[Stinky123]

I am looking at replacing the intake manifold on my '06 Crown Vic.

I am gonna pull it off tomorrow and see if it is cracked, or what.

I was looking for new ones. Rockauto has some, and I think that I am gonna pass on them.

Summit and Jegs both carry the Dorman manifold. It is supposed to be thicker than stock. One of the reviews says that the user put it on and lost about 25HP. Anybody have experience w/it?

It is about $160 and they also carry a Ford manifold that is about 260. Which one is a better deal?

 

[CatSkinner]

Personally, I've had no issues with Dorman and I've not heard of any HP loss, but generally it's best to go with OEM.

 

[85ltdcrownvic]

Its well documented on multiple mustang forums there is a loss of power with the dorman intake because of its smaller ports in shorter runners and poor contruction compared to oem.

 

[Stinky123]

Am I wrong here?

Theoretically, the smaller diameter runners would give higher velocity in the flow at lower rpm and thereby give an improvement to power at low, and maybe mid-range.

A shorter runner, would that work in the opposite direction as far as power goes?

And, of course at higher rpm, it would restrict the flow and therefore restrict HP.

 

[85ltdcrownvic]

The smaller ports would restrict flow leading to lower numbers. As far as runner length, well a longer runner creates more low end torque and restricts top end whereas a short runner intake favors high end horsepower and less torque down low. The bottom line is that using an aftermarket intake such as dorman will lead to less power.

For what its worth my old 98 p71 had a dorman intake and you could feel the loss in the powerband. Torque wasnt as good as factory and top end suffered quite a bit. At highway speeds it lacked any power.

 

[Stinky123]

At highway speeds...Do you mean to say that it lacked power?

 

[85ltdcrownvic]

Yes