So I swapped my S4 intake onto my S5 block today. Where the ACV part was on the S5 it had a small rectangular port, the S4 n/a intake misses about half of that port and when the car is running it can be heard and some air felt around it.

My question is, will this hurt anything? I opted for the S4 intake for my own reasons, so far it idles tons better and the power is a bit better overall (VDI was wired on the S5). I feel the extra mid range picked up from not having the VDI wired is a bit better choice than the latter.

I searched on the forum and google for an answer but didn't find anything useful. Information is appreciated.

 

The ports you're talking about lead directly into the exhaust ports. That's the port air path from the air pump / ACV, so you're going to want it to be sealed off.

Why don't you just keep the S5 manifold and use an RPM switch to open the VDI properly?

 

I personally prefer the S4 manifold over the S5 for one. I've never had anything but trouble with S5 manifolds, even working ones, and every car I've ever had has always pulled much better at all rpm's with the S4 manifold. Also, for some reason, with the S5 manifold on this car it barely idles and will sometimes die, and will die if revved and the rpm's are left to just drop, with the S4 manifold it idles perfectly and can be revved without worrying about it dying after you let off the gas.

Is there anything I can use to seal off that little bit of overlap that isn't too complicated?

 

Well, I took a piece of thin copper sheeting I had and cut it to fit the port on the gasket (3 layer metal gasket) and put it between one of the layers of gasket. Put it all back together tight and it successfully blocked the leak without causing an intake leak around the gasket.

Hopefully this will work, don't really see any reason for it to fail, but track time and time in general will tell. Will periodically update this thread with what happens.

 

I remember seeing someone just welded a little tab on the LIM to cover the port.

 

I just did this when putting an S4 intake on my GSL-SE block. I used JB weld and Qwik weld to build the area up. Smoothed the mating surface with a razor blade. Works beautifully.

 

Forgot to post a pic.