i have a 420a engine, and i have heard alot about swapping a jeep tb off a 4.0l onto my engine, with very little modifying, i want to do this, what do i need to modify it, so it will fit and work properly?, tryed to find a sticky on this but couldn't? thanks

 

why would you want to do that. you will need no gains for power.

 

thats not what i have heard. you are going from a 30mm tb to a 60mm tb, so you will get more air.

 

dude its a naturally aspirated 2.0L 4 cyl. And where is all the "extra air" you are claiming of going to go and come from. First off the intake piping isnt going to be all that much bigger therefore you not getting this over abundance of air. Secondly the intake manifold is not going to be any bigger therefore that manifold is only going to flow so much anyway. And thirdly what do you expect to gain by adding this "extra air".

Maybe you will run alittle leaner or the computer will obviously adjust the fuel to add a tiny gain. But again this is a very small basic engine and unless you have something forcing more air in (turbo, supercharger, ect) simply adding a larger bored TB is not going to gain anything besides possibly alittle throttle response. Which is why people think they are getting this major gain.

Its like when people put on a Cold Air Intake and claim they really feel the difference when all you are feeling is alittle more response because the air has a smoother path to the manifold. But in reality (and proven dyno charts) a CAI only gains about 3-5hp at most which is what i would possibly expect from this TB. The only time i can see this being a necessity is if you were to go turbo on your car and the stock TB was creating a bottleneck in the system.

So dont believe everything you hear.