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laxer44 04-23-2011 05:04 PM

Hi flow cats or straight pipe... and header ??
I have a 2008 4.7L with a magnaflow 22" muffler that i welded on. I still have the stock resonator at the end. My question is would it be better to keep or loose the resonator, while adding either magnaflows hi flow cats or just weld a straight pipe in place of it.

I am also thinking about fabricating a set of headers. I know that they sell a set for the 4.7 dodge truck, do you think it would be easier to get that and modify or get one of those header kits to fabricate. Would the bolts and ports be somewhat in the same spot?

05WK 04-24-2011 07:42 PM

Re: Hi flow cats or straight pipe... and header ??
Go to and look at the picture to compare for the headers.

As far as the cats, you'll get a check engine light for the missing cats, because you have downstream O2 sensors. Best bet, is to stick with the normal cats..

And if you were to custom fabricate a set of headers, you need a header flange. I have tried to find one for the 3.7L with no luck ANYWHERE..

Escape 04-24-2011 09:02 PM

Re: Hi flow cats or straight pipe... and header ??
Long Tube Headers and a straight pipe will be very very loud.

Mine is so loud I'm now looking into a electric cutout to dump the exhaust after the turbo and a nice quiet muffler as I have to yell inorder to be heard when going down the highway and talking while accelerating just isn't going to happen. Don't get me wrong it is fun and it has startled many a unsuspecting bystander, some to the point of falling over as they turn and run from it.

With a CMR you can turn off the rear 02's, I'm not sure on the 4.7 though???

Without cats it's gonna smell like gas and the fumes will burn your eyes if you stand behind the Jeep for to long. Vehicles behind me in traffic probably hate!

There is absolutely no room to fab a set of headers up, if you want some I'd just buy a set and be prepared for some blood, sweat and cussing on the installation as it is not something I ever want to do again. But they are worth every bit of the hassle!


robpp 04-24-2011 09:18 PM

Re: Hi flow cats or straight pipe... and header ??
there is NO CMR TUNE for the 2008 4.7 so you are going to have a problem with the rear O2 sensors.

if you have to worry about Emmisions tests i wouldnt even consider it. the standard o2 spacer with steel wool trick DOES NOT WORK ON A 07+ Chrysler CAN BUS. sct NOPE. no one has a tuner to turn them off so you will have a CEL. CEL = FAIL E Test. they wont even plug it in.

if E test is no problem then get rid of them.

2 points. it will be LOUD and DRONE some. It will also stink out the exhaust pipe. KEEP the resonator for sure.

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