4.0 tb conversion?....(sorry)

[sharpxmen]

Speaking of throttle bodies. wth am i supposed to do about my 1990 2.5? there isnt shizzzle for em!!

i have one that i cannot test so i don't know how and if it works but if you're up for some testing send me a PM - have a look here http://4bangerjp.com/forums/index.php/topic,8142.msg64698.html#msg64698

[Eucalypta]

I have a '94 2.5 YJ with the manifold on the left.

Today I swapped my TB with one of a 4.0L.
The flange opening in the manifold is about 56mm and the outlet of the 4.0L TB is 56mm.
By only swapping the TB's I increase the minimum air intake diameter from 48mm (outlet opening from the 2.5L TB) to 56mm.

I drove just a bit along the countryside today so cannot yet tell if it is a big improvement on the highway with a strong head wind. 

I guess if you go to a full bore without changing the injectors, fuelpressure valve and possible O2 sensor, you might not gain extra power? 

[xjaz]

Speaking of throttle bodies. wth am i supposed to do about my 1990 2.5? there isnt shizzzle for em!!

Sure there is, just do the MPI conversion like this http://www.naxja.org/forum/showthread.php?t=950222&highlight=multi+port+injection.  Not an easy swap, and in hindsight, not really worth it.

[sharpxmen]

I have a '94 2.5 YJ with the manifold on the left.

Today I swapped my TB with one of a 4.0L.
The flange opening in the manifold is about 56mm and the outlet of the 4.0L TB is 56mm.
By only swapping the TB's I increase the minimum air intake diameter from 48mm (outlet opening from the 2.5L TB) to 56mm.

I drove just a bit along the countryside today so cannot yet tell if it is a big improvement on the highway with a strong head wind. 

I guess if you go to a full bore without changing the injectors, fuelpressure valve and possible O2 sensor, you might not gain extra power? 

no point in changing the injectors unless you find them cheap - fuel pressure will be sufficient in your case. You should have some improvement but you need to make sure there are no other restrictions in the airflow (get a high flow filter, remove the tube in the airbox cover (called a velocity insert) and the inlet tube going into the bottom of the airbox.

not sure what you mean about full bore if that is a 4.0L t/b, or a 62/64mm throttle body - if that's what you meant then indeed you'll get better output by increasing fuel delivery, again the fuel pressure would be sufficient if you're only interested in wide open throttle performance, otherwise you're in closed loop and the O2 sensor feedback will cause the ECU/PCM to adjust fuel delivery and target 14.7AFR

[chardrc]

didn't the ford injectors have multiple noises resulting in better fuel atomization. which would be an advantage (even if a small one) over the stock one nozzle injectors?

[sharpxmen]

didn't the ford injectors have multiple noises resulting in better fuel atomization. which would be an advantage (even if a small one) over the stock one nozzle injectors?

i can guarantee you that if you compare 2 brand new sets setup at the same set AFR at wot you will not see any differences between them as far as produced power is concerned.

the design is different, the stock one is pintle and the ford are disc (if i remember correctly) - the latter has better response (less inertia) and like you said better atomization - can't tell you if that would benefit the Jeep 2.5 or not but i would say yes from what others have reported - the spray pattern and intake runners shape and size are matched so sometimes even if an injector is better you might not get the full benefit of it's features as it was not designed for that specific cylinder head and intake - but like i said, in this case from what i heard it works.