[zekthecat]

I have an 88 YJ 4.2 nuttered weber carb. The question that I have is: Is the L shaped tube that goes from the intake to exhuast manifold needed. I have no clue on what it is there for and didn't know if it is needed. Thanks to everyone with helping me in my NOOBIE questions that I have asked. Still just getting into the whole Jeep thing.

[timatoe]

I can't place the part off the top of my head, but if it's emissions related, then you don't need it due to the Nutter Bypass, it won't be working anyhow.

As for some other questions that are bound to arise, read through this site http://home.sprynet.com/~dale02/ there's tons of good info in there on the 4.2.

[Brandon_YJ]

sounds like the EGR tube

[zekthecat]

Thats sounds like it. do I really need the EGR tube?

[Delta347]

Well what the EGR does is recirculates exhaust gases into the combustion chamber (or intake first). What this does is pass already combusted materials back into the combustion chamber resulting in fewer materials to be well combusted.

Basically if there is less to break down then there is less energy being liberated. Less liberation = Less Heat.

This causes you to get LESS Power out of each cycle of the engine BUT it grants Better fuel economy by lowering the combustion temperature and the amount of NOx gas being released (which can help on smog).

If you take out the EGR you will get:
1. A gain in Power
2. A higher operating temperature
3. Lowered Fuel Economy (lower MPG)

Leave it in, and its the opposite of that.

[zekthecat]

Delta, Thanks for that. The EGR vavle is not hooked up so the tube on the bottom of the intake going into the side of the exhust manifold is not needed and I can cap the holes. Right