Down Pipe Q?
Senior User
Joined: Oct 2004
Posts: 104
Likes: 0
From: Pearland, TX
okay- here comes the ignorant question of the month:
so catback is from the catalytic converter to the back.
turboback is from the turbo through the cat and back.
what is the downpipe? is that the pipe from the turbo to the cat? or is this another pipe from the turbo? and how does it differ from a wastegate?
so catback is from the catalytic converter to the back.
turboback is from the turbo through the cat and back.
what is the downpipe? is that the pipe from the turbo to the cat? or is this another pipe from the turbo? and how does it differ from a wastegate?
Postmaster
Joined: Aug 2003
Posts: 4,483
Likes: 2
From: Central Texas
The down pipe is the exhaust pipe that goes from the turbo "down" to the exhaust pipes on the bottom of the frame. A waste gate is a device that your 6.0 doesn't have. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down.
Your turbo is a variable geometry turbo that uses vanes to direct more or less exhaust flow onto the turbine blades as determined by the PCM.
Your turbo is a variable geometry turbo that uses vanes to direct more or less exhaust flow onto the turbine blades as determined by the PCM.
Senior User
Joined: Oct 2004
Posts: 104
Likes: 0
From: Pearland, TX
Hey thanks for the scoop. One last clarification:
so the difference between a catback&turboback is that one pipe (and any associated handers, hardware)?
so the difference between a catback&turboback is that one pipe (and any associated handers, hardware)?
Originally Posted by SBV45
The down pipe is the exhaust pipe that goes from the turbo "down" to the exhaust pipes on the bottom of the frame. A waste gate is a device that your 6.0 doesn't have. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down.
Your turbo is a variable geometry turbo that uses vanes to direct more or less exhaust flow onto the turbine blades as determined by the PCM.
Your turbo is a variable geometry turbo that uses vanes to direct more or less exhaust flow onto the turbine blades as determined by the PCM.
Postmaster
Joined: Aug 2003
Posts: 4,483
Likes: 2
From: Central Texas
Originally Posted by skippyp
Hey thanks for the scoop. One last clarification:
so the difference between a catback&turboback is that one pipe (and any associated handers, hardware)?
so the difference between a catback&turboback is that one pipe (and any associated handers, hardware)?
Super Moderator
Joined: Jul 2004
Posts: 21,113
Likes: 3,939
From: Ohio
To answer your question, you can drop the exhaust with no cuts. I did not intend to say it is easy. If I was to do another truck a few cuts and the exhaust would be off in shorter time. 3.5 or 4 is another debate. The 3.5 flares out to 4 right away but no porting required at the firewall. I doubt if you notice any differance. The stock exhaust is a real bungle......anything is better than that.
Hotshot
Joined: Dec 2003
Posts: 15,368
Likes: 121
From: Stuttgart, Ar
In my 04 I found that I actually had more restriction in the short pipes leading into the cat than in the downpipe itself. As far as the 3.5 vs the 4 downpipe--magnaflow dynoed both and the 3.5 came out the winner. just my .0000002 
Super Moderator
Joined: Jul 2004
Posts: 21,113
Likes: 3,939
From: Ohio
My Tech informed me the 6.0 likes back pressure.......not saying he is right.
The 3.5 would provide some pressure where the 4 would not.
The 3.5 would provide some pressure where the 4 would not.
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New User
Joined: Oct 2004
Posts: 4
Likes: 0
Recently installed a 4" turbo back system without cat manufactured by Hog. Love it, more torque and hp, about +1 mi/gal, quicker throttle response and less turbo lag. Installing the 4" downpipe wasn't hard, but rather than take the time to port the firewall weld seam, I got a neumatic grinder and ground it off flush. Bending the lip was too much of a chore. So that's just a time saving idea if you don't like working with a hammer in tight spaces.
As far as insulation goes, my uninsulated downpipe hasn't created any more noise than the stock one that i've noticed. The turbo whistle is a LOT bigger at the tailpipe, but that's because of the straight through muffler, no resonating chamber, and cat delete.
After talking to my Ford mechanic, I heard that the 6.0L turbo does like backpressure, but only PRE-turbo, i.e. in th uppipe. Downpipe pressure just increases EGTs and turbo lag (both decreasing performance) as well as making your engine work harder to breathe and wasting all that glorious power.
As far as insulation goes, my uninsulated downpipe hasn't created any more noise than the stock one that i've noticed. The turbo whistle is a LOT bigger at the tailpipe, but that's because of the straight through muffler, no resonating chamber, and cat delete.
After talking to my Ford mechanic, I heard that the 6.0L turbo does like backpressure, but only PRE-turbo, i.e. in th uppipe. Downpipe pressure just increases EGTs and turbo lag (both decreasing performance) as well as making your engine work harder to breathe and wasting all that glorious power.
Senior User
Joined: Oct 2004
Posts: 104
Likes: 0
From: Pearland, TX
I was snooping around under my 04 (trying to decide if I'm man enough to do the turboback myself).. my downpipe has no insulation. It is bare pipe from the clamp all the way out. seems a little different than what others have.
in fact, I'd say the bends are fairly good on it. A little rippling in the bends, but certainly not crimped to restricted in any way.
in fact, I'd say the bends are fairly good on it. A little rippling in the bends, but certainly not crimped to restricted in any way.
New User
Joined: Oct 2004
Posts: 4
Likes: 0
the turbo-back system really wasn't too hard, i spent about 3 hours in the garage total, and with fairly modest tools - a socket set and some wrenches, a sawsall to cut the old exaust at the muffler and downpipe and the fat ends off the stock hangars, and the grinder to grind the seam off for clearance. The big thing was that i had access to a lift which made my life a lot easier, but i suppose it could have been done without. I had one major hang-up when removing the stock downpipe - carbon buildup had frozen the clamp and downpipe onto the turbo exit, but a little bit of brute strength popped it all loose.
overall, it was a pretty easy install. i don't think it would have been worth the money to have it installrd for me. one thing to note...this was a completely bolt on system, so no welding required.
overall, it was a pretty easy install. i don't think it would have been worth the money to have it installrd for me. one thing to note...this was a completely bolt on system, so no welding required.
Cargo Master
Joined: Jun 2003
Posts: 2,203
Likes: 0
From: Carlsbad, California
One thing that I have found with a bolt on stainless steel cat back system I put on my F-150 was that it really did need to be at least tacked welded here and there because the clamps just wouldn't cinch down hard enough to keep things tight if I went 4-wheeling.
I had access to a MIG welder so I went ahead and welded all the pipe joints and never had any further problems with it. It was a fairly nice K&N system by the way.
I had access to a MIG welder so I went ahead and welded all the pipe joints and never had any further problems with it. It was a fairly nice K&N system by the way.
New User
Joined: Oct 2004
Posts: 4
Likes: 0
it's been just over a thousand miles with the new exhaust, all sorts of driving (city/highway/towing/off road/etc) and i still check the joints periodically for just that reason, but as of yet, nothing has moved. If i do end up with a problem, i'll definetly end up tack welding the joints.
Should be here on Tues, I can't wait.