Hey Mason Here,
I was wondering what the difference between a 4.6 and a 5.4 is other than size and horsepwoer. I know the 5.4 is the bigger motor. But i heard some rumors that i wonder if they are true. I heard that the 5.4 gets 10 more horse power than a 4.6. But i also heard that the 4.6 gets a higher top end speed then the 5.4. I was wondering if those were true. I also heard that the 5.4 is like a 351 and a 4.6 is like a 302 or a 289. I have a buddy who has a 4.6 with a superchip in it and it gets 21 mpg's. I was just wondering what the main differences were besides size.

Thanks,
mason

 

It depends on what years you're talking about. Pre-1999, the 5.4 only had 235 HP/335 TQ while the 4.6 had 220 HP/265 TQ.

Then after ford introduced the performance improved heads (PI), the power of both engines increased. The 5.4 went up to 260 HP/350 TQ and the 4.6 went up to 231 HP/291 TQ. The 5.4 got PI heads in 1999, while the 4.6 had to wait until 2001.

The cubic inch for the 5.4 is 331 while the 4.6 is 281, but they perform so much better than the 302's and 351's.

The modern 5.4's and 4.6's are now 3 valve engines, which make more power, torque, and MPG's compared to their 2 valve counterparts. The only trade off is reliability.

The rumor that the 4.6 has a higher speed is wrong and I seriously doubt your friend gets 21 MPG's with just a CrapperChip. He's either pulling your chain or can't work out simple simple simple math.

 

 

I can sometimes pull off 21 mpg on the hwy...city driving is a totally different story though.

 

^my dad averages 20 or so with his 99 4.6. He drives highway everyday though. All stock.

 

i averaged 20.6 on a 300 mile drive to Austin, interstate the whole way CC (when it worked) at about 70 AC on low

 

and this is a stupid thread already, bouta be a big debate and argument and banning and buncha butt hurt people!!

 

Damn good post Punisher. Yea , they took their time upgrading the 4six. Maybe it wasn't as fun to upgrade ? The 5.4L was a very nice upgrade. Your absolutely right , - for sure; ~ The 351's were out done big-time by the 331.

Right , the 5fours in 99 and the 4sixs in 01. But, as far as the 5four, you want a F150 engine to late 2000, maybe even 2001.. The F250's/350's and E250/350's (w/the 5.4L) were still non PI for awhile. At least 2 years after the F150.

 

yea man thanks alot. that does make sense. and yea he told me that he was getting 21 mpg's and told me if i had a 4.6 i could do the same thing if i dont get on the gas. but i do have to ask you this, which would you rather have?

 

yea the one my friend has is all stock

 

yea. I really dont mean to start a big arguement and hurt feelings, you can just never know whats right and whats wrong so i was hoping to see what feedback i get on here because if different people keep telling me the same thing then it must be true. I'm just trying to get info i really dont mean to cause hard feeling and stuff. If it starts to get bad i'll try and delete this thread but like i said im just trying to see whats true and whats not.

 

Neither. I really want one of those new 5.0's or 6.2's.

 

Don't worry your not hurting anyones feelings by asking your questions. Some people around here like stirring the pot for no good reason.

 

You meant to say, the 5.4 really needed the PI upgrade b.c it was way under powered, so they had to do it first