Eaton M122H Supercharged E38 728i

This project was the first E38 in the world to be fitted with the M1 kit made by Hyde Motor works. The kit was designed to fit on the M52B28TU engine but not in the vastly different E38 chassis.

The subframe, steering box, engine mounts and fixed coolant pipes are all different and require the kit to be modified in one way or another.

The car is a immaculate show car already fitted with are ride and amazing BBs 19" wheels fitted with 275 wide tyres.

We Forgot to take pictures of the car when it was dropped off but here is what we have, the car is an immaculate show car and will now have to "go" to match the "show".

We got straight to work and stripped off the intake side so we could see the scale of the task that lay ahead.

The M122H Supercharger from a Mustang GT500 fresh from the states.

Intake side removed to show the nest or wires and PCV system. This started to highlight the differences in the E38 chassis. The engine mounts attach further down the block and the front subframe is a tubular rather than the e36/46 style beam.

We got the supercharger mounted up in the bay and fabricated a custom rear brace. But most importantly spent hours getting the pully lined up perfectly. This involved using a laser level to line the pulleys up.

Next Task was to tackle the fuelling, the manifold supplied in the kit is a m50 style manifold. This mean that it would either need a M59 fuel rail or a bracket making to clamp the rail to the manifold. We chose to keep the M52 rail and make a bracket, this keep s the car as OEM looking as possible, plus a m50 is not a good looking part.

The next task was a figure out the intake, the engine is lot further back in the bay than E36 which this inlet was designed for. WE started by chopping the inlet and pie cutting it back into shape. Once its all mocked up every part that has been altered will be powder coated.

Very rough mock up of the inlet of the fuel rail and the inlet, picture to follow later that cover all

Final Mock up of all intercooler piping using cut factory viscous fan shield covering a hugely powerful Spal fan, this will be controlled by the link Fury X ECU.

The Alternator duct clashes with the discharge pipe so this was trimmed with a Dremel to allow a close fit.

Intercooler sat on some wooden blocks in the ideal location, this position allows maximum air flow behind the bumper which uses a E28 front lip.

We tried to maintain the OEM auxiliary fan but this would involve cutting large amounts of the bumper out. This was not inline with the clients OEM PLus look. We decided fit a high output Main fan and leave space for a auxiliary fan if needed.

Intercooler mounts welded to the factory crash bar

Intercooler mounted up and secured to the crash bar.

Mocal Oil cooler to increase oil capacity and cooling.

Mocal Oil cooler mounted up to the crash bar and bumper side mount. This will sit directly behind the fog light, the extra oil capacity in the system will provide cooling due to the additional capacity. If oil temperatures become an issue then the fog light can be removed and ducting fitted.

Front slam panel back from the powder coaters and looking OEM.

Hyde Motor Works M1 kit complete with 7 series adaptions ready to be mounted back on the car when the bespoke loom arrives back from Brands Hatch Performance.

With the loom back it was time to fit the Link Fury X in the cramped 7 series Engine bay. The ECU must go inside the factory ECU box to keep it safe and dry. We decided to use the standard mounting frame and adapt it to house the Fury X, merge harness plugs and additional fan relays and fuses.

Now to fit it back in the standard ECU box and keep the car looking standard.

---

Manual Conversion

After working through a few running issues we took the car down to the dyno to be mapped. It was obvious early on in the session that the standard auto box was overheating and slipping.

We knew this may be an issue from the start and it was not un expected. After some extensive research we designed two options. the first was to fit a manual gear box, this presents a multitude of challenges the main one been BMW never produced a manual RHD E38 728i (As far as we can tell). The second option was to retro fit a 8 Speed ZF ( 8HP 70).

The manual conversion was selected for many reasons, but the £4k saving over the ZF auto conversion also helped.

After ensuring we had the over 100 parts needed for the swap, most of them coming from BMW in Germany we plunged into the unknown to establish if all the cut outs, grommets and mounting points were present on the UK delivered RHD car.

The exhaust, prop shaft and heat shielding was removed and placed to one side.

The gear box (5 Speed ZF) was fitted to the engine using a 330D DMF and a sash performance uprated pressure plate and full face unspring clutch plate. All fitted using new hardware and torqued to factory BMW spec. New release bearing and clutch arm was fitted.

The first of the new parts, a LHD manual cross member was offered up to the chassis and bolted straight up to some previously unused bolts holes. The gear stick brace was fitted with all new bushes and offered up to the chassis to discover the rear support bush bracket was missing. This was the first of what will be many unknowns. A custom bracket will me made and attached to the chassis.

We could have used a chassis mounted gear stick like a CAE, Cooler works but a seamless OEM finish was the end goal. This is the driving philosophy behind this whole build.

Stay tuned for more updates.