Thats about all i can say. I went from the stock size just straight piped to a 5 right after the d/p to infront of the rear tire. Chose to put it out there since i built it myself and that was alot easier. Man did the tone change. Sounds alot deeper and i can here it much better through the passenger window, not to mention the cool factor of having a 5 inch pipe sticking out from under the bed right infront of the tire lol. Sorry for the long post but i thought i would share my excitement with you all. Derek

 

i am in the process of building mine too. i am going over the axle though. i am excited. cant wait to let er rip with it on there.

 

I'm with you there! There is no replacement for displacement.

 

what sise down pipe are you using?

 

or, in your case, cross-sectional area.

i just did the math- the cross-section of a 3.5'' pipe is 9.61sq.in, while the cross-section of a 5'' pipe is 19.63sp.in. crazy!

 

I also have a 3 inch downpipe so i'm good there since thats all that will fit half way easy lol. I hooked her to the trailer today with 18 round bales on it and man did she make some noise wound out in 3rd gear. Also my egt's are down which is the reason i really wanted to try to to begin with. I did it this way cause it was free before i go and spend the money for a complete system. It fullfilling to know i built it too if you know what i mean. Gotta love that PSD!!!!!

 

do i get extra points for having double the cross-sectional area with two 5'' Stacks? mwahahahah....can i add some "cool" points on that too?

Farmboy, if i hadn't done my stacks, it woulda been the same setup as yours. i had my stock-size pipe runnign out that way. looked pretty nasty with the silver paint on the pipe and all.....but then i got all caught up with stacks...you know.....pretty hard to pass them up

Hey, Stokin, feel free to do the math on two 5''pipes that are about 23 inches long, plus another 6' of 4''. i would give it a try, but i finished Hydraulics math last week at Fire School. still don't wanna see any math for a while. i've had enough of Gallons per minute and Friction Loss per section of hose.... BLEGH! that my friends is why i wanna be a truckie...but thats besides the point. ya'll have a good evenin.

 

FarmboyAc, how much did the 5 inch lower your egt's? I am running a 3" down pipe to 3 1/2" cat delete on back to where the muffler was then turned it down to the ground. Soon I'll have 5" stacks and was curious of how much it will drop egt's.

 

I'm not real sure on the egt's quite yet as i havent had a chance to cruise 10-20 miles down the road with a load but unloaded i think they have went down at least 50-100 degree's. I'm hoping that with a load they will go down around 150-200 but i'm not quite sure about that yet. I'll find out next week on the way to the National Livestock Exposition in Louisville, Kentucky hauling the cattle trailer. Hope to report back then.