Renix Throttle Bodies

[Jeep-Power]

I have been boring out the '91 and up 4.0 throttle bodies by removing the reduction below the throttle plate.

I am wondering if the Renix TB has the same reduction, or is the throttle bore the same diameter for the entire length of the bore?

Thanks!--Peter

[Muad'Dib]

I have been boring out the '91 and up 4.0 throttle bodies by removing the reduction below the throttle plate.

I am wondering if the Renix TB has the same reduction, or is the throttle bore the same diameter for the entire length of the bore?

Thanks!--Peter

Its the same diameter the entire length of the bore. So a new butterfly valve is also needed when boring a RENIX TB.

[Jeep-Power]

Thanks for the confirmation.

How extra oomph is had from a larger Renix TB bore? I know it makes a difference opening the 91-06 TB's up to 60mm straight through...

[yuppiexj]

Oletshot punched out my renix TB (61mm, i think), and the wife dyno asked if I "tuned up" the Heep.
She's about as non car savvy as you can get.

I did notice a very noticeable change in tip in and it picked up .5-1 MPG over 4 tanks (probably due to not having to floor it and waste a bunch fuel on a downshift)

[Muad'Dib]

Thanks for the confirmation.

How extra oomph is had from a larger Renix TB bore? I know it makes a difference opening the 91-06 TB's up to 60mm straight through...

Its fairly significant as far as throttle response is concerned. I had to install a spacer to help even it out... it just was way to sensitive.

No numbers, just ass dyno.

[oletshot]

I did both yuppiexj's and Muad'Dib's to 61mm. I don't know how much actual HP is gained, but as both have said throttle response is outstanding (maybe to good, if there is such a thing). I have found that some of the Renix casting's don't like being opened up to 61mm.

[5-90]

It's unlikely that you've actually gotten a performance gain from the bored TB, other than by BD ("Butt Dyno") readings. Since the OEM throttle bodies are even able to support strokers, it's not strictly necessary.

What a bored throttle body (and larger throttle valve) /does/ do for you is exaggerate the rate at which the throttle opens, giving you a more crisp part-throttle response. /That/ is what you're feeling.

If part-throttle response is important to you, then that's the way to go. You're not going to really change WOT response or raw power figures, since the main choke point is in the cylinder head (and not in the throttle valve.)