You have all seen photos of this combo before, but this will give some insight on the set up.
All these photos were when I had the set up using pauter heads...I never got a full power run with this combo,
but when originally set up using AF bugpack heads on a smaller 2827cc engine it ran 9.76 at a whopping 147mph
and the car weighed 1870lbs (850kg).
The slide rule showed 455hp.
The 1/8 mile time was 6.4@117mph.(best was 6.32)
In my chassis car with ballast up to 1850lbs it ran 6.19, so it would be very fast in a 1600lb car.

[ Edited on 19-9-2006 by dangerous ]

More info Dave.....please....

These units are 3150 model Autorotors that are made by the Opcon Group in Sweden.
They were special ordered with a 2.3 pressure ratio, which is the ratio of inlet to outlet pressure(absolute pressure)
that is achieved inside the blowers before the air is released into the manifold.
I chose two units because at the time there was not a single unit that would be big enough(there is now).
3150 means series 3 (rotor diameter) and 1.5 litres per revolution.
Because they are of the screw design, they use less power to drive, and create less heat in the air as it is compressed.
The factory says that each one, if run flat out (14000rpm) is good for 400hp...which I believe, having tried to drive this thing with only 10700 rotor speed.

[ Edited on 27-5-2006 by dangerous ]

OMG....

Thanks Dave...how long till the chassis car sees some track time

These have been sold off to buy food.

The air comes in through these 65mm butterflys mounted on the end of the blowers and is compressed internally and released through this 3" adapter.
This is no show-piece.
I mounted the two blowers between two pieces of 10mm aluminium(6061 I think).
On the forward facing end it attatched to the two top engine bolts,
and on the pulley end it bolted to the top of the case with four 10mm bolts.
Those butterflys (which were too small) poked through the Volksy firewall and had K&N air cleaners attatched.

who bought em? and what are they going on?

The air went into 3" tubes, and into small plenums, on the first set up with the bugpack heads.
But in this case, I made these frankenstein lookin' boxes (that swelled under boost) and welded them onto Pauter IDA manifolds.

You guys love gossip!
The owner has sworn me to secrecy.
He would be cranky if I told....

Hey Dave

You certainly etched your name in Australia's VW drag racing history!

I'm still in awe of what you achieved on a wage and how you manufactured so many of your own parts...!!!! :thumb

OK.
The pulley system used a Gates multi-vee set up with 10 grooves.(should have had 12)
The overdrive is 1.53 times engine speed.
Depending on the engine size (2827cc up to 2965cc) and cam (258derees up to 292 degrees@ .050")
it had at least 30psi boost and up to 42psi.
At 30psi the belt life was fair ...about 10 runs, but at 42 it only lasted about 5 runs
before turning into a bunch of black rubber strings.
Power consumed by the blowers was about 100@30psi..so125hp?.
This sounds like alot, until you compare it with the old Godfrey that used the same power
to make only 270hp on my 1775cc engine (28psi boost).

[ Edited on 19-9-2006 by dangerous ]

starts to dribble and continues to play in the sandpit :duh

The blowers weighed 16kg each and are made from billet aluminium.
The cost? I have put that deep into the recesses of my psyche, but
I remember that it took me a year to save up the money for the blowers alone
and over 3000 dollars in fuel system parts.
Just the aluminium materials for the brackets and pulleys was over 500, so you can understand that this project
was indeed madness.
This blower is the same unit used on Top Fuel Motorcycles, like Jay Upton in Australia
and Elmer Trett in the USA.

[ Edited on 27-5-2006 by dangerous ]

The fuel system on this combo was a night mare.
The biggest trouble was under estimating the power output.
I ran methanol fuel and it consumed about 8 litres per run.
Current normally aspirated combo uses only 2 litres, and that is driving to and from the start line from the pits.
The blown deal was towed to each run from the pits.
The N/A combo at 7000rpm flows about 600ml in 10 seconds.
The blown deal flowed 3litres in 10 seconds.
It had 10 nozzles.
Two in the blower intake, and eight in the ports.
Four of those in the ports ran at Idle to even up the cylinder temps and the other four opened at 3000rpm.
The two in the blower intake were there to cool the charge and seal the rotors. They ran all the time.
About one third of the fuel used went through the blower.
On the old roots blower it was the other way, about 3/4 went through the blower.

[ Edited on 27-5-2006 by dangerous ]

The pulley system was a bit of a mission to make.
In between the pulleys on the blower there is an idler that
is positioned so that there is maximum belt wrap.
There is a tensioner that is spring loaded, and it is bolted
to the mounting plate, just below the left pulley.
I got this tensioner from a Cummins diesel engine and
fitted a sleeve to its wheel, to allow for the wider belt.
The tensioner has to be spring loaded so that it can unload in the event of a backfire. Otherwise the blowers would be damaged.

This photo shows the bracing welded to the plenums and
the other one shows the linkage for the barrel valve.
The barrel valve controls the fuel flow using a progressive depth slot,
to give a gradual transition from idle through to full throttle.

Dave,

I can NOT believe how many hours must of been spent making things.
And then to make it all work! Good stuff. pity it's not all in a new car.

keep it all coming to educate us turbo people.