Classic Mini, Supercharged!

How about some pics???!!

It’s really worthwhile to reinforce the bottom end of that motor, as the rods and crank take a pounding with forced induction such as a supercharger or turbocharger. What I mean by reinforcement is to upgrade the rods, such as using real Cooper S rods, or aftermarket rods like Carillos, and maybe even a four-bolt main cap. Remember, those motors were designed for use in generators, not high-performance, and they have three main bearings. Argh…..ask anyone who races one what fun that is!

I have seen numerous minis with similar mods blow up due to rod or crank failure. The old Cooper S block was reinforced, the “1300″ block was OK, but the newer 1300 Metro block is the best (strongest).

Not to be a nay-sayer, horsepower is good, but so is a few ounzes of prevention!

http://www.hi-flow.com/HP3Mini%20Super.htm is a kit that works, is installlable in a bugeye or a mini, runs to around $5,000 australian, and has been around for a while. I believe the moss kits are possibly this kit re-badged.

I was originally going to use the supercharger off my mini (pre-jcw update) to supercharge my austin healet bugeye, however the charger is just oo large for the installation.

this kit now remains my first choice for charging the A-series in my austin healey.

The real key to the ‘A’ block Mini is the crank – the original ‘S’ cranks were forged, nitrided EN40B steel, done by Rolls-Royce suppliers, and were stronger than most production cranks available for many years. If you’re lucky you’ll find one that hastn’t been re-ground and the nitriding removed. They’re like hen’s teeth, so dig around and get a good crank, or it’ll grenade for sure. Vandervell bearings only.

The ‘A’ series is a long-stroke design, with the piston speeds reaching critical if you rev even moderately high – this was the main limitation the factory accepted to get plenty of low-down torque. Remember, the factory was concentrating on rallying rather than track racing – the only over-square ‘S’ engine was the very limited 970 S, which was for the Saloon Car handicap specs. Good rods are a must, but the other limitation from there on in is the head. The non-crossflow, siamesed ports and relatively shrouded combustion chambers are only amenable to reworking up to a point, then the whole Westlake design hits a brick wall.

The usual lowering of the compression ratio is mandatory – the ‘A’ block just doesn’t handle high ratios very well for long. Remember – the tranny is running the same oil that lubes the motor, so oil change intervals should be speeded up if you boost the HP very much. The weak point on the power transfer is the little bitty needle roller bearing on the outer end of the drop-gear – gotta mod that for sure.

I’ve run across a few old Shorrock or other brand vane-type superchargers on Minis, and their relative inefficiancy compared to Rootes-types is actually a blessing – you just can’t push the ‘A’ series too hard in this respect, IMHO. I do like that Aussie HP blower, tho – looks like best for the ‘A’.

The ‘A’ was never designed as anything but an automobile engine – I don’t know where the generator thing comes from, Peter, that was Coventry Climax motors coming from fire pump use, I’m guessing. They have some seriously modded ‘A’ motors out there, so it can be done, but a street Mini with some good basic mods will yield a better HP per hundred-weight than a lot of modern cars. Hey, 10 inch Cosmics with Yokos look real cool, too.

            BCNU,
          Rob in Dago

The moss spridget kit is not a rebadged kit! It is home grown and will make your midget/sprite(even bugeye’s) scoot. The supercharger is a modern roots-type blower. This is a nice kit. It is not likely that it will fit underneath the hood of a mini. Although, a little modification may fix that.

rdb

That sounds super hot!!! I have the mags, tailpiece, bullet- head mirrors, wheel arches, a supercharger is on my list!!!

just finnished building a blown a series for competition use.. used orig 19320 s pistons a 76mm 40b forged crank with arrow rods. compression is down to 7to1.x drilled centre strapped etc etc. thought ya may like to know after about six hours on the rolling road its putting out a real 180 at the wheels about fifty horse up on my 1398 8 port.. the motor has lotts more bottom end than the normally aspirated lump and the torque rather than the power was the most supprising about 170lb ft, thats not far from a golf vr6.. building the unit for the road would not be a great deal of hassle just running the pulley slightly larger maybee only 1.4 to 1.5 to 1..will mail again after the first test day…..

Of course!

You first need to get hold of a Supercharger, I used the BMW MINI supercharger (very cheap on ebay) and made a bracket up that allowed me to mount it in front of the spark plugs, I then got hold of a multi v belt pulley and got that lathed down to fit onto the mini crankshaft, that left an alternator to fit and then lining all the pulleys up so the belt doesn’t jump. I have retained the water pump that BMW use on the end of the supercharger and just made a bracket up that let me connect into the old water pump plate.

If you are still using carbs then you need to bolt one onto the supercharger and sort out the pipework to the manifold. I have bosch k-jetronic fuel injection so I just made up some connections to the manifold and had to fit a recirculating dump valve to stop the throttle butterflies bending under boost with the throttle closed (idle and decelleration)

I have fitted water injection which helps with detonation but still need to fit an intercooler to get the best out of it!

If you want to retain the standard pistons then you will have to get a Spacer plate machined up to put between your head and block with a head gasket either side, this will help bring the compression down to a reasonable level, although the most reliable option is to fit low compression pistons and maybe grind out the cylinder head to bring the compression ratio down even more.

I will email you a few photos buggychap so you have an idea what I have done!

miniman

just a quick question for anybody in the know!ive just ordered a new mini cooper s with the jcw kit on it,does anybody know if a dump valve can be fitted,if so would be an easyish job to do 2)is it mini specific(if not what would i be looking for ie fitment for which car) 3)where would you recommend one from?any help with this would be gratefully received.cheers

im wondering if miniman could contact me & give me some tips of how i can pimp up my mini’s engine.

I have a classic austin mini-1000cc engine & the only thing i have done so far is install a hi-power air filter.i tried your link but it did not work.

waiting for your response!

mmm…….

If you really have to keep the engine then I suppose the best places to start are the places which cause the most restriction to power output.

Without hurting your wallet too much I think you would be safe with a stage one kit comprising of a good inlet manifold, lcb exhaust manifold, rc40 exhaust system and a needle for the carb, as you have the filter I think you should be ok, although I have always found that a K&N filter in the mg metro filter housing is superb!

Anything more than that will start to cost money and involve engine rebuilds, although a high lift rocker set works pretty well and can just be bolted on if your valve springs will take it at full lift without binding.

Next on my list would be cylinder head and cam!

I would seriously consider putting in an MG metro engine as these things standard will produce far better torque and power than you could hope to sensibly achieve with a 1000cc and you could always go 1380cc later if you fancied it.

And before anyone asks, yes it is a very easy engine swap to do and all the parts interchange pretty well!

If you want to read a book on engine tuning for the A-series then I can thoroughly recommend Tuning the A-series by David Vizard, it is very informative and will help you to build an excellent machine!

Hope that points you in the right direction!

miniman

Hi miniking!

The vmaxscart kit sits on an inlet manifold at the rear of the engine, so it is really a bolt on goody!

do a google on it and you should find some good photos!

Miniman

By all means you can fit it to a 1098 but the crank,clutch,conrods,gearbox etc aren’t really up to the extra torque that it would produce! If you bought the kit then your best bet is to rebuild a mg metro turbo lump at the minimum and use that as a basis for a good setup.

My friend has the vmax blower and his mini produces 160bhp! poor old gearbox!

I have almost sorted my traction problems now! I have stopped it from wheelspinning in third by only taking the mini out in the dry!…………..

check out my website and have a laugh at my long minivan!

miniman

Hi miniking,

I think 286 is probably a little too much overlap for blower on the road, not sure about the swiftune though, stage 3 head sounds good but you need to ensure that you have the largest possible combustion chambers which means don’t skim it more than is required to clean it up. Flat top pistons are probably a big no no as you need a deep dish piston to lower the compression ratio to around 7.0:1

I have a 3.1FD and find that with the extra torque it wheelspins in first second and a bit in third on 12″ wheels with yokohama a539 tyres. When I get the chance I might change it up to 2.9FD as it screams along at 4000rpm @80mph at the moment!

The main problem with supercharging is that you need to lower the compression a lot to stop the engine knocking, I have managed to get mine to a reasonable level but have still had to fit an intercooler and water injection to get it to run reasonable amounts of timing advance to run off boost nicely.

I was wondering why build a tuned 1098 at 54bhp when a standard 1275 can easily give 56bhp, is there a shortage of available parts in your area? If I wanted a good engine to start with then I would use an MG metro turbo lump and rebuild that but it would have to stay to standard bore sizes as the 73.5mm(1380) doesn’t leave enough meat between the bores to take the boost pressures reliably. The other good thing with the turbo engines is they have sodium filled exhaust valves and slightly better sizing on some gearbox parts.

It is always fun making things that are different so keep at it and have a look over at alt.autos.mini newsgroup if you have any problems as there is always someone who can answer a question, however silly it might seem to you!

miniman

You will find my email address here for a while until I have rejigged my website properly!

http://homepages.nildram.co.uk/~deffee/page3/contact.html

miniman

You’ll find the 1300 MG complete unit will go straight in. Just swap the right hand engine mounts from your mini onto the new gearbox before you start. The only messy bits are swapping the thermostat housing (dependent on year) so it mates with your rad housing, and I recommend fitting a 3 core or better rad to cope with the increased output, too. Oh, and the later engines had a verto clutch with a shorter arm and different clutch slave cylinder and hydraulic pipe etc. These bits are costly if you dont have them, so use the old (long arm)parts from your existing engine. It all works fine, the verto was just a smoother (less flex in the arm) development. Easy job overall – if you’ve had an engine out before, there’s little to worry about, just replace all the consumable parts and oil seals you can get too to keep it all nice and clean.

Have you had any information or replies to your request. Iam seeking the same answers to your questions. Iam fitting a M45 charger to my healy sprite. Repowered with Nissan/Datsun A 15 1500 cc engine and 5 speed box. This is a jap copy of the BMC A series engine. Has 8 port alloy head and 5 bearing crank. Iam from New Zealand. Thanks for your help Regatds Ben Stimpson

big problems keeping it cold please help