Sunday, April 23, 2017

mini love - part 1

Since the acquisition of the Porsche GT4, I appreciate and love my Mini more than ever.

the Mini now

the Mini in 2004 new

changing the engine oil

I have gotten very good in not making an inevitable dripping mess; I use a used plastic bag to catch the oil filter as I lifted it off the filter cavity on the engine

I have not check the air filter a long time - out of sight, out of mind

I am so embarrassed of finding the air filter being so clogged up; fortunately the other side has absolutely no sign of dirt

I have a big stash of genuine Mini tuneup parts

I also removed the intercooler and cleaned out the engine oil that has condensed inside

changed the set of spark plugs

all four plugs removed have the same healthy appearance; they are made by NGK which I think is as least as good if not better than Bosch; these plugs are supposed to last as long as 100k miles

The peppiness of the car can immediately be felt after the tuneup. I am amazed how bad I let the maintenance slipped. With the lightweight wheels and sticky tires, it is like a different car - like when it was brand new.

the Mini is as gorgeous if not more as the day it arrived in the summer of 2004; at the time I ordered it 2800 miles through an online forum from Ohio built to order

Only recently I read about the very common front strut tower mushrooming of my generation of Minis. I checked and mine have absolutely no sign of this affection. But with the upcoming suspension upgrade with stiffer springs and stronger dampers, the risk is very real.

left and right front strut tower has no sign of mushrooming

putting on the light weight wheel with R compound tires

all the brakes are in very good condition; the rotors and pads have been changed once

the brake rotors are the only thing you can find rust on the Mini

To make the Mini more fun I have decided to do a number of performance updates. The foremost is the suspension.

As I initially was thinking of a set of very good coilovers here I am checking for any potential installation issues, such as tires rub against the coilover assemblies. My wheels and tires are very conservative and are very close to the factory dimensions.

I can see a potential problem; the distance between the existing factory strut body and the inner sidewall of the tire is very small, and this is with the factory strut that has a flatten side already. There is where most coilovers' lower spring perch and the bottom of the coil spring is at.

all the suspension parts are in extremely good shape; you can see the flatten section of the strut damper casing to maximize clearance against the tire sidewall

soon most of these suspension parts will be taken out

I initially was all ready to invest in a set of very good coilovers. The advantage of coilovers is one can tailor the ride height easily, as well as perform 4-corner balancing of the suspension. However seeing the potential rubbing issue, and that a lot of coilovers come with less than stellar spring coils I begun warming up to conventional fixed coil spring with good dampers/struts. While tire rubbing against the coilovers may be cured with the addition of wheel spacers in the mild cases, I simple do not like to deal with wheel spacers if there are other options.

this is some photos that I found with coilovers where the tire rubs against the spring perch and the spring (you can see the black rubber transfer onto the lowest turn of the spring and the spring perch)

After a lot of forum reading I decided to go with the coil spring set from Swift. I chose Swift as, unlike most aftermarket lowering spring set, they spring set offer very conservative drop and are carefully designed to work with the factory strut stops. Mini has very little suspension travel, and the damper stops function as a part of the suspension spring when the suspension is compressed even modestly. Swift designer knows this. Swift is a Japanese company and is well regarded by many performance drivers. KYB while also a Japanese company, but is generally regarded as consistently one of the worst.

the Swift springs are the first parts to arrive

while the packaging is very efficient, the white paper that wraps the front springs are of high quality as Japanese are connoisseurs of fine paper; the paper stands out on me that is is not bleached white as western paper normally is

there are progressive springs

these definitely are for Mini - the smaller one is for the rear; I can actually compress the spring an inch or so

Koni Sport Struts and Dampers for the R53 Mini are reportedly one of the best as well as very affordable so I chose them. It turns out my order would not be shipped until the end of May, and I would risk missing the $50 rebate's cutoff day.

As a part of the suspension upgrade, I would also swap the factory 16mm rear sway bar with a beefier 22mm one, to significantly the understeer tendency of the car. There will also be a set of front camber plates to modestly increase the negative camber. A set of adjustable lower control arms for the rear will also be needed to add some negative camber as well as to adjust for proper toe in. For now, I plan to keep all the factory rubber bushings as they are in like-new condition.

22mm adjustable rear sway bar
 adjustable rear lower control arms

fixed camber plate with more negative camber than factory

One thing that I've wish my Mini came with from the factory is a limited slip differential (LSD). At the time in ordering my 2005 Mini Cooper S only rumors that BMW may offer as a factory build option. This is one single most important performance that the Mini sorely need. Just as well now, as the Mini's factory LSD is reported to be rather poor in quality.

I opted now to add a Quaife LSD. Quaife is an UK company and has nothing but great reputation and is amongst the most reasonably priced LSDs for the Mini.

Quaife LSD is a Torsen design, hence is low maintenance compared to more expensive clutch type

As with most front wheel drive cars replacing the open differential with an LSD requires taking out the entire clutch/transaxle assembly. It is an extremely labor-intensive procedure. One would want to take the opportunity to replace any parts that have expended some service life even if they are in extremely good condition with very little wear. These items are the clutch and may be the main crank rear seal.

I begun investigating the high performance clutches. I prefer clutch that has sharp engagement and I begun to lean towards high performance clutches. Most owners replace the factory dual-mass flywheel with aftermarket single-mass flywheel that come with the clutch conversion kit.

single mass light weight flywheel

South Bend high performance clutch kit - they have many levels of selection

 Spec is another usual suspect choice but I read a lot of very poor reports

On the engine I only plan on some easy and modest performance upgrades. This includes a 15% suprecharger reduction pulley, and a cold air intake with a performance air filter.

15% reduction pulley for the supercharger

some photos from circa 2005

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