Ive read on the FTE forums, that the computer restricts power during the break in period? can anyone confirm this? Because ive seen dyno sheets of the 04 f150 5.4L only puttin 210 rwhp, which is way too low if it is rated at 300 hp. A lot of ppl have claimed their truck wakes up after about 1 or 2k miles.

 

NO the computer has no effect on break in.

Wearing of components and the computer learing driving habits make the truck stronger as time/miles wear on. you will notice as much as 10-20 hp difference at about 4-5k miles.

my 300hps showed up about a month ago.

 

I've also heard that the 300hp rating is rated at the crankshaft, not at the tires, so there will be a significant difference in rated hp versus what you'll see on a local dyno.

 

i should of made more clear that the rwhp ratings should be around 240-250 rwhp to the wheels if it rated at 300 hp.

 

Never saw a car that quoted rear wheel HP. Since different trans will translate different amounts, to stay consistent, and quite frankly to make the numbers bigger, they rate with flywheel power. Typically, sticks sap 20% and autos 25% of rated power. An auto 300hp should expect about 225 rwhp and stick 240.
An auto 240hp would be about 180rwhp and stick 192. Most people rate their vehicles with RWHP because its easy to dyno in the car instead of pulling the motor and it more closely reflects what their car will do. So you probably do have a 300hp powerplant even if you only see 225 on the dyno. Hope this clears this up.

 

hmm, the dodge ram hemis are considered overrated at 345hp, but they put down 270-280 hp at the wheels, which is considerably more than the f150. They r prolly only making about 320-325 at the crank. Just a little FYI

 

I missed by 5%. Auto is 80% and stick 85%. This makes 300 auto 240 hp. A 345 hemi with auto would rate 276hp. Fits right in with what you are seeing.