Another possible issue--

Does the VQ engine have any type of torsional dampner on the stock crankshaft pulley?

If so, does the Unorthodox pulley have it also?

 

Hitman,

From what I've been told this is not something of concern with the VQ. That's what I've been told by a performance shop that has actually taken out and disasembled a VQ engine.

'03 AT Sedan | Brilliant Silver | Willow Leather | Sport | Premium | Aerokit w/Spoiler | Nav

 

<blockquote><font class="small">In reply to:</font><hr>

do you understand that something ALREADY in motion (such as pulleys) are much easier to accelerate than something static?

<hr></blockquote>Not according to simple ( and not-so-simple ) physics. F=ma. Mass is constant. Acceleration is linear. Thus the force required is linear. It doesn't matter what the starting speed is, the force required to accelerate anything remains the same. Go back to school.....

 

<blockquote><font class="small">In reply to:</font><hr>

But to say that disconnecting an alternator that is producing 746 watts of power will equal a 1 HP gain is wrong. Sorry, but it doesn't work that way. It's just not that simple.

<hr></blockquote> It is exactly that simple because that is how it works. The 350 watt output requires 750 watts of energy input to produce ( an auto alternator is ca. 55% efficient ). Energy in, energy out.

<blockquote><font class="small">In reply to:</font><hr>

Also, to say that your average alternator puts out .25A and 15V is wrong. The voltage varies due to demand.... demand of accesories, demand from the battery (after start-up) etc.....

<hr></blockquote>And why is the averge output "wrong"? Of course, it is not, it is an average. We do not know what the actual output is; on a spring day the battery is fully charged, the fan is on low so the output is almost zero. On a winter night the battery is low, the heater fan is on, the headlights are on, the wipers are running....and the demand is high.

<blockquote><font class="small">In reply to:</font><hr>

The very fact that the alternator will be underdriven (yes, even by 20%) means that the alternator will, under certain circumstances, have to work harder.... And we all know what that means....

<hr></blockquote>So you are saying that underdrivng the alternator increases the demand, thus reducing total engine power to the wheels? Hmmmmm....... ;^)

 

Shawn, unless we give a remedial high school physics course to the group, some posters will still argue that mass equals weight and acceleration is caused by magic. I believe your premise because science ( and many dyno charts ) prove it to be true. I may wonder about the actual gains - 10+ hp seems like alot to me - but I will not doubt that figure unless it is disproven.

 

Here's an explanation of the physics - scroll to last question http://www.nissanperformancemag.com/march03/ask_sarah/

The example was using a flywheel, which as I mentioned earlier in this thread is a much more dramatic way of freeing up HP by reducing weight due both it's larger diameter and heavier weight. If you calculate the moment of inertia of the significantly smaller pulley(s) with the weight reduction you'll see that in a higher gear (which is what is used on the dyno) the gain is merely a small fraction of 1 HP. That is why if they actually show say 5HP on a dyno the vast majority of that gain must be from underdriving. Note that in say 1st gear you probably DO see a small but measurable gain from weight reduction of the pulley.

2004 Black 6MT

 

ok. im so confused. never liked physics so ill just let you physics guys figure this out and ill decide from there.
but a couple of questions:
1. if I am running a 600 watt amplifier with my subwoofer and plan to upgrade my speakers with an amp as well, can i still use the pulleys? you said something about a 600 watt system.
2. i also need the AC on. im in California in a freaking desert. is this set for me and others like me?

please answer. thanks shawn.

G35S 6MT
Technosquare ECU
350Z Springs & Struts
6-wire ground kit

 

its the alternator is underdriven, it will not put out the 110 amps it is rated for. Thats why they said 600 watts systems (very small in this day and age). You go over 600 watts or so, your headlights will dim, voltage will drop to try to compensate, and if you have lots of power drain from the stereo, your cars computers can start acting funny. There was posts a couple months back about ppl with huge systems havign their cars act up when the voltage dropped too low. (PPl , please dont say that adding a cap will fix that bc if your voltage drops for more than a couple seconds the cap just adds to the problem bc that now needs to be recharged as well)

not sayin that all that wont happen if you dont have UR pulleys, but it will happen quicker.

 

Fluid,

Regarding the alternator:

1- No, it is not that simple. You're assuming that an unplugged alternator will have ZERO drag on the engine, which we both know is fasle. (At least I hope you can realize that). The alternator itself will require power to spin, no matter how much "power" it is producing.

2- Alternator output is NEVER "almost zero" as you say. Alternator output must never drop below 12.6V, or the battery will become discharged even while driving. On a healthy electrical system, alternator output usually remains above 13.5V (average)

3- I was saying that an alternator that is underdriven, will, under certain conditions, have to "work" harder to produce (given the demand) and that we all know that a harder working alternator "steals" more power from the engine (by the way of increased drag). Understand?

 

Fluid,

Are you telling me that the same exact amount of energy is required to spin an object at rest as is required to continue to spin that same object already in motion?

Are you serious? Break out the pocket-protector, pal, and hit those books again.......

 

so that means a pulley set would one day end up causing a dead battery? oh heeeeccckkk no. thats a drag. please tell me im wrong in this asumption.

G35S 6MT
Technosquare ECU
350Z Springs & Struts
6-wire ground kit

 

Dead battery - realistically no, maybe if you let the car idle for a very long period. While cruising there is no problem at all, the underdriven pulley is spinning plenty fast for a full charge.

2004 Black 6MT

 

Here is my observation on UR crank pulley based on Accord V6 both NA and FI. However, keep in mind J30A1 is different from VQ35DE so we need dyno from UR on G35.

UR lightened/underdriven crank pulley is the only one proved to deliver gain due to smaller diameter and reduced weight the others worth ****. I wouldn't recommend changing stock alternator pulley especially for people who rely constantly on AC as well as those who have "crazy" stereo systems, so dont purchase kit (3 pulleys) just a crank one.

Guys with Accord V6 (keep in mind AUTO) felt the immediate difference after 5 days break-in period and some felt right away with most gains on the highway when they punched over 55mph, others also noticed that stop and go became a little better. Several made dynos showing 5-8whp and 5-8wtq across the powerband on NA engines.

For boosted Accord guys Unorthodox Racing has produced the stock diameter lightened but not underdriven crank pulley. However, based on DYNO, supercharged guys showed ZERO gains with it, therefore those who bought it wasted $260 since stock crank pulley delivered the same.

In conclusion, for G35 NA engines UR underdrive crank pulley could be YES, however only DYNo will tell.
For FI G35 engines:
1. not recommended.
2. if UR make the stock size not underdriven crank pulley its not worth the penny, so NO.

2004 G35s auto (bone stock)
-----------------------------------
2002 s/c Accord V6 auto
so far best 1/4 mile - 13.9@101.8
coming soon: custom internals, cams, performance auto tranny w/LSD

 

i dotn know if it was posted in this thread..

but... our cars do not require a harmonic damper on the pulley.. the OE pulley does not have a harmonic damper on it..

the Crank pulley is the only pulley that makes power.. the accessory pulleys are the same size and about the same weight...

there is no need to worry about putting a crank pulley on the VQ35

Jason
AIM: PerformanceNISMO
Yahoo: MyNISMOParts
http://www.performancenissanparts.com

 

Your A/C should still be fine here in AZ. If your idle drops really low and you have the pullies, it may not work quite as well as stock, but it'll still work. it's not like your A/C will feel like it's turned off, but if you're stopped, say in a drive through at Wendy's it may not blow as cold as when you're driving down the freeway doing 65mph.... I've had pullies for a few years now and I've been fine in the summer time. I'd put a set on our Project Coupe to test out here in Phoenix, but I can't run them, due to the supercharger....

And from actual experience with a lightened flywheel and UR pullies (on my car), they both work, they both gained hp on a dynojet dyno and they both made the car faster to where it registered on the butt dyno as well. Just revving the engine in neutral you could very easily tell a difference too. FWIW, the flywheel made a much larger difference, but it was almost more weight saved and further out from the center of rotation, if that means anything....

Justin McClanahan
Heavily Modified 95 Infiniti G20
Working on a G35 Project Coupe
http://www.EverythingG35.com