can i put and does a VDI fit in an S4
 

hi im wondering if an s5 VDi fit into an s4 motor. if it does, how do i install it and how much of a difference would i feel..from your opinions. thank you!

It is possible, with a fair amount of modification. There is a site that goes into detail. You need an S5NA BAC, fuel rail, upper intake manifold, lower intake manifold and dynamic chamber. And a RPM switch would be handy too. I forget what else, but you definitely need all that. There is quite alot of modding needed though, definitely a big project; but from what I have heard its worth it.

You'd have to do a full S5 intake swap. There are enough differences that it's not a bolt-in swap, and I've heard reports that the S5 intake on a S4 motor actually reduces power slightly - it's tuned for the S5 motor specifically.

I believe if you search there are some good threads on S5 intake swaps & some dyno sheets from before & after.

-=Russ=-

I heard the opposite, it flows better and in increases power by about 10-15hp when the VDI kicks in. (according to a dyno)

You can get away with using the s4 LIM and s5 uim/dynamic chamber/tb with a little modificating/drilling. But it's easier to just use the whole setup.

On stock ports it'll increase power because it is a much better setup/design with the variable intake length. There's a full s5 intake setup on ebay right now if you're looking for one.

Actually my dyno testing showed a loss of HP and torque at below 5000 RPM when using a complete S5 VDI intake system on a stock port S4 non turbo 13B. The only gains (when the entire S5 intake was used on a S4 motor) were above 5500 RPM to about 7000 and even then only about 6-8 HP.

The only system that showed a true across the whole RPM range gain was using the S4 LIM port matched with the S5 VDI and UIM, on a stock port non turbo motor. The LIM on the S5 system has narrower runners, which while increases high RPM power, lowers low RPM power. The S4 LIM is a better compromise as the runners are considerably bigger internally. This produced a 3-12 HP gain across the board, and a 3-6 ft/lb gain, again through the whole RPM range and on a stock ported motor.

The standard S5 intake on a S4 motor write up (that many people use) on Carl Davis's site also mentioned the power loss in a later update, and the original gains posted turned out to be a loss on a more stock spec compression/newer motor.

There is no difference in the s4 and s5 stock block intake port setup, so there should be no difference in how much power this setup makes on one or the other. That said, the sheets I've seen show a 5-8rwhp gain with a properly functioning vdi setup.

Your older car does not have the ecu inputs or outputs required to operate the vdi valve. You'll have to rig up an rpm switch, an rpm pill, and a solenoid to do this for you.

To put the whole vdi intake setup on an older engine is not that big a deal, a little grinding is necessary as well as removing most of the emissions and rerouting a few hoses. Honestly though, unless your intake is off for some other reason or repair, I wouldn't do the job just for the sake of putting the vdi intake on.

I did the swap, used s4 LIM and s5 uppers. I gained more power, and have smoothe power all the way to fuel cut (at 8k). There are two great threads full of information at www.teamfc3s.org/forum that go through the whole process and shouldanswer any questions you have.