<a href="http://forums.audiworld.com/s4b6/msgs/157881.phtml">Just reposting something from the B6 S4 forum</a>.

I noticed that the sc from MTM is for a B6 S4 engine -- and that's different from the C5 A6 4.2 engine.

But they also show an sc on a S8 4.2 -- is that the same 4.2 as ours?

I tried searching on the internet for a MTM S8 supercharger.....but nothing found.

I surely enjoyed the pictures! But there is no intercooler on that S4.....really reduces a supercharger's efficiency.

11:1 compression ratio of the 4.2, as well as the prospect of only seeing 8psi of boost. Still though, most supercharges don't return That much pressure eh?? Turbos are typically much higher... comments?

check yah later

But normally an engine is retrofitted with a supercharger versus turbocharger....so you are starting with a higher compression engine.

Plus, with no intercooler, it can't produce nearly as much power as without, it reduces the efficiency drastically.

I imagine they had to lower the compression ratio.

Here's the supercharger, it hangs below the intake manifold, just above the V on the engine, you see the screws of the compresor in the opening:

<img src="http://pictureposter.audiworld.com/46874/MTMS4supercharger6kleemannsc.jpg">

It bolts into the bottom of the new manifold here....

<img src="http://pictureposter.audiworld.com/46874/MTMS4supercharger1.jpg">

Here's the picture of the S8, you can see both of them are attached, the new intake manifold on top, with the roots blower on the bottom being driven by the belt:

<img src="http://pictureposter.audiworld.com/46874/MTMS8compressor.jpg">

The old manifold is on the floor, see how big it is? The Audi manifolds have different length runners in them that open at low/high speed, that's what the thing is on the front, a vacuum device to move the round intake runner inside the manifold.....which isn't in this system:

<img src="http://pictureposter.audiworld.com/46874/mtmapollomotor.jpg">

So now you run a lower efficieny roots blower and put it right on top of the engine below the intake manifold.....how hot do you think that thing gets?

I would say WAAAAY too hot.

On my proposed centrifugal blower, it could actually compress the air and the blower might even cool off a little relative to the location of the other blower on top of the engine....

Plus I would most defintely add a intercooler.....would make tons of sense....

It seems to me a better application.....but I've never designed a system, so I'm sure I am missing about 85%!!!! ;-)

<img src="http://www.procharger.com/SPORT_COMPACT/images/FX35_uh_lg.jpg">

so yea, i guess case cooling comes before intake-air cooling...

but all in all this is great stuff! i'm keen to see where this all goes. The reason I watch this board is b/c one day the dream is to do a 4.2L swap into my B4 90q. So prettymuch I'll be adding as much extra crap as possible, and will be able to place it as needed since the whole engine bay will be apart. MTM would be sweet, but I understand that anything which carries their name is mucho deniro

check yah later