Dave, I greatly appreciate your kind words. I do my best to provide relative information in a friendly manner because at the end of the day each and every one of us is an enthusiast that enjoys these cars more than we probably should. To be honest I have not removed the pulley on my G35 and as such my response was one relative to my knowledge of other pulley's that I have removed.

It seems that we may very well be contending the same point, though we are using different words. I beleive, and you seem to support the fact, that the dimples are used for balancing (correct?). If that is the case then all that one would need to do to check the true balance of the pulley is to have it spun on a dynamic balancer. If it is 0-balanced it will remain so throughout the rev range (agreed?). If it is not 0-balanced it could be assumed that it was in fact balanced to the specific needs of the motor. Furthermore, if it is balanced specific to the motor two paths of thinking could develope:

1) Is the balance of the pulley the same for every G/Z?
2) Is the balance specific to each individual car?

If the answer to question 1 is yes then all a manufacture would have to do is assess the balance and build their pulley accordingly.

If the answer to question number 2 is yes then several things would complicate the equation of a mass-produced-one-size-fits-all pulley. This would also mean that a great more engineering and subsequent development by Nissan would be needed to produce this motor. Why you ask? Because if every car required a different pulley that is balanced to the needs of its crank (or entire rotating assembly) then production of said pulley would escilate production cost and time. Even in this age of mechanized work forces I can't imagine that a bulk manufacture that produces thousands upon thousands of cars anually would specify something so detailed. Most modern automotive manufactures practice "lean manufacturing." As such, doing something like what is proposed by answer 2 would throw a cog in the works relative to efficient supply and demand.

Here's why: Let's imagine that a G35 customer were to experience a pulley failure...or a crank failure for that matter. If every pulley were specific to an individual VIN number it would require the customer's issue to be reports to his respective dealer; the dealer would report to their field representative; the representative would report to his supervisor; the supervisor would share the news with corporate; who would then contact their rep in Japan and then the same process would occur in reverse for the information to trickle down to the actual person responsible for building the specified pulley. This is highly unlikely.

I would imagine that like most automotive manufacturers (I have worked for a few) Nissan probably outsources the pulley to another company that builds this part in bulk and ships them to the Nissan plant responsible for motor assembly. The likelyhood is that the pulley manufacturer is not the same as the crank manufacturer. As such, these parts would have to have a universal fitment that is determined prior to production.

I hope that I haven't been too verbose this time. Again, I appreciate this discussion and your opinions whether they be in line with my thinking or not. Have a good evening!

 

Jeff - Picked you because you turned discussion into argument, then you stopped arguing your point, and started arguing about the argument. It's funny.

Besides... I have, actually, done this. I've owned my Prelude approximately 10 years, and have rebuilt the motor close to 20 times. I've done a lot of stuff over the years that I imagine you haven't. Not saying this is a good or bad thing, but I do have the scars and "shop tattoos" on my hands to prove it.

In my experience, and the experience of the machine shops that I was using for assistance in mic'ing and examining the cranks and internals, after examining crank journal wear there has been no indication that a properly balanced lightweight flywheel lends itself to premature wear or spinning a bearing.

The reason I'm staying out of this "discussion" is because I have never run a lightweight flywheel on a VQ, therefore I feel that my experience doesn't necessarily apply to this particular matter on this board. Trey, on the other hand, has over 200 passes at the drag strip with a lw flywheel and has had no issues other than finding that launching a whole other beast.

Try asking him his opinion on this.

 

Really? I've torn down and rebuilt L16s, L18s, I've worked on my VE30DE and had the heads taken off. I've installed numerous clutches, flywheels, engines and engine parts. I've custom build a BBK and have welded my own exhaust. Even dabbled in automotive painting back in my earlier days.

Tell me something. How many ways ARE there to install a crank pulley?! It's keyed! You can only install it ONE way! LOL.

Tell me your PERSONAL experience and get back to me okay?
Why don't you get off the personal attacks and post something readworthy? Because up to know, you have only succeeded in stating the exact same thing no less than 2-3 times. I got it. thanks.

 

Does the prelude feature a dual mass flywheel as OEM? Did you find that a light pulley resulted in excessive wear?

If you want to find fault with someone that's arguing w/o substance, look no further than dofu. IMHO, he's contributed the least amount of technical info in this thread.

As far as Trey, I agree that light flywheels make it harder to launch. I've stated that fact or agreed with someone that stated that.

This one of the first replies to the thread and it states:

You've seem to be confusing the argument here. I have NOT specifically stated that switching from a DMF to a SMF would SPECIFICALLY damage the engine. But I HAVE stated that if people want to put lightweight pullies on the dangerous list, then perhaps SMF flywheels should be seen in the same light. Either BOTH should be seen as dangerous or BOTH should be seen as relatively safe. THAT is my contention and I've read no reasonable post to the contrary. If you read spec-01's posts, he indicates that as long as the aftermarket unit is 0 balanced (itself balance and not assembly balanced), that part should not pose any more damage than it's oem counterpart.

Dave is stating that pullies are assembly balanced. Spec-01 is stating while that's possible, it's unlikely due to the costs associated with balancing each and every pulley/crank together as a specific assembly. I'll further support that notion by stating if you ever damaged your oem pulley, one would have to get a new one rebalanced with the crank. That would require one to tear down the engine, take the crank out and sending both out to a machine shop to be balanced together. Now where in the manual does it require that?

 

You're right. I've just been stating that it's not the flywheel's job to balance the crank, so it shouldn't do any damage while you keep arguing that it will affect the motor...

Want some technical info based on experience? After having a lightweight flywheel on my G for years now, I need new struts... must be related because the lightweight flywheel is so bad for my car...

 

Hi, I'd like to introduce you to my friend, Captain Reading Comprehension.

He's a cool cat... you should take the time to get to know him a little better.








**** on a boar hog and lips on a chicken.

 

Then why did you interject this bombshell of information that no one was disputing? Just because?

Context is what you need.

 

Again wrong comprehension. I contend that the IF pullies are deemed dangerous, so would flywheels (in a greater amounts IMHO). See the difference.

But I'll ask anyway. Of the engines that were torn down, how exactly was it determined that the PULLEY itself was the majority factor in the engine's demise?

Keep getting ridiculous.

 

Here's a picture of an engine that I did for a friend. Not it's not F1 quality work but you will notice the ACT stage 1 flywheel and the alunimum Fidanza flywheel. So yeah, I think light flywheels are dangerous.

 

I'm not saying one specific pulley matches one specific crank. It's a "one piece fits all thing", but the VQ35DE pulley is designed to match the VQ35DE crank for balanace and dampening. That's all I'm trying to say.

 

Dave, how can the crank and pulley be balanced specificly for each other when Nissan has to account for manufacturing tolerances?

And if you alluding to the machined dimples on the oem pulley, I do believe the oem flywheel has those same machined drilled dimples also. So is the oem flywheel also crank matched?

 

Here's my real world experience with an UDP on a VQ. I use to own a decently modified 96 Maxima 5MT. After lots of stellar reviews and claims of 5-10whp, I bought a UR UDP for my Maxima. I installed it and immediately noticed three things:

1) The super smooth VQ30DE became grainy feeling above 5000rpms. There's was this vibration and sound that came from the motor that wasn't there before when taking it into the high rpms.

2) The motor revved quicker at idle.

3) It was harder to modulate a smooth start. Yes, even removing just 4.5lbs in rotational mass accepts driveability and MOI.

I drag raced that car a lot. With the UDP, I was no quicker and if you want to get nit-picky, I was actually fractionally slower by a few hundreths overall. Most of the loss came in the first 330'. My 60 foots were less consistent too. On the Dynojet, absolutely no power was gained.

After two years use, lots of research, and a bit of concern regarding the longevity of my VQ30 since I had added 25% more power over stock and was revving it to 7100rpm vs the stock 6500rpm limiter, I yanked the UDP pulley. IMMEDIATELY I noticed a smooth running motor and better driveability and not surprisingly better MPH/ETs at the strip. The car was far easier to launch. I can only imagine how hard it would be to effectively launch a VQ with a lightened flywheel. It has to totally neuter the launch capability of the car to the point it probably feels like an I4 Honda motor.

 

Pretty much the case...and I have owned several MT Accords!

Just to get a smooth start I have to rev pretty high (around 2-2.5k)... people probably think I can't drive a MT

 

Guys, I really do enjoy discussions of this type, and though one would think I get enough of these talks at work, it is nice to exchange ideas with others that have different perspectives based on individual experiences. I do ask that you all realize that respect for other ideas and those that share these ideas is significant to continued dialogues of this type. Remember you don't have to agree with each other...but you should do your best to share your opinions without taking or making the discussion personal. After all, discourses of this type are catalysts for new ways of thinking.

Now, back to the topic at hand...it seems that the majority of you with experience relating to the use of lightweight flywheels reference a change in responsiveness at low RPM and its subsequent affect on launching the car. As discussed previously, this change is expected as it reflects the reduction in MOI. If I had a single statement that summarized my view relating to the use of lightened flywheel (or pulley's for that matter) it would be this: Decide what you want to achieve with your vehicle before choosing to reduce the mass of any of its rotating components. Do this before making a modification and you will be better able to determine what is right for your specific needs and as a result be better able to determine what changes best suit your goals.

 

X1000

If I had a road race 350Z, I'd probably have a lightened flywheel to help improve upper rpm responsiveness and rev matching. If I had a drag 350Z (which seems like a stupid idea), I would have an automatic and line-lock.

I'd never put an UDP on my VQ or any car for that matter, but I have considered getting a HEAVIER Fluidamper crank pulley. I'd most definitely get one if I had a race car. The Fluidamper has superior damping capability and actually gains a few HP to the wheels even though it's a bit heavier than the stock pulley damper.