04 HO or the 4.5 325/600 engine

[CLAYTON]

Originally posted by MO'Donnell

Get what you want option-wise, either engine is a great one. If you happen to find a truck JUST the way you want it and it has the 305/555, go for it, otherwise order what you really want. I honestly don't think 20 HP & 45 ft/lbs will make a big diffference in driving fun. I LOVE my 305/555!!!!!!!!!!

I agree

 

[BApple]

Maybe I just don't get it. If the 04 doesn't have a cat converter, then why should the 04. 5? Who gonna say anything to you when you remove it. In my case, I don't have anything smog checked, gas or diesel. Would it be hurting anything to remove the cat as far as performance? Tell me the advantges to not running a cat on an 04. 5 please.

 

[thejeepdude]

Originally posted by BApple

Maybe I just don't get it. If the 04 doesn't have a cat converter, then why should the 04. 5? Who gonna say anything to you when you remove it. In my case, I don't have anything smog checked, gas or diesel. Would it be hurting anything to remove the cat as far as performance? Tell me the advantges to not running a cat on an 04. 5 please.

The 04. 5 has them because of the new smog requirements as of 1/1/04. No there would not be any harm in removing the cat from an 04. 5, other than you would be breaking the law. Of course, for 'off-road use only' you could cut the cat out and probably see a tiny improvement in flow (lower egt, quicker spool) but from what I hear, that new 4" in-out cat is barely any restriction at all. Catalytic converter technology has improved a lot. That said, anything that air is forced to go through on it's way out is going to cause some amount of backpressure.

 

[geusterman]

Performance wise, I just tested my frisky 02 six speed with 20k miles and we got 60mph in 15 seconds, one aboard and a half tank of fuel. My new 04. 5 with 900 miles and 2 aboard with a full tank did 60mph in 10 seconds. Seat of pants did not tell me that.



Additionally, there are new valves, oil cooling and manifold in the 04. 5 that apparently are good things. AND, don't think less of me here, I hate the smell of diesel in the morning. Too old, I guess. Try hanging in a big city in Asia for a few months and you never want to smell diesel again. NOT a tree hugger. I use them for traction for my snowmobile. geusterman