Engine HP & Torque- Boost #
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Mountain Pass
Joined: Mar 2007
Posts: 163
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Engine HP & Torque- Boost #
Just wondering about how the factory engine specs were arrived at. My research show the stock 1999.5 to 2003 engine makes 275 hp @ 2800 rpm and 525 lb-ft @ 1600 rpm. My question is- what is the boost level (psi) that Ford used to get these results? This knowledge will give me a starting point for adding boost without going too crazy and overwhelming the stock platform, really it's just a matter of curiosity.
It's a Van Gogh
Joined: Feb 2010
Posts: 7,813
Likes: 1,335
From: Elk Grove, CA
Stock engines on stock tunes will do 15 - 18 psi. How Ford calculated the HP is arcane. Like seriously, vastly arcane, to the point of irrelevancy. The place to start your quest is to state your goals, as in your planned use of the truck. There is waayyy more than boost to consider when making more power. Folks are very helpful here, just let us know what ya want to accomplish and we'll tell you how to get there. Or at least how to spend your money. 
Plus exactly what vehicle we're talking about, because things changed over time.
Plus exactly what vehicle we're talking about, because things changed over time.
Post Fiend
Joined: Jun 2004
Posts: 9,293
Likes: 10
From: Parker, CO
You aren't going to overwhelm the engine with too much boost. We aren't talking gas engines here, totally different platform.
Tell us what your goals are for adding power/boost and we can point you in the right direction.
Tell us what your goals are for adding power/boost and we can point you in the right direction.
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Mountain Pass
Joined: Mar 2007
Posts: 163
Likes: 9
Thanks for the replies. It was mostly a matter of curiosity. My truck is a 2000 2wd auto with a 6637 filter and a 4" Aeroturbine muffler,a Hutch mod with a frame mounted filter before the low pressure fuel pump,and a Tru-Cool auxiliary transmission cooler, in all other ways it is box stock with ~210,000 miles on it. It is a farm truck that will develop up to 18lbs of boost under a heavy load. I have some oil leaks in the valley that need to be addressed so I'll be rebuilding the turbo and adding a compressor wheel to stop cavitation, probably RR, along with the EBPV delete with new turbo outlet and bellowed up pipes for a bit better exhaust flow. I've secured a Turbomaster waste gate controller and plan on installing it when I do the rest of the work. My goal is a bit more power down low to help with my heavy towing while maintaining everyday driveability and reliability.
I've been planning this for awhile and will be starting the work next month so any thoughts or advice would be appreciated.
I've been planning this for awhile and will be starting the work next month so any thoughts or advice would be appreciated.
Lead Driver
Joined: Dec 2006
Posts: 7,093
Likes: 147
From: San Diego, CA
The 275 Hp / 525 lb-ft were the final stock tune numbers for the 2003 with the ZF6.
Even though the change wasn't that drastic, as with any generation they build over time as they "improve" the design and tuning. My '03 (with the 4R100) was published at 250 Hp (@ 2800 RPM) and 505 lb-ft (@ 1600 RPM).
Stock boost is just under 20 psi as aawlberninf350 mentioned. Stock tuning will start to defuel around 24 psi boost.
Here's the power "timeline" for the Powerstroke to see what your year "came with":
Power Stroke Horsepower & Torque by Model Year
Even though the change wasn't that drastic, as with any generation they build over time as they "improve" the design and tuning. My '03 (with the 4R100) was published at 250 Hp (@ 2800 RPM) and 505 lb-ft (@ 1600 RPM).
Stock boost is just under 20 psi as aawlberninf350 mentioned. Stock tuning will start to defuel around 24 psi boost.
Here's the power "timeline" for the Powerstroke to see what your year "came with":
Power Stroke Horsepower & Torque by Model Year
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Mountain Pass
Joined: Mar 2007
Posts: 163
Likes: 9
Well it looks like my 2000 F250 auto came with 235 hp and 500 ft/lbs of torque, I stand corrected in my orthopedic shoes. My idea is to see how the turbo wheel and friends perform with the stock tune and then decide whether to reprogram the truck. Like I said it's a farm truck and when hauling hay I tow ~19000 lbs, hay and trailer. I'm ignorant as far as tunes go and wonder if at these loads a reprogrammed truck will run cool enough EGTs so as not to hole a piston or do other damage.
The exhaust is another concern. It is in good shape and with the new free flow muffler the truck runs a bit stronger/smoother with less Surge (cavitation). If I have to replace it with a 4" turbo back system then I will but I also wonder if going to a new downpipe of 3.5" diameter might be a good stop gap compromise for moderate performance. It looks like my stock downpipe is 3'' and bulks up to 3.5" around the transmission crossmember. My understanding is that some or most of the aftermarket kits come with a 3.5" downpipe. Any thoughts or experience with this idea? The cost difference between a new downpipe and whole system is around $250, not a whole lot but if I can get by until the rest need replacing then its a good trade off.
The exhaust is another concern. It is in good shape and with the new free flow muffler the truck runs a bit stronger/smoother with less Surge (cavitation). If I have to replace it with a 4" turbo back system then I will but I also wonder if going to a new downpipe of 3.5" diameter might be a good stop gap compromise for moderate performance. It looks like my stock downpipe is 3'' and bulks up to 3.5" around the transmission crossmember. My understanding is that some or most of the aftermarket kits come with a 3.5" downpipe. Any thoughts or experience with this idea? The cost difference between a new downpipe and whole system is around $250, not a whole lot but if I can get by until the rest need replacing then its a good trade off.
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Lead Driver
Joined: Dec 2006
Posts: 7,093
Likes: 147
From: San Diego, CA
Without any aftermarket tuning the stock exhaust should be fine. The only restrictions are the downpipe (it's not mandrel bent so there's a crease in the bend as it goes under the truck) and the muffler. Many have been happy with a Walker Big Truck Muffler.
The turbo on our trucks is 100% mechanical so no need to get tuning for modifications.
A 3 1/2" downpipe should be more than enough, especially for stock sticks. I upgraded to a 4" turbo-back MBRP exhaust awhile back (the downpipe b-a-r-e-l-y fits through there). I rebuilt the turbo at the same time so I couldn't tell you if it made a difference or not in performance but making a bigger hole for the exhaust to leave can't hurt.
I cured my turbo surge with Riffraff's billet 4/4 wheel.
The turbo on our trucks is 100% mechanical so no need to get tuning for modifications.
A 3 1/2" downpipe should be more than enough, especially for stock sticks. I upgraded to a 4" turbo-back MBRP exhaust awhile back (the downpipe b-a-r-e-l-y fits through there). I rebuilt the turbo at the same time so I couldn't tell you if it made a difference or not in performance but making a bigger hole for the exhaust to leave can't hurt.
I cured my turbo surge with Riffraff's billet 4/4 wheel.
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Lead Driver
Joined: Dec 2006
Posts: 7,093
Likes: 147
From: San Diego, CA
Timing yes, boost no. Tuners can remove the defuel at 24 psi so the fuel doesn't stop but the turbo builds the boost that the turbo builds.
As I mentioned our turbos are 100% mechanical so tuning can't change the turbo's characteristics. That's where housings, wheels, red line mods, aftermarket turbos, etc., come into play.
As I mentioned our turbos are 100% mechanical so tuning can't change the turbo's characteristics. That's where housings, wheels, red line mods, aftermarket turbos, etc., come into play.
Mountain Pass
Joined: Aug 2018
Posts: 188
Likes: 8
Timing yes, boost no. Tuners can remove the defuel at 24 psi so the fuel doesn't stop but the turbo builds the boost that the turbo builds.
As I mentioned our turbos are 100% mechanical so tuning can't change the turbo's characteristics. That's where housings, wheels, red line mods, aftermarket turbos, etc., come into play.
As I mentioned our turbos are 100% mechanical so tuning can't change the turbo's characteristics. That's where housings, wheels, red line mods, aftermarket turbos, etc., come into play.
Logistics Pro
Joined: May 2017
Posts: 4,667
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From: Muskogee, Ok
Well it's not JUST timing. They also adjust ICP, injector pulse width, add extra fuel, some adjust the barometer and ambient temp as well, basically anything with a sensor gets messed with.
Then there's transmission stuff to fiddle with on autos
Then there's transmission stuff to fiddle with on autos
Lead Driver
Joined: Dec 2006
Posts: 7,093
Likes: 147
From: San Diego, CA
You can adjust your wastegate. Many do the “red line mod” which is remove the red air line from the wastegate and cinch it up in an intake clamp. This leaves the wastegate shut longer. Anything more than 30 psi on the stock turbo, though, and you lose efficiency.
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