I believe it was the late 90's cherokee TB.

 

The spring on the auto TB is weaker, and the cam profile makes for a much quicker opening. Definitely not the same.

 

what does the cam have to do with the TB?

 

LOL

Not the camshaft...

Inside the TB, there is a shaft that attaches to the butterfly plate. On the other end of that shaft, where the throttle cable attaches, is a nautilus-shaped "cam". There is a visible difference between the atx and mtx versions. I'll snap off a couple of pics if I can figure out where my box(es) of spare parts are... Most people that I know that have swapped to the atx TB have done the work and kept the mtx parts. I was lazy... Definitely a difference in driveability.

 

while a 52mm tb will suffice for a while, i wouldnt call the 60mm a "waste" since it will provide gains over the 52 and even 55mm tbs. ive seen a 60mm outperform a 52mm tb on the dyno on an otherwise bone stock neon.. so i doubt its a "waste"
granted, its a bit more expensive, but it does provide better gains, as well as look better of course

 

It messes with the power curve, you will gain top end, but you will lose low end. on a stock neon, intake loses low end, exhuast loses low end, PCM loses low end, add the TB and you are losin a lot of low end. That is a lot of mods to do without some torque and low end mods, and those are all the mods people do.

 

it loses low end? interesting. the larger tb (up to 60mm) from every dyno comparison i have seen, has lost NO low end. low end stayed the same on both bone stock neons ive personally seen dyno.

heres nick riley's old dyno comparison for the throttle body.. show me again where the larger tb lost power? mind you, this is on a stock head, stock cams, stock bottom end.. but otherwise just boltons. and all the dynos ive seen in person, definately looked pretty much exactly the same:


pcm loses low end? ugh. need i dig up dyno comparisons on that too? the pcm DOES NOT lose low end!