down pipe questions....

[ianstew]

Who makes a down pipe for my truck that doesn't require a porta power to bend the flange? i've heard some stories about installing downpipes and was wondering what kind of luck you guys have had....... thanks in advance

[dhanna6powerstroke]

Originally Posted by ianstew

Who makes a down pipe for my truck that doesn't require a porta power to bend the flange? i've heard some stories about installing downpipes and was wondering what kind of luck you guys have had....... thanks in advance

More than likely you will have to bend the flange no matter which brand. Just not enough clearance.

[Dieselfever78]

Originally Posted by dhanna6powerstroke

More than likely you will have to bend the flange no matter which brand. Just not enough clearance.

There is just no way around it when going to a 3" downpipe. Ford had been using the chassis configuration for a while and when they went to put the PSD in these trucks they had to do some shoe-horning. Guess where it was.

The best downpipe depends on what your going to do with the exhaust that follows it. If you buy an exhaust system, then get one that comes with a downpipe so everything will match up easier. If your keeping the stock exhaust or CAT at least, get one with the correct end on it(ITP sells one like this) to match up easiest.

My personal favorite is the Hypermax downpipe, theirs goes from 3" to 4" as soon as posible under the cab and you can build back from that.

-Michael

[Jamie V]

I can't believe someone doesn't make on that uses oval tubing so you don't have to use the jaws of life on your cab. (Oval tubing not crushed tubing like Ford uses)

[jcmagone]

If the portapower is the problem I know you can find them on sale failry cheap at Harbor Freight. The one I bought was about $69 on sale and I have found that I use it for far more than just my down pipe install.

[Dieselfever78]

Originally Posted by Jamie V

I can't believe someone doesn't make on that uses oval tubing so you don't have to use the jaws of life on your cab. (Oval tubing not crushed tubing like Ford uses)

The problem is the problem with the stock downpipe. It's been calculated that the flat pipe has the same surface area as 3" round pipe. The thing is that air flows better through round pipe than oval. That's the whole point of the aftermarket downpipes.

-Michael

[Jamie V]

I design and install commercial ductwork everyday. all I deal with is air flow (CFM, Velocity, Static Pressure) You could get an oval pipe to flow what that 3" round pipe flows. It's just easier to make it out of round and crush your fire wall. The stock ford pipe probably would be out flowed by a 2-1/2" piece of round tubing which would probably fit without any firewall mods. Does anyone make a downpipe kit out of 2-1/2" tubing?

[Hardline]

[dzlstroker]

Originally Posted by Jamie V

I design and install commercial ductwork everyday. all I deal with is air flow (CFM, Velocity, Static Pressure) You could get an oval pipe to flow what that 3" round pipe flows. It's just easier to make it out of round and crush your fire wall. The stock ford pipe probably would be out flowed by a 2-1/2" piece of round tubing which would probably fit without any firewall mods. Does anyone make a downpipe kit out of 2-1/2" tubing?

Commercial duct work and PSD's downpipe (any turbo exhaust for that matter) couldn't be any more different.

Turbo exhaust leaves the turbo in a circular direction (think tornado). If it has to then pass through anything other than a circular pipe, the flow is disrupted greatly which equals back pressure which defeats the whole purpose.

That's why no one makes and/or sells an oval downpipe. That's why Ford also quit using a crushed downpipe like we got stuck with and went to as much as a 4" downpipe in the SD's - round. Not oval, not crushed, not rectangular... round.

A 2 1/2" downpipe?

To the OP. How much you have to bend the pinch weld, will depend on how the factory set your engine. If it's set forward you may not have to bend it at all. If it's set back, you may have to bend more than others. It's a crap shoot really.

Bending the pinch weld doesn't "require" a porta power. It just makes it easier. A sawzall, 2x4 and a prybar, and/or a BFH will take care of that bad boy.

[Jamie V]

Originally Posted by dzlstroker

Commercial duct work and PSD's downpipe (any turbo exhaust for that matter) couldn't be any more different.

Turbo exhaust leaves the turbo in a circular direction

What do you think pulls or pushes air through ductwork? The air outside?

I use inline and centrifugal fans everyday (that pull and push air in a circular direction just as a turbo does. Is a round pipe/duct more efficient then an oval? YES Is an Oval pipe more efficient then a square/crushed pipe? YES The more you flatten out a round or square pipe the larger the pipe must be to flow the same as the round.

Would I love if a 4" round pipe would drop right in off of the turbo? You know I and everyone would. But some guys don't like to have use hammers and portapowers to crush back there fire wall (no matter how minor it is). I was just curious why no one makes something that fits right in? Even if it isn't the best it would defiantly be better then the stock downpipe.