I am considering getting a lightened UDP on my Maxima. Are there any downsides to it, such as noise, reliablity, or anything? Any help would be greatly appreciated. I'm not planning on going SC anytime soon, so I'm probably going to purchase UDP's.

 

Well it COULD underdrive your water pump or alternator to the point that you fry them but I personally havn't heard of anyone with a maxima having that problem. Supposedly RVM pulleys have had problems with the crank seal leaking or something of that nature, if i recall correctly. UR pulleys i havent heard of any problems with.

 

if you like your A/C or you like to play your music loud dont get one

 

no problem with the UR pulley here.

 

well if you don't mind spending $150 for 0 hp and 1 hour worth of labor.. then i would say their is really no down side to it

 

Are you serious?? I thought you could get like 5-8 horsies!!

 

My A/C cranks frigid air, and I play my music as loud as it can go and I don't have any problems. UDP makes the engine rev so smooth and quick. I don't know about that 0 hp deal.

-Sean

 

That's not really true.. I mean if you have like a 2500watt system then yeah I could see a problem. But if your running like a 1500watt system then you can crank it with no problems. Just have a good cap.

You're a/c will still be cold. But maybe a tiny bit less then before

 

That's why I went with the RVM for $80 instead of the UR. Basically just so I could say "I have a UDP" You'll barely feel any performance gains with the pulley. SLIGHTLY less lag off the line, but nothing drastic.

I do know that DaThrillr dyno'd the RVM pulley and got a max gain of 6hp at the wheels. There was a huge thread about this a few months ago, I think he posted the dyno chart as well.

 

Unorthodox Underdrive Pulley was installed on my Max the other day. The air condition is just the same in my car. Blows just as hard and just as cold.

 

I was about to mention that about the water pump lol.

 

The overall benefit of the lightweight UDP is that it saves wear and tear on your engine by spooling/revving faster due to the lighter weight than the stock flywheel.

From what I know of them you don't necessarily gain any hp, just the added benefit of faster revving engine and longer lasting as I stated earlier.

 

so which one is the ONE to get? also how much were the belts?

thanks

 

 

RVM is half the price and is 99% identical to the UR. New Gates belts should run about $15 for each belt (you'll need 2)


-Tony

 

Ant

 

I was going to get a UDP until I read this:

http://www.dinanbmw.com/html/danger_...er_pulleys.htm

 

Last time I checked, this is a Maxima board and we all drive Maximas, not BMWs. That article relates specifically to BMW engines...

 

Is your maxima a BMW? no

Has anyone EVER ran into any serious problems with a UDP in their maxima? no

 

Let me try again:

I am talking about harmonics of the crankshaft. It does not matter who makes the engine, or even the layout (I6, V6) the engine operates on the exact same principals.

With that in mind, if the gains were so easy to get, with out any harm, why wouldn't Nissan shave ~4 pounds off the crank pulley? I think there is a VERY GOOD reason why Nissan designed the crank pulley to weigh what it does.

Who would connect a bearing failure (or something of that nature) to a UDP. No one.

If you lease your car, who cares. You won't have to deal with any long term problems. If you own your car, and you want to keep it a long time is it worth it for 4-5 HP?

 

I'm just going to comment on the RVM UDP...

They SUCK!!!!!!!!!!! if you want to spend $80 and labor for a nice paper weight......

 

MaxVQ, I was of the same opinion as yourself concerning UDPs until I did further research into the UDPs and the VQ. I found out the VQ DOES NOT have a harmonic balancer as the crank pulley. The crank pulley is simply that, a crank pulley. It does nothing to quell harmonic frequencies of the crank. In a nutshell, the VQ is internally balanced thanks to forged, hydro-cut, and knife-edged crank. I should note that the VE/VG are NOT balanced and DO have harmonic balancers. DO NOT add UDPs to these motors.

The I6 motors in the BMW are NOT internally balanced and the crank pulley also serves as a balancer therefore it would not be wise to add any sort of non-harmonic balancer.

To answer your question as to why Nissan made the pulley rather heavy, it is to keep up the momentum of the motor during shifts. With the light UDP, the VQ has the tendency to loose revs quicker between shifts which can make it hard to engage gears as smoothly.

You're definately free to do what you want since it's your car, but there are gains with the UDP. Contrary to what Sprint says, I saw 5 fwhp/fwtq from 3000-6500rpms on the dyno and an average .1 and 1mph gain in the 1/4.


Dave

 

ok, well then how long has everyone had their pulleys for? i for one plan on driving my maxima until it explodes whether from something i did or from being too old.

thanks for the belt price info

 

Interesting. You have a good point on the weight of the crank pulley reducing the RPM drop between shifts. I never thought of that.

Thanks for the insight.

 

I've had mine on for about 20 months now. No problems. Mine is the Unorthodox UDP.


Dave

 

NOPE ...i have definitive...2 months now...installed by Jay25

 

Have you done your research on the VE Davey?

There a LOTS of VE owners with UDP's and the gain is .10-.20 easily.

 

Im Calm

 

I think the screwup with the RVM UDP may have been a simple case of RVM specifiying too high a torque rating for the bolts than they were supposed to be. The RVM instruction said to use something 146 lb-ft of TQ to screw in the bolts. I checked my FSM for the stock pulley. 46 Lb-ft. Someone may have just put a one where there wasn't supposed to be, and all those pulleys failed. Shame.

DW

 

Dave,

i have a 3rd gen with the VG. and i have shyed away from the udp, as i am never given a straight answer about it. or the information does not overlap. you are saying that the VG/VE motors are not internally balanced. and i have read things about that, btw. so, then, DOES the stock pulley on these engines act, then, as the harmonic balancer? is there a final answer for this?

-bonz

 

According to my Chilton's service manual, the VE and VG crank pulleys are indeed harmonic balancers. The VQs crank pulley is not. I would NEVER run an UDP in place of a harmonic balancer. NEVER.


dmontzsta-

Sure, they make UDPs for the VE/VG, but that doesn't mean they're safe. I don't know of any failures, but snapping a crank because of running an non-harmonic balancer UDP seems crazy to me. It's not worth the risk for a little extra power. To each his own.


Dave

 

yes, Dave B, i hear you. your advice is sort of the "last in line" for me. that is all i needed to hear further about this whole UDP issue. i have read this and that and this subject has come to a head >>> an extra 4 or 5 hp is absolutely NOT worth getting if my VG, in great shape, is going to be destroyed. absolutely not worth it. a UDP cannot be a harmonic balancer in a million years. btw, brian catts of Cattman recommends AGAINST the UDP in the 3rd gen as well. so i have heard enough. thank you so much, good sir. and happy motoring in your awesome ride. for all else who actually can get away with a UDP, in a way, i do envy you all. but i am fine no matter what. VG-to-VE VLSD 5spd tranny swap, lightweight fidanza flywheel/exedy stage one, here i come.

 

Excellent point.

 

would that effect a vb equipped auto?

 

I thought that was the purpose of the heavy OEM flywheel, not the OEM drive pulley.

DW

 

hmmm...this is interesting. I am looking in the FSM and do not see anything about a harmonic balancer. Where did you hear about it?

 

Good call. I'm dumb.

 

I'm going by what I read in my Chilton's manual since it uses many of Nissan's FSM diagrams. Chilton's makes many references to the VE/VG pulley as being a "damper" whereas the VQ's pulley is referenced as a "pulley". Damper is usually another way of saying balancer. My 1996 FSM referes to the VQ pulley as a pulley only.


Dave

 

Gotcha, I will look for that and let you know what I come up with.

 

Sorry to ***** the thread but what is the cheapest/best place to get a UDR pulley, im thinking of ordering one soon.