Alpine Supercharger - my experiences
Many people have asked lots of questions about the Alpine Supercharger, so I have created this page to document my experiences with it, in the hope that it will be a useful resource for other Coupe owners.
At the time of writing this, I understand that the Alpine s/c is available for £1600, although I am sure mine was more when I purchased it in 2001. In addition to the cost of the kit you will need to pay VAT @ 15.5 and import duty at around 10%, plus any handling charges from the courier.
The kit [mainly] comprises of -
- Eaton MP45 generation 4 supercharger
- Custom intake manifold
- Fifth injector (although this is not needed)
- Custom nose
- Fuel pressure regulator
- Assorted vacuum tubing
N.B. The kit does not come with the head spacers as shown on the Alpine website
The idea is that the s/c kit will bolt onto the engine and run with very little work, however I did not find this to be the case -
1. The injector rail needed to be moved slightly, but in its new position it was 'rammed' against the engine, my mechanic was not too keen on this and it seemed like the rail was being forced into a new position.
2. The supercharger unit sat too high and stopped the bonnet closing. The engine mounts were machined to drop the engine and gear box by 20mm.
3. The pulley supplied with my kit was a blank and this had to be machined to match the supplied belt.
This all sounds straight forward, but as this was the first kit fitted in the UK it was a case of trial and error to find these problems and resolve them.
The chip provided is a Unichip, unfortunately for me the chip supplied had such a poor map on it, that I made more power with it disconnected. Owen Developments in Abingdon were my nearest Unichip dealer so I left the car with them to sort out. Several dyno runs later and that car was making 171bhp at the flywheel and running boost at 3-4psi.
N.B. At this time I also had an induction kit, F2 Evo cam, BBTB, 4-2-1 exhaust manifold and catback exhaust.
171bhp was OK, but after a couple of years I felt that the supercharger setup should be capable of more, especially as the Alpine website tells you that it should make 213bhp on its own with no other modifications !
The car went back to Owen for some more tinkering including -
- Aquamist water injection kit
- Uprated clutch
- Lightened and Balanced flywheel
- Boost increase
- Pulley diameter reduced by 2mm
There was some difficulty in getting the supercharger to run at more than 4psi,
this was overcome by adjusting the bypass valve and machining 2mm from the
pulley, which resulted in 6-8psi (psi is variable on s/c), also anything above
8 is going to create a lot of heat and negate any performance gains from
running more boost. The water injection was the most major modification and
helped to prevent possible pre-detonation caused by the higher boost pressure
and air-intake temperature.
The Unichip has the ability to control the water injection and was set up to only spray water as required.
The final result was 199.5bhp (flywheel) and 201nm of torque.
Points worth noting...
I am on my fourth supercharger belt, after each tuning session it does seem to weaken and snap. My last belt did last for over a year, but then started to fray, this was replaced at my 80k service. The belts seem to be hard to track down and I would advocate carrying a spare.
Last month the Eaton unit developed a grinding noise at high revs, it was discovered that the fins inside the supercharger were touching the inside of the unit. This may have been caused by the bearings failing inside the unit. The cost of a new Eaton Mp45 was £1000, however since having it installed the car does seem to be considerably quicker. I am hoping to have the car dynoed soon to see if there is any difference.
For those that are wondering I didn't get the car dynoed, coz I sold it :-(