Hey guys, I need a little more help now. I found a nice 3" exhaust system for my 1998 dodge dakota 3.9L. Its made my dynomax and it is relaticely cheap. $230. Its from the cat back, and im guessing it should sound good. it has an ultra flo muffler on it. should i buy it and install it, or do you think 3" for a 3.9L will be a waste?

 

lol i'd do it, is your motor all stock?? might wanna get a few engine mods to help with all that flow comming out of your exhaust, some people told me my 2.1/2" exhaust was too big, but I have a few engine mods and it runs great and sounds great, 230?? thats kinda cheap............... try it.......

 

So what engine mods should I do? I already have a cold air intake.

 

I think 3" sounds a lil bit big for a stock 3.9
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Kitchen Measures

 

jonnys right, 3" is too big, unless u supercharge it or somthing. my 3.9L has 2.1/2" pipes.

 

A little big and a little expensive in my opinion.

Try this http://store.summitracing.com/partde...5&autoview=sku

 

everyone who has posted in the one is correct. 3" piping is way to big for a 3.9. 2 1/2" is about where you want to be. the cheapest thing to do is what i did. go get the hi flow muffler you want with the correct fittings on both sides. then get some 2 1/2" piping in the length and turn you want, then either weld it or clamp it together. i built a full cat back for $100.

 

Do you still have your cat?

 

if your truck is relitively stock and its only a catback it wont hurt performance. it will probably help out a little. as long as you have stock manifolds/y-pipe/and cat youll be good. and may i add if you got a magnaflow cat that combo would sound awesome.

 

I still have my cat. I got a flowmaster 40 from a friend and put it on, it was a 2 1/2" front and rear and thats my stock exhaust. I noticed a nice throaty tone, but my gas mileage also went from 20-22 to 12-14 mpg. i need to take it off, its killing me in gas, and i drive a lot a week so im filling up 2 to 3 times a week. does anyone know of a good sounding muffler that will help mpg better than stock? wat shud i doooo im getting frustrated. the muffler sounds really nice when warm, but i feel the loss of torque and power, so im guessing the flowmaster was meant for a v8 and not a v6.