
    Since the meth only comes on under boost on my application I ensure my stoich value is richer under boost. I shoot for 10.5 with meth. I use my P.E. table for this since I'm usually within these parameters when in boost. I haven't tuned with a race fuel yet but I'm assuming I'll be doing things the same way. Unless I plan on daily driving with race fuel then it will be a mute point since I won't be able to afford driving the car lol.

    Subscribed to this thread in case im screwed up....
    Last edited by Ironmancan; 01-16-2010 at 07:54 PM.
    06 Twin Turbo GTO

  3. #3
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by angrygoat View Post
    Im curious what everyone's technique is for dealing with two fuels of different stoich value whether it be meth injection or a mix of 93 and race gas. Thanks

    you have to run two different tunes for two different fuels...
    at normal driving...under closed loop operation...it really wont matter...your car will always correct itself to a stoic burn ratio....the o2's in your car will always report stoic at the same voltage regardless of fuel used..it doesnt care about AFR..it cares about Lambda=1.0

    but you have to run different tunes for the open loop operation...no way wround it...in open loop you are telling the PCM to command a certain amount of fuel delivery...and differnt fuels = different mass = different AFR for WOT needs

    while in closed loop your car will correct for e85..at WOT..is gonna try to put in a value based on the MAF/VE tables and a multiplier.. which if left alone could equal 13.0 on gasoline...and wont even be close to enough for e85 WOT.

    you can see how somebody who runs a gas tune would be extremely lean at WOT for E85...or somebody with an e85 tune would be extremely rich on Gasoline...


    so...as stated earlier...
    different fuels = different tunes...no way around it
    -Scott -

  4. #4
    Advanced Tuner angrygoat's Avatar
    Join Date
    Oct 2008
    Location
    New Baltimore, MI
    Posts
    358
    I should have been a little more specific. I meant a mix of two fuels at the same time. I guess I mean what AFR should you shoot for if you are running pump gas with meth injection or a mix of 93 and C16.
    Joe
    2006 M6 GTO
    APS TT
    10.76@131

    "The goal of tuning is for the tune to run well enough you dont need any corrective mechanisms"

  5. #5
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    Quote Originally Posted by angrygoat View Post
    I should have been a little more specific. I meant a mix of two fuels at the same time. I guess I mean what AFR should you shoot for if you are running pump gas with meth injection or a mix of 93 and C16.

    that gets even more tricky....

    you need to find out the stoic values of both fuels..
    then you can do some math to figure out what the blended stoic value should be...
    a safe bet to start at would then be an AFR value that is approximately .85 lambda
    if you had a 50/50 blend of gasoline and e85 you would have a 14.63 for gas and 9.65 for e85

    14.63+9.65 = 24.28
    24.28/2 = 12.14 for stoic
    12.14 x .85 = 10.319 for .85 lambda
    that would be the starting point for me if that was the case...

    if you dont know your exact ratio of the mix...then start with the one that has a lower stoic AFR and tune for that...then you can always lean it out a little at a time and check knock, exhaust temps, and horsepower/torque gains to figure out if its still safe or not
    -Scott -

  6. #6
    Senior Tuner S2H's Avatar
    Join Date
    Apr 2005
    Location
    Schexnayder Racing - Arnaudville LA
    Posts
    4,387
    and I used e85 as the example becasue I dont know what c16 stoic is and didnt feel like researching to answer the question that I could just use a different already known example for.
    -Scott -

  7. #7
    Senior Tuner Mep_q8's Avatar
    Join Date
    Mar 2006
    Location
    Kuwait
    Posts
    1,564
    Quote Originally Posted by soundengineer View Post
    that gets even more tricky....

    you need to find out the stoic values of both fuels..
    then you can do some math to figure out what the blended stoic value should be...
    a safe bet to start at would then be an AFR value that is approximately .85 lambda
    if you had a 50/50 blend of gasoline and e85 you would have a 14.63 for gas and 9.65 for e85

    14.63+9.65 = 24.28
    24.28/2 = 12.14 for stoic
    12.14 x .85 = 10.319 for .85 lambda
    that would be the starting point for me if that was the case...

    if you dont know your exact ratio of the mix...then start with the one that has a lower stoic AFR and tune for that...then you can always lean it out a little at a time and check knock, exhaust temps, and horsepower/torque gains to figure out if its still safe or not
    great info

    Bader Norris
    MEP Tuned
    Telephone: +965-55446651
    Email: [email protected]
    Instagram

  8. #8
    Tuner in Training DevilsOwn's Avatar
    Join Date
    Jul 2009
    Posts
    27
    With figuring for meth injection you should call the company and ask them for the actually flow rattings of the nozzles. Most are rated at 100 psi with a 1/2" id feed line. But its very common for people to not know about this.

  9. #9
    Advanced Tuner
    Join Date
    Dec 2008
    Location
    Old Orchard Beach Maine
    Posts
    915
    Quote Originally Posted by soundengineer View Post
    if you had a 50/50 blend of gasoline and e85 you would have a 14.63 for gas and 9.65 for e85
    14.63+9.65 = 24.28
    24.28/2 = 12.14 for stoic
    thanks for posting this sound engineer confirms all the calculations i have been doing for upcoming e85 blending are good
    PB's 1/4 mi 12.21 117.75 trap ,1/8 mi. 7.779 93.99trap , 1.949 short time (FWD W body)