Results 1 to 4 of 4

Thread: Tuning for new larger tires. Need Help

  1. #1
    Member
    Join Date
    Sep 2005
    Posts
    91

    Default Tuning for new larger tires. Need Help

    I went from a 31inch tire to a 33inch tire and EFIlive readjusted my transmission settings. However Ive also noticed that my LTFT's are at +10 more often. Can anyone explain. SOS!
    2002 GMC Sierra ECSB
    Turbonetics T7675 6lbs boost, 42lb injectors, Single 4 inch exhaust with Hi-Flow Cats, 6.0 swap, Comp Cam LS9 Cam, EFIlive Tune, E-fans, Snow Performance Meth Kit, soon to add KB Boost a Pump,

  2. #2
    EFILive Distributor dfe1's Avatar
    Join Date
    Jan 2005
    Posts
    837

    Default

    Installing larger tires has the same effect as switching to a higher (lower numerical) drive axle ratio (that's the politically correct replacement term for rear axle ratio). The higher the ratio, the less torque multiplication which means the engine has to work harder. It may just be that the engine is now running under enough of a load increase that it's getting to parts of the VE and spark tables that it didn't previously. If you logged data before and after the tire change, check MAP under similar operating conditions. You'll probably find that MAP readings are now noticeably higher than they were with the original tires.

  3. #3
    Member
    Join Date
    Sep 2005
    Posts
    91

    Default

    Thanks! I'll try that. Has anyone else run into the same problem? My tires were originally 275-75-r16 new ones are 285-75-r16 a gain of 2 inches in diameter. Please advise
    2002 GMC Sierra ECSB
    Turbonetics T7675 6lbs boost, 42lb injectors, Single 4 inch exhaust with Hi-Flow Cats, 6.0 swap, Comp Cam LS9 Cam, EFIlive Tune, E-fans, Snow Performance Meth Kit, soon to add KB Boost a Pump,

  4. #4
    EFILive Reseller kbracing96's Avatar
    Join Date
    Sep 2005
    Posts
    584

    Default

    Quote Originally Posted by jamesbond2509
    Thanks! I'll try that. Has anyone else run into the same problem? My tires were originally 275-75-r16 new ones are 285-75-r16 a gain of 2 inches in diameter. Please advise
    :? :? :? You shouldn't be gaining 2" in diameter by only adding 10mm to the width???
    01 ECSB 1/2 ton 4x4 Forged 5.7 LS1 GMC

    Custom KBracing front mounted, BW S480, intercooled turbo


Similar Threads

  1. 668Hp/1189Ftlbs at the tires in LBZ on #2 only and EFILive!
    By Danville Performance in forum Duramax 06 LLY / 06+ LBZ & LMM
    Replies: 17
    Last Post: October 28th, 2011, 04:19 PM
  2. Correct Spedo For Larger Tires
    By dobby in forum Duramax 06 LLY / 06+ LBZ & LMM
    Replies: 10
    Last Post: January 30th, 2008, 11:38 AM
  3. Basics for tuning with a larger cam
    By LuhrsTSF342 in forum General (Petrol, Gas, Ethanol)
    Replies: 8
    Last Post: October 10th, 2006, 04:31 AM
  4. Idle tuning for larger TB with ETC.
    By DrX in forum General (Petrol, Gas, Ethanol)
    Replies: 27
    Last Post: April 2nd, 2006, 06:07 PM
  5. Is it a bad thing when front tires come off the ground?
    By Danville Performance in forum General (Petrol, Gas, Ethanol)
    Replies: 9
    Last Post: February 20th, 2006, 03:34 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •