DIY: WRP Under-Drive Lightweight Crank Pulley installed

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Old 04-14-2008, 08:36 AM
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Thumbs up DIY: WRP Under-Drive Lightweight Crank Pulley installed

Had the pulley for a while, but never got around to installing it until this past Saturday. All in all, a painless process (for me at least, being the photographer, ),

Total time, roughly 30 minutes.

The following is my recollection and terminology of the parts & process. I may have miss-named some things, but overall, you should get a pretty clear idea of the parts and the process.

Step 1: Get the in the air. Most may use a jack and jack stands, we had a lift at our disposal, so....up it went.





Step 2: Once in the air, begin removing the plastic air-dam, skid plat, (whatever you want to call it), by taking out about 1k bolts.







Step 3: Once the air-dam is removed, you will now be able to see the pulley and belts. Begin loosening the center bolts on the tensioner pulley. There are 2 in total. One is to the right of the crank pulley, and the other is to the left.





Step 4: Now that the center bolts are loosened, you must loosen tension on the main and secondary belts by loosening the bolts that actually raise and lower the tensioner pulleys.





Step 5: Remove stock belts and loosen the center bolt for the crank pulley. Now, this can be a little bit tricky. How do you loosen the bolt, when it will spin the pulley? Lower the car back towards the ground, and position the breaker bar so that it is on the bolt, and also on the floor. Then, once everything is where it should be, you turn the key on the ignition to turn the starter motor, but you don't want to actually turn over the engine.





Step 6: Unscrew crank pulley bolt, remove pulley, and clean the now exposed surface. WD40 should work just fine. Be sure to run a clean finger along the inside to ensure that no debris is left behind, then spray the area with a lubricant (I think we used a lithium specifically for this application...)





Step 7: Take a moment to compare the stock pulley with the new lightweight under-drive pulley. There is a dramatic weight and size difference.





Step 8: Put on the new pulley. Be sure the line up the key-notch to the correct locations, and uniformly push on the pulley so as not to teeter it. Tighten the crank pulley bolt by hand until it starts to move, then find a method of securing the pulley from spinning freely. We used a ratcheting strap, through the pulley, around the sway bar, and secured to a point on the frame behind the engine.





Step 9: Once secure, begin slowing tightening the crank bolt until you reach the correct tightness (don't recall exact torque number, but oh well...)



It should look like this once correctly tightened down.



Step 10: Put on your new belts (remember, this is an under-drive pulley, so it is smaller, thus requires smaller belts) and tighten your tensioners, in reverse order as when you took them off in steps 3 and 4.









Money Shot:



Step 11: Put the air-dam back on, lower the car

Step 12: Take the car for a test drive, and enjoy the smooth, quick reving response.


Conclusion: The car feels a little more peppy and smoother during acceleration. This may a placebo effect, after all, getting back the percentage of wheel horse power from this is very small compared to the total power output prior to the upgrade, but you cannot argue the positive impact that this pulley has once you see and feel the stock compared to the new pulley.

Most impressive find: There have been plenty of comments by others about other Lightweight Under-Drive Crank Pulleys that other manufacturers have made, in that there is a constant squeal. For some, it is that the belts had not been properly tightened. For others, it's that the sleeve/collar of the new pulley flexes, as it is made from aluminum, and thus is rubs against the seal behind it. This WRP Technology crank pulley uses a stainless steel sleeve/collar, and thus resists flex far better than aluminum.

Why is this impressive? My stock pulley had been squealing for the past 2.5 years. Tightening the belt tensioners, changing the belts, etc... nothing fixed the problem. This is the first time that I have been squeal free in years!
 

Last edited by f r e z N Y; 04-14-2008 at 10:45 AM.
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Old 04-14-2008, 05:32 PM
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nice- i like it! good write up
 
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Old 04-14-2008, 06:52 PM
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only one thing speaks to me about performance parts = Dyno...
 
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Old 04-14-2008, 06:58 PM
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Nice write up. So the stock pulley just wiggled off? Was there any better place to secure the tie down so it wouldn't experience so much side forces vs the forces required to keep it from moving?

ie.. tiedown secured somewhere to the side of the car vs directly under the car?
 
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Old 04-15-2008, 08:12 AM
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Originally Posted by shabarivas
only one thing speaks to me about performance parts = Dyno...
Why is that? You cannot deny that reducing the rotational mass of the system helps regain power. Thus, the fact that this is the lightest UDCP that I know of, equates to more power regained at the wheels then with any other pulley I'm aware of.

Just how much power, I won't know unless I conduct a dyno.
 
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Old 04-15-2008, 10:10 AM
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Originally Posted by Jeff92se
Nice write up. So the stock pulley just wiggled off? Was there any better place to secure the tie down so it wouldn't experience so much side forces vs the forces required to keep it from moving?

ie.. tiedown secured somewhere to the side of the car vs directly under the car?

eh, there is so many ways of doing it - some people just use a slip wrench to hold it in place, i just prefer to put it on with that method, and then crank on it till it's tight enough that i can tighten the bolt to the needed tq settings - there's truely no difference in doing it this way over holding it with a slip wrench
 
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Old 04-17-2008, 05:39 PM
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nice, i just put in my UR kit not too long ago. i noticed a big difference just driving down the street at moderate speed. could be butt dyno, but the car just seemed more responsive.
 
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Old 01-10-2009, 04:06 PM
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What is the new belt size for the mod?
 
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Old 01-12-2009, 01:08 PM
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Originally Posted by shabarivas View Post
only one thing speaks to me about performance parts = Dyno...
Are you questioning the effectiveness of the lightweight UDP? Mathematically speaking, this is a no brainer compared to most other mods - it's impossible to reduce the weight of the rotating mass and the amount of drag from accessories and NOT see a gain in WHP. It is usually one of the biggest "bang for your buck" mods for many cars, but there is the debate about the risks associated with the lack of a harmonic balancer/dampener.
 
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Old 01-12-2009, 01:45 PM
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Okay I'm a newbie, what risks are associated with this mod, other than the obvious possible install errors?
 
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Old 01-12-2009, 01:47 PM
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Originally Posted by IdriveG>35 View Post
Okay I'm a newbie, what risks are associated with this mod, other than the obvious possible install errors?

http://en.wikipedia.org/wiki/Harmonic_balancer
 
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Old 01-12-2009, 01:51 PM
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Good enough for me not to participate in this one.
 
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Old 01-12-2009, 01:54 PM
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Originally Posted by IdriveG>35 View Post
Good enough for me not to participate in this one.
It's been a heated debate for years... I've known plenty of people that ran LWUDPs for years with no issues.
 
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Old 01-12-2009, 02:52 PM
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Did WRP sponsor you?

Does it come in regular size or under-drive only?
 
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Old 01-12-2009, 03:22 PM
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Risk reward I guess. A broken crank is considerably different than changing an alternator. LOL
 

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