I am interested in this mod as well, and have read posts and what not on the subject matter. Im only holding back for fear that the pulley will #1 void my warranty and #2 cause crank/engine issues, thus voiding my warranty....I've had my car for about 5 months...6k miles..so I'm a bit hesitant...but as I read more posts about ppl not having probs...the closer I get to hitting the 'SUBMIT' on the order screen....

 

Give in to the darkside, Todd

Search function on Maxima.org is down right now or I'd look for ya. They didn't say when it would be back up.

 

The 3.5 VQ crank pulley is indeed a damper just has is the crank pulley on my 3.0 VQ. The 1/8" rubber ring does goes through the entire pulley and actually holds the pulley together. I have seen older VQ crank pulleys that have detoriated to the point were the pulley actually seperates. The rubber ring acts as damper for the crank and to quell belt noise.

I use to have the Unorthodox UDP on my Maxima. Immediately upon install I noticed the ultra smoothness of the 3.0 VQ disappeared. There was more engine noise and I could feel more vibration, especially as the rpms climbed. I doubt you can feel the additional vibration with the 3.5 VQ because it's not remotely as smooth as the 3.0 is. Other things I noticed with the pulley was the reduced rotational inertia of the engine made it harder to start out in 1st gear and made it harder to shift smoothly into 2nd. There was lots of jerkiness. At the track I was no quicker or faster with the UDP. Earlier this year I took it off and I was no slower and I actually ran a new PB...with less mods. This data was generated from approximately 60 1/4 mile passes spread over 1.5 years. There is absolutely no proof this thing worked.

Will the lack of damper cause problems on the VQ? I doubt it because the VQ is a very stout block with 4 bolt mains and a lower girdle. The crank is also forged.

The lack of a damper will cause more crank vibration. In some cars this can cause the crank to break. I've never heard of any such case in the VQ series. However, the vibration WILL cause the valve train to operate ineffectively and can cause lower power. I've read a lot about this. Grassroots Motorsports had a great write up about this. If you want a pulley that makes power, then you want a fluid damper. The fluid damper is actually quite a bit heavier than the stock pulley, but it perfectly balances the crank and allows the valvetrain to operate at peak efficency. This means more power. NASCAR, F1, and Prodrag cars run fluid dampers and they'd laugh in your face if you told them to run an unbalanced lightweight pulley.

IMO, UDPs on the VQ are nothing more an snake oil.

 

Well, everyone's entitled to their opinions. However, yours goes against the laws of physics. Up until now, no one really doubted the performance benefits of the pulley. The safety was the issue. You're the first person who has doubted the positive effects.

Fact: lowering rotational mass via the crank pulley/flywheel/lighter wheels and tires will improve performance. If you can change the laws of physics, you can argue that it doesn't. Calling it snake oil, well...

 

Here's a question for those WITH and WITHOUT the crank pulley installed.

When you're engine's all warmed up, and you're at idle, sitting in the car with your windows rolled down. Can you sense or hear a click in the engine? A random click/bump as the engine is running.

I've been told many things... Ranging from "It's the VDC" or "It's the engine ticking from the engine temperature change"(much like when you shut off your engine and it starts clicking) or the simple "it's your Crank pulley effing up your car"

Just want to know if it's present in Gs that haven't had the pulley mod done.

Thanks all...

 

If anyone thinks that rubber ring that is GLUED ON is helping an internally balanced motor then I have a news-flash - the earth is not flat!

A billet cut pulley is perfectly balanced and thousands of these things are on the VQ series. If one bad motor comes from the crank pulley it will get mentioned!

 

Just curious, do you have an UDP and do run at the track on a regular basis? Like I said earlier, I've got 1/4 mile data of before, during, and after UDP install. That's well over 60 passes spread throughout varying conditions at the same track. I've taken into consideration atmospheric conditions and 60 foot times. Trap speed is the clear indicator of HP. You can't really F-up trap speed, only ET. My trap speed was not quicker with the UDP not was my ET. With the UDP I averaged 14.48@98.5mph with a best of a 14.40@98.1mph. Without the UDP, I've averaged 14.44@99.1mph with a best of 14.31@99.54mph.

I am well aware of the physics involved with using lightened rotational components. Rotational inertia can be a killer in terms of performance hence the reason I run lightweight 17" rims. I'm also well aware of the underdriving accessories since most of my car background comes from modding F-Bodies and Stangs.

The truth of the matter is the VQ crank pulley is a damper. The rubber ring acts as a damper and it keeps the two pulleys (though they look like one to the naked eye) together. Adding a lightened UDP technically should gain you some power, but at the expense of valvetrain ineffiency. It doesn't matter if the UDP is perfectly balanced, the question is the crank. It's not perfectly balanced so if you take away the device that calms it's vibration, then you introduce vibration and valvetrain ineffiency. If you have a manual, you will experience a car that is easier to bog on launch and on the 1-2 shift.

I think this whole UDP following trickles down from the Mustang crowd who typically see 8-10whp/wtq gains with a UDP kit which includes a water pump pulley, crank pulley, and alternator pulley. I bet most people don't know that most of that gain comes from underdriving the water pump and that many Mustang guys do experience cooling problems with these setups. I bet most guys in this Org don't know that the timing chain runs the water pump on the VQ. I've read numerous articles in Stang mags with dyno comparions of adding UDPs and then going to a fluid damper. The fluid damper blows the UDP set out of the water plus the engine becomes more reliable when operating at higher rpms.

Believe what you guys want, but from the stuff I read on this site, it's pretty clear 99% of the people in here believe what's fed to them by the aftermarket companies. I too believed that an UDP was a great mod until I put it to the test and I turned out to be a lightweight paper weight and hurt driveability.

 

So then, what's that ring there for? It's odd you say it does nothing when the Nissan/Infiniti FSM refers to the pulley as a crank pulley damper.

Taken from a Nissan tech that spent 4 years over in Japan on their racing circut:

 

This is all fairly well known in automotive engineering. here's a good reference:

http://www.eng-tips.com/viewthread.c...=107602&page=1

Read for yourself and make up your own mind.

 

Well I have the URP in my 1997 Maxima for over 2 years now and the car has 87K miles. No problems at all. I'm a member of the maxima.org also and plenty of guys have it with engines that have more 130K miles. Some guys have been using them for years with no problems. The only downside to it, if you have amps and subs your electrical system might not generate enough current. The upside... a faster reving engine and few more HP. I love it personally.

 

This is the next item on my list! FASTER, Baby, FASTER!

 

allright, someone asked if they had one on a VQ for 100,000+ .....i had one on my 2000 5sp maxima(3.0) for 60,000+ and no problems......car felt lighter and engine revved quicker........i'm by no means an engineer to break down the harmonic dampers and all that, so those were just my impressions...............now, i've got one on my sedan and alls well at 20,000+...........until someone with one reports an actual problem traced to the underdrive pulley, hopefully not me, i'm keeping it on...........

 

I had the UDP on my Maxima for 25K miles and had no engine problems whatsoever and the engine had 80-100K miles at the time. I know of plenty of other Maxima owners running UDPs with no problems either and I have never heard of an engine failure on a VQ with a UDP. Never. HOWEVER, the point of this topic is "UR Crank Pulley: The Final Word". Well, seeing that I'm the only one in here that has actually compiled data on this thing, I'd think I'm somewhat an expert with UDPs and VQs. Go search Maxima.org and do a search for "Dave B". You'll see I'm one of ten members on a 15,000 member base that is highly respected when it comes to VQs and modifying them. I don't talk BS.

You guys can tout "more power", "revs faster", etc, but you're simply going by the butt dyno which most of us know is severely influenced by the price of the mod you added multipied by any additional sound the mod might have added (ie loud exhausts give the sensation of going fast). Many of us have put these things to the test and they simply don't perform and at the expense of more engine vibration. I've read two posts from G35 drivers that reported that the UR UDP did indeed add more vibration. On the dyno, I've seen the UDP gain a whoping 2whp over the span of 300rpms on the 3.0 VQ.

Call me pessimist and a hater, but I'm just trying to get the point across that these things don't make any performance difference on the VQ series and there are better mods out there for the money. It's your money, but if you think you have a faster car because of the UDP, you're wrong and I've got a stack of timeslips to prove it broken down by 60', 330', 1/8 mile ET/MPH, 1000', and 1/4 mile ET/MPH.

 

There are too many variables that can affect trap speed. Besides the ones you mentioned above, you have to include tire pressure, tire condition, tire temperature, quality of gas, weight of the car, consistency of launches, clutch wear, etc.

You agree that rotational mass is a performance killer yet you still doubt that a lighter pulley doesn't help performance. The two positions are contradictory.

 

Like my post above stated, there are too many variables that affect trap speed. Respectfully, your compilation of slips doesn't really mean anything. If one could get the same time for each run, then it would be a different story. However, you can take a car out, run ten runs with no modifications, and I'd wager, get 10 different results.

Not to sound like a broken record, but I'll take the laws of physics, (to which you have agreed to be true) over your stack of slips.