Is there any mechanical difference between 158 and 175 hp?

chris142 · Oct 1, 2022

My f250 has the high elevation 158 hp engine.i realize that these trucks are slow but mines pathetic. I can't run the 55 mph speed limit when pulling a small flatbed trailer.

Is the only difference between the HP ratings the pump output or is there more to it?

IDIBRONCO · Oct 1, 2022

I believe that there isn't any mechanical differences.

Clb · Oct 1, 2022

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chris142 · Oct 1, 2022

Clb said:
D
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Man

Just wondering if the only difference is the pump and possibly the injectors or is there more like a different cam .

Is the basic engine exactly the same between 158 and 175 hp?

03wr250f · Oct 2, 2022

Yes the engine is the same
They change the calibrations on the ip to not produce as much heat /fuel (egts) in higher elevations
How many miles on the pump and injectors?
Do you have a egt gauge? If so you can likely turn the pump up and get more power out of it, unless the pump is wearing out, when they are worn they can also give symptoms such as lacking power

hacked89 · Oct 2, 2022

Only thing I’ll add is IPs are designed with consumables and have 100k rebuild intervals, wherever that fits in to your application

chris142 · Oct 2, 2022

03wr250f said:
Yes the engine is the same
They change the calibrations on the ip to not produce as much heat /fuel (egts) in higher elevations
How many miles on the pump and injectors?
Do you have a egt gauge? If so you can likely turn the pump up and get more power out of it, unless the pump is wearing out, when they are worn they can also give symptoms such as lacking power

Pump was rebuilt just before I bought the truck by a stanadyne place in Alaska. No info on the injectors. May be original or may or may not have been tested at least. Dunno.

I am old school and added a smoke mirror after turning the pump up slightly. It's getting plenty of fuel. It's just too gutless

chris142 · Oct 2, 2022

Oh. Pump has about 67000 miles since rebuilt

gnathv · Oct 2, 2022

Are you able to check your timing? It can make a difference.

chris142 · Oct 2, 2022

Yes I have a meter and timing light. Set @ the recommended 8*btdc @2000 rpm

03wr250f · Oct 3, 2022

If it's still gutless, but It feels like it's running properly, as in it always has the same amount of power vs the power comes and goes, that is a n/a idi
My suggestion find a turbo kit. Makes a huge difference
Helps even more if you start making about 10-12 psi over what most kits are regulated to of 7psi

Booyah45828 · Oct 3, 2022

I don't think there are differences engine wise, just the pump being turned down to accommodate having less air at altitude.

If you've got the mirror, keep turning it up a flat at a time until you get haze/smoke, then back it off. NA tuning is pretty easy, and you don't really need a pyrometer for it IMO. If it's still pathetic, your next step is turbocharging and intercooling.

You can throw air and fuel filters at it too, as both of those being past due can lead to a decrease in performance.

Old Goat · Oct 3, 2022

W/O a turbo, I call then naturally exasperated.

I agree, a turbo will wake them up.
You can only do so much on a NA Engine.
More Fuel = black smoke. Need more Air.

Goat

WrenchWhore · Oct 3, 2022

When I ran my truck a 8 degrees it was ok but It really likes 9.5 degrees. It's an NA 6.9. If the air filter is nice and new it's not outlandish to think the exhaust is plugged up if it's the original muffler. Then again my truck has pretty good compression 400-430+ psi and it's still pretty slow.

chris142 · Oct 3, 2022

Booyah45828 said:
I don't think there are differences engine wise, just the pump being turned down to accommodate having less air at altitude.

If you've got the mirror, keep turning it up a flat at a time until you get haze/smoke, then back it off. NA tuning is pretty easy, and you don't really need a pyrometer for it IMO. If it's still pathetic, your next step is turbocharging and intercooling.

You can throw air and fuel filters at it too, as both of those being past due can lead to a decrease in performance.

Filters are new. It's getting plenty of fuel lol

Is there any mechanical difference between 158 and 175 hp?

chris142

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IDIBRONCO

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Clb

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