Yes again a tb question, need clarification

Been searching 62mm and 60mm throttle bodies and I'm getting mixed reviews, I have a throttle body I got for dirt cheap and a shop that will bore it to 60mm for dirt cheap which is awesome till I started looking around, I was thinking on going to 62mm but since this isn't a stroker I read it wasn't necessary, but while reading, I read that the top opening is actually 59mm? And that when boring it out, you should only go from where the butterfly is down or you'll screw up your idle. Is that butterfly only 59mm then? Because I'd like to be 60mm all the way through. Would I need a new butterfly then? Basically is the top half actually 60mm or would having the whole thing bore to 60mm screw things up and if it does, where can I buy a 60mm butterfly?

The difference 59 - 60 is 1mm/.039 inch. Not enough that it matters. Bore out the lower end to 60mm and call it good. I have bored about a dozen TB and never have measured the butterfly.

Well that's the issue, I've read that going past the butterfly will cause bad idle, so that 1mm really does make a difference, so that's why I'm trying to make a confirmation, because I'd like to bore straight through but if that causes an issue with the butterfly, ill tell the guy to go from the butterfly down

Bore out the bottom up to the butterfly. Leave the rest alone. Like I said, 1mm isn't going to make any noticeable difference.

Read this JP Magazine article:

http://www.jpmagazine.com/techarticles/engine/154_0911_jeep_4_liter_engine_myth_busting_true_lies/

joe_peters said:

Read this JP Magazine article:

http://www.jpmagazine.com/techarticles/engine/154_0911_jeep_4_liter_engine_myth_busting_true_lies/

Click to expand...

Already read that, I have a cai, 2.5 exhaust, 00' manifold, etc..

Demonoid369 said:

Well that's the issue, I've read that going past the butterfly will cause bad idle, so that 1mm really does make a difference, so that's why I'm trying to make a confirmation, because I'd like to bore straight through but if that causes an issue with the butterfly, ill tell the guy to go from the butterfly down

Click to expand...

Not true. If you're hell-bent on a larger tB with the associated butterfly, contact www.strokedjeep.com.

I bored my TB out to 64.4mm. Mainly just to see how it would work. I had to match bore the opening in the intake manifold because it whistled loudly. In the end I have no idle issues, very good throttle response and a TB that is ready if I ever get the money to do a stroker. The butterfly should be about .1mm or so smaller than the opening.

OP, I take it you have an HO.. and not a renix? Either way. x2 on strokedjeep.com Money well spent. His price includes a proper fit butterfly.