4.0 Throttle body on a 2.5?

jeepjoe43

jeepjoe43

YJ Enthusiast
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Stumbled on to a another forum thread about replacing the the 2.5 TB with a 4.0 and adding a spacer plate, supposedly adds about 16% more flow.
I'm just curious if anybody here has tried this?
We 2.5 Low Output guys are always looking for more...
 
Now,now...were told you cannot flog a 4 banger for another 16% of anything. ;) But...Im all ears on this one. I have read several posts saying the spacer itself is a waste. The bigger TB...who knows.
 
I've heard it makes no difference. I've also heard it does make a difference. You could certainly try and see.

I have the BBK 62mm throttle body on mine because I was trying to eliminate some low idle issues on my 4.0 and thought the throttle body may be causing trouble. It doesn't make the Jeep "faster" but you do notice a little pickup, mainly because the spring loaded throttle isn't as heavy so you hit the gas harder/easier, and because the slightly larger throttle body is shooting in more air with less travel of the pedal. So technically it does make a difference. Certainly didn't hurt anything except it made my wallet quite a bit lighter. Doubt I'd do it again but it did make the engine feel a tiny bit more responsive. Probably not worth $350 though. A cheap 4.0 throttle body on a 2.5, maybe the cost is worth it.
 
That's kind of what I thought, I'm not going to waste any of my time on it.
Like I said, just something i stumbled on.
Really can't complain about 125HP from a 4-banger, had it been 10 years older it would have only had 75HP.
The 360 in my '80 J20 was only rated for 150HP!
 
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jeepjoe43 said:
That's kind of what I thought, I'm not going to waste any of my time on it.
Like I said, just something i stumbled on.
Really can't complain about 125HP from a 4-banger, had it been 10 years older it would have only had 75HP.
The 360 in my '80 J20 was only rated for 150HP!
Click to expand...
Yeppers, the dark years I refer to them as. We had a few mid 80ies chevy 3/4 tons to haul hay and animals. I think a 350 back then didnt even quite put out 150 ponies, pretty sad. Good thing was they last forever because the didnt make enough power to break or wear out anything.
 
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Very Sad, indeed. Thank You smog & CAFE regs.
Briggs & Stratton was doing better than that, They were getting 5HP from only 9 cubes, with an old school flat-head engine!
Those were definitely the dark years.
 
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