So I just found out that the left side manifold is cracked on my 2007 JK. Two questions.........
1. How bad will this screw up fuel mileage, cause mine has fallen off big time?
2. Would you replace with headers, or just go back with stock type manifold?

 

Headers and full exhaust

 

With hi flow cats and possibly bigger pipes.

 

Depending on your budget, you have a couple options:

1. Weld the crack in the existing manifold. Cheapest option, but you're most likely just waiting for it to crack again.
2. Replace with OEM stock manifold. Second cheapest, but like #1 - they're still prone to cracking.
3. Replace with shorty headers. More expensive, won't crack, but you don't get much for your money in noticeable performance gains, and people tend to have heat issues with them. (Melted spark plug wires and such)
4. RIPP long-tube headers. Most expensive option, but you WILL definitely have noticeable gains in performance, with none of the heat issues that shorty headers seem to have.


I had the same issue about a year or so ago & (unfortunately) went with the JBA titanium ceramic shorty headers. (Damn you, lack of money!!!) Now, they've been fine for a replacement, but don't think that you're going to get much for gains with shorty headers. If you really want to get your money's worth, then just bite the bullet and go with a set of RIPP long-tubes.

REALLY wish I had done that the first time around.

 

Yeah I'm sure they are good! They must be for $1500 or more!!!

 

For clarification is it the driver side manifold or passenger side manifold that is cracked?

I'm pretty sure my driver side is cracked but I only notice it (exhaust noise) at high altitude

Anybody know if both sides are prone to cracking or just one side

 

Weld it and save for the rips when you get the next crack. Then you'll know exactly how much it'll set you back. You could even purchase them when you have the cash and install them when you really have to or have more cash or time.

 

It's the driver side manifold that is leaking. I first noticed a different sound to my engine! Then I noticed a drop off in my MPG by about 2 or 3 MPG. On occasion I notice the raw fuel smell.
Bushmaster I'm not sure what to do! Would like to have those RIPP headers, but wow that's a lot of money!! Do you have any problems with your headers leaking?