(The MAP/Performance issues on most Wrangler Jeeps have been covered before here)
Anyway, there was an interesting piece by the moderator over at 4x4xplorer about his install of the Edge TrailJammer kit on his 4.0. Thinking that most of the information holds true for the 2.5 as well. Basically, his post clarified, for me, the nature of the Jeep sensors (knew was not "mass-air," but needed a review on what factors were measured by the sensors -- apparently, MAP, Intake Air Temp, RPM).
http://www.4x4xplor.com/phpBB2/viewtopic.php?t=2540It clarified a couple of questions I've had about the performance of my 2.5 after doing doing intake/exhaust mods. Frankly, right now, with basically an open cone-filter intake + big TB ,
my MAP levels must suck a$%, my intake air temp is boiling and, as a result, my 2.5 is running way too lean. Therefore, my engine performance and emissions are in the toilet.
Frankly, I conclude that I can do a few things about this:
1. Lower intake temperature (CAI kit) + install MAP adjuster - more complicated to do right, but better performance than air box.
2. Or just raise MAP in a low-dollar fashion (install air box and paper filter which will likey do just that); air temp would stay the same
Bottom line, though, is I think it's pretty F'ed up that aftermarket shops & others sell performance items to 2.5/4.0L owners without explaining, front and center, the Jeep MAP issue to buyers (vs MAF). Sure RPM and air temp affect fuel/air ratio in Jeeps, too. But, you drop $1000 on replacement upgrades for your 2.5L (say full exhaust, performance intake) thinking that your Jeep "weekend toy" is going to fully self-regulate for the air-flow increase like a any MAF vehicle and that is just not the case. Think that jeep aftermarket retailers need to put this issue at the top of the list of any performance section on their sites related to 2.5/4.0s. And, I do believe that aftermarket retailers would foster long term customer relationships if they took the initiative and kept their customers clearly "in the know from the gitgo" about this issue.
