Posted 2010-07-12 2:31 PM (#122257) Subject: F250 gas engine Capabilities
New User
Posts: 4
Location: Lovettsville, VA
I have a 2002 F250 basic 4x4 work truck with a measly 24,600 miles on it (I'm 2nd owner, bought the truck in 02 with 4k miles on it) and I tow a '08 Kiefer 24' 2+1 Genesis gooseneck. I'm usually hauling 2 horses. Last weekend a friend & I took our horses from Frederick, MD to Deep Creek, MD along interstates 70 & 68. The highway has pretty long slogging climbs with similar descents. We towed my trailer behind her 550 Diesel dually. I was hugely impressed by the engine braking system and am now concerned about my truck's ability to handle the climbs as well as the descents, pulling my trailer. Would it be prudent to down shift and support the engine with the brakes or solely rely on the brakes? It seems like using the engine would provide much more stability. Thoughts????Thanks,MJ
Posted 2010-07-12 3:35 PM (#122259 - in reply to #122257) Subject: RE: F250 gas engine Capabilities
Expert
Posts: 3802 Location: Rocky Mount N.C.
Welcome to HTW...!!
By all means, down shift and let the engine use it's compression to aid in braking. Is your truck equipped with the 5.4 V8 or the 6.8 liter V10? Straight gear drive or automatic transmission? Remember, that F-550 your were riding has alot more wheel braking than your F-250. Even though both trucks a simular in size, the 550 is a whole different truck, larger frame, wheels, axles, and alot LARGER BRAKES.....
Posted 2010-07-12 3:35 PM (#122260 - in reply to #122257) Subject: RE: F250 gas engine Capabilities
Veteran
Posts: 274 Location: Memphis, TN
Hi MJ & Welcome. What engine and transmission do you have in your 02 F250? What year F550? BIg difference in those trucks braking and transmission systems.
Posted 2010-07-12 4:12 PM (#122262 - in reply to #122257) Subject: RE: F250 gas engine Capabilities
Expert
Posts: 2953 Location: North Carolina
Welcome to the forum ...
Trucks are grouped into classes by weight capability. Your truck is a class 2. Your friend's F-550 is a class 5 vehicle... you were towing your trailer with a truck three classes larger, heavier, and capacity. So, your truck is suffering from a severe case of unfair comparison.
Likely, your truck and trailer are well matched. I would continue to enjoy the combination. Maintain your truck according to the manual and downshift the transmission when descending long, steep grades to save brakes. Never rely solely on your brakes to control downhill speed. Brakes can over heat as well as wear out. A gasoline engine has inherently better braking than a diesel engine.
Posted 2010-07-12 4:59 PM (#122268 - in reply to #122257) Subject: RE: F250 gas engine Capabilities
New User
Posts: 4
Location: Lovettsville, VA
Thanks!!!! I have the 5.4L V8 automatic transmission on the 250. My friend's 550 is an '06 and she just had to have the turbo replaced. the truck only has 44k miles on it!!!I don't know if she has exhaust brakes or not...I don't think so based on the conversation. I hate the thought of getting rid of my truck because it's not worth much and I've done some things to it: wired for pony cam with the trailer, XM radio, upgraded the headlights, Turtle wind deflector, hideaway gn hitch...and only 24k miles...I appreciate the input!
"...A gas engine has more engine braking than a comparable displacement diesel because at low throttle levels a gas engine is working against a closed throttle plate. A diesel has a wide open intake manifold without a throttle plate.
Think of a diesel piston and cylinder like an air cylinder. If you press the piston up to near TDC with the valves closed, it takes a lot of pressure, right? But guess what, after rotating beyond TDC all that compressed air now pushes down on the piston to accelerate it to BDC.
A gas engine will generate about 25" of vacuum with the throttle closed, so when the piston comes up to TDC, very little pressure is there to push the piston on the down stroke. Then, when it wants to pull in a fresh charge, the engine has to pull against the vacuum. All this consumes energy and creates what is termed "compression braking".
Of course, a diesel does produce some compression braking due to mechanical losses and heat generation, but a similar displacement gas engine will always generate more "compression" braking. ..."
A "Jake" brake on a diesel works in the opposite manner. The Jake closes the exhaust so the diesel engine is working against the exhaust restriction. This produces the loud "braapping" and compression braking
Posted 2010-07-14 12:35 AM (#122353 - in reply to #122257) Subject: RE: F250 gas engine Capabilities
Expert
Posts: 3853 Location: Vermont
Also oil will be drawn through the valve guides. This, however, can be a good thing by lubricating the valve stem and guide. It will lead to coking if the guides are out of tolerance or the valve stem seals are leaking.
Posted 2010-07-16 8:06 AM (#122443 - in reply to #122257) Subject: RE: F250 gas engine Capabilities
Expert
Posts: 5870 Location: western PA
My wife and I came over the same mountains a few weeks ago; Pit, Morgantown, Deep Creek and Cumberland round trip. Your truck will be hard pressed to match the performance of your friend's diesel. Those grades are long and fairly steep, and need a motor with quite a bit of torque to maintain the uphill speeds.
If you use your truck's gearing and start out slowly at the top, you shouldn't have too much difficulty maintaining a safe descent speed. This issue was discussed a while ago, with many good tips:
With the recent temperatures, it's imperative that the truck's cooling system and lubricating fluids are properly maintained. The long hills will greatly tax any systems with fluids, and any overheating of coolant, engine oil or transmission fluid can result in significant repair costs.
F250 gas engine Capabilities
