Upon further investigation i determined i have the 4.0 bolted on already. I found some good pics of the 4.0 butterfly v.s. the 2.5 and my butterfly is big and silver like the 4.0 pic. The 2.5 butterfly was a brass color and noticebly smaller than what is on my jeep already. Hope i am right.
heres two threads i made about the same topic when i was doing the 4.0 tb swap.
a simple way to check is pop up that black intake hose off the tb and see if the intake diameter is larger than the manifold's
Wasent sure where to measure on the manifold? I popped the black hose off and it looks like it is slightly wider at the mouth of the TB where the air intake hose connects And gets slightly narrower closer you get to the butterfly. Is the 4.0 TB the same diameter from the mouth down to the butterfly? and the 2.5 bevels in and gets narrower? If so i got the 2.5 on....will have to change that
that definitely looks to be the 2.5 tb. i just want to say youre welcome for going out to the workshop in this cold ass weather to snap a quick picture of the 2.5 tb and 4.0 tb for you. the top one is the 2.5 one and although it is the same outside diameter as the 4.0, it bevels inwards like yours. the one on the bottom is the 4.0 and although it has a little bevel, it is pretty smooth and straight all the way down. the placement of the screws in relation to the end is also a giveaway
Awesome deal! Thanks for braving the cold weather for the picture. Now i get to replace my 2.5 with a 4.0 im excited to see if it helps at all. Hopefually get to the jeep grave yard next week to find the TB.
Awesome deal! Thanks for braving the cold weather for the picture. Now i get to replace my 2.5 with a 4.0 im excited to see if it helps at all. Hopefully get to the jeep grave yard next week to find the TB.
haha no problem. i was in the same boat as you are a few months ago, if you read through the threads they might help you with any more questions. good luck with the swap
edit: i realize the picture came out landscape instead of portrait, but you see the left one is obv. the 2.5 and right one is 4.0
Yea i caught on with the pic. And you can notice small differences when you look at them side by side.i been putting lots of time into the yj last few weeks touching up paint, cutting and painting fender flares etc.... I sea foamed my engine a few days ago and was like wtf do i have a 2.5 on here still? Gotta try the swap out!
I just did this but ended up with the 4.0 iac housing and sensor. that's the only way I can get it to idle down to about 800 RPM. to to make sure I wasn't overlooking something I just went out and put the 2.5 housing and sensor back on and back up to almost 2k rpm. I'm trying one more disconnect of the battery for a few hours. A little confusing.
So if I left the 4.0 housing and sensor on there, what would be the down fall? I only have about 20miles on this rebuilt motor so I'm not rapping it out to really tell but if there is a downside I'd like to know.