Underdrive Pulley-need your opinion!
Jul 22, 2003 | 07:04 AM
#41
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From: Urbandale, IA
Originally posted by <96 Runner>
On a related note...
For those of you who desire a similar performance gain to UDP's, you can always pull your AC belt during the cold months/spring.
Keep in mind, this will do two negative things:
1. Your Defrost works off the AC, and therefore it wont work right
2. This belt take about 1/2 and hour to take off, unless you slice it off with a razor blade and replace it later.
But, for the power hungry person, or someone who is going to the track and desires a little more power, this works good. I dont suspect many to go for this on the boards, but you never know. I did it on my Tacoma, and noticed a slight gain.
I dont want to hassle with it on my 4Runner.
On a related note...
For those of you who desire a similar performance gain to UDP's, you can always pull your AC belt during the cold months/spring.
Keep in mind, this will do two negative things:
1. Your Defrost works off the AC, and therefore it wont work right
2. This belt take about 1/2 and hour to take off, unless you slice it off with a razor blade and replace it later.
But, for the power hungry person, or someone who is going to the track and desires a little more power, this works good. I dont suspect many to go for this on the boards, but you never know. I did it on my Tacoma, and noticed a slight gain.
I dont want to hassle with it on my 4Runner.
Jul 22, 2003 | 07:28 AM
#42
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Joined: May 2002
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From: Southern MD USA
The 3.4 is an internally balanced engine.
The elastomeric damper is tuned to dampen axial acceleration and deceleration forces and not to balance and externally balanced engine like some of the other ones mentioned.
Have you looked at this elastomeric stuff that joins the inner and outer protions of the pulley? Have you put one in a vice and tried to get the other section to move at all? Did you have any luck doing so? I have, and no, I can not get any movement out of it at all. This is not the typical harmonic balancer that you are used to seeing on those big block domestic engines that have moving parts on them.
I seriously doubt it will affect wear on the engine bearings, as that is not what its purpose is.
Reducing rotational mass will allow the engine to accelerate faster and that will show up as HP on an acceleration dyno.
For example a similar engine, the V6 Nissan engine used on the older Z cars have been reported to gain 30 HP on an acceleration dyno from replacing the heavy crankshaft pulley with a light weight one. Wouldn't it be nice to get the same result from a bolt on part on the Toyota 3.4? Remember the Supercharger by its self only shows up as 40 HP on an acceleration dyno.
30 HP sounds real high to me, but 10-15 would be nice.
Gadget
www.GadgetOnline.com
The elastomeric damper is tuned to dampen axial acceleration and deceleration forces and not to balance and externally balanced engine like some of the other ones mentioned.
Have you looked at this elastomeric stuff that joins the inner and outer protions of the pulley? Have you put one in a vice and tried to get the other section to move at all? Did you have any luck doing so? I have, and no, I can not get any movement out of it at all. This is not the typical harmonic balancer that you are used to seeing on those big block domestic engines that have moving parts on them.
I seriously doubt it will affect wear on the engine bearings, as that is not what its purpose is.
Reducing rotational mass will allow the engine to accelerate faster and that will show up as HP on an acceleration dyno.
For example a similar engine, the V6 Nissan engine used on the older Z cars have been reported to gain 30 HP on an acceleration dyno from replacing the heavy crankshaft pulley with a light weight one. Wouldn't it be nice to get the same result from a bolt on part on the Toyota 3.4? Remember the Supercharger by its self only shows up as 40 HP on an acceleration dyno.
30 HP sounds real high to me, but 10-15 would be nice.
Gadget
www.GadgetOnline.com
Jul 22, 2003 | 07:40 AM
#43
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Joined: Jan 2003
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From: El Paso, TX
Originally posted by mertztr
Isn't there an A/C fuse you can pull as opposed to taking off the belt? On my old 280 ZX, I just pulled a fuse in the winter.
Isn't there an A/C fuse you can pull as opposed to taking off the belt? On my old 280 ZX, I just pulled a fuse in the winter.
Jul 22, 2003 | 08:51 AM
#44
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Joined: Jul 2003
Posts: 8,807
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From: Montreal, QC Canada
Originally posted by Gadget
The 3.4 is an internally balanced engine.
The elastomeric damper is tuned to dampen axial acceleration and deceleration forces and not to balance and externally balanced engine like some of the other ones mentioned.
Have you looked at this elastomeric stuff that joins the inner and outer protions of the pulley? Have you put one in a vice and tried to get the other section to move at all? Did you have any luck doing so? I have, and no, I can not get any movement out of it at all. This is not the typical harmonic balancer that you are used to seeing on those big block domestic engines that have moving parts on them.
I seriously doubt it will affect wear on the engine bearings, as that is not what its purpose is.
Reducing rotational mass will allow the engine to accelerate faster and that will show up as HP on an acceleration dyno.
For example a similar engine, the V6 Nissan engine used on the older Z cars have been reported to gain 30 HP on an acceleration dyno from replacing the heavy crankshaft pulley with a light weight one. Wouldn't it be nice to get the same result from a bolt on part on the Toyota 3.4? Remember the Supercharger by its self only shows up as 40 HP on an acceleration dyno.
30 HP sounds real high to me, but 10-15 would be nice.
Gadget
www.GadgetOnline.com
The 3.4 is an internally balanced engine.
The elastomeric damper is tuned to dampen axial acceleration and deceleration forces and not to balance and externally balanced engine like some of the other ones mentioned.
Have you looked at this elastomeric stuff that joins the inner and outer protions of the pulley? Have you put one in a vice and tried to get the other section to move at all? Did you have any luck doing so? I have, and no, I can not get any movement out of it at all. This is not the typical harmonic balancer that you are used to seeing on those big block domestic engines that have moving parts on them.
I seriously doubt it will affect wear on the engine bearings, as that is not what its purpose is.
Reducing rotational mass will allow the engine to accelerate faster and that will show up as HP on an acceleration dyno.
For example a similar engine, the V6 Nissan engine used on the older Z cars have been reported to gain 30 HP on an acceleration dyno from replacing the heavy crankshaft pulley with a light weight one. Wouldn't it be nice to get the same result from a bolt on part on the Toyota 3.4? Remember the Supercharger by its self only shows up as 40 HP on an acceleration dyno.
30 HP sounds real high to me, but 10-15 would be nice.
Gadget
www.GadgetOnline.com
I agree that it is internally balanced, but it also has external balancing as well (I believe).....why would toyota make such a heavy part in the first place if it didn't play a role in the operation of the engine? After all they are into saving every penny possible....so why put so much metal there?
By lowering the rotating mass....especially on the crank you will undoubtably gain quite a few horses, torque and get up to RPM faster. I just worry about reducing the engine life because we don't fully understand the original part's full purpose.
I did not pull mine off and mess with it but I just went out and checked again (cause I thought I was going crazy) and there is a very visible elastomeric ring and two distinct parts to the front pully. In my (all be it naive) judgement, that would indicate a harmonic balancer to me.....please correct me if I am wrong here. Mine is also a 96 so they may have changed the design in later years.....
I am not pretending to know the answers, but I would worry about messing with the engineering that has been done on the development of the engine by Toyota.
Anyone know a Toyota engineer who they can ask?
Last edited by MTL_4runner; Jul 22, 2003 at 09:00 AM.
Jul 22, 2003 | 10:07 AM
#45
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From: Southern MD USA
Lets review.
The 3.4 is an internally ballanced engine, not an externally ballanced engine.
The pulley dose not balance the engine. It dampens acceleration and deceleration forces along the long axis of the crank shaft. These are sometimes called firing pulses.
Running the engine without the pulley will not cause it to be out of ballance.
Do not confuse the operation of the pulley with the type used on an externally balanced engine.
Gadget
www.GadgetOnline.com
The 3.4 is an internally ballanced engine, not an externally ballanced engine.
The pulley dose not balance the engine. It dampens acceleration and deceleration forces along the long axis of the crank shaft. These are sometimes called firing pulses.
Running the engine without the pulley will not cause it to be out of ballance.
Do not confuse the operation of the pulley with the type used on an externally balanced engine.
Gadget
www.GadgetOnline.com
Jul 22, 2003 | 10:33 AM
#46
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Joined: Jul 2003
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From: Montreal, QC Canada
Originally posted by Gadget
Lets review.
The 3.4 is an internally ballanced engine, not an externally ballanced engine. (I have not looked at the shop manual but I assume you are saying that because it has balance shafts).
The pulley does not balance the engine. It dampens acceleration and deceleration forces along the long axis of the crank shaft. These are sometimes called firing pulses.
Running the engine without the pulley will not cause it to be out of ballance.
Do not confuse the operation of the pulley with the type used on an externally balanced engine.
Gadget
www.GadgetOnline.com
Lets review.
The 3.4 is an internally ballanced engine, not an externally ballanced engine. (I have not looked at the shop manual but I assume you are saying that because it has balance shafts).
The pulley does not balance the engine. It dampens acceleration and deceleration forces along the long axis of the crank shaft. These are sometimes called firing pulses.
Running the engine without the pulley will not cause it to be out of ballance.
Do not confuse the operation of the pulley with the type used on an externally balanced engine.
Gadget
www.GadgetOnline.com
Last edited by MTL_4runner; Jul 22, 2003 at 10:50 AM.
Jul 22, 2003 | 11:14 AM
#47
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Joined: Jan 2003
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Originally posted by Victor
how does the defrost work without the dehumidifying effect of the A/C?
how does the defrost work without the dehumidifying effect of the A/C?
I personally think its annoying cause it robs some power. Oh yeah, and I use Defrost about 1 day per year here in Hades.
Jul 22, 2003 | 03:09 PM
#48
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From: Southern MD USA
Originally posted by MTL_4runner
I agree to everything you are saying except your statement that it is nothing but a pulley. Just because it also functions as a pulley does not disclude it from performing any other functions. Aren't the firing pulses going to damage the bearings if not dampened? I am 100% positive Toyota did not make it as heavy as it is for no reason at all. Now why they did it is another story all together.....we need to figure out the thinking behind the engineering to ensure there is no encroachment on engine life.
I agree to everything you are saying except your statement that it is nothing but a pulley. Just because it also functions as a pulley does not disclude it from performing any other functions. Aren't the firing pulses going to damage the bearings if not dampened? I am 100% positive Toyota did not make it as heavy as it is for no reason at all. Now why they did it is another story all together.....we need to figure out the thinking behind the engineering to ensure there is no encroachment on engine life.
Again you are confusing the function of this pulley with the function of a typical harmonic balancer of the type used on an externally balanced engine.
I think you are mistaken on bearing wear in this application. There should not be any additional wear on the bearings. The pulley is not used to balance the engine.
The only component that would receive additional stress is the crankshaft its self, not the bearings. This is not an externally balanced domestic engine of the past.
There are no internal balance shafts in the 3.4. Where did you get that idea from?
I have stated my opinion and you have stated yours.
Gadget
www.GadgetOnline.com
Jul 22, 2003 | 05:03 PM
#50
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From: Barrigada,Guam
So the engine is an internally balanced engine but the crank pully is there to balanced the crankshaft. . Picture a swing set with four kids on it when they swing you can see the top of the pipe where the swing connects is bending because of the weight. Imagine that on a the crankshaft but spining very fast.
If it is hard to understand go to www.howstuffworks.com look for how a V6 engine works.
If I am wrong please tell me I really want a set but if it will shorten the life of my engine
If it is hard to understand go to www.howstuffworks.com look for how a V6 engine works.
If I am wrong please tell me I really want a set but if it will shorten the life of my engine
Jul 22, 2003 | 05:25 PM
#51
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From: Southern MD USA
OK, let review, again.
The pulley on this engine does not balance ANYTHING. The engine is internally ballanced. It does not need nor is it equiped with an external ballancer.
Other then acting as a pulley it absorbs or dampens torsional accleration and decelleration forces. So, what does that mean?
When the crankshaft makes one revolution there will be 3 firing pulses which acclerate the rotation, and three other pulses that work oposite of that and are trying to slow it down. So if you ran this in super slow motion you will see it does not rotate all the way through perfectly at the same speed. Every 60* it will speed up and slow down. This is a change in rotational speed. The elastromeric action of the stock pulley absorbes or dampens this a small bit. That is all it does. It does not ballance an otherwise out of ballance engine.
The pulley does not absorbe up and down, back and forth, side to side imballances like a true harmonic balancer on some other engines will. There are a great many engines on the market that don't even have a torsonal dampner let alone a true harmonic ballancer.
Now pay attension. The pulley on this engine does not ballance anything. The crankshaft is fully counterweighted and internally ballanced. It does not need an nor is it equiped with an external ballancer. Now, let me say it again. The pulley does not ballance anything including the crankshaft.
Gadget
www.GadgetOnline.com
The pulley on this engine does not balance ANYTHING. The engine is internally ballanced. It does not need nor is it equiped with an external ballancer.
Other then acting as a pulley it absorbs or dampens torsional accleration and decelleration forces. So, what does that mean?
When the crankshaft makes one revolution there will be 3 firing pulses which acclerate the rotation, and three other pulses that work oposite of that and are trying to slow it down. So if you ran this in super slow motion you will see it does not rotate all the way through perfectly at the same speed. Every 60* it will speed up and slow down. This is a change in rotational speed. The elastromeric action of the stock pulley absorbes or dampens this a small bit. That is all it does. It does not ballance an otherwise out of ballance engine.
The pulley does not absorbe up and down, back and forth, side to side imballances like a true harmonic balancer on some other engines will. There are a great many engines on the market that don't even have a torsonal dampner let alone a true harmonic ballancer.
Now pay attension. The pulley on this engine does not ballance anything. The crankshaft is fully counterweighted and internally ballanced. It does not need an nor is it equiped with an external ballancer. Now, let me say it again. The pulley does not ballance anything including the crankshaft.
Gadget
www.GadgetOnline.com
Jul 22, 2003 | 05:55 PM
#53
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From: Southern MD USA
What war are you talking about? I don't even think this is an argument. It is an exchange of information and I thought a friendly one. Everyone that comes here learns. I know I have learned a lot. Hell even Schafer has taught me a couple of things...
Gadget
www.GadgetOnline.com
Gadget
www.GadgetOnline.com
Jul 22, 2003 | 06:22 PM
#54
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Joined: Mar 2003
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From: Barrigada,Guam
Gadget
So if the UDP's is INSTALLED correctly then no one would have no worries. So is the alternator pully the same on all engines in the Tundra 4Runner and Taco I know that the crank is the same. One last quetion when is the pully going to be ready for the public and who's producing them ,or can I use the ones from www.sportruckspecialties.com/22Perf.htm
So if the UDP's is INSTALLED correctly then no one would have no worries. So is the alternator pully the same on all engines in the Tundra 4Runner and Taco I know that the crank is the same. One last quetion when is the pully going to be ready for the public and who's producing them ,or can I use the ones from www.sportruckspecialties.com/22Perf.htm
Last edited by 03TundraTRD; Jul 23, 2003 at 05:03 AM.
Jul 23, 2003 | 03:59 AM
#55
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Joined: Jul 2003
Posts: 8,807
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From: Montreal, QC Canada
Originally posted by Gadget
What war are you talking about? I don't even think this is an argument. It is an exchange of information and I thought a friendly one. Everyone that comes here learns. I know I have learned a lot. Hell even Schafer has taught me a couple of things...
What war are you talking about? I don't even think this is an argument. It is an exchange of information and I thought a friendly one. Everyone that comes here learns. I know I have learned a lot. Hell even Schafer has taught me a couple of things...
Anyway I did some research and yes you are 100% correct that toyota and for the most part all the japanese manufacturers do internally balance their engines. My terminology was incorrect! This adds considerable manufacturing expense but also greatly improves the reliability (and revability
) of their engines.....that is one of the reasons you can even get 200 or 300k out of a motor before a rebulid, while domestics are lucky to hit 100K (they are getting better now). Check out these links for help on internal vs external balancing:
http://www.clubcobra.com/t39618.html
http://www.pro-race.com/removable_counterweights.htm
http://www.familycar.com/engine.htm .....scroll to bottom of page.
Some like honda go one step further to reduce all vibrations by the use of balance shafts:
http://list.miata.net/miata/1997-08/1391.html .....very informative!
For the real engineers...do a "find" for balance on the page:
http://gypsy.cad.gatech.edu/courses/...4041_fall.html
It seems that the underdrive pulleys have been common with the ricers for a while but the common concencus for the reason it has an elastomeric ring is to smooth out the ascessory drive vibrations....especially the shock of the AC compressor turning off and on. As we read in the above sources that the firing pulses are dampened by the torque converter on an automatic and a heavy flywheel on a standard. Take a look at what I got off of a ricer mod page.....seems to explain quite a bit too.
Being skeptical of the claims for big horsepower on the Unorthodox Racing web site, we ordered up their underdrive pulley to do some dyno testing. When received, the pulley was obviously CNC machined from billet aluminum and anodized a nice shade of red. It was significantly lighter than the stock pulley. We measured the TDC mark in relation to the keyway to make sure that the TDC mark was right on. It was.
To install the pulley, we removed the passenger side wheel and wheelwell splash shield, exposing the front of the engine. An air impact was then used to remove the main pulley nut. A puller was used to remove the stock pulley.
After running the car, our SOTP estimate of power gain was moderate, about 2-4 hp. The engine felt more eager to rev and there was less drag when the AC compressor kicked on.
We plugged in a CONSULT to test for charging function and overheating. The battery output stayed above 12 volts with all electrical accessories going full blast. We tried to make the car overheat in bumper to bumper traffic, plus extended high speed cruising. The coolant temp never went above 94 degrees C. We also did some violent slalom maneuvers to test the power steering. There was no sign of power steering pump up. The AC was perhaps a little less effective but it was hardly noticeable. After all this testing I conclude that the pulleys are at least safe.
Some list members have been concerned that the underdrive pulleys lack of an inertia ring as the one in the stock pulley could have some negative effects on motor life. We believe that this is not true. The GA16DE, unlike most domestic motors, is internally balanced. It does not rely on a counterweight on the front pulley and flywheel to give dynamic balance like Ford or Chevy engines. Highly modified domestic motors are internally balanced at a great cost but us Nissan owners get that stock! We believe that the damper on the stock pulley is mostly to damp out accessory drive noise. With the underdrive pulley in place there actually seems to be less idle and high rpm vibration. We could not detect any increase in accessory drive noise.
On the dyno the pulley gave us 1 more peak hp but 3-4 through the often used midrange. We think we proved that the pulley does not harm anything. Overall the pulley is a pretty decent gain for the low price of this mod and gets the nod as a good bang for the buck from us.
Last edited by MTL_4runner; Jul 23, 2003 at 04:05 AM.
Jul 23, 2003 | 05:07 AM
#56
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Joined: Mar 2003
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From: Barrigada,Guam
Ok so is the crank and alternator pully the same on the 4Runner ,Tundra and Taco with the 3.4 motor. I would really like a set of pullies.
Gadget who is making the crankshaft pully that you are talking about.
Gadget who is making the crankshaft pully that you are talking about.
Jul 23, 2003 | 02:19 PM
#59
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Joined: Jul 2003
Posts: 8,807
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From: Montreal, QC Canada
Originally posted by Tacoma Dude
So what is the general concensus now?
It's all good don't have to worry about engine wear?
You guys lost me a bit with all them big words
So what is the general concensus now?
It's all good don't have to worry about engine wear?
You guys lost me a bit with all them big words
Last edited by MTL_4runner; Jul 23, 2003 at 02:20 PM.
