is there any advantages disadvantages of the swap?

 

non turbo or turbo???

 

non turbo

 

I am assuming that you mean using a S5 intake manifold on a S4 motor???

A complete swap, there would be no advantage, and has actully been shown to lower peak HP, however a hybrid S4 lower intake manifold used with a S5 mid/upper intake manifold with the VDI and aux ports functioning correctly has been show to provide about a 10 peak HP increase.

The disadvantage to that hybrid set up is simply the time, and cost to port match the manifolds and fitting them to the car as well as the loss of the EGR, which may make you fail any smog tests in your area.

 

Your loss of the VDI and several horsepower.

 

where is the VDI located on the manifold? I think mine was removed

 

middle section of the manifold

 

Ok. Which is it. A series four on a series five or series five on a series four?

IF you have a series four you don't have a VDI. The series five has the VDI.

 

I already had my emissions removed so I mated the S5 UIM to my S4 LIM and put in an electronic VDI activation system. Throttle response seems a bit better and there is definatly a power gain, especially when VDI kicks in.

The only problems I've had is that the idle is a bit rough and it stutters a little for the first few seconds of startup. These problems could be caused by something else and I lack any form of ECU tuning so I can't do any fine adjustments to smooth it all out.

I also found that wiring the aux. ports open after the swap worked better then having them actuate (they were working flawlessly but I'm guessing it's because the S5 UIM doesn't allow as much flow as the S4 so the aux. ports open help even that out?)

I've also read that if you have a ported motor or have any form of forced induction the S4 manifolds flow alot more and will work better for you.

 

With some careful grinding, you can keep your EGR