underdrive pulley
#31
Race Director
#32
Racer
We love the UD pulley, but the unit we use has a solid center. The CVheetah looks fine, just don't use this one! We've seen three fail this year alone that came in one customers engines. This one didn't have another track day left in it.
But it could have been worse. This is what happens when fashion is employed where it has no place.
I have engines with hundreds of track hours using our solid center UD pulley with zero issues and thousands of miles. The top one above has less than one track season under its belt. The factory isn't the ultimate authority on these sorts of things, hell they are the ones who created an engine with 23 documented modes of failure, most of which occur on the street and not on the track.
But it could have been worse. This is what happens when fashion is employed where it has no place.
I have engines with hundreds of track hours using our solid center UD pulley with zero issues and thousands of miles. The top one above has less than one track season under its belt. The factory isn't the ultimate authority on these sorts of things, hell they are the ones who created an engine with 23 documented modes of failure, most of which occur on the street and not on the track.
#33
Race Director
I installed the UD pulley Saturday. What was a 3-4 hour job on the 986 is a 30 minute job on the 996. There's even room for a RotoZip w/ grinding wheel attachment to take care of the TDC boss, much nicer than the mini-hacksaw I had to use on the Boxster.
#34
Instructor
Really old thread but to be meaningful, voltage measurement of the output of the alternator with a UDP will need to have full load on it. At some point the slower-turning alternator may not be able to keep up with the demands of the car. If you turn on headlights, rear defroster, AC at full blast, wait until the car is hot and radiator fans are on, and turn on the seat heaters, you need to be sure the alternator can produce enough voltage at the RPMs you will be running at.
Just saying that there is likely a spectrum of possibilities. Slower spinning accessories can be a plus or a minus depending on what you need from them.
Just saying that there is likely a spectrum of possibilities. Slower spinning accessories can be a plus or a minus depending on what you need from them.
Last edited by mklein9; 07-11-2014 at 04:22 PM.
#36
Really old thread but to be meaningful, voltage measurement of the output of the alternator with a UDP will need to have full load on it. At some point the slower-turning alternator may not be able to keep up with the demands of the car. If you turn on headlights, rear defroster, AC at full blast, wait until the car is hot and radiator fans are on, and turn on the seat heaters, you need to be sure the alternator can produce enough voltage at the RPMs you will be running at.
Just saying that there is likely a spectrum of possibilities. Slower spinning accessories can be a plus or a minus depending on what you need from them.
Just saying that there is likely a spectrum of possibilities. Slower spinning accessories can be a plus or a minus depending on what you need from them.
Here's mine and pretty much supports what I said above.
#37
Rennlist Member
I've had BRRacing in Los Gatos do some work on my car lately. Those guys know how to set a car up for the track as well as anyone. I asked Bruce what he thought about the UD pulleys and he told me it's all good, nothing bad and almost a necessity on tracked Boxster/caymans. I'm going to have the one I got recently put on since I'm looking for all the cheap power I can get!
#38
I've had BRRacing in Los Gatos do some work on my car lately. Those guys know how to set a car up for the track as well as anyone. I asked Bruce what he thought about the UD pulleys and he told me it's all good, nothing bad and almost a necessity on tracked Boxster/caymans. I'm going to have the one I got recently put on since I'm looking for all the cheap power I can get!
I wonder if GT3's had higher output alternators or smaller alternator pulleys? They came stock with a smaller crank pulley.
I need to get one b/c my power steering pump is starting to weep at track days after sustained high rpms.
#40
Race Director
Gentlemen, silly question on these things.
I'm about to install one on my 986 boxster, and every instructional guide tells me that you must use a tool or some other sort of device to lock the crankshaft pulley to keep it from moving when loosening or tightening the crank bolt.
Now, with the car on the ground, with the transmission in gear and the parking brake engaged, the crank should not turn and the pulley is held relative to the crank with a keyway.
So, in light of that information, no tools should be needed to keep the crank from moving.
Am I missing something here?
Thanks
I'm about to install one on my 986 boxster, and every instructional guide tells me that you must use a tool or some other sort of device to lock the crankshaft pulley to keep it from moving when loosening or tightening the crank bolt.
Now, with the car on the ground, with the transmission in gear and the parking brake engaged, the crank should not turn and the pulley is held relative to the crank with a keyway.
So, in light of that information, no tools should be needed to keep the crank from moving.
Am I missing something here?
Thanks
#41
Former Vendor
Gentlemen, silly question on these things.
I'm about to install one on my 986 boxster, and every instructional guide tells me that you must use a tool or some other sort of device to lock the crankshaft pulley to keep it from moving when loosening or tightening the crank bolt.
Now, with the car on the ground, with the transmission in gear and the parking brake engaged, the crank should not turn and the pulley is held relative to the crank with a keyway.
So, in light of that information, no tools should be needed to keep the crank from moving.
Am I missing something here?
Thanks
I'm about to install one on my 986 boxster, and every instructional guide tells me that you must use a tool or some other sort of device to lock the crankshaft pulley to keep it from moving when loosening or tightening the crank bolt.
Now, with the car on the ground, with the transmission in gear and the parking brake engaged, the crank should not turn and the pulley is held relative to the crank with a keyway.
So, in light of that information, no tools should be needed to keep the crank from moving.
Am I missing something here?
Thanks
#42
Race Director
What you are doing, by using the driveline to lock the assembly, is killing the dual mass flywheel.. the link that connects all these items to allow the crank to be locked. The load it is experiencing is also opposite of what it sees in operation. I use a strap wrench, and a second person to hold the crank pulley when removing it. I don;t even trust the locking pin boss on the crankcase, as I have seen them break when doing this job.
#44
Rennlist Member
Anyone try the EBS Racing underdrive pulley? Im considering buying this one. Seams to be built well and the price is great. $165 and it comes with the belt. Sold on eBay.
http://www.ebay.com/itm/Porsche-Boxs...pZlc4V&vxp=mtr
http://www.ebay.com/itm/Porsche-Boxs...pZlc4V&vxp=mtr
#45
Rennlist Member
Anyone try the EBS Racing underdrive pulley? Im considering buying this one. Seams to be built well and the price is great. $165 and it comes with the belt. Sold on eBay.
http://www.ebay.com/itm/Porsche-Boxs...pZlc4V&vxp=mtr
http://www.ebay.com/itm/Porsche-Boxs...pZlc4V&vxp=mtr
Go to a brand with more material in the center.
I am not sure about this pictular brand, but the majority of the ones that have failed, from my research are the machined out centers.
Take a look at RSS, mine was made very well.