4.2L engine manifold intake for racing

[VikingoTropical]

I'm building an little car for track use and I need some help with the strange manifold intake on the 4.2L engine.
As this is my first Audi engine (I normally just use Porsche units) I don't have a clue what to do to this complicated intake full off flaps and channels!
I have eliminated the flaps but all that wrinkly channels.....
I don't want to build an new manifold but this one doesn't look as I think they suld do on an race engine.
Anybody has an idea what to do?
http://i57.tinypic.com/m9y32w.jpg
http://i62.tinypic.com/dgnwhw.jpg

[v8a6]

OK so, Ill preface this by saying that I am not an Engineer or engine builder. I can only give my opinion in laymans terms with a bit of knowlege of these engines.

So, first, Audi has a lot of different 4.2 engines. I am going to assume that your engine is from a C5 A6 4.2. Only because I see you cross post in the C5 section. If this is wrong, then the specifics will not apply, but the general information may still be helpful.

The best manifold for a street car in the C5 A6, S6 or D2 S8, is the S6/S8 stock intake manifold. It has variable dual length runners that either boost make a differnce in peak hp or tq, of about 30-40hp or 30-40 lb/ft torque at either end. That being said, you should really have the S6/S8 heads to get the most out of the high end. This is a dyno from my 4.2 that had ported S8 heads and S8 intake manifold

http://gp1.pinkbike.org/p4pb9624584/p4pb9624584.jpg

Compare the tq lines. The blue one is when things werent quite working right on the car, including the intake manifold. You can see the TQ fall away after 5000 rpm in the blue. But on the red line, once the manifold was working properly, at around 5300rpm, and then the RED takes off. By 7000 rpm this equates to about a 50hp difference.

Now, on a race engine, I am guessing you would keep the revs up, most of the time. If so, you would probably just want a single plane short runner intake manifold tuned to your engine. If you want something easy, you could use the S6/S8 one, and just lock it in short runner mode. This would be very simple, and you wouldnt have to worry about the ECU controlling it.

If you want something better, then you would want something like the R8 or Spyker design.

http://pictures.topspeed.com/IMG/crop/200701/2008-audi-r8-64_600x0w.jpg
http://wiki.quattroworld.com/images/c/c5/Spyker_01.jpg.jpg

Here is a video of an awesome setup on a v10 Audi engine. Same idea

https://www.youtube.com/watch?v=6WeohBoqV9I

All of this is assuming that you are keeping the revs high, and the engine will be an NA build

[mk1 rabbit gti]

you could always use the rs6 single plain manifold

[v8a6]

In almost all cases, you are better off sticking with an intake manifold that was designed for an NA car, and made to work well with matching cams. For a forced induction car, the intake manifold is not tuned to provide a natural increase in volumetric efficiency, because it is not needed. The supercharger or turbos just force the air through.

Best affordable setup for the C5 S6/A6 4.2 or some of the 40v D2 engines is the S6/S8 intake manifold along with complete matching heads (cams included).

[VikingoTropical]

I dident know that Spiker used Audi engines![up][QUOTE=v8a6;9956827]OK so, Ill preface this by saying that I am not an Engineer or engine builder. I can only give my opinion in laymans terms with a bit of knowlege of these engines.[up]

[VikingoTropical]

First I want to say that this is just an low budget racer for the local championship but as I own an work shop that build composite parts for racing (Porsche) I do this car in spare time with parts from udder cars.