Podifold, the blow through supercharger manifold system for the classic Mini.

What is podifold?

Podifold (POsitive DIsplacement maniFOLD) is a cast aluminium intake manifold that provides a platform for creating a custom blow through supercharger system on an A series engine.

It accurately positions and securely mounts a BMW Eaton M45 supercharger to the engine and incorporates provisions for all the necessary pipework, fuelling and ancillaries in a way that allows a blow through set-up to be installed in the tight confines of a Mini engine bay without any modifications to the bodywork or alterations to the existing hardware.

The Podifold system is available in two configurations: the carburettor version is a single manifold which uses a suitable HIF44 carb to provide fuelling and an atmospheric dump valve to handle boost on overrun while the fuel injection version is a two part manifold which uses two Bosch style injectors for the fuel and a by-pass valve connected between the two manifolds to re-circulate the unwanted boost back into the supercharger inlet on overrun.

Podifold, the blow through supercharger manifold system for the classic Mini.

Who are we?

Podifold, the blow through supercharger manifold system for the classic Mini.

Well, we're not a company, and this isn't our day job.

We don't have a rolling road or a workshop full of machinery. We're just two guys with sound engineering principles and a passion for Minis who set out to make the best possible supercharger system for ourselves. People seemed to like it so we made some more.

We're immensely proud of what we've managed to achieve and are happy to pass on what we've produced to anyone else who wants it. It's not the cheapest, it's the best! It's that simple and if you like what you see we'll make you one too!

We've spent countless hours refining our manifold to be better than everything that came before us and we're not ashamed to boast about it.

What makes it better?

We've worked hard to develop the ultimate A-series supercharger system, overcoming many of the flaws in pre-existing designs.

  • Lower charge temperature - Let's start with the main one. Forget sticking ridiculous tanks of water on top of your supercharger! Using an intercooler is the correct, industry standard way to lower the charge temperature of the compressed air and reduce the risk of harmful detonation. Because the charge is so efficiently cooled reduced size supercharger pulleys can be safely used to increase boost and gain both power and performance.
  • Equal length inlet tracts - The Podifold system has equal length runners going to the two inlet ports at the rear of the cylinder head for a more balanced and smoother running system.
  • Large bore exhausts - The podifold system has been designed to easily accommodate a large bore LCB exhaust manifold without clearance issues. Others can't.
  • No carb icing - Our design completely eliminates the well documented carb icing problems associated with suck through systems without the need for compromised work-arounds such as inlet air heaters or hot water coils.
  • No modifications needed - Unlike previous blow through set-ups which tried to mount the supercharger at the front of the engine our kit can easily be fitted into a round nose or clubman fronted Mini with no body modifications. Being rear mounted means no drastic modifications need to be made to the position of the alternator and you can still get to your spark plugs and oil dip stick. Other kits require modifications to the inlet flange of the supercharger prior to fitting where as ours bolts straight on.
  • Unrestricted outlet - The design of our manifold enables the pressurized air from the charger to exit freely from a large diameter opening. Other kits are severely constricted at the point where the air leaves the charger, compressing the charge unnecessarily and creating more unwanted heat.
  • Better fuel economy - Podifold's unique use of either a dump or re-circulation valve means that when cruising under low throttle load the pressure is reduced and petrol isn't being forced into the engine unnecessarily, meaning better fuel economy and more miles per gallon.
  • It's future-proof - Our manifold comes with a number of blank lugs cast in various places ready to be drilled and tapped for a number of accessories you might want to fit now or in the future. Additionally carb version manifolds can be sent back to us and re-machined to upgrade to fuel injection at any point.
  • Beautifully crafted - The Podifold is cast in LM25 aluminium for a high quality OEM appearance with no risk of rust, warped steel or flaking paint. The strong one piece construction ensures a perfectly smooth flowing inlet tract with no welds or joins.
  • Extended Supercharger life - The Eaton M45 charger was designed to move air, not petrol. Some users of traditional suck through systems have reported the teflon coating on the rotors being stripped off as a result of the petrol passing through.
  • Fuel pooling - Our system completely eliminates the highly dangerous fuel pooling fault common with suck through systems where fuel collects at the base of the inlet tract and soaks into the air filter when the engine is shut off.
Podifold, the blow through supercharger manifold system for the classic Mini.

Suck through sucks!

Podifold is a blow through system, but what does that mean? And why is that better than other sytems?

Suck through:

Also known as 'draw through' these systems have the carb on the intake side of the supercharger, meaning that the air is 'sucked through' the carb on it's way to the engine.

The main problem with this system is that as the supercharger compresses air it heats it up. Ever noticed how a bicycle pump gets hot in your hand while you're using it? Same thing. Forcing hot air into an engine isn't good and can lead to detonation. The answer would be an intercooler but with a suck through system the air has already been through the carb and it's now full of fuel vapour. Passing through an intercooler at this point would lead to the petrol dropping out of suspension and puddling.

Blow through:

The alternative to a suck through system is a blow through system, where the carb is on the outlet side of the supercharger. In this arrangement the air is 'blown through' the carb.

Of course, if you've been paying attention you'll have already realised that a blow through set-up doesn't have the flaws that a suck through system does. Once the air has been compressed and heated it can be safely passed through an intercooler to reduce it's temperature before entering the engine and a blow off valve can be installed between the supercharger and the carb to vent off any unwanted pressure whist at cruise or idle.

Podifold, the blow through supercharger manifold system for the classic Mini.

Frequently Asked Questions

Is the Podifold system a complete kit?

No. The basis of the Podifold system is the cast aluminium manifold which securely and accurately connects the supercharger to the cylinder head. This provides the starting point from which a custom blow through set-up can be created.

Why don't you supply the rest of the stuff I need?

Basically because there's other people out there making the other parts better than we ever could and you can probably get them cheaper than we can supply them anyway. We've worked closely with those companies to make sure our system works perfectly with their parts.

So what else do I need to fit the carb version manifold?

To complete the system firstly you'll need an Eaton M45 supercharger off a BMW cooper. These are commonly available second hand as the standard charger was replaced by John Cooper Garages when BMW Mini owners purchased the Works upgrade kit for their cars. Next up you'll need a bottom/crank pulley designed to take both a standard v-belt and an additional multi-rib belt. The system was designed around the dimensions of the MED Engineering pulley and this is the one we recommend. To provide fuel to the engine you'll need a suitable carb. Being a pressurized blow through system you'll need one which is sealed. The system was designed around the HIF44 carb and plenum combination off a Metro turbo and these are regularly sold second hand with rebuild kits also available. The carb needs to be fed by a high pressure fuel pump and the easiest solution here is to source a petrol tank from a later MPI Mini which has the pump built in along with feeds for the dual fuel lines. The flow of petrol to the carb needs to be controlled with a fuel pressure regulator and the standard Metro Turbo version is recommended. One of the benefits of a blow through system is the ability to cool the charge using an intercooler and fitting one is highly recommended. There are many types available and choosing one is simply a case of finding one which fits within your engine bay layout. To vent the pressurized air created by the supercharger when at idle and low load conditions you'll need to fit a dump valve specifically designed for a supercharger system - turbo dump valves simply aren't big enough. Some form of electronic ignition management (Specialist Components, MegaJolt, Nodiz etc) is highly recommended but not essential if you've got a distributor that can handle the timing of a forced induction system.

Can I fit this to my standard engine?

Probably not. Over the years standard production engines had various compression ratios all the way up to 11:1, way too high for a forced induction engine. To run the Podifold system you really want a compression ratio of around 8.5:1, which for most engines will mean either using dished pistons or increasing the combustion chamber volume in the cylinder head or a combination of both. The engine also needs to be in good overall condition. Remember, you're expecting much more from it than it was ever expected to do when it left the factory.

Can I run this system using my standard gearbox?

Again, probably not. The weakest link in the Mini drive train is the well known single pin differential issue and it's well worth, at the very least, upgrading to a cross pin diff before running the Podifold system. From there you can upgrade all manner of gearbox components. A lot will depend on your driving style and the car's intended purpose.

Can I use this system to upgrade my existing suck through set-up?

Yes. There'll be some additional parts to buy but your supercharger, bottom pulley and belt tensioner should all be fine.

Can I use it on my 998cc engine?

998cc engine blocks are 3/8" shorter than 1275cc ones and this causes clearance issues between our manifold and the engine steady bracket under the master cylinders. However, we can supply a subframe raising kit which moves the engine upwards by 7mm and eliminates the problem with the additional better handling benefits you get from solid mounting the subframe.

Can I use it on my MPI Mini?

Yes, but not without a lot of work. You would need to change the bottom/crank pulley to a twin v-belt/multi rib belt type and the water pump and alternator pulleys to the v-belt type as well as removing the brake servo and changing the entire ECU and fuel injection system.

I've got a bulkhead mounted brake servo, can I still use the Podifold system?

No, it gets in the way.

Why do I need a dump or re-circulation valve?

Superchargers are linked to the crankshaft with a belt, so it's always spinning, therefore, it's always pumping air and creating boost.

Problem is, you don't always want boost. That's where your dump/re-circ valve comes in. Under idle and low load conditions (waiting at traffic lights, cruising on the motorway, etc.) it opens up, venting the boosted air to the atmosphere or re-circulating it into the inlet of the supercharger instead of forcing it into the engine. It's open when there is vacuum in the intake manifold - basically when your foot is mostly or completely off the accelerator pedal. By not forcing fuel and air into the engine when it's not needed you'll get better fuel economy.

However, when there is demand from the engine (foot on the pedal, no vacuum in the intake manifold) the valve closes and all the pressurized air from the supercharger goes into the engine. You get boost, and you smile.

Why do I need a massive dump valve? Can't I just use any turbo dump valve?

Small dump valves work great on turbo installations where their role is to quickly 'dump' the pressurized air in the system when you take your foot off the pedal and the throttle closes. This eliminates any back pressure on the turbine that could stall and potentially cause damage. However, a turbo doesn't create boost in idle or low load situations like a supercharger does.

Why don't suck through systems have dump valves?

Dump valves are used to release built up pressure. The only place there's a build up of pressure on a suck through system is in the manifold between the supercharger and the engine. At any one time this manifold is filled with the air/fuel mix and opening a dump valve here would mean venting a load of petrol vapour into your engine bay close to a hot exhaust. Not a great idea.

Why can't I use my standard HIF44 carb?

Carbs for normally aspirated engines are designed to work in a vacuum situation where the engine is sucking air through them. Blow through systems pressurize the carb by forcing air into it. If the carb isn't sealed this will cause petrol to leak out from the fuel bowl. Standard HIF44 carbs can be converted by using the turbo service kit with the cup washers turned the other way, fitting our dashpot sealing gasket and sending a feed or pressurized air to the fuel vent connection on the carb body.

What gasket do I need between the supercharger and the manifold?

Genuine steel gaskets can still be bought from BMW dealerships, part number M17.51.1.520.044

How much does it weigh?

A bare, machined Podifold casting weighs around 2.7kg.

What size silicone pipework do I need?

The diameter of the outlet stub at the back of the manifold is 45mm to match the inlet size of the Metro turbo HIF44 carb plenum.

  • Podifold, the blow through supercharger manifold system for the classic Mini.
  • Podifold, the blow through supercharger manifold system for the classic Mini.
  • Podifold, the blow through supercharger manifold system for the classic Mini.
  • Podifold, the blow through supercharger manifold system for the classic Mini.
  • Podifold, the blow through supercharger manifold system for the classic Mini.

Podifold (carb) - £550

This is the basis of your new blow through supercharger system - the Podifold manifold. Once back from the foundry the casting is cleaned up and grit blasted before being precision machined and drilled for the inlet flanges and the supercharger/carb mounting faces. Comes fitted with a 6mm vacuum take-off and includes a stainless steel fitting kit to mount the supercharger to the manifold. Please note that each manifold is custom made to order so please allow up to 28 days for delivery.

Podifold (fuel injection) - £850

The ultimate A-series supercharger set-up! Our fuel injection system includes two cast alloy manifolds: the supercharger "outlet" manifold is as above but machined to accept 2x Bosch style 14mm injectors as well as a BMW by-pass valve which connects to the additional supercharger "inlet" manifold. Comes fitted with a 6mm vacuum take-off and includes the billet aluminium fuel rail and a stainless steel fitting kit to mount the supercharger to the manifold. Please note that each manifold is custom made to order so please allow up to 28 days for delivery.

Dump valve spring

Replacement spring of the correct strength for fitting to Tial Q and QR 50mm dump valves. Remanufactured by us to the same spec as Tial's supercharger specific green 3psi spring.


Belt tensioner kit

Avoid belt slip with this tensioning pulley kit of our own design. Laser cut from 4mm steel for strong and accurate pulley alignment.


Water pump plate

Used to blank off the end of the supercharger once the redundant BMW water pump plate is removed. Laser cut from 4mm stainless steel and supplied with stainless mounting bolts.


998cc fitting kit

A set of solid mounts which move the front subframe upwards by 7mm allowing fitment of the manifold to 998cc engines without fouling on the engine steady bracket. Only for use with later type twin bolt subframes.


Dashpot gasket

High quality laser cut gasket used to seal the dashpot to the main body on N/A HIF44 carburettors. Our own design and available exclusively from us.


Plenum Chamber

Currently still in development is our own cast alloy plenum chamber which will be a direct replacement for the original Metro Turbo item.


Podifold, the blow through supercharger manifold system for the classic Mini.

Podifold, the blow through supercharger manifold system for the classic Mini.