yup.mines real slow.

[chris142]

i posted the other day about how sluggish mine is. especially pulling a trailer. today i drove a customers 85 f250. this truck is also a n\a 6.9 and it has 35in tires. this truck would chew mine up and spit it out!

funny thing is that its all original injectors and pump. the engine is covered in layers of grime and it idles with a shake.

it has a 4 inch straight exhaust and i have a 3 inch with a flowmaster. would a straight pipe make that much difference?

 

[kuskoal]

An engine is one giant air pump. The more air you can effectively move through it, more efficient it becomes! Bigger exhaust can't hurt unless you are running n/a. Then you have to properly size it. Are you sure your truck has the timing set?

 

[icanfixall]

What gears were both trucks. Timing has plenty to do with it also. Tire size will be a factor too.

 

[chris142]

my timing is somewhere between 8-9.my meter is not as exact as garys. mines a stick and the customers is auto. my tires are 285's and his are 35's

my air and fuel filters are new. im getting full throttle( i checked that first). they can build 10 engines. 2 run great,6 run ok and 2 are dogs. mines a dog

 

[ryanecvbrown]

My '87 with a slushbox was a pig. Dropped in a ZF and 3" exhaust and she woke up a bit. Had 285's and 4:10's. My '84 has all my goodies from from the '87 except 3.55's spinning 285's. This truck has way more cojones. It seems to me that diesels in general like to "tug" against the gears. At least my pants dyno says so. '87-screaming up grades in 4th at 65 with a decent amount of go-pedal. '84-cruises up the same grades in 4th at 65 with little effort and much less throttle input. My old service truck was a '97 PSD with 4.10 on 255/70r19.5s. Bosses truck was of the same vintage but with 4.88s and I could dust him everywhere we went. Both trucks outfitted the same and scaled-in 200lbs apart with mine being the heavier rig. Again, my pants dyno felt that letting the engine "pull against the gears" was what kept the pigs away. Just my not scientific $0.02.

 

[fordf350man]

mine was really slow, aggravating slow, i turned the pump up and it made a huge difference, and it only puffs out smoke at full throttle

 

[Greg5OH]

I know what you mean about "pulling against the gears" its the torque doing work of actually accelerating, instead of horsepower..if that makes sense.

 

[ryanecvbrown]

Makes plenty of sense. Seeing as how anemic our factory hp rating are vs a pretty decent torque rating, let the torque do the heavy lifting and the ponies will somewhat follow suit. I get a lot more out of each gear with the 3.55 ratio. I also don't mind winding the engine to the moon when it's time to tow or haul either.