I have a 2001 5.4 liter with the 4r70 tranny. Questions:

1) How much horsepower will these stock motors stand?

2) How much horsepower will these 4r70's withhold?

I'm figuring i have around 300hp at this moment, and a 65% increase would put me up to 495hp and about 620 on the torque chart at the motor. So will the motor and tranny hold up and for how long....(shift kit will be installed prior to supercharger install)?? Any input will be greatly appreciated. Thanks.

justin

 

ok, what you have done to your 5.4 wont be 300 hp, sorry, but its true....

anyways, i have been told that the tranny will take easy 450tq stock, and the 5.4 block is very stout. i wouldnt doubt it will hold 400 hp easily, cast iron block. you would have to have a lot of mods done to get that....at least some sort of un natural aspiration, or major engine work...

 

Most people seem to feel the stock 5.4 block will handle between 800 and 900 HP.
How much horsepower does the stock engine make? I though it was 280 HP. If that is the case, a chip alone would get you up to about 300. If it is 260 or so then probably not. There isn't much point in guessing about horsepower numbers. Either go to a dyno or don't worry about it
Transmissions do not handle horsepower, they handle torque. The 4R70 is rated to handle 700 lb/ft of torque (the 70 in 4R70 means 70 x 10 or 700 lb/ft).

This may seem like a lot of torque considering your engine will only be making 620 lb/ft of torque. Unfortunately, you need to take into account the torque converter. The torque converter can more than double the engines torque at certain points in the power band. That means your 620 lb/ft of torque is now 1240 lb/ft going into the transmission.

That would obliterate the 4R70 in stock trim. As it stands, the stock 4R70 is already pretty close to its limits.

Forget a generic shift kit and get the Factory Tech valve body. It will really firm up the shifts and help increase the life of the transmission by reducing clutch wear. Factory Tech (Gregg Evans) makes the valve bodies used in most of the Lightnings and has recently started making valve bodies for the 4R70. I would also add a transmission cooler to help keep the heat down.

If you really plan on making 620lb/ft of torque you are probably going to need a "built" transmission. Again I would suggest speaking with Gregg but there are several other shops that also build good 4R70's. Level 10 is good but very expensive.
The real limiting factor in the stock motor is the fuel delivery system and the connecting rods. The stock injectors are only good to about 300-310 horsepower (I believe). The stock fuel pump is good to about 350 or so. The connecting rods are good to about 450 HP. Beyond 450 and you really need a race built lower end.

This is all just guesses and approximations from other posts on the board. Your mileage may vary. Some people have excellent luck far beyond these numbers, some engines fail below them but they are good ballparks.

-Don

 

The stock 5.4 puts out 260.

I believe the injectors can go higher than 310. I have that to the rear wheels on stock injectors. But, maybe the fmu has something to do with that. Not sure, I haven't done a whole lot of searching around on that.

Are you planning on putting a supercharger on this? If so, don't expect those numbers.

 

this is a subjective question so my take on is that the piston on a stock 5.4 is the first shortfall. the powdered metal rods are living is some lightnings. the injector can easily be changed (when i say easy i mean easier than pistons or rods)

the advertised hp and the real world are 2 different things.

very good point, dont get caught up in this guessing game, always lower than you expect.

i would say that as you get get close to 400 hp start saving for a trans rebuild.

 

hey where did u get that chip from and for how much?

 

I am actually not aware of any piston failures (that were not caused by mistuning) but I am aware of plenty of rod failures. Pistons die because of too much heat, usually due to running the engine too lean. Avoid a lean condition and even lousy pistons will hold up.

Once you start making power with enough RPM, the rods will let go. The Lightning guys are all worried about rods, but then again they have a different piston. Despite that, I still think you will see a rod failure long before you see a piston fail in a stock 5.4.

Is there anything that leads you to believe the piston would or should fail?

-Don

 

the lightnings has a forged piston, regular 5.4 has cast piston. to hit the mid 400 range requires a lot more boost and high boost and cast pistons dont mix. we havent seen a lot of regular 5.4 failure because not alot of people here have attempted these higher levels. i "think" that if you took a mid 12 second lightning (and there are quit a few of these) and put cast piston in with the 10 to 16 #s of boost, that piston failure would occur.
the forged piston is more forgiving when high boost and aggresive tunes are present. with weather change, different gas from different stations with differnt additives and denotation just a few variables away.

my opinion is that the lightning and regular 5.4 longblock are identical, accept that the lightning has a forged piston, so Fords must have a reson for putting a forged piston in the lightning.

also remember that the regular 5.4 has a higher compression, blown motors like lower compression.

 

Very true.

The stock 5.4 has a compression ratio of about 9.5:1. The Lightning uses a dished piston and has a compression ratio of 8.4:1.

-Don

 

i have a 2004 f-150 5.4 2wd with a roush supercharger. I was wondering the same thing. I want to upgrade my trans, but I don't know where to begin. right now it shifts hard when I get on it. what should I do?

 

hello, I have a 2002 super crew cab 5.4 L triton. v8 2WD
well, I have a 2 inch lift on my truck & I run 265/70R16 for now
my motor was rebuilt at 195,000 miles and my transmission was rebuilt at 197,000 miles
I put a new exhaust system and actually just cut the dome of my air cooler and a half and made my own air intake works well.

last quarter mile I had it I was at 115 mph

I was up against a 2012, 5.7 L hemi dodge second gear kicked in, and I was down the road

but it is possible to get 1000 hp out of a 5.4 L triton engine.

I had a 2004 Ford expedition 5.4 L we had 1250 hp in about 1750 torque
I know this motor is Bill to handle a supercharger, and that is coming or I might go with turbos I’m determined to be 1250 hp I’ll let you know how the 5.4 L triton block handles it

 

so you bumped a thread from 2003