UR Pulleys.....
Originally Posted by Z1 Performance
Honestly, you are the one confused, as you are mixing your terminology up, but its been discussed at length before, on this site, and I'm not going to bea the dead horse anymore. The info is out there...feel free to search for it if you like, or you can call Unorthodox Racing yourself, and they can explain it to you in as great a detail as you wish.
The accessories most certainly DO make slightly more noise at idle with the pullies installed vs without. It is a very faint difference, but it is there.
The accessories most certainly DO make slightly more noise at idle with the pullies installed vs without. It is a very faint difference, but it is there.
not sure to laugh or what...I would've thought this thread would be locked by now. IMO, read through all the preivous threads related to this, and if you have something new to add, start a thread w/ a very specific title and back up what you're saying w/ facts (not just your experience or knowledge).
The horse is a gluestick by now 
I'm not misled at all - I've examined the "wonderfully designed" stock pulley at length, taken it apart, had it on a balancer, and know precisely what it does and how it behaves, even when spun without a crankshaft behind it. You just seem to "think" you do.
As stated, go whatever direction you want..pulley, no pulley. I could care less, and I suspect everyone else here feels the same way.
I'm not misled at all - I've examined the "wonderfully designed" stock pulley at length, taken it apart, had it on a balancer, and know precisely what it does and how it behaves, even when spun without a crankshaft behind it. You just seem to "think" you do.
As stated, go whatever direction you want..pulley, no pulley. I could care less, and I suspect everyone else here feels the same way.
Pulleys IMO are not worth it. I have seen pulley changes on other cars start throwing off the crank rotation characteristics. IMo not worth the risk for a $150 part that might/more then likely might not cause any performance gain.
I stick with stock pulleys. The power can be made elsewhere safer.
I stick with stock pulleys. The power can be made elsewhere safer.
Originally Posted by PM-Performance
Pulleys IMO are not worth it. I have seen pulley changes on other cars start throwing off the crank rotation characteristics. IMo not worth the risk for a $150 part that might/more then likely might not cause any performance gain.
I stick with stock pulleys. The power can be made elsewhere safer.
I stick with stock pulleys. The power can be made elsewhere safer.
ill add that if you are getting your engine build you shoudl get pulleys, properly assembeled times etc etc etc...
id suggest ait crank pulley adn ur pulleys for the other ones
id suggest ait crank pulley adn ur pulleys for the other ones
Originally Posted by Cannysage
what is your theory based on? There are members here that have ran after market pulleys for 50k without issues (others prolly more). I had mine for 20k with 0 issues, and crank pulley and testpipes were the 2 heaviest gainers for me.
I guess if you get the right ones and install them right, they arent bad. But I have seen too many people killing bearings and such and have those pullies on.
Could just be my speculation, but I stay away from them.
Just like i stay away from lightweight flywheels and Synth oil. Maybe Im picky or partially retarded, but my cars make power. So I am doing something right. lol
Last edited by PM-Performance; May 17, 2007 at 11:57 AM.
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if the pulley install is done correctly, there's nothing to worry about. The stock pulley is way too heavy comparing to the UR. i've had mine for 20k miles....best bang for the buck imo(immediate improvement in throttle response).
Originally Posted by Ztalker
if the pulley install is done correctly, there's nothing to worry about. The stock pulley is way too heavy comparing to the UR. i've had mine for 20k miles....best bang for the buck imo(immediate improvement in throttle response).
Also, throttle response might be slightly better in the lower gears, but that doesn't mean there is any more power. I can post up a dyno of a G35 that dynoed with a UR UDP and it didn't gain a single HP. When I had my UR UDP on my VQ30, I wasn't any faster or quicker in the 1/4 mile after well over 40 1/4 mile passes and multiple track outings.
Originally Posted by Dave B
You can't mess up a pulley install. The crank and pulley are keyed and it only goes on one way. However, I have seen a UR UDP fail and it blew up a VQ35. The keyed area in the pulley cracked and the pulley freewheeled, got wedged at an angle and totally threw off the balanace of the motor.
Also, throttle response might be slightly better in the lower gears, but that doesn't mean there is any more power. I can post up a dyno of a G35 that dynoed with a UR UDP and it didn't gain a single HP. When I had my UR UDP on my VQ30, I wasn't any faster or quicker in the 1/4 mile after well over 40 1/4 mile passes and multiple track outings.
Also, throttle response might be slightly better in the lower gears, but that doesn't mean there is any more power. I can post up a dyno of a G35 that dynoed with a UR UDP and it didn't gain a single HP. When I had my UR UDP on my VQ30, I wasn't any faster or quicker in the 1/4 mile after well over 40 1/4 mile passes and multiple track outings.
there is no way the UR pulley "threw off the balance of the motor", but that's a whole other discussion. The pulley in no way affects the balance of the motor...no ifs, ands or buts about it.
People have blown motors using stock pullies too...and people have had stock crank pullies literally sheer themselves apart; no mechanical part is infallable
People have blown motors using stock pullies too...and people have had stock crank pullies literally sheer themselves apart; no mechanical part is infallable
Originally Posted by Z1 Performance
there is no way the UR pulley "threw off the balance of the motor", but that's a whole other discussion. The pulley in no way affects the balance of the motor...no ifs, ands or buts about it.
People have blown motors using stock pullies too...and people have had stock crank pullies literally sheer themselves apart; no mechanical part is infallable
People have blown motors using stock pullies too...and people have had stock crank pullies literally sheer themselves apart; no mechanical part is infallable
Early version of the UR UDP. 
http://g35driver.com/forums/showthre...n+engine+crank
BTW, you are the one that is wrong. The stock pulley does in fact dampen the crank, no if's, and's, or but's. Your only supporting information is what UR is telling you. You have offered absolutely no supporting information and I am doubtful you understand half the things I'm saying.
Last edited by Dave B; May 20, 2007 at 01:09 PM.
No..I am not wrong, but I'm also tired of arguing.
A broken keyway - can easily (and I mean easily) be done by a sloppy install (ie not lining the keyway up 100% and forcing the pulley on). But even with this, that in no way "screws up the balance of the crank", which is balanced internally, not externally (as it is on many old school Chevy motors, for example). If you've ever seen what a true crank balanced is, you'll know its alot more than a tiny elastomer ring. Again, I HAVE had both the stock pulley, the UR underdriven pulley, and the UR stock diameter pulley on a high speed balancer, so I know how "balanced" all of them are - care to guess what the results were? If the factory pulley were such a marvel of engineering, and so critical to the internal balance of the motor, it wouldn't be made from stamped steel, and also would be far better balanced than it is from the factory. Both UR ones I recently balanced were, out of the box, much better than the factory ones - none of them were perfect, but the UR
s were off by several grams less than the OE unit. While on topic, have you had a stock crank on a balancer? It's one of the nicest factory cranks I have ever seen, from any manufacturer, and I've been involved on motor builds ranging from a Volvo to Ferrari's, but guess what, it aint perfect either (we took quite a bit of weight out of mine in fact).
If everything in the bottom end of a VQ, or any other motor, were the representation of some mechanical ideal as far as balance and torsional movement, Nissan would not sell cranks, or pistons, or rods, or even a single internal BOLT by itself. They also would not have umpteen combinations of bearings (take a look at the chart sometime..I've never seen a motor have so many possibilities for main/rod bearing specs). They would only sell preassembled units. But the fact of the matter is, while there is certainly a level of balance applied to all the rotating parts within this motor (and any other motor), they are by no means 100% balanced, not even to the stock rev limiter.
You made the point of saying no "race" Z's use a lightened pulley (you're wrong, but that's not for this discussion). Ever notice how many don't use a factory clutch or flywheel? Explain to me, since you profess to have such a vast understanding of the topic, how the crank "knows" it's got a non factory pulley mounted to one side of it, but doesn't know (or care?) it's got a non factory clutch and/or flywheel mounted to the other side? The simple answer is that it doesn't - nor does it care. The most critical aspect to ANY part that you put into this, or any other motor that rotates, is simple - it, in and of itself, needs to be balanced at least as well as the component it is replacing.
A broken keyway - can easily (and I mean easily) be done by a sloppy install (ie not lining the keyway up 100% and forcing the pulley on). But even with this, that in no way "screws up the balance of the crank", which is balanced internally, not externally (as it is on many old school Chevy motors, for example). If you've ever seen what a true crank balanced is, you'll know its alot more than a tiny elastomer ring. Again, I HAVE had both the stock pulley, the UR underdriven pulley, and the UR stock diameter pulley on a high speed balancer, so I know how "balanced" all of them are - care to guess what the results were? If the factory pulley were such a marvel of engineering, and so critical to the internal balance of the motor, it wouldn't be made from stamped steel, and also would be far better balanced than it is from the factory. Both UR ones I recently balanced were, out of the box, much better than the factory ones - none of them were perfect, but the UR
s were off by several grams less than the OE unit. While on topic, have you had a stock crank on a balancer? It's one of the nicest factory cranks I have ever seen, from any manufacturer, and I've been involved on motor builds ranging from a Volvo to Ferrari's, but guess what, it aint perfect either (we took quite a bit of weight out of mine in fact).
If everything in the bottom end of a VQ, or any other motor, were the representation of some mechanical ideal as far as balance and torsional movement, Nissan would not sell cranks, or pistons, or rods, or even a single internal BOLT by itself. They also would not have umpteen combinations of bearings (take a look at the chart sometime..I've never seen a motor have so many possibilities for main/rod bearing specs). They would only sell preassembled units. But the fact of the matter is, while there is certainly a level of balance applied to all the rotating parts within this motor (and any other motor), they are by no means 100% balanced, not even to the stock rev limiter.
You made the point of saying no "race" Z's use a lightened pulley (you're wrong, but that's not for this discussion). Ever notice how many don't use a factory clutch or flywheel? Explain to me, since you profess to have such a vast understanding of the topic, how the crank "knows" it's got a non factory pulley mounted to one side of it, but doesn't know (or care?) it's got a non factory clutch and/or flywheel mounted to the other side? The simple answer is that it doesn't - nor does it care. The most critical aspect to ANY part that you put into this, or any other motor that rotates, is simple - it, in and of itself, needs to be balanced at least as well as the component it is replacing.
Originally Posted by Z1 Performance
You made the point of saying no "race" Z's use a lightened pulley (you're wrong, but that's not for this discussion). Ever notice how many don't use a factory clutch or flywheel? Explain to me, since you profess to have such a vast understanding of the topic, how the crank "knows" it's got a non factory pulley mounted to one side of it, but doesn't know (or care?) it's got a non factory clutch and/or flywheel mounted to the other side? The simple answer is that it doesn't - nor does it care. The most critical aspect to ANY part that you put into this, or any other motor that rotates, is simple - it, in and of itself, needs to be balanced at least as well as the component it is replacing.
Yes, the VQ has a balanced rotating assembly, but that balancing does not account for the various order vibrations that occur within the crank when the pistons are being flung downwards by explosions in the combustion chamber. That force sends vibrations through the crank and since only 3 three cylinders are firing at once and the rpms are often being varied, the vibrations not consistent. These changing vibrations can wreck a crank or bearings. That's a fact. This is where the dampers (flywheel/clutch, torque converter, crank pulley) come into play. The shear mass (~40lbs) of the flywheel/clutch/torque converter acts as the main damper. The crank pulley on the other end does the same, but at a smaller scale. Adding a 10-20% lighter clutch/flywheel assembly is a common and acceptable practice is race cars which helps make for easier high rpm rev matching and to reduce driveline shock on downshifts. The negative impact is slower launch because you've reduced the moment of inertia. Basically the motor is far more prone to bog. The reduced mass with a lighter clutch/flywheel is acceptable because a majority of the dampening characteristics are still there. However, replacing the crank pulley damper with one that isn't dampened is not acceptable because you're removing the entire damper.
A little off topic, but - If you're looking for better throttle response; a better flowing intake and/or grounding kit will help greatly with no adverse effects...
Last edited by gothchick; May 21, 2007 at 09:27 AM.
I understand the concept just fine
So you are telling me that dropping roughly 25 lbs off the one end of the crank (ie switching from a stock clutch and flywheel to, say, an ATS twin, a common clutched used) is LESS of an issue than dropping 5 lbs off the other end of the crank (swapping from the stock pulley to, say, the UR stock diameter one)? Or swapping from the stock, dual mass flywheel alone, to, say an ACT streetlight flywheel (an 8.6 lbs reduction, ~35%), or to an ACT Prolight, or a JWT, or any of the other flywheels on the market. Better yet, show me what aftermarket flywheel, from any manufacturer, has a damper in it? The stock one does, not by virtue of it's weight, by by its design, being a dual mass type. The argument could certainly be made too that spinning a 15 lbs flywheel is less stressful to the bearings than spinning a 25 lbs flywheel as well, assuming all other conditions of the motor were held equal (coolant type, oil type, rev range, air fuel, etc etc)
So again I pose the same question before, which you did not answer - how does the crank know what is bolted to one end of it but doesn't know (or care) what's bolted to the other?
If I have not already made the request, I'd ask you to take a look at the stock crank pulley again. Then explain to me how a 1/4 inch thick piece of rubber which is glued into the pulley, is controlling the vibrations occuring on the compression stroke of ~100 lbs rotating assembly at 7000 rpm. My stock pulley was removed a few days after I bought my car in 2003. It's since sat in the shop in the UR box, taped since that time. I just removed it from that box today, and the rubber ring on the back is already dry rotted and cranking - it has maybe 500 miles on it, total. Imagine what it would do sitting in the engine bay, under the heat conditions it goes through, after spending all its life spinning, warming up, cooling down, day after day after day.
Again, I am not endorsing or recommending this product for use on every engine out there - all are constructred differently. But as far as the VG/VQ is concerned, both in older and current iterations (save for an 07 which I've never looked at), I've yet to see any downside whatsoever. And again...ultimately, its the buyers choice to make.
So you are telling me that dropping roughly 25 lbs off the one end of the crank (ie switching from a stock clutch and flywheel to, say, an ATS twin, a common clutched used) is LESS of an issue than dropping 5 lbs off the other end of the crank (swapping from the stock pulley to, say, the UR stock diameter one)? Or swapping from the stock, dual mass flywheel alone, to, say an ACT streetlight flywheel (an 8.6 lbs reduction, ~35%), or to an ACT Prolight, or a JWT, or any of the other flywheels on the market. Better yet, show me what aftermarket flywheel, from any manufacturer, has a damper in it? The stock one does, not by virtue of it's weight, by by its design, being a dual mass type. The argument could certainly be made too that spinning a 15 lbs flywheel is less stressful to the bearings than spinning a 25 lbs flywheel as well, assuming all other conditions of the motor were held equal (coolant type, oil type, rev range, air fuel, etc etc)
So again I pose the same question before, which you did not answer - how does the crank know what is bolted to one end of it but doesn't know (or care) what's bolted to the other?
If I have not already made the request, I'd ask you to take a look at the stock crank pulley again. Then explain to me how a 1/4 inch thick piece of rubber which is glued into the pulley, is controlling the vibrations occuring on the compression stroke of ~100 lbs rotating assembly at 7000 rpm. My stock pulley was removed a few days after I bought my car in 2003. It's since sat in the shop in the UR box, taped since that time. I just removed it from that box today, and the rubber ring on the back is already dry rotted and cranking - it has maybe 500 miles on it, total. Imagine what it would do sitting in the engine bay, under the heat conditions it goes through, after spending all its life spinning, warming up, cooling down, day after day after day.
Again, I am not endorsing or recommending this product for use on every engine out there - all are constructred differently. But as far as the VG/VQ is concerned, both in older and current iterations (save for an 07 which I've never looked at), I've yet to see any downside whatsoever. And again...ultimately, its the buyers choice to make.
Last edited by Z1 Performance; May 21, 2007 at 10:13 AM.
Originally Posted by Z1 Performance
Better yet, show me what aftermarket flywheel, from any manufacturer, has a damper in it? The stock one does, not by virtue of it's weight, by by its design, being a dual mass type.
Well, to be fair, you can't use that flywheel by itself - its only sold with, and can only be used with, the ORC/OS Giken clutch. That's why I did not include that type in my statement.
I wonder why they dont call it the No Vibration Type, vs the Silent Type? Maybe Silent Type fit better on a sticker or something, or made for a better magazine ad.
I have the same clutch for my own car...not the Silent version as there was no such part offered when I got mine about 4 years ago. The damper they use is to quiet the ratlle typically associated with integrated type clutches (where clutch and flywheel are one integrated unit, bolted together)
So is that to mean that the non silent types are also the 'your bearings will wear faster and your motor could blow up type" too?
I wonder why they dont call it the No Vibration Type, vs the Silent Type? Maybe Silent Type fit better on a sticker or something, or made for a better magazine ad.
I have the same clutch for my own car...not the Silent version as there was no such part offered when I got mine about 4 years ago. The damper they use is to quiet the ratlle typically associated with integrated type clutches (where clutch and flywheel are one integrated unit, bolted together)
So is that to mean that the non silent types are also the 'your bearings will wear faster and your motor could blow up type" too?