Has anyone dynoed there stock 5.4 Ive seen sheets any where from 200rwhp-250.Can u even do a real dyno pull with the speed limiter?Maybe thats why the numbers are all over the place any thoughts.I find it hard to believe that if u have 300 on the motor u lose 100hp threw the drive train.The trany cant suck that bad.Can it?

 

there are many factors to a dyno. ranging from the dyno type itself, elevation, to ambient temp, motor temp, humidity, and how recent it was calibrated.

alot of the 200 HP sheets you see are from companies trying to sell something. they dyno the truck with the engine hot and multiple pulls. 99% of unaltered dyno runs are done while the engine is cold since it makes it's peak power at colder temps. they could have also done a run while the temps were 90+ outside and the air charge was less dense.

then these companies slap their CAI/Programmer/Exhaust on there and don't fudge the dyno up. you instantly see a huge result.

in the forums, I've seen roughly 240 rwhp is standard for guys who have nothing to sell/prove. Once a product is involved, it appears 200 rwhp is the magical #.

I'd like to dyno my truck as is, but I'm honestly too cheap to pay somebody somebody so I can floor my truck. Maybe if I buy and Edge. that would be a nice dyno set. A before/after run

 

nowadays with the high quality fluids and components there isn't as much loss as in the "old" times... i'd say if the 5.4 is rated 300, you're likely getting 240-260 on the ground depending on the configuration of the truck.

 

Hyper techs web site says 251rwhp on stock motor that sounds about right.

 

tylus has a good explination.
50 hp loss from the crank to the rear wheels is about right.


There could be many differences between dyno pulls.
It's usually best to pop the hood too for different engines.
There are so many different factors.....



You loose power through the transmission, transfer case, and rear axle.
Synthetic fluids seem to help, and I've seen a 6 hp gain switching engine, transmission, and rear end fluids to full synthetic, and if it is time to change your rear axle oil, it would be worth it to go full synthetic, but if you just changed it, it wouldn't be worth draining it and adding synthetic.

I even put Synthetic Mercron V in my transfer case.
Not for the power, but it was time to change and it was on sale.

 

I had my truck on the dyno in April. Factory tune, factory intake true duals.

We wanted to see what the truck would actually do stock. I was surprised to see the
results; however that made sense to me because the truck seemed like it
had no power at all. That is due to Fords factory PCM programming.

Factory ---201 RWHP was all we got with 5 pulls.

Then I added AFI 3 1/2 CAI\ custom tune; 6 more pulls.
257 RWHP. We were not fudging the results or anything like that.

The computer controls everything on these trucks so it is possible to lose quite a bit of HP.

 

is that the 5.4 with 200hp?? find that hard to believe that they'd lose 100hp through the drivetrain... interesting...

 

It is typical to loose around 50 hp through the drivetrain.
The other 50 hp lost is from the computer controling everything.... This computer tells this computer to go WOT, but the other computer sends the first computer a hazard code, and it doesn't give you full WOT.

Nothing techical about that, just saying I hate computers that don't let me control MY truck.

 

No stock 300 HP F150 is going to see 250HP at the wheels with corrected dyno numbers. Also, power loss is not from the computer. The reason the throttle seems laggy is not because of power loss due to the computer, but from throttle response. Bad throttle response and good throttle response, with all other things equal, will both show the same numbers on the dyno but the bad throttle response will "feel" less powerful.

The rear axle alone is about 97% efficient and loses about 9 HP. Plus the large wheels, transmisson, power steering pump, cooling fan, etc. It all adds up very fast. Figure if you are lucky and a more efficient drive train about 60HP loss but most folks will see much, much more loss. With 4x4 and/or larger tires it gets worse and the numers will quickl approach a 100 HP loss. Remember, these dyno runs are in second gear on an F150, usually with the torque converter unlocked. That will cause lower HP numbers but higher torque numbers. You cannot do an 3rd or OD pull on them because even without speed limiters tire and axle speeds would get dangerously high. 2nd gear pulls can exceed 90 MPH.

The gains seen by good tuning is because the tuner is squeezing more out of the engine but the underlying losses are the same. The stock PCM was not "lossing" more than the new program is.

The throttle response hasn't anything to do with computers talking each other (there aren't computers talking each other, there is a single PCM). The throttle response (which is not related to horsepower) has to do with the PCM on the late model F150 trying to control part and light throttle vacuum, tip-in and throttle bobble sensitivity and the pedal slope in order to try to improve mileage (it gets very complicated down deep in the PCMs ETC tables).

It can all be demostrated with tuning software at a dyno...

 

So slf06150 picked up 56rwhp with a tuner and cai.That would be about 75hp at the motor improvement if we lose 33% to the wheels.Sign me up that would be great.

 

I call bull***** on slf's post...

 

I don't know what my "before" hp was, but after installing my 3.5" AF1 and custom tunes, I had about the same hp as his.

I know guys run 16 and 17 second quarters bone stock and I ran a 15.5. CAIs and tunes definitely increase HP.

 

Tunes can help by firming up the shift points, and WOT settings. CAI's don't do anything. Do you really think the intakes were an afterthought by the manufacturer? They spend a whole lot of time and money on those, just to have someone sell a new tube with a sticker on it, with a big oiled-up cotton ball on the end of it.

Reading that guys original post, he said he had a factory intake on it...No cai. I responded to the other guy who replied to his post. I still have trouble seeing 57rwhp (since it was dyno'd at the rear wheels I'll assume) from a tuner and exhaust.

 

Only reason I could see a tuner adding that much power would be it getting rid of the computor limiters (for a lack of a better word).
Other than that, you are right, the CAIs don't help, and a tuner doesn't add that much power either, but they do get rid of the throttle delay...

 

that's why I believe the true HP #'s are about 240 rwhp.

The exhaust doesn't really do anything but make happy noise. The tuner is where it's at power wise. Honestly though, I wouldn't be surprised if the better transmission controls didn't free up alot of ponies with 0 other PCM changes