Im thinking of Porting my stock TB and spacer to get a better throttle response and maybe better MPG. I heard 62-63mm but can you do more and how to do it because i seen the top part only. ANY TRICKS! on how to do it because i want to take it to a machine shop, I dont trust the Dremel i seen some really UGLY out of round ones out there and i want mine to look clean.

 

Honestly it would be easier to buy one already done. Reason being #1 you need to replace the butterfly part if you bore it out. #2 if there is any out of round where the butterfly closes it will cause all kinds of idle problems.
Check out strokedjeeps.com he has some reasonable prices.

 

You can only go 63mm. I have mine at 62 and i did mine on a metal lathe. It was free for me to do and it came out perfectly round and smooth on the lathe.

I tried the drill/hole saw/sandpaper trick and i broke my first one. So either have a machine shop do it, a honeing tool, or a lathe

 

Where did you get new butterfly ? or did you make that to...

 

Whats the advantge of an larger TB
Or what about this kit for $600 intake, bigger TB and a chip
would this be an option for little more power and better mpg

 

Made that with a piece of 18ga aluminum. It ended up being perfect size.

Take the stock butterfly trace it with a fat tip sharpie evenly around the edge. Cut that out on the outside of the line (i used a dremel tool). Trim until it fits the throttle body. I got mine perfectly round and have not had any issues at all.

 

That is 1) way over priced. 2) the chip has no advantages.

You can get a premade bored throttle body from strokedjeep.com for $90 and the K&N cold air intake for $250 from 3rd party sites.

Not worth it

 

the hole in the manifold is 62mm. Top of the stock TB is 60mm, bottom is 55mm. Butterfly is 60mm.

Therefore, unless you replace the butterfly, the most you can do effectively is 60mm on the bottom to match the top. I've head of people tapering the bottom from 60 at the butterfly to 62 at the manifold, but you really can't get that exact.

good writeup here: http://www.go.jeep-xj.info/HowtoTBboring.htm

 

The bottom of the manifold is 65mm. I measured mine to confirm.

That is a great write up tho

 

Did you guys have noticable results with the 62 mm "over the counter" throttle bodies? I was thinking of purchasing one, pretty sure BBK makes one for Cherokees..

 

It wont do much for you without a high flow exhaust and air intake, and then it wont be a big differance but it will be something, If you put a high perf. cam in it than you would really have a big differance in power and driveability. you will have a real small amount to not really even noticing any change buy just a bigger t/b.g/l