The 'S' Pack


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The Cooper S is back

Now this could possibly be a complicated subject, why ? Because a lot of cars done at different times had slightly different specifications. Now some cars were converted when new, some at some point when the Factory Warranty was still valid. The first Mini Cooper S since June 1971 was a modified Mayfair, it had the chassis number of a normal Mayfair but with an S type plate affixed to the crossmember by the drivers door. The number on the plate was #0001-P, the first proper S was Mike Coopers own car, H15 FUN, which was actually a Mainstream car, that was #0001-S. The numbering of carb'd Coopers, whether they be RSP or Mainstream was the same, and adds much confusion to people like me who try and work out some kind of logical order from it.

This is the very first Cooper S since June 1971. It's the modified Mayfair which was John Coopers prototype. It has all the extras from the catalogue for the 1000cc Cooper conversion, including the white wheels.

The first 'production' Cooper S was in fact John Coopers own car, registered G808 KJW, although this was an RSP version, it wasn't one of the really early cars, though still under the 30's. Luckily, this car is now owned by a member of the register, so the details are readily available from it.

The standard RSP and Mainstream gave a rather disappointing 60-ish bhp, I say disappointing because the old Cooper S 1275 from 1964 was giving somewhere in the region of 76bhp, that was not my idea of over 25 years of progress !

There are however, reasons for this, one of the main reasons is the fact that the RSP runs on 95RON (unleaded) fuel, which in itself brings it's own problems. It also has a catalytic converter to clean-up emissions.

The Cooper S pack aimed to put back some of the power lost to poor fuel and catalysts, it boosted power to 78bhp by virtue of a gas-flowed head, modified by Janspeed, allied to twin 1.25" SU carbs to give it a proper S look of old.

This was the legend that adorned the bootlid of an S Pack car, it's slightly smaller that the side decals. They were in 2 different colours, depending on the paintwork, the other colour cars had white laurels.
This is  the underbonnet of a car featured earlier, H15 COO. It has minor detail changes from original in the form of a non-original coil and a pair of K&N filters. The standard filter casing was a new design, it could only use one filter, unlike the earlier Cooper and S which used two. Outwardly, it looked the same.

This not only boasts an S pack, it also has the handling pack, which consists of some 165/60x12" Dunlop tyres and some Koni shock absorbers, as if this isn't enough, it also has a non standard 5 speed gearbox.
This is the side decal found on the Flame Red RSP Cooper with an S pack fitted, it appears the same as the rear decal, but it is 30% larger.

This is a comparison between the S Pack air filter case and a Cooper S Mk3. You may notice that the S packs case (the one at the front) is a fair but thicker in height, it also has the air-feed tube welded instead of clamped.
This is the sticker on the air-filter case of the S pack, this sticker is unique to the RSP and Mainstream models as other cars converted are the fuel injected models with different parts included.

Here you'll see that the internals are different too, the S pack only uses one filter in it's housing, whereas, the older model uses two. Sadly, this setup is very poor for performance and the twin filter case is far more efficient at filtering air and gaining power.
This is the twin filter case from the Mk3 Cooper S version, please excuse the dirtiness of the filters, they will soon be put in the dustbin. Also note that this filter casing has a breather at the front, not present on the S pack of 1990.

On the left you'll see the lid of the filter casing for the Mk3 Cooper S and on the right is an RSP S Pack lid. Even if you wanted to try and put the superior twin filters in the S pack case, you'll see that the design prevents it, as there is a metal locator groove for the single element.

I can make no excuses for the state of this engine bay as this is my car, I also have to make apologies for the ignition leads, which are not only hideous, but non-original. There should be an ignition shield fitted, but it has been taken off to allow this photograph. Main differences to the non S Pack cars are the MG Metro rocker cover and twin carburettors. Although it isn't very noticeable in this shot, S pack cars have a red block with a dark blue painted cylinder head. The heads have a stamping behind the thermostat hosing with a number on it. The inlet manifold of the S pack is also a slightly different design too, not noticeable in this shot. Just noticeable on the slam panel is a sticker telling you to use 95RON fuel, which is a left-over from the standard RSP, the S pack cars use Super unleaded (97RON), but it is correct that the old sticker is left in place, even though the S pack is fitted.  I think I'd better pay this engine bay some attention soon and take some better pictures.

This is the stamping on the cylinder head to identify an S Packs' modified head, they were only lightly modified with Cooper S size inlet valves (35.6mm) and standard exhaust valves. The gas-flowing was only very slight, to keep fuel consumption to as near as standard as possible. You can just about see that the head is painted blue.

Now this is a very special car, it has a unique place in Mini history, let alone the history of the RSP. This was the very first Cooper S since June 1971. It's now owned by Roger Hunt, who obviously keeps it in outstanding condition as can be seen here. This was John Coopers actual car, and features just about every S pack option available, including the Mk1 type bumpers kit.

This was the steering wheel offered by John Cooper in his catalogue, it is made by Moto-Lita and has an engraved John Cooper signature in the spokes, very stylish, very expensive, again, this one fitted the John Coopers own car.

This is the kit that John Cooper Garages offered to people who weren't particularly impressed with the 78 bhp offered in the S pack. This kit known as the MCC1400BC offered 115bhp and a 0-60mph time of just 7.95 seconds. It comprised of a set of 74mm Forged pistons, a seriously modified head and twin 1.5" SU carbs, allied to a set of forged 1.5:1 ratio roller rockers it made a real difference to the performance. It wasn't cheap though, which is why it didn't sell particularly well. It cost 4930:00. Other parts of the kit included a lightened flywheel, high capacity water pump and some K&N air-filters. As this kit was only offered to carburettor cars, it also included an oil-cooler for the Mainstream cars. It also included a slightly more 'classic' type of alloy rocker cover, not the plentifully seen MG Metro one given to S pack owners.



Site Updated 16/05/2008
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