Hello. I was thinking about adding underdrive pullys to my 04 but already have the tp tunes.. Would I need new tunes if I chose to do this? Is the power gain worth the cost including new tunes? Hey mike, how much are new tunes????

 

you'd only need to bump up your in-gear idle speed a lil bit to comp for the slower turning accessories. No new tunes need.

 

cool, so is it a bad idea to bump up the in gear idle speed without adding the underdrive?

 

That really depends on whether you have enough power steering assist - see, in a number of the 2002 & newer F-150's, Ford has the idle speed in gear as low as just 525 rpm - and that is just too low. They do that because idling is part of their fuel mileage strategy of course, so in many cases the idle speed in gear in the newer trucks is so low that it's really not comfortable to do parallel parking - this is why we increase the idle speed in gear on many of our tunes even if the owner does not have underdrive pulleys.

SO if anyone has a tune from us, then we have already taken care of an idle speed in gear being too low if that is the case from the factory - as it is in virtually all 2004 & 2005 F-150's, and some 2006's, just for example.

 

I appreciate you taking the time to answer

 

You're very welcome, as always.