Thread: Supercharger on a 4.6 in a classic

Is there much difference in size and layout of the 3.9 and 4.6.
Graham Coopers did the supercharger conversion on the 3.9 in my 93 Vogue SE. I still had the air con working along with everything else

same motor just different insides and 4 bolt main rather 2.... stops the the engine from pushing itself apart

Well then....they should be able to fit the s/c without losing the air con...best of both worlds. Personally, if I had to chose, i'd keep the air con

I'm also seriously considering going down this road.

I have collected a 1995 4.6 manifold and also a 2000 4.6 Bosch style manifold to compare the differnces, mostly in height when the blower is sitting on top.

I have a Magnuson Eaton M90 which is a lovely blower as it has a spring loaded drive pulley, meaning that when you back off hard, it just doesn't stop boosting but winds down. Really good to take that 'slam' out of a manual gearbox.

Anyway, it appears that some myths are true and that a bad adaptor can make the rear cylinders get a starved mixture. This is because the manifold (or plenum) chamber does not hold sufficient volumetric capacity to feed all cylinders particularly at high RPM's.

Deacon made their first adaptors out of a base plate with holes to line up with the eight inlets. This then had a wall of about 16mm welded on, and then the top plate welded to the wall, thereby creating an enclosed 'box' or chamber where the blower would feed the pressurized air. Problem was that the 'box' didn't hold enough air to maintain sufficient pressurized volume for all cylinders to drag their required air from. The front four cylinders were directly under the blower, but the rear ones had to rely on the limited capacity of the 'box' or plenum chamber.

They later made a box that was closer to 40mm high and fitted it to a car, which is still running (very) strong after four years. Imagine the pressurized volume difference between a chamber that was more than twice the height!

No more starving cylinders, but this setup required a bonnet bulge, or a body lift, not always feasable on a nice late P38 for instance.

I'm investigating alternate methods to mount the blower, or at least to supply sufficient capacity to the pressurized section of the inlet manifold.

The other issue worthy of note here is the actual air intake and feed to the engine.

I have an M90 blower on a Lexus V8 fitted into a Soarer. It has a chamber on the rear of the blower onto which the throttle body is mounted. The blower pulls air through the throttle body, pressurizes the air and feeds it directly down into the chamber of the inlet manifold, nestling between the two heads.

This configuration is typical of a suck thru roots blower.

With the P38 it may be possible to blow through the throttle body but I'm not sure how this would be.

Blower could be mounted sideways above the pass side exhaust manifold. Pulls air through the rear plenum chamber via stock pipe and airflow meter connected to airbox.

Pressurized air is then fed into the stock Rover plenum through the throttle body. My question to the more learned amongst us is, can the Range Rover throttle body handle a 7psi pressurized air flow, and will the throttle butterfly seal correctly to retain base idle etc?

from a topic in here or general chat a URL was posted to ebay regarding a 6Lt gen 11 $4k for it complete plus all wiring and computer, add another 2K to fit

now no matter what you put in it a blower or a bigger engine when you start talking the torque that either will put out you are going to turn the ZF inside out. Holden have started importing the 6L80E Auto tranny which is the six speed heavy duty jobbie used in their full sized tanks over there in good old US of A. It will take the sort of power you are talking about

Gas Research in Melb go Turbo LPG cars....

I had a Scungy 740 Turbo Volvo running 14psi on Fuel and 28psi on LPG..... Ohhh baby.... 2.3litres and being able to turn the tyres at 80kmh on the black stuff..... FUN......
I sold it, as it was another Demerit point project.....

Originally Posted by sclarke

Gas Research in Melb go Turbo LPG cars....

I had a Scungy 740 Turbo Volvo running 14psi on Fuel and 28psi on LPG..... Ohhh baby.... 2.3litres and being able to turn the tyres at 80kmh on the black stuff..... FUN......
I sold it, as it was another Demerit point project.....

Now that sounds like a Volvo worth driving.

Cheers
Simon