Hey All,

New guy here. I've been reading all of the great info on this site for the last couple of days (in great anticipation of my MCS that is still almost a year away, curses!) and I have a couple of burning questions so I may as well go for broke here (and I have tried looking at all the discussion threads but if I missed all the answers, sorry).

1) Many of the hp upgrades (supercharger pulley, pitch change of the supercharger fan (a la the JCW upgrade), intake, exhaust, ECU tune) seem to involve unrestricting the airflow and/or increasing the (cold) air into the engine. Even now I am salivating thinking about all of these but I have to wonder do we ever hit the point of diminishing returns?

That is, if you already have the Madness performance upgrade (Intake, Exhaust, ECU) which promises 26 whp, would getting the supercharger pulley really buy you the extra 20 whp that it claims or would the sum be something more like 40 or 35 because you have already reached the saturation point of how much air the engine can process?

(if this is true then maybe we don’t need to mourn the loss of the JCW upgrade that may never reach us stateside anyway)

2) Why has there been only very limited discussion about a limited slip differential? Is it because it is expensive (it is less than a set of coilovers)? Is it because it would invalidate the warranty? Is it because installation is really arduous? Or is it simply because the rewards are not as significant as they are with other modifications? I personally am very much attracted to the LSD because it a) gives you max torque on the wheel with traction and b) should not change the quality of the ride and c) if you really have to drop the transmission to make the change, then what better time to also put in a lightweight flywheel and get more of that power to the wheels. Granted, b) might not seem like much of a reason but I am not planning on racing or anything and I still will need to get to work and go over speed bumps and all that.

3) Emissions. If I were go for the Madness performance upgrade or the supercharger pulley for example, would my MCS automatically fail an emissions test (CA in particular)? Am I ok as long as I don’t change out the exhaust header?

Thanks,

Chuck

 

Answers on all three

1) The gains are not linear. A 5 hp intake and a 10 hp exhaust probably wouldn't give you 15 hp.

2) MINI2.com has a lot more discussion on the Quaife LSD. For one of many threads on the topic, try here: http://www.mini2.com/forum/showthrea...threadid=21055

3) You should be fine in modding as long as you dont change the Catalytic Converter. Even then, many cats are actually cleaner AND more free flowing than the OEM one. Even headers should be fine. All the cats you'll see for the MINI are marketed for "off-road use only" because they aren't certified...but that doesn't mean they wont pass.

 

Thanks. I read the qualfie thread. Man, that seems like a lot of effort. No wonder people are shy about undertaking that task.

I kind of expected that the hp gains would not be strictly addative but, and I'm not trying to open a science forum here, is there a good understanding as to why? I mean is there a max limit to the air/fuel density that can be achieved in the combustion chamber? Is it more to do with the ECU?

Just wondering