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2004 Grand Cherokee
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Discussion Starter · #1 ·
hey guys,
by the end of the summer i plan on installing Kolak's exhaust on my 2004 4.7 non-HO. this exhaust is supposedly highly rated on JF. for those of you unfamiliar with this exhaust, it converts all the exhaust piping from a 2.5 inch pipe to a 3 inch pipe, and replaces the muffler with a flowmaster 70. because of my year i have the pre-cats so there is no need for a new cat, but he puts a magnaflow 6 inch resonator that will sit before the muffler (i don't know exactly what the resonator does)

now my questions are, is this worth it? is there still going to be enough back pressure in my exhaust so i don't lose power? am i going to gain or lose mileage?

this would be the second mod on my car, after the K&N intake kit.

please all help is greatly appreciated.
 

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Jeep Garage's hunky Australian co-founder
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I've heard good things about it.
You certainly won't lose any power in the bottom end, and should gain a bit in the top. A 3" system for a 4.7l V8 is hardly over-exhausted.
 

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2018 Jeep Trackhawk
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I'm with dummy^^^^^^^
 

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Jeep Garage's hunky Australian co-founder
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I want more top end

what can I do for the big 6?
Unfortunately the L6 is a lugger, not a revver. It has a very long stroke, therefore it will never have good top end. It's forte is low rev torque. Sorry to burst ya bubble champ.

Sure small gains can be had by adding free low intake and exhaust, but it won't turn it into a top end screamer.
 

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BMW 325es
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I know just a little more HP than torque would be nice in a mod.

---------- Post added at 08:29 PM ---------- Previous post was at 08:28 PM ----------

wouldn't a shorter intake do the trick?
 

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Bro i have Kolak's 3inch exhaust on mine and i love it now i changed the muffler because it wasnt loud enough for me but hey lol....If i was u i would not even install the resonator...I didnt think the 4.7ho came with one ?? Wheres richie whenu need him lol
 

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There is no need for that Magnaflow resonator. Thats just a waste....the Flowmaster 70 is plenty big to keep sound levels down....it'll still be loud...but just not as loud a a Super 40 or Super 44...

Don't worry about it running rich....your Jeep is smart...it just needs a couple of days to learn how you drive with the new mods...

Mileage depends....it might get worse because you want to hear it all the time....lol....thats usually what ends up happening...
 

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2004 Grand Cherokee
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139 Posts
Discussion Starter · #15 ·
There is no need for that Magnaflow resonator. Thats just a waste....the Flowmaster 70 is plenty big to keep sound levels down....it'll still be loud...but just not as loud a a Super 40 or Super 44...
so when i order it should i just ask Kolak to not even include the resonator?

Mileage depends....it might get worse because you want to hear it all the time....lol....thats usually what ends up happening...
when i installed my intake i was hard on the gas but i got over it quickly, so i figure i'll go through a tank of gas and then start driving easy again.

you guys have been a great help, now i just gotta find a shop that will weld it all together for me.
 

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Yeah....the resonator will probably just quiet it down a little more....but I think its unnecessary..might even save you little money that way...

Just look for a good shop that has been around a while, that has friendly people working there....I'm sure you can one up there in CT...lol!

And you're welcome...thats what we're here for...
 

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Metal Gear
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You should really consider the Flowmaster 50 series suv, amazing sound on wot and yet very tamed at cruising speeds, you can actually have a conversation without getting annoyed. i only wish i had gone 3''
 
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