7.3 PS, extra hp from a 3" downpipe compared to 4" exhaust alone

[pmurf1]

Anyone do the exhaust in steps like me? I put a SS magnaflow 4" system on my 96 PSD from the downpipe back this weekend. It definitely made it more responsive getting rid of the 3.5" stocker, cat, and exhaust brake. I knew the stock downpipe was crushed down under the hood where it follows the firewall, but it's really crushed all the way back to the downpipe flange. They're like $100, how much more power is on tap changing this out? I have read 1-2 mpg and 40 ft/lbs. Anyone done the exhaust first, downpipe second?

[sucmah]

I straight piped my 96' first. Then about 2 years later i put the full downpipe on. The first mod only helped out on the top end i thought(above 2500) but the downpipe was def. kick ass. All around power gain and way louder turbo noise. Not really all that much louder decibal wise but the turbo really sang after the downpipe. I would do it again in a heart beat if I got another one of these trucks. Truck just felt much faster after the downpipe. FYI, the above and a tow program were all i did to this rig and i swear its faster than my 05 dodge. I think the auto in the ford made it feel alot faster as far as tearing off the line. I miss the turbo noise also, gonna have to fix that. Also, the ford had much less lag than the mopile turbo.

[LCOwner]

pmurf1, go to www.thedieselstop.com if you haven't already. Lots of good info and relatively cheap mods listed there.

[demonranger]

Haven't done it that way. Honestly unelss you're not burning the fuel you aren't going to get more power what it will do is shift the power band somewhat lower because it'll allow the turbo to spool much faster.

I was given a chip so the intake was easy and parts could be picked up locally to update that but I didn't have the change for the downpipe. So I drove w/ a very light foot to manage EGT's The kitty already had been scattered splattered & smothered so that wasn't a problem. The downpipe helped the power come on lower that before but i didn't feel any seat of the pants difference. The EGT guage thanked me w/ about 150-200° @ WOT and about 100 cruising down the highway.

[pmurf1]

I ordered one, looks like a little firewall massaging is in my future. I rarely even hear the turbo on mine, not really something I want particularily. I hate the way the 6.0's sound personally, both in the cab and at the exhaust tip with a 4" plus exhaust. It sounds like Ford cut a hole in the firewall and mounted the turbo in the glovebox. I'm mainly interested in getting the EGT's down and a place to mount a bung for a pyrometer before I chip it. I already put in the Bullydog shift kit, it hits hard now without a load. With a load, it's definitely a better shifting truck.

[LCOwner]

I think it's mostly the pinch weld that needs work. If I do any work around the exhaust I usually have to go back and adjust because the pipe is hitting the cab.

[Lil Toe]

If you need new cab mounts, do those at the same time, it will help with the amount of firewall massaging. When I put my H2 turbo on with the Hypermax 3-3.5 DP, (I had a Banks 3" DP before that) I couldn't massage the firewall enough. Of course, my cab was almost a 1/2" low compared to the bed with the old mounts and almost a 1/4" higher after the new urethane mounts. Also, get a band clamp for the DP instead of using a standard clamp. Makes it easier to take apart and helps with the space issue.

Chris

[FF3PM]

The DP is usually the first mod us diesel guys do on any truck but especially the OBS (old body style) trucks due to the stock pipe being so dang restrictive. It is also very easy to bend the pinch weld to clear a 3.5" DP, a 4" DP will require a little more then just folding down the pinch weld. Some trucks have more room then others due to engine position variances from the factory.
pmurf1 don't waste your time with a post turbo pyrometer, they are rather inaccurate, pre turbo is the only way to go. I ran both pre and post turbo pyros in my OBS truck and had as much as 400 degree difference between them, and that depended on what kind of load the engine saw. If the load was light the difference was less. Also IH recomendation for max sustained EGT is 1250* and that is pre turbo not post.
Another good mod is to get rid of the crappy factory intake. The air box does not seal well to the air filter element no matter whose element. Ford had a recall on these years ago it is such a bad design. I have used the Tymar intake on all three of my diesels and I am very happy. It will help with EGT's, and will let the turbo breathe a lot better.
The above mentioned site is a good place to start, some others are;
http://pages.prodigy.net/stevebaz/_import/pages.prodigy.net/stevebaz/index3.html
http://www.thedieselgarage.com/
http://www.oilburners.net/
http://www.superdutydiesel.com/
http://www.turbodieselregistry.com/
http://www.dieseltruckresource.com/
http://www.thedieselplace.com/