Underdrive pulleys [ merged 1/6/07]

[larryd]

Worth it or not? I'm thinking of going with the AEM tru-power pulley kit. Anyone used them?

 

[greyforestgst]

Originally posted by loreak
ok to the guy who said his crank pulley separated and the ac belt got into the crank sprocket and messed up his timing belt, i aint buying it, your full of shit

the only way that could happen is if you dont have your timing belt cover on, and if you dont have it on then thats pretty damn stupid and your asking for trouble

please dont say something if you have no ####ing clue what youre talking about.
thanks

stock pullies seperating are a known problem.

 

[loreak]

yes the outside separates from the inside at the harmonic damper and the inside is still bigger then the hole in the timing belt cover which covers the crank sprocket, i had it happen, theres no way any belts are going to somehow go through the tbelt cover and hit the crank sprocket to get tangled in the tbelt, unless you dont have your cover on its not happening

 

[GRNDSM]

As you can tell, I am not a big fan of aftermarket underdrive pulleys (with out "balancer"), but if negleced, stock pulleys CAN take out your timing belt! And once that happens, you I can destroy your entire engine.

But that to me means that you just have to keep in eye on the factory pulley and replayce it every 5-6 years .

Leon
RR

 

[SOURCE1064]

Originally posted by R-O-B
If you get a crank pulley make sure it is a balancer also. Buschur's is the only one that I know of.
If it isn't a balancer you could run the risk of damage to the lower end.
Our engines are externally balanced.

Forced Performance makes one too for those who are looking for one. I just got one and it looks real nice.

 

[91TalonTSiCT]

I recently read that the only pulleys that should be used are ones with dampeners. Without the dampener, the crank bearings are said to wear out faster bc there is no way to cushion the force created by the rotation of the crankshaft. The only aftermarket crank pulley made is the buschur racing for $350. The stock pulley is approx. 6lbs compared to the 1.8 lb one i bought. what do you all think?

 

[Mike 99GSX]

This has been discussed to death. There are small performance benefits to running the aftermarket pully. Some people will say that the lack of a dampener is not worth the potential risk to the crank. I've had the Unorthodox one on my 2g for 50000 miles and have no problems but the results and theories vary.

 

[Cirus_93TSI]

u could have used the search, there are half a dozen threads askign the same exact thing
getting only a crank pully will mess up ur accesory speeds, ur alternator wolnt spin at the right speed and it wolnt work right, same goes for any thing else run off a pully under ur hood, u have to get en entire matching set of underdrive pullys, weight doesnt matter(although lighter weight is what makes power gains), only size, every has to have the same size ratio as stock when compared to the other pullys, meaning if (just for an example) ur crank pully was 5" and every other pully was 3 inches then ur new pulleys would have to be exactly 3/5 the size of ur new crank pully, or else nothing is going to work correctly
u cant just throw on a crank pully, it will give u absolutly no increase in horse power and it will make ur accesories not function correctly, getting every pully under ur hood might give u 3 to 5 hp(at the crank, not the wheels) altogether, if u do get just a crank pulley and ur car runs out of power and dies because ur alternator isnt working and ur battery is dead u will know y it happened

 

[motomatt]

Has anyone used the AEM underdrive pulleys? Are they all the same? Is one brand better than another? How hard are they to install? Thanks for any input

 

[goalieman24]

the af/x one seems to be the most popular. havent heard anything about AEM's. There are discussions about how to install them but im not sure where specifically

 

[interceptor]

http://seangordon1.tripod.com/UDPinstall.html

heres an installation on a AF/X UDP
pretty simple

 

[VRMAN]

I know that under drive pullies are supposed to free up rotationial mass and allow more power to the wheels. What do you guys think? Is is worth the money to purchase one or is it better spent elsewhere?


Looking at something like this:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=6763&item=2438653924

 

[Trekman8]

from my experience with underdriving the belt system or vehicles, it proves to be a worth while mod time and time again. For $64 5hp without more boost cant be beat. I have installed underdrive pulleys on my 4.6l mustang gt convertible, my 98 jeep grand cherokee limited 5.9L (world fastest SUV before porsche's cayane was released, look it up) and pleanty of customer's vehicles. And I plan to get one for my dsm. I say go for it, and if it doesnt work out for you, which is unlikely, you can always resell it on eBay and post about it, then the whole community will be the wiser

Chris

 

[dudasd]

As far as I know, the AEM ones are for the drive pulleys themselves, but they are only available for the 4G63 guys. I think, OBX makes some for our cars though but I'm not sure how good they are. The difference between those and the AF/X is that the AF/X is a crank pulley where the AEM are actually accesory pulleys.

 

[leet]

Unless your rotating assembly has been fully balanced, I would not recommend any undampened pulley.

 

[95AWD_TSI_TALON]

hey i have pretty much that same pulley on my 95 tsi and i put it on when i first bought my car with a blown head on it. so i have no idea if it made a difference our not. BUT there was a site i lost it tho that talked about ALL the dissadvantages about running one and it made me want to take mine off.....even tho my car is sitting outside with a huge hole in the block from rod #2. So the 6 bolt motor I am building i will not be putting that on so if you want it 35 shipped its your.
matt

 

[Eclipse96Ryder]

AEM doesnt make a pulley for our car. Get the AF/X one, its sweet, its on my car and i could tell a difference. It gave me good low end and top end power. You can get it at www.howellautomotive.com

 

[Defiant]

Bizarre in here how things fade in and out. Gangs of balancer questions, while the automatic-to-5-speed swaps have mostly gone away.

Anyhow, consider:

http://members.core.com/~faldrich/harmonic.htm

http://www.dalemfg.com/dale_008.htm

I don't know if I buy the lack of a HB being all that much of a threat.

 

[lawdaman]

Yeah, OBX R does make "Power Pulley" kit for our cars along with a a$$ load of other parts. You can get them for $99.95 at streetstyler.com. I plan on ordering a set after my OBX 2pc CAI comes in...(If it ever does!!!). I'm not sure how they perform, so why dont you cop it and let me how it turns out.

 

[Raph]

yeah,but some Opel motors (eg 2.0 16v) have the harmonicbalancer in some modells,but the same engine in another(eg a hatchback) dont,and i havent noticed any difference in how the motors run(in terms of vibration or Cranks breaking)

maybe i does makew a difference,but i guess only in6, 8 and 12 cylinder motors

hell,most diesels dont have a harmonic balancer(and they vibrate alot)
but i guess its because of the increadable low end torque that they produce.

 

[Plague]

Looks like my earlier post was overlooked. If you plan on keeping the car and dont want to worry about it down the road throw another OEM in there or grab the Vector. I posted this question all of a couple days ago, I went ahead and bought the Vector unit for a hefty $350. I got it becasue Im running it with a Fidanza and without balance shafts. I thought I would go ahead and be on the safe side.

 

[dsmturboawd]

just get the buschur one. it comes with a harmonic balancer for peace of mind.

 

[Plague]

The one on the Buschur site is the one that I got.

 

[Cirus_93TSI]

there was a very long duscision topic about this a month or 2 ago, most people agreed with this conclusion

installing only an underdrive pully will mess up your accesory speeds(alternator, ect) unless its the exact same size as the stock one, and if it is the same size then the performance gain will be almost unnoticable
you need to get a full matching set of pullys for it to be even the slightest bit worthwhile in terms of performance. if you get a full matching set of smaller lighter pullys you will get a noticable power gain, and with a matching set your accesorys will spin at the correct speeds and your car will run right
if you get just an underdrive pully or a mix matched set of pullys dont be supprised if your belt driven accesorys turn out to be spinning to slow after your car stops running the way it should out of the blue one day

 

[jdmawd]

Underdrive pulleys are larger in diameter then stock pulleys. A larger pulley will spin slower then a small one at the same crank speed. Every set of underdrive pulleys are larger then the stock pulleys. Dont think so? buy a set.

 

[ericismyname]

there are huge threads about this, i think basically it comes up, that its very risky to be runing one without the hole set of pulleys. even then i think they said something like only dynoed 1hp gain from a whole set of unorthadox racing pulleys or something.