TORREY1150

Hello,

I just got a 99 motor with 92k miles in my 97f150 and it does not seem as powerfull as the old one. is there time needed for the tranny and motor to learn each other? It shifts fine and smooth maybe just a little early at normal acceleration. When I step on gas to pass someone or speed up to get on the interstate or even from a red light it seem the engine works harder to push the truck and i dont feel the force back in the seat like the old engine.

ymeski56

Thread moved to 97'-03' section.

ibd2328

iTrader: (2)

Have you checked your tranny fluid?

Also you moved up from a non pi enginge to a PI enginge. So their is a combustion chamber difference and ratio difference.

Tackle

I hate older trannys.

ibd2328

iTrader: (2)

Don't hate. They just have a few extra parts that aren't needed

Cmanjr

What is a PI engine? I never figured that part out. And what's the difference?

ibd2328

iTrader: (2)

Pi are the heads. They came out in 99. They have a combustion chamber of 44cc. The non pi are 51 cc.

ibd2328

iTrader: (2)

If you put PI heads on a Non PI enginge, you will see an increase in power due to compression. THe pistons were dished differently on both.

If you want 25-30 hp or even better put some pi heads on a 97-98 block.

Cmanjr

Ah. Is there any difference on a pi engine other than the heads and the other things you stated? Cause if you can get 25-30 hp.. That sounds pretty cool. Maybe something to be done eventually down the road.

ibd2328

iTrader: (2)

PI heads stands for performance improved. They have different style intakes and require a intake manifold from a 99-03.

The reason the HP went up 30 from 98 was the PI heads. But also realize, when they changed to PI intake they used greated domed pistons than the Non PI heads.

If you were to add PI heads on the Non PI block with the Non PI heads, I would expect to see 300hp at the crank (if new).