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By BryanSouza
Hey everyone,
I've been busy the last six months which has required my absence from this community. Also I bought a house in June so that put the brakes on the Speeduino project. I've checked in a time or two and am glad to see the progress people are making.

Anyways the reason for this thread is my MINI had a puddle of water under it in the driveway the other day so I pulled it in the garage put it up on ramps and tore into it. It has 105k miles, I had planned to replace the water pump at 100k miles but that didn't happen yet so here we are.

I found the problem. The o-rings for the flange(part #3) that mates the coolant pump outlet to the engine block both(1 on pump, 1 on flange) failed. Image

So I removed the supercharger and coolant pump assembly from the block and then separated them from each other. The pump bearing is in good health but here lies my need for knowledgeable assistance. :D

The Eaton M45 is belt driven, of course, and drives the coolant pump via PTO gears on the back side of the supercharger. The coolant pump meshes with a fork type shaft end coupler on the PTO shaft.

These PTO gears are prone to failure either from lack of oil or coolant pump failure. Lack of oil is supposedly caused by the shaft seal wearing out and allowing oil to be sucked past. The oil level should give me an idea of the condition of the seals. An electric coolant pump can bypass the need to use the PTO.

My supercharger looks great(no obvious visual wear, coating still present on rotors) and feels tight and smooth. There is very minimal play in the PTO gears probably no more than 3°.

I will be checking oil levels in both ends of the supercharger and uploading pictures when I get home tonight.

Where do I go from here?

Should I replace the coolant pump with an OEM replacement or replace it with an electric coolant pump (https://m.summitracing.com/parts/cvs-8000bk)?

Should I just refill the oil reservoirs on the supercharger and check in 25k miles? Or should I have it professionally rebuilt with new bearings, seals, and coupler(not in the budget at the moment)?

Any positive input appreciated. I'm trying to prevent any possibility of future catastrophic failures. Thanks.
By klotzy_550
Supercharger: I would leave it alone, if you do anything to it I would just swap the coupler if the bearings all appear to be good and give it an oil change. I did this on my M62 on my cobalt and didn't have any issues. Plus Eaton has these blowers built appropriately, the M90 on the 3800 series engines go for 200+ miles without issue, similar with the M62 on the Cobalts.

Water cooler pump: If electric is the route you go I would HIGHLY recommend not getting a brushed motor. This is what the cobalt was fitted with and they were prone to failure from the brushes wearing through. The Polaris RZR Turbo MY16 and MY17 has a brushless water pump for the charge air cooler system. I would recommend this pump, more than adequate for flowrate and efficient with a long life.

Hope this helps.
Last edited by klotzy_550 on Fri Jan 06, 2017 1:26 pm, edited 1 time in total.
i would put new oil into the charger and use an electric waterpump.
the oil should be renewed anyway at specific intervals, and the OEM pump is expensive and the gear drive, too, if it needs replacement later.
i would use an OEM electric waterpump, like a lot of modern cars have. resonable priced and proven to work. for the one BMW uses, Pierburg i think, you can get a stand alone controll box
By BryanSouza
UPDATE: Pictures and Video here. In the pictures you can see minimal wear on the ends of the rotors. The rotor coating looks great.

I pulled the fill plugs on both ends of the M45. The snout/pulley side was about 3/8" below the fill level and the PTO side spilled clean oil out. This made my week! :lol: The seals seem to be holding up well for the mileage. I'm leaning towards changing the oil and checking it every 25k miles and plan on a complete supercharger service around 150k miles.
Anyone object to me installing the 17% overdrive pulley at this time since it's out? My research says more rpms=more heat=more wear but nothing detrimental to the longevity.

So I need to explore my electric coolant pump options...
Mounting is going to depend on the pump selected.

PM on the way Klotzy

KLAS thanks for mentioning the stand alone controller I found this: http://tecomotive.com/en/products/tinycwa.html
By klotzy_550
What is your stock Boost pressure and What is the ratio between your primary drive pulley and your supercharger pulley? or rather, what RPM did your blower run at stock?

All can be calculated off of the efficiency chart:
Blower Efficiency Map

I ran a 3.06" pulley on my blower for quite a few miles without any significant issue, stock is 3.4" => ~11% undersizing.
By BryanSouza
The 17% overdrive pulley I refer to earlier is an ALTA Performance. I already own it. Just sitting in a box in the garage.

I found this:
The stock crank pulley size is stated by MINI as 140mm
The stock supercharger pulley is stated by EATON as 65.5mm
This gives a ratio of 2.13 meaning at 6,750 rpm the supercharger is spinning at 14,427 RPM
Eaton state the maximum RPM for the M45 is 16,000rpm
Based on these numbers and the information for the 17% pulley I have: the new pulley size is ~54.365mm which gives a SC/CC ratio of 2.58 so at engine redline 6750rpm the supercharger spins at 17415 rpm.

Stock pressure ratios seem to be right around 2.00atm

Supposedly stock is ~14psi boost and 17% is ~19.5psi

This is just a family car. Not tracked and rarely revved past 5500rpm(low torque band stock best between 3k rpm and 4k rpm)
Everything is stock. :)
By klotzy_550
Take a look at the spreadsheet I threw together, I am willing to bet that Max RPM that it is 50-55% efficient. Estimated boost to be around 19 psig. The blower would spin at 16821.7rpm according to my calcs :o which is quite fast for a positive displacement pump. play with the numbers a bit you can edit the vehicle info and it should update the calcs live.
(39.46 KiB) Downloaded 81 times
By BryanSouza
Thanks again! That spreadsheet is great! Helps put things into perspective!
I've been playing with the numbers a bit and the thing I find interesting is the stock pulley is 55% efficient everywhere except between 2500 rpm and 4000 rpm where it slides into that top piece of the 60% island. I guess that makes sense as to why that's the best part of the rpm range in every gear.

It seems the 17% pulley will be like you said in the 50-55% island , hopefully only the 55% island but it should flow ~17% more air. Lose some efficiency to gain some airflow. The M45 will spin to 16000 rpm at ~6200 engine rpm. There are guys who autox their MINIs with the 17% pulley and even more of the track cars are running the 15% pulley. The 15% and 17% pulleys have been available for around 10 years now and they have great real world results. MPGs usually decrease but SPMs(smiles/mi) always increase! Haha
By noisymime
Just chipping in with some (barely) relevant experience. I'm actually really surprised to see that the Mini used a 2.13 ratio stock! I had an M45 (Though from a Merc rather than a Mini) on a 1.6 at one point and was only running a 1.8 ratio with it due to the serious heat it started putting out beyond that.

I know they're rated for 16000rpm, but as the compressor map shows, they're really dipping into some low efficiency areas above even 11000rpm.
What charge cooling do you plan to use?
User avatar
Just dropping these M45 and M62 inlet flow charts for reference. In-return, if anyone has good maps and charts for my M112, I would appreciate it. The ones at Eaton are fudged thumbnails that I can find. Thanks!

EatonM45flow.gif (28.46 KiB) Viewed 2669 times
EatonM62flow.gif (27.46 KiB) Viewed 2669 times
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