Saturday, October 14, 2017

mini love - part 27

About a week ago I ran into some problem while installing the Milltek cat back exhaust system. The flange of the main pipe is not co-planer with that of the factory exhaust header.

the flange on the Milltek main pipe (left) is not square WRT the pipe, while the flange on the factory header (right) is perfectly square

I ended up ordered another set as the vendor will not ship out a replacement until the return kit arrives to them. A week would gone by and the second kit finally arrived.

Recently I found this Gardena nozzle return to Amazon. This is the cheapest and yet is one that I like the most. I immediately bought one to test as it has gone over some minor changes.

the Gardena (left) and the piece of shit one from Home Depot (left) which the trigger cannot overcome the water pressure

The Gardena nozzle is about $12 and is very well design despite the all plastic construction. It is simply a pleasure to use and very ergonomic. I bought a spare after it passed my inspection.

A Mini owner in San Francisco is nice enough to donate this used oxygen sensor and ship to me. I need to cut off the harness for used with the wide band air/fuel meter that I plan to install.

I performed a more thorough tests on the Dual XGPS150A using their free GPS Status App

the Bluetooth pairing is very painless and seem robust enough every time I tested it after switching off and reparing

my homemade char siu 叉燒

it is so delicious - better than any you can find in town and without the disgusting sugar glaze; mine is full of umami goodness

Some reader may be taken aback by why I put down store bought char siu. It is because I know how it should taste, and in the West the chance is what you find has been bastardized. It has been made too sweet, with little care and lost the original great taste that is made with the right technique and ingredients.  I taught myself how to make this, by taste from childhood memory. I use no food colouring. Just do a google image search and you can see all the disgusting sugar glazed bright red char siu. Delicious char siu should not taste overtly sugary sweet, but umami sweet.

this is all the condiments that I use in addition to some salt for seasoning - the two on the left is most important; the right most is a gift from grocery shopping which I am not too crazy about due to all sugar content

I never buy store bought cha siu ever

This is one simple meal that is very common in Hong Kong tea parlor restaurants if you want to spend very little for lunch. Just char siu served with a bowl of rice and some vegetable. Mine is much better because of the top quality Thai Jasmine rice, and my char siu simply kicks ass, and I cook the Chinese broccoli just right.

char siu fan 叉燒飯 - meaning Cantonese barbecue pork with rice; instead of pork fat, I drizzled virgin olive oil onto the vegetable and add a dash of good quality soy sauce

With the abundance of homemade char siu 叉燒 I think I would make a batch of glutenous rice.

Back to the Milltek saga. It would turn out the flange on the main pipe of the second has the same crookedness as the first. I was not amused. I was just about to call the whole thing off, but I decided to contact Milltek directly in UK. I called them at 9:30 AM UK time. The chap that I spoke to is as you can expect a pleasant British fellow. I have always have excellent experience dealing with the Brits. I sent him the pertinent description of the problem as well as photos. He was not technical and he promise will forward to the right people.

Within a few hours, he got back to me via email after checking with their production team whom checked against their master sample. The off-square flange is normal, was the answer I got back from Milltek. For whatever reason Milltek chose not to maintain the perfect perpendicular flange as the interface to the factory header. Now I know this is as-designed. I decided to go ahead and proceed with the installation despite of the differences between the two mating flanges, hoping it would come out OK.

It would turn out the angle difference is mostly vertical, and very little horizontal component which was my main concern. The vertical difference of about 7-10 degree is easily absorbed by the flex joint of the header. I was able to reuse the factory flange gasket which is a mere 1mm thick stainless gasket. I prefer it over the compressible aluminum one that is shipped with most aftermarket exhaust.

Sorry for the out of order organization of this post. It is dictated by the sequence of the photos that I uploaded, as it would be a lot of work for me to reorganize them. Here we jump to the back pressure of the stock exhaust compared to the Milltek.

the stock resonator - I put this paper cup there with a hole cut out to blow on it for gauging how much back pressure it has

the one-ball exhaust modification that removed the resonator - I also blow through it to gauge how much back pressure it has

unboxing the Milltek cat back exhaust - it is a non-resonated version
I chose the non-resonated Milltek cat back exhaust for many reasons:
  • It is lighter than the resonated version
  • It does not have the resonator under the gear shifter which can get very hot driving on the track
  • It has less back pressure but is a bit louder 

the hanger bars on the main pipe has a sleeve welded on to increase the diameter for better engagement with the MINI shock mounts

a closeup of the flanges of the two section pipes

here shows the weld that is done inside the lips of the flanges

all the pieces has a welded on tag showing the part number and country of origin

the two section main pipe mated up

this is the twin muffler of the Milltek - I blew at the flange to gauge how much back pressure it has and there is very little, compared to the stock resonator or the muffler alone

you can see here how small and light the Milltek exhaust is; the reduce weight should be easier on the silicone rubber shock mounts

Before proceeded to install the Milltek cat back system, I carefully weighed all the components of the stock exhaust as well as the Milltek.

muffler - 20 lb 3 oz
straight pipes (2) - 9 lb 1.5 oz
misc hardware - 2 lb  (not include two pre-05 hangers)
Total: 31 lb 4.5 oz

resonator - 20 lb 14 oz
muffler and pipe - 27 lb 4 oz
hangers - 14.6 oz x 2 = 29.2 oz = 1 lb 13.2 oz
Total: 49 lb 15.2 oz

So Milltek is 18 lb 10.7 oz weight saving. I did blow test on both system and Milltek is significantly less restrictive than the stock resonator and muffler which are in series. I expect the Milltek to complete resolve the heat problem with the stock muffler driving wide open throttle at the track.

One thing that I was concern initially with the Milltek is the hanger bars. They don't have the nubs like on the stock exhaust to prevent it from slipping out of the silicone rubber shock mounts.

you can see the nubs on the stock exhaust hanger bar

this looks to be a heat shield for the battery box but it is actually an aerodynamic undercarriage baffle; this baffle was a liability with the stock muffler as it traps the heat but it should not be a problem with the Milltek cat back

the one-ball exhaust (left top) and the Milltek cat back (right bottom)

one of the rear shock mount is torn

I bought this German shock mount from a local Mini onwer for $10 and it is very close to the red MINI one that costs 3 times more money

the MINI shock mount (red) and the HJS shock mount (black)

I managed to get the Milltek finished between showers with everything squared up. I initially was very concern how well it will fit. It turned out quite well. As the total length of the exhaust will increase significant at maximum operation temperature (like driving wide open at race tracks) I will need to carefully monitor the potential stress it will put on the rubber shock mounts.

I was most concern with the hanger bars of the muffler adequately engage with the silicone rubber shock mount. I checked all four hanging points at the twin muffler after tightened all the fasteners.

do note that the mufflers will tend to move rearwards the higher the temperature, especially driving at full tilt on a track

Another area of my initial concern is this rear flange. On the stock exhaust there is no flange here so the muffler tunnel is quite narrow for the new flange interface. I knew should the flanges turns out to be too close or touching the aluminum heat shield, I can widen it slightly. It turned out I didn't need to as the entire cat back sit very snugly.

the twin tail pipes centers as well as I could hope for as there is no adjustment if they are not; the vertical space is just right

the skid plate of the battery box got bang up at the track when the muffler came loose; I restored the folded lip in just a minute; I should have a last name Hammerschmidt

the skid plate is actually a undercarriage aerodynamic device

the exhaust tips align quite well with adequate clearance from the plastic bumper valance

So what is the Milltek exhaust like? It give the Mini a lot more presence. It is significantly louder than the one-ball exhaust that I modified from all stock. Since my experience with extremely hot muffler which threatened to boil the battery electrolyte I am now willing to live with a louder exhaust for the benefits on the tracks. With the Milltek not just the exhaust is louder and sportier, there is also an incremental step of more drivetrain vibration that can be felt. It is still very pleasant and not enough to cause unpleasant rattle of the interior. Now one can sense each firing of the engine cylinders.

I took the Mini for a test drive and the video is recorded with an iPhone

I have a very time efficient photo post processing work flow, and one of my go-to tool is this excellent free Canon Photo Professional. It makes grading, editing, and resizing photo incredible fast and effortless. The power is the ability to process multiple photo in the few clicks of the mouse and keyboard hotkeys. The is a similar free app from Nikon but it is inferior - with the little time that I tried it.

I just looked at these poser racing tow hooks that is flooding Amazon, but decided it is no good; I will stick with the no-nonsense one that came in the Mini's tool box

trying on 15 inch wheels that were used for autocross; Mini sits almost another 1/2 inch lower

the new storm drain with double basin is as well installed by the crew as I could ask for

Milltek header - now paying more attention to the details, the feeder pipes are bent to be covered by the factory head shield

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