[wohi]

Auch von mir viel Spass mit dem neuen Gerät.

Zufällig hab ich gestern einen interessanten Artikel von Randy Webb gelesen, was er bei einem MCS empfiehlt. Möcht ich dir bzw. euch nicht vorenthalten:

Enjoy:


So you have a MINI now - congratulations! One of the great things about owning a MINI is the fun and satisfaction that comes from making it your own. The aftermarket is one of the easiest ways to accomplish that. Webb Motorsports concentrates on street and track performance - braking, suspension, engine and gearbox upgrades. I am here to make it as easy and reasonably priced as possible for you to appropriately personalize your MINI with upgrades based on what you use the car for.

Since we have established that you use the car for a daily driver, but visit the track occasionally, we know what specific areas to address based on the track, street and dyno testing we have done here on our five car fleet of Cooper S's.

It is important when building a package to make it balanced - if you give the car more power, it is equally important to be able turn and stop it. Based on this approach, we will start with power.

The biggest bang for buck is the supercharger reduction pulley. What does this actually do though? By using a smaller pulley, the supercharger rotors are spinning faster. This creates more boost (pressure), but it also creates more heat - that bothersome physics thing again. All superchargers are designed to operate in a certain window, a "sweet spot" where boost can be created as thermally efficient as possible. With our Eaton M45 based Roots type supercharger, a 15% smaller than stock supercharger pulley is the most efficient at all RPMs. Since the car will see track time, where the full rev range will be exploited, this is the size pulley I recommend. We have also seen drive belt issues on cars that visit the track with pulleys smaller than the "15%" pulleys, which reinforces my selection for this application. The pulley we use is a stainless steel unit which has a similar thermal expansion rate to the shaft of the supercharger. Considering how small the radius of the pulley is (less than 1.25"), the additional weight of this rotational mass is more than worth it for the piece of mind afforded by not only the thermal expansion properties, but by the anti-corrosion properties as well. There are no measurable power differences in 15% pulleys of different materials. Typical gains from the 15% pulley are in the 15-20 horsepower range. Our pulley is $120-129.

The next step in our quest for more power is the cold air intake (CAI). To gain power, we want as much potential energy in the combustion chamber as possible. One of the main ways to achieve that goal is by maximizing density. Density is directly proportional to pressure, and indirectly proportional to temperature - in other words, as pressure goes up, so does density, but as temperature goes up, density goes down. We have increased pressure with our supercharger pulley, and now we can do two things with a CAI: decrease temperature, and increase flow. This generates the second biggest bang for buck. We do this by increasing the surface area of the filter, isolating the filter from the heat of the engine, and gaining access to more colder cowl area intake air - the duct just below the windshield wiper. Webb Motorsports uses an intake with a high flow foam filter element, which has proven itself the most durable and highest flowing after four years of track testing, and by removing the cowl partition and creating a new firewall with the airbox itself. Gains are in the 7-10 horsepower range. Our intake is $200-260.

These two upgrades will get you to 90% of the factory John Cooper Works power level, at a fraction of the cost. It is also reliable - we have over 1,000 customers running this set up, a few with over 100,000 miles. Of course, there are a couple more modifications you can make to go beyond the Works package - an ECU, cat-back exhaust, etc., but we want to upgrade other areas of the car to go with our new found power and remain within a reasonable budget. There will always be birthdays and holidays down the road!

You may notice I mention the ECU as a performance upgrade, but do not initially recommend it as a necessary safety upgrade in conjunction with the supercharger pulley. The MINI uses a Seimens EMS 2000 ECU to monitor and meter air/fuel ratios, ignition timing and a host of other functions. This is a very advanced system. Instead of using a mass air flow sensor (MAF) for metering fuel, which is upstream of most density and flow changes, the EMS 2000 uses a temperature and manifold air pressure sensor (T/MAP) downstream of the entire air intake path. This is true density and because of the location after the CAI, throttle body, supercharger and intercooler, the ECU is able to meter fuel accurately and safely even after our upgrades. Bottom line to this important sidebar: an ECU upgrade is nice to have, not need to have.

The good news for MINI owners looking to upgrade their cars is the Cooper and Cooper S are good right out of the box. This makes the remaining areas of concentration - brakes and suspension - straightforward and minimal.

On the suspension front, there is one very significant change to be made - a larger rear swaybar. The Sport + suspension has great spring rates, and they are linear, which means that as the spring compresses through suspension travel, the spring rate reacts the same. This gives the car a very predictable, linear feel under cornering loads. Therefore, unless it is for aesthetics, lowering springs are not necessary. The OEM (original equipment manufacturer) shocks are also spot-on in both compression and rebound, especially after some mid-2003 tweaks done by MINI. This makes a shock change, for our street driven, occasional track car, unnecessary. Why only a rear swaybar instead of both front and rear? The car comes with a front and rear swaybar, and for mass production safety, our MINI is programmed to understeer. At the limit, the car will continue in the original direction of travel even with more steering input until the coefficient of friction (the stick) is increased in the front, decreased in the rear, or a combination of the both. This usually occurs through weight transfer from rear to front when panic sets in because the car isn't turning and we lift on the throttle or even - gasp - brake. A rear swaybar will transfer load to the front wheel - the larger the bar, the sooner the transfer. If both front and rear swaybars are used, the car will exhibit less body roll, but will still understeer. That is why we only use the rear swaybar. Front camber adjustment, through camber plates, is another upgrade to consider for track time, but given our limited use, I think it is an upgrade better suited for a later date (like after you are completely addicted to track days). Rear swaybars range from $160 all the way to $475 (which also includes droplinks). A 22mm effective rate is a must based on our track and autocross experience with the Cooper S.

Finally, we will address the braking capability of our MINI. The stock brakes work great at the limit - once or twice. We will address two issues with brakes. First, the performance. To give the car more than one or two adequate applications at the track, we will do a simple brake pad change and brake fluid change. This will give us a higher coefficient of friction on the pad - more effective braking - and a broader heat range to work with which will prevent brake fade. To prevent the spongy pedal common with track days, we want to upgrade the fluid to a higher boiling point - that will keep us from having air in the brake lines/calipers. This set up will give a higher margin for track days without breaking (no pun intended) the bank. The second issue this will address, and it is really just a bonus, is aesthetic. We will get rid of most of that dreaded brake dust the MINI is so notorious for. I recommend using Motul RBF600 for fluid and a good combo pad like the Hawk HPS or the Mintex. I usually only recommend front pads, as most of our braking is done with the front brakes due to weight transfer and our static weight distribution front to rear of 63%/37%. Motul runs $15 a bottle, which is enough to flush the system, and the pads range from $70 to $140 per axle. If more track days are being considered in the future, it may be time to start asking for a big brake kit from your loved ones for your next birthday...

So in the end, we have come up with a few upgrades that will give you a very well balanced dual purpose car at home on the street as a daily driver, and competent for a weekend warrior on the track. Starting with power, we did a 15% supercharger pulley and a cold air intake. From there, we addressed handling with a larger rear swaybar. Finally we hit the wall (or avoided it) with braking using a simple pad upgrade and a higher boiling point brake fluid flush. The nice part about this baseline set up is it gives anyone with these needs a perfect starting platform to further identify a MINI as uniquely their own, and that's what this whole little cult car is about after all!