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Completed 4/17/2002

Install the EvoSport Underdrive Pulley set.

1 - Underdrive Pulley Set
     (EVOSPORT $399 part #evo-e36pp1-v1)

10, 13, 16, & 17mm sockets
Ratchet Wrench
24mm Impact Socket and Wrench
T25 Torx Driver or Socket
Flat Head Screwdriver
Phillips Head Screwdriver
Anti-Seize Compound
Lubricating Oil
3 Gallon Catching Basin
Up to 4.4 qts BMW Coolant (optional)
Up to 4.4 qts Distilled Water

First, you might notice that the part number for my pulleys doesn't match the EvoSport website's list. I believe this has to do with the different sets available. The Valeo and Bosch alternators use different pulleys and, depending on whether you have a serious stereo system electrical load, you can opt to not underdrive the alternator (they simply send you a OEM-sized, yet lightened pulley for it).

Second, I did this install myself in my garage, however, looking back I would recommend you have it done at your local BMW shop. I only uploaded this DIY for those who choose to take it upon themselves to try. EvoSport's included instructions are accurate, but they take a 3hr job and shorten it into about 13 steps. I will elaborate on those instructions as we go.

1. These are the pulleys. From left to right: power steering, alternator, water pump. The belt is a 6-rib 62-inch AC-Delco serpentine. I bought another belt from AutoZone just to keep in the car (Photo A).

2. Disconnect the negative battery cable in the trunk with a 10mm socket.

3. Start with the airbox. There are 5 clips to detatch (Photo B - Red Circles). Lift the airbox cover and pop the 2 silver clips off the MAF (Mass Airflow Sensor) to the rear of the box. Remove the airbox cover.

4. Remove the (2) 10mm screws from the airbox (Photo C - Red Circles). You can now pull the rear of the lower airbox up and out. You will most likely pull the small front air duct out with it, this is OK.

5. Time to get under the car. Lift and support the front end of the car. Remember safety first.

6. Remove the splash guard from under the engine. There are 6 Phillips-head capture screws (Photo D - Red Circles) and 2 plastic pop rivets (Photo D - Blue Circles) in the front valance.

7. Underneath the car, find the blue coolant drain plug. It is below the airbox location (Photo E). Move the catching basin in place and remove the plug with a Phillips-head screwdriver. CAUTION: The coolant can still be scalding hot.

8. Crack open the radiator cap and loosen the bleed screw (Photo F - Red Circle) to help the radiator drain.

9. Once the radiator is empty, we need to remove the radiator overflow tank. BMW uses ingenious connectors in the cooling system. There are wire clips, that once released with a flat head screwdriver, allow the hoses to be quick-disconnected. There are 2 of these on the top of the overflow tank (Photo F - Blue Boxes). I found it easier to disconnect the other end of this hose and remove it (Photo G). There is also a heater hose leaving the rear of the tank that needs to be removed (This will release quite a bit more coolant, so make sure your catching basin is still under the car.)

10. At the bottom of the tank, there is a small tab. Pull this tab to the left to release the tank. It will take a bit of force to pull the tank up and away from the radiator. Take care to allow for removal of the Low Coolant sensor which can be removed from the bottom of the tank with a counter-clockwise twist. The sensor is about 2 inches long and fragile, be careful removing it.

At this point, the last 6 steps describe EvoSport's step 4 (Photo H).

11. Loosen the (4) 10mm bolts on the water pump pulley and the (3) 13mm bolts on the power steering pulley.

12. I was able to pull the water pump pulley off to release the rear belt. You will have to remove the front A/C belt at this time as well. The A/C belt is easy to remove. Press down on the tensioner in the center and slip the front belt off, then take the rear belt with it.

SIDE NOTE: Do *NOT* believe everything you read. The Bentley Publisher's Service Manual is WRONG when it comes to relieving the belt tensioner's pressure. There is a 13mm bolt under the dust cap, which when twisted clockwise (as per the manual), will snap off. This is no fun at all and I had to replace the bolt. Luckily, it came out in one piece. However, to do this, I had to remove the fan (which is why it is missing in some of these pictures). Let's not do this, OK? I found that using a large wrench as a lever, I could pry on the upper tensioner to release/replace the belt.

13. Finish removing the pulleys. Ahhh, the alternator ain't easy at all. If you don't have the BMW Alternator Pulley Nut Removal Tool #12 7 110, you are gonna have fun with this one. Since I don't have that tool either, I finally pulled the alternator out of the car, put a 24mm socket on the alternator pulley nut, and air impact-wrenched the nut right off. I also used the air wrench to put the new EvoSport pulley back on. Worked great. The correct torque is 44 ft-lbs. Before and after shots are in (Photos I & J).

We are now at step 8 in the EvoSport instructions. We even get to skip step 9.

14. Lubricate the centers of each EvoSport pulley with a little oil before putting them on. Also, use some anti-seize compound on the bolts.

15. The water pump pulley goes on easy. The power steering pump pulley was a bit tight, but it fit fine. Tighten both to 7-8 ft-lbs. (Photo K).

16. Replace the belts, the one closest to the engine first. Make sure the belts are securely on each pulley (Photo L).

17. Going backwards, put everything back into the car. Don't forget to replace the radiator drain plug.

18. Reconnect the battery. Turn the ignition ON, but don't start the car. Turn the climate control heat on, and the fan to low.

19. Slowly add a 50/50% mix of coolant and distilled water to the radiator. I was able to capture almost all of my original coolant into a brand new basin, so I reused it. You will have to do this slowly as the system fills back up.

20. Once the little "stick" tells you the system is full (or the bleed screw leaks), tighten the bleed screw, and replace the radiator cap.

21. Start the car and check the belts. Rev the engine a few times to make sure the belts are completely on each pulley. If it all looks good, take it for a ride and you are done.


Photo A

Photo B

Photo C

Photo D

Photo E

Photo F

Photo G

Photo H

Photo I

Photo J

Photo K

Photo L

Photo M


These EvoSport pulleys look great and the craftsmanship is outstanding. They fit perfect and are lighter than OEM. I included a nice closeup of the water pump pulley's machining in Photo M.

The instructions could use some elaboration, but this is a new product and this DIY will help.

I did drive the car fairly hard after the install. I didn't notice huge power gains really, but the horsepower gain from this pulley set on a 225hp engine isn't immediately noticable. It is one of those modifications that adds up with those software upgrades, CAIs, exhaust, etc. I will say that, even though it could be in my mind, I had 3 people in the car and it felt like I was driving alone. The car didn't seem to be affected by the extra weight at all. Maybe that is worth noting...

In the end, I really liked this modification. Again, they are beautiful and seem like they belong there. The install wasn't the cleanest I have ever had, but I wanted the pulleys installed in anticipation of my supercharger. They might just make up for some of the drag placed on the engine by the blower.

  © MarvelPhx