wvumtnbkr

(Puts on Flame suit!)

First, I have been searching for awhile (even through the archives) and haven't found an answer to my question. I know it has been asked a bazillion times and I have seen references, but nothing solid.

So here goes... I have an S5 motor I am putting in an S4 car. It is for road racing in a budget limited series. Becuase of this, I would like to keep it as simple as possible. It looks like I can bolt the S4 upper onto the S5 lower intake manifold.

The part of the S4 upper (mounting flange) where it would bolt to the S5 lower would need a notch cut out at the rear most mounting stud.

Do I need to do anything else? The gasket for the S4 looks like it will work if I cut a little notch in it at the same place. Am I missing something?

Next, I don't want to take the S5 front cover off. Can I just unbolt the S5 OMP and put a block off plate there? Do I have to remove the shaft that goes into the front cover? If so, do i have to remove the front cover?

Since this is a S4 NA, I know I don't have to worry about the computer going in limp mode. I will be running pre-mix.

Thanks!

Rob R.

j9fd3s

iTrader: (3)

we did this on our race car years and years ago, we just pulled the rear most stud out of the lower intake, and just bolted it on minus the one bolt (stud).

you can just pull the metering pump off and put a block off plate on. in fact this is the best way, if you remove the guts, then you need to plug oil passages, and so its just simpler to leave it

RotaryRocket88

iTrader: (7)

In order to bolt an S4 UIM to an S5 LIM, you would need to drill a hole in the UIM flange to accommodate the rear-most stud on the S5 LIM (if there is enough material). It sits further away from the rear runner than on the S4 version. It'll end up something like 3/8" out from the original hole. I did the opposite when I used an S5 UIM on an S4 LIM. I don't know what you expect to gain from notching a stud; you need to be able to bolt down the back of the manifold, or you'll get a vacuum leak. If there isn't enough material to drill, just get an S4 LIM. It will bolt right up, and if this car is for racing, the emissions port differences won't matter.

wvumtnbkr

The S4 doesn't bolt right up. There is a rectangular port right below the two center ports that the S4 intake does not cover. That is the entire reason I was going to use the S5 lower.

I didn't mean I was notching the stud (Yes, I realize that is exactly what I wrote). I was going to notch the flange of the S4 upper manifold. This would allow me to slip the manifold over the studs. I can then use a washer and a nut to sandwich the flanges together for that one stud.

So the OMP is fine just being blocked off?

I guess that means I don't need to run an S4 Front cover.

Derekcat

iTrader: (8)

Will your race series let you run the S5 upper intake? If so I'd just do that.. Free power ^_^

wvumtnbkr

How do you operate the S5 intake WITHOUT adding anything to it. What i mean is: I don't want to add an rpm sensor, air compressor, linear actuator, etc... I just want it to work. The S4 accomplishes this for me.


What about the OMP? Just leave the shaft and gear in place? (I guess I have this correct according to J9FD3S).

Thanks!

Rob R.

j9fd3s

iTrader: (3)

you wire it all open, how much time do you spend under 5200rpm on a race car?

Derekcat

iTrader: (8)

And if you don't wire it open it'll.... Be just like the S4, but bolt on.

The S4 you still have to have a method to activate the aux ports on.. [exhaust back-pressure is the WORST way to do this]

…What? Aside from the airpump, I'm not sure what you're talking about... S5 intake just needs a slightly modified S4 throttle body [there's a protrusion on the bottom that has to be partially ground] and if you decide you want to reinstall the OMP, it'll work if you carefully re-bend the control rod.

wvumtnbkr

I bolted it all up tonight. It all fit. I just had to grind one part of the S4 upper flange. I just used the stock stud on the S lower an dused a washer to clamp the flange. Everything fit just fine.

I am just keeping the ports wired open. I plan to be above 3500 rpm all the time anyway. Maybe I will do something to activate the ports next year.


Thanks for all the help!

Rob R.