Is Ur Crank Pulley Worth It
#46
01-01-2006, 05:42 PM
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#47
01-02-2006, 12:41 AM
Originally Posted by helldorado
Hmmm... 1 out of 20? Glad I was that 1 then. 
So before you spend too much time discrediting my run I would like to note that I have the Unorthodox Racing underdrive pulley; the "proof" comparison thread you noted uses the KJR lightweight pulley and they are two different units as the KJR is not an underdrive pulley. While my car and G35StrongMan's have similar supporting mods, we are on different dyno's and comparing different pulleys.
KJR should not show a gain on they dyno because it is OE sized, and is only a reduction in inertial mass. I would expect the engine to rev more freely and to have more responsiveness, but not increase power because it is not inducing underdrive like the UR pulley.
I have it, am happy with it and would recommend it. Thats good enough for me. Take it for what its worth.
So before you spend too much time discrediting my run I would like to note that I have the Unorthodox Racing underdrive pulley; the "proof" comparison thread you noted uses the KJR lightweight pulley and they are two different units as the KJR is not an underdrive pulley. While my car and G35StrongMan's have similar supporting mods, we are on different dyno's and comparing different pulleys.
KJR should not show a gain on they dyno because it is OE sized, and is only a reduction in inertial mass. I would expect the engine to rev more freely and to have more responsiveness, but not increase power because it is not inducing underdrive like the UR pulley.
I have it, am happy with it and would recommend it. Thats good enough for me. Take it for what its worth.
#48
01-02-2006, 12:46 AM
Originally Posted by caelric
What I would like to know, DaveB, is why you think an underdrive and lightened pulley would not produce any gains?
As taken from a recent discussion on the 350Z site. Some will apply, some won't, but you'll see my rational.
The stock pulley is in fact a harmonic damper. It's a two peice pulley with a sandwiched elastomer ring inside. The elastomer ring quells crank vibration/resonnance when the pistons are firing. The fact that the VQ is internally balanced HAS ABSOLUTELY NOTHING TO DO WITH THE OPERATION OF THE CRANK PULLEY/DAMPER!!!!!!!!!! When the pistons are firing, first and second order vibrations are occuring. The dual mass flywheel or torque converter act as a damper on one end of the crank and the OEM crank pulley acts as the damper on the other end. Remove the damper from the crank pulley and there will be uncontrolled resonance in the crank. That's a fact. Will the VQ fail? Very unlikely because the lower end of the block is very stout as is the crank. Gains? No.
I had a UR pulley on my 96 Maxima VQ30 (1.5lbs vs 6.5lbs). The car felt more lively, but was more prone to bogging off the line and on part throttle shifts. I also noticed a grainy vibration through the pedals and shifter that wasn't there before. Over the span of 1.5 years and 40 passes and one dyno, the UDP gained me absolutely nothing. It was a waste of time and money. I put the stock pulley back on and the grainy vibration disappeared and the car felt better.
The facts are UDP on the VQ show minimal to zero gains. And fellas, don't be dumb. Reducing rotational weight will be seen on the dyno. If you remove 15lbs of rotational weight from your wheels, you'll see it in HP/TQ on the dyno. Why don't the UDP pullies see any real gains?
1) They're connected DIRECTLY to the f-ing crank. The further away the rotational device, the harder it is to accelerate (ie wheels/tires). The pulley is mounted directly to the power source. Think about it.
2) The pulley diameter is super tiny and the weight is nothing. The larger the diameter of the rotational device, the harder it is to spin. A 7" 8lb pulley is going to be far easier to accelerate than a two 26" 50lb wheels.
Removing 10lbs from each wheel (20lbs less rotational inertia, less 40lbs static weight) will net almost .1 seconds and 1mph. Why in the world do people believe that removing 6lbs from a single pulley mounted directly to the crank is going to do much of anything.
People, this isn't your brother's 5.0 Mustang and the VQ isn't going to make the same gains. Yes, a 5.0 Stang with an UDP set (crank and water pump pulley) will see a solid 8-10whp gain. Guess what though? The VQ has a timing chain driven water pump and the UDP of the 5.0 water pump pulley is what nets most of the gains.
Don't believe the hype or the myths. Research it for yourself and get a better grasp of late model engine design before believing the aftermarket nonsense.
I had a UR pulley on my 96 Maxima VQ30 (1.5lbs vs 6.5lbs). The car felt more lively, but was more prone to bogging off the line and on part throttle shifts. I also noticed a grainy vibration through the pedals and shifter that wasn't there before. Over the span of 1.5 years and 40 passes and one dyno, the UDP gained me absolutely nothing. It was a waste of time and money. I put the stock pulley back on and the grainy vibration disappeared and the car felt better.
The facts are UDP on the VQ show minimal to zero gains. And fellas, don't be dumb. Reducing rotational weight will be seen on the dyno. If you remove 15lbs of rotational weight from your wheels, you'll see it in HP/TQ on the dyno. Why don't the UDP pullies see any real gains?
1) They're connected DIRECTLY to the f-ing crank. The further away the rotational device, the harder it is to accelerate (ie wheels/tires). The pulley is mounted directly to the power source. Think about it.
2) The pulley diameter is super tiny and the weight is nothing. The larger the diameter of the rotational device, the harder it is to spin. A 7" 8lb pulley is going to be far easier to accelerate than a two 26" 50lb wheels.
Removing 10lbs from each wheel (20lbs less rotational inertia, less 40lbs static weight) will net almost .1 seconds and 1mph. Why in the world do people believe that removing 6lbs from a single pulley mounted directly to the crank is going to do much of anything.
People, this isn't your brother's 5.0 Mustang and the VQ isn't going to make the same gains. Yes, a 5.0 Stang with an UDP set (crank and water pump pulley) will see a solid 8-10whp gain. Guess what though? The VQ has a timing chain driven water pump and the UDP of the 5.0 water pump pulley is what nets most of the gains.
Don't believe the hype or the myths. Research it for yourself and get a better grasp of late model engine design before believing the aftermarket nonsense.
Last edited by DaveB; 01-02-2006 at 12:50 AM.
#49
01-02-2006, 12:54 AM
Originally Posted by G35_TX
Good info helldorgado. DaveB likes stabbing people for mods he thinks do not gain because its his opinion but he never has the correct facts backing his statements up. I think everyone around here is starting to get tired of him.
Dave, because you got proven wrong again, doesn't mean its the end of the world.
Ah yea, my 10 sec argue limit is passed for DaveB.
Dave, because you got proven wrong again, doesn't mean its the end of the world.
Ah yea, my 10 sec argue limit is passed for DaveB.
As for your argument time with me, you sure do like to spend a lot of time debating with me, yet you'll never post data supporting your claims. All you do is cower behind someone else's claim that mod "X" works. At least I post stuff to back up my claims. BTW, I'm not here to win friends.
Last edited by DaveB; 01-02-2006 at 12:57 AM.
#50
01-02-2006, 12:10 PM
Originally Posted by DaveB
No, I like to open people's mind to the fact that the usefulness and gains of many of these mods are simply myths.
As for your argument time with me, you sure do like to spend a lot of time debating with me, yet you'll never post data supporting your claims. All you do is cower behind someone else's claim that mod "X" works. At least I post stuff to back up my claims. BTW, I'm not here to win friends.
As for your argument time with me, you sure do like to spend a lot of time debating with me, yet you'll never post data supporting your claims. All you do is cower behind someone else's claim that mod "X" works. At least I post stuff to back up my claims. BTW, I'm not here to win friends.
You post stuff that isn't facts! It isn't correct data! It's peoples opinions! Like above. Maxima is not a G35. But I see Dynos with Maximas getting 8-10 hp from a UDP. Hmmmm. Strange.
#51
01-02-2006, 01:27 PM
Originally Posted by G35_TX
Myths? But there are a ton of dynos proving you wrong time and time again. LOL. Because I don't feel the need to post **** which has been posted before. When you can do the search or anyone else can.
You post stuff that isn't facts! It isn't correct data! It's peoples opinions! Like above. Maxima is not a G35. But I see Dynos with Maximas getting 8-10 hp from a UDP. Hmmmm. Strange.
You post stuff that isn't facts! It isn't correct data! It's peoples opinions! Like above. Maxima is not a G35. But I see Dynos with Maximas getting 8-10 hp from a UDP. Hmmmm. Strange.
Yeah, a Maxima isn't a G35, but they both have VQ motors, the pulley's are within 1lb of each other, both use an elastomer sandwiched damper ring, and the overall design and purpose is identical.
As for VQs gaining 8-10whp from a UDP, I can show you a dyno of a VQ gaining 6whp by nothing more than making a back to pass on the dyno and no changes to the car.
#52
01-02-2006, 03:19 PM
Originally Posted by DaveB
Yeah, myths and I'm one of the few to actually test the mod both on the track and dyno. Over 40 passes of 5 to 6 different track days. How's that for data?
Yeah, a Maxima isn't a G35, but they both have VQ motors, the pulley's are within 1lb of each other, both use an elastomer sandwiched damper ring, and the overall design and purpose is identical.
As for VQs gaining 8-10whp from a UDP, I can show you a dyno of a VQ gaining 6whp by nothing more than making a back to pass on the dyno and no changes to the car.
Yeah, a Maxima isn't a G35, but they both have VQ motors, the pulley's are within 1lb of each other, both use an elastomer sandwiched damper ring, and the overall design and purpose is identical.
As for VQs gaining 8-10whp from a UDP, I can show you a dyno of a VQ gaining 6whp by nothing more than making a back to pass on the dyno and no changes to the car.
I also know people who ran with them on the track and saw small results but it had results.
Both have VQ motors but different internal parts between them.
#53
01-02-2006, 05:17 PM
Originally Posted by DaveB
As for VQs gaining 8-10whp from a UDP, I can show you a dyno of a VQ gaining 6whp by nothing more than making a back to pass on the dyno and no changes to the car.
If back-to-back runs can show as much as 6hp difference(I've never seen a difference that large, at least on our cars, but I have seen 1-2hp differences), then why pay attention to dynos in the first place?
#54
01-02-2006, 07:12 PM
Originally Posted by trey.hutcheson
I've stayed out of the pulley thread, but this statement really confuses me. On many topics about mods, you request 1/4 times or dynos. But now you seem to be arbitrarily acknowledging certain dynos. What gives?
If back-to-back runs can show as much as 6hp difference(I've never seen a difference that large, at least on our cars, but I have seen 1-2hp differences), then why pay attention to dynos in the first place?
If back-to-back runs can show as much as 6hp difference(I've never seen a difference that large, at least on our cars, but I have seen 1-2hp differences), then why pay attention to dynos in the first place?
As for the 6whp difference, I've seen 4-6whp differences on back to back passes with my Maxima, my friend's 03 G, and a 350Z.
Dynos are great for measuring mods that actually make substanial gains, but not something as insignificant as a pulley. That's why I added in the fact that I ran so many 1/4 miles passes with the UDP. It's been my experience that running on the track seems to be the best way to gauge a mod's benefits assuming you're a half way decent driver and correct the passes to standard atmosphere, etc. I doubt I'll ever dyno my G or any other car for that matter. IMO, it was a waste of about $350 when I could have just made some passes on the track for 1/2 the price.
#55
01-02-2006, 07:18 PM
Originally Posted by G35_TX
Maxima 3.5L VQ Dyno after UDP install.
I also know people who ran with them on the track and saw small results but it had results.
Both have VQ motors but different internal parts between them.
I also know people who ran with them on the track and saw small results but it had results.
Both have VQ motors but different internal parts between them.
Most everyone else on Maxima.org understands that the UDP is simply a waste. Years ago the same myth existed on Maxima.org. As many us true 1/4 racers started testing the pullies, the truth became quite clear. A waste of money. No gains.
#57
01-02-2006, 11:20 PM
Purely lightened pullies make virtually no power after 1st gear (ignoring underdrive for a moment). I was so sick of arguing with people about this that didn't understand the mechanics involved that I wrote a little "proof" about it to pop out an equation so you can calculate the gains for yourself on your motor. Here's the link if anyone has an open mind and is interested: http://www.stanford.edu/~mpg/lighten...omponents.html
In my opinion, these dynos showing gains are just run-to-run variability (environment, engine temperature, etc).
In my opinion, these dynos showing gains are just run-to-run variability (environment, engine temperature, etc).
#58
01-03-2006, 12:35 AM
#59
01-03-2006, 02:36 AM
Originally Posted by caelric
Yes, and agree with you that the lightening makes very little difference, on the order of 1 HP in 1st gear.
But we are NOT JUST TALKING ABOUT A LIGHTENED PULLEY.
We are also talking about an underdriven pulley. Caps added for emphasis.
Dave
But we are NOT JUST TALKING ABOUT A LIGHTENED PULLEY.
We are also talking about an underdriven pulley. Caps added for emphasis.
Dave
#60
01-03-2006, 11:54 AM
I've got an early UR crank pulley, anodized blue , new in box, never installed, if anyone is interested. Decided it wasn't worth it to install, for me at least, but if anyone wants one, you can't get the blue anodized any longer... ...unless you're lucky enough to find some old stock somewhere.
Blue UR pulley and Gates belts included. $200 shipped OBO. Send me a PM if interested.
Blue UR pulley and Gates belts included. $200 shipped OBO. Send me a PM if interested.