4" + exhaust question

[dvst8r]

So I installed the Hx35 this weekend, forced the stock exhaust back a couple inch's and put it on for temp. I plan on going to a 5" exhaust as soon as I get enough time to fab up the piping to get my HT60 on there.

Back to the point, when I was crawling around under the truck trying to get the exhaust moved back, I noticed that there was barley enough clearance for the stock 3" passed the t-case. So my question is: What is everyone doing at that point? Are you necking down to 3"? Are you going under the t-case? Is there and easy way to make more room? I would really love to keep the clearance of not having the exhaust under the t-case as this truck does go off road quite often. Pictures of 4" + exhausts would be great too.

[nooblet]

I've wondered this myself. The only solution I saw was going a little bit inside the frame rail, but I'm not sure if thats what everyone is doing or not.

Chris

[ford69557ci]

I removed the little cross brace for the crossmebmer and beat the floor up a little and run a 5"dp then it goes to 6" right after the t case

[cummins king]

really, i fit my 5 inch around with no problem
joel
well i did cheat abit i used flex in that part.

[DTanklage]

josh used flex too, but that flex stuff flows like crap

didnt someone already prove that 4" is adequate for 600 hp?

[cummins king]

i dont think flow matters at 5 inch, but when you have a 5 inch turbo it there is no point in going to 4 inch

[DTanklage]

i built a turbo gasser (for the street races) and ran it all thru the stock ex with the stock muffler

still flew

[gear jammer 91"]

I'm runnin a 3" down pipe and a 4" past the transfercase, the pipe is tight to the frame rail but that has more to do with lettin my buddy help instal it and not checking his work. I think thier should be plenty of room for a 4" without it being up against the frame if you install it correctly. My exhaust was a kit from farm boys diesel.

[DTanklage]

farm boys...

dont they sell produce?

oh, thats 'plow boys'

or 'farmers market'

never mind

[fourwheelininajeep]

This is my 2 cents dont know if it helps but, I have done exhuast on a bunch of cars so I only can bend 3 inch, but I have always wondered if someone has ever tried splitting the down pipe at the turbo and running dual 3 inch and here is how i propose to do that, looking from the top down on the left side of the turbo(back of engine) there is a mud rubber flap that can be removed and a 3 inch pipe will go betweent the frame and the inner fender(maybe a small bit of cutting) then you could run one 3 inch pipe on the outside of the frame rail under the cab until the high spot in the frame where you could come back under the frame rail and go out the back, or just dump the pipe in front of the tire, then the other three inch exhaust could be routed downt the same passage the it is now, dual 3 inch is 6 inches of flow, I think that is the way I am going to do it but I dont know if 6 inches of overall flow would be the same as flowing through a 6 inch pipe because the gasses cant expand and cool. That is the only advice I have for exhaust I have looked at every other direction and if you use your truck at all going any where other than the stock direction would lower your clearance. Let me know what you think

[fourwheelininajeep]

The pipe bender that I have at my shop will only bend 3" so I was brain storming, would dual 3 inch be the same as 6" pipe. In my mind it works its the same amount of flow, but smaller pipe would mean less area for the gasses to expand and cool meaning still high egts. The way a wanted to do this is, looking from the front of the engine on the left of the turbo in between the inner fender and frame there is a rubber mat, dont know what it is for, maybe to keep mud out of engine compartment, anyway if you where to get creative and split the down pipe as close to the turbo as you could, you could run a 3 inch pipe through that gap under the inner fender above the frame and run it along the outer part of the frame rail until the rear spring front perch where you have the high spot in the frame and you could run the exhuast back in the fram rail and out the back, or even dump it right there in front of the tire, then the other 3 inch pipe you could run in its stock location. Again I dont know if 6 inches of flow would equal a 6 inch pipe but that is my philosophy

[cummins king]

two three inchs if you do the math is just a bit bigger then 4 inch it would be a waste of time,

[ford69557ci]

the cummins sounds funny with duals anyway

[fourwheelininajeep]

Sorry about the double post, my computer locked up and I wasnt sure if the thread went through, welll that is good to know that dual 3 inch exhaust is only 4 inches of flow I had a feeling that I was missing something but I couldnt tell wether my thinking was legitimate or if dual 3 inches is 6 inches of flow. Sweet now back to the drawing board

[SChandler]

To figure cross section on a round pipe to compare dual 3" to single 4" you need this formula: 3.1416 x d^2 / 4. For area of a 3" pipe it works like this: 3.1416 x 3 x 3 / 4 = 7.07in^2. A 4" pipe works out to 12.6in^2