horsepower and torque
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New User
Joined: Oct 2003
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From: tennessee
horsepower and torque
i have a 1984 f-250 with a 6.9 that has been modified by a previous owner......in short he increased the fuel 15% and retimed it ...he also turned the rpm up to around 4,000 or he claims that anyway...on the valve cover it said it was 175 hp from the factory.....4 speed trans.....it also has duel 2 3/4" pipes on it............does anyone have a realistic idea of how many horses i have and how much torque......all i know is it is ....STRONG!!!....i live in the mts and 13,500 lb loads of hay don't strain it much.....any ideas?..............inquiring mind wants to know
More Turbo
Joined: Nov 2000
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From: Erie, PA
If what you said is true, you better get a pyrometer (exhaust gas temp guage) ASAP!!!!! Turing up the fuel and not increasing the air into the engine will cause the EGT's to skyrocket. A stock fuel setting runs your EGT's 850-900 degrees, I would hate to see what yours is. BTW pistons start to melt at 1250.
With a 6.9 turned up and no turbo, your looking at about 185-195HP, with a turbo I have seen some folks run over 250HP.
With a 6.9 turned up and no turbo, your looking at about 185-195HP, with a turbo I have seen some folks run over 250HP.
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From: tennessee
horsepower and torque
hey fordiesel69.....the truck seems to be getting plenty of air...i don't have a guage...will have to look into that....the operating temp barely gets to the operating range unless i am really pulling it hard.....the dual exhaust seem to let in a bunch of air....motor has very little back pressure....my previous truck had a 6.9 and a single 2 1/2" exhaust......this on has the duals 2 3/4" from each side.....same as a 5 1/2" dia single exhaust............if you stick your hand in front of the intake it will try and suck your hand down the breather......do the duals add much in the horsepower area.......any idea as to ft/lbs of torque......i don't hot rod the truck but i do tend to pull large heavy loads with it.....4 speed and 3.55 gearing......an auto wouldn't hold up.....that is why they put gears on those 4 speeds.........thanks for the help so far
More Turbo
Joined: Nov 2000
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From: Erie, PA
The dual exhaust definatly helps over the crappy factory exhaust. But what I meant by not increasing the air is, not having a turbo. I know your engine will defianatly flow better than stock.
I will try to explain better. Right now, you have a lot more fuel in the cylinder than the amount of air. If you had a turbo, it actually "compresses" the air into the engine so the amount of cylinder fill is much greater, therefor the piston has alot more air to compress on its way, allowing you to turn the fuel up safely.
More Fuel + More Air= Safe EGT's and more power.
More Fuel + Same Air= High EGT's and not much significant gain.
Also, you stated that you don't hot rod the truck but pull alot of weight, the problem is short bursts of full throttle don't really hurt it as much is running wide open lugging it down under a load.
Trust me on this one, get a pyrometer. They are a little pricey but they really are worth while if you pull. They are a snap to install.
I will try to explain better. Right now, you have a lot more fuel in the cylinder than the amount of air. If you had a turbo, it actually "compresses" the air into the engine so the amount of cylinder fill is much greater, therefor the piston has alot more air to compress on its way, allowing you to turn the fuel up safely.
More Fuel + More Air= Safe EGT's and more power.
More Fuel + Same Air= High EGT's and not much significant gain.
Also, you stated that you don't hot rod the truck but pull alot of weight, the problem is short bursts of full throttle don't really hurt it as much is running wide open lugging it down under a load.
Trust me on this one, get a pyrometer. They are a little pricey but they really are worth while if you pull. They are a snap to install.
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From: tennessee
reply to hp and torque
fordeiesel69........i understand what you are saying.....give you an idea of how i use the truck.....never,never wide open.....about as much as i have ever done with it is 3/4 throtle.....usual pull would be about 6,000 to 13,500 on the trailer.....running in 2nd and 3rd gear up the mtn.....don't have a tach on it so i listen to the engine when it starts to lug i go down a gear and will then back off the fuel to keep the rpm reasonable.......where would you find a pyrometer...never heard of one....the truck does not smoke where the fuel is now unless you get on it....exhaust is clear while running at speed unless you put your foot into it then it blows black until the engine rpm speeds back up......wish it had a turbo......i had rather have the mechanical diesel than all the electronic stuff
Posting Guru
Joined: Jul 2003
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From: San Antonio
autometer makes pyrometers to monitor your exhaust temps. If you have a big exhaust more than likely it shoots the heat out with exhaust. I know my exhaust blows it out pretty far it like a large leaf blower even from over 10 feet away I got stans header and 3" duals on my truck less resrictive exhaust also means more air. alot of the things that apply to gas also apply to diesel(exp. you don't need backpresure ,etc.) as far as hoping them up increase the fuel/air mix going though the motor = more power . stans headers claims that their header are 7 hp less than a turbo I can say this has to be close to the truth my truck get up and goes (I haven't touched the pump yet) the best about not throwing on a turbo is you don't have to wait for it to spool up. You can get more power in the lower rpm bands with gas n/a tricks(exp. a different cam grind)
Last edited by nogo73; Oct 24, 2003 at 11:09 AM.
