why aren't more people fitting them?
from what I know, and it is very little (any pointers to web sites'd be handy 
), these can be bolted on (proper belt driven ones not these
electric fan nonesenses) without any changes to engine internals and either carbs or better still TBs with ecu to control.
there seems to be a flood of ex BMW mini s/c on ebay so it looks to the untrained eye that one could be bolted on after making the bracketry in
regiion of £ 200.
any one have any figures for power increase percentage vs boost?
item number: 270193875833
[Edited on 7/12/07 by blakep82]
Trying to work out power output at various boost levels is tricky. Infact, trying to work out precisely anything to do with a S/c install is tricky
because there are so many variables...
If a supercharger was 100% efficient it would be easy. 2 Bar of boost would give double the power...
Trouble is superchargers aren't 100% efficient so they heat up the air that they compress. Then you need an intercooler to cool things down a
bit. That results in some pressure loss.... If you try to work it out it'll make your headache!! Books like Graham Bell's Forced Induction
Tuning will get you close to the answer but at the end of the day it's an estimate.
Trying to work out the boost @ various supercharger speeds is virtually impossible as it depends so much on plenum design, valve size, valve timing
etc etc....
I've still got a Mini S/C waiting to be strapped onto the BEC... I'm aiming for a 50% power boost but it could be anything from 0% to 100%
in actuality...
i think though, if i could buy and install a supercharger for £200, i'd be happy with any reasonable increase in power. say 25% minimum
I suppose there would be extras needed in addition to intercooler and SC, unless you are 100% certain that transmition and drive train are up to the extra power. Especially on a BEC install.
yep this kind of bunny.
how big are these?
Am I right in saying that the speed it is driven at determines the amount of boost so taking a s/c off a 2l engine onto a smaller capacity one, it
could still be used but just driven at lower speed?
and is plumbing it a matter of sticking an air filter onto one end of s/c and other goes into an air box out of which the TB or carbs are fed? Or is
the fuel/air mixture compressed?
to get an increase of 50% is v.good I'd say bearing in mind it is gonna sap some power plus the losses.
There are some pictures here of an A series kit using the Bini supercharger. Gives you an idea if you've ever had a mini head on the bench.
http://vmaxscart.brinkster.net/supercharger.html
very useful artricle 
step 1 unpack supercharger, step 2. fit to car
NOT!
once im on the road i will be looking at one.
It is also an idea to reduce the compression ratio and although the charge is forced into the cylinders, so you don't need bigger inlet valves,
larger exhaust valves/piping can be a good idea, to stop the engine choking.
Also adjust your cam timing to give a smaller overlap, so that you don't waste any charge down the exhaust ports.
It isn't just as simple as bolting one on, if you want best results
Just my humble two penn'th.
quote:
Originally posted by blakep82
if i could buy and install a supercharger for £200
^
I was intending to fit one of the mini superchargers but they are quite large and the only place i could mount one would be in place of the alternator
which would then have to be relocated possibly in front of the crank pulley using brackets and tensioners.
I now think a turbo installation is going to be easier as there is no mechanical drive to worry about and more room to mount a turbo on the exhasut
side of the engine.
The other parts such as intercooler will be required for either turbo or supercharger.
Subaru turbos are available on Ebay for less than £100 in good condition having been removed for upgrades and will do the job.
Paul.
If you want me measure up the mini supercharger let me know. Might not get a chance to get into the garage for a few days but let me know if you need
to know....
They're not the lightest bit of kit in the world though!!!
Chop shop wisdom is that 7 psi of boost will give you at least 20-30% power increase with no mods and no intercooler as long as you route cool
external air to the inlet.
If you already have a high compression ratio then a thicker head gasket can often cut it back enough to avoid pre-detonation.
If you are going to intercool then lengths of air run plus diameter of tube plus DP of cooler will all need careful checking to avoid the increased
losses negating the cooling advantage...
Next mission on mine!
what do you mean I'm putting 2 of them on one engine....
looky foto album
will measure up one tommorow
Grtz Thomas
But this book if your thinking about supercharging, it spot on, covers all main issues .
good book but old school approach.
very usefull though.
BTW have been so stupid to make all measurements, but forgot to take photo's to get all measurements put in via windows-paint.
grtz Thomas
[Edited on 8/12/07 by thomas4age]
quote:
Originally posted by BenB
Trying to work out power output at various boost levels is tricky. Infact, trying to work out precisely anything to do with a S/c install is tricky because there are so many variables...
Trouble is superchargers aren't 100% efficient so they heat up the air that they compress. Then you need an intercooler to cool things down a bit. That results in some pressure loss.... If you try to work it out it'll make your headache!! Books like Graham Bell's Forced Induction Tuning will get you close to the answer but at the end of the day it's an estimate.
Trying to work out the boost @ various supercharger speeds is virtually impossible as it depends so much on plenum design, valve size, valve timing etc etc....
I've still got a Mini S/C waiting to be strapped onto the BEC...