the theory behind one is less weight=less effort for the shaft to turn correct? This would mean that the shaft should be able to turn quicker, and turn the wheels quicker in turn, creating quicker acceleration? And this is what happens, guess I just kind of answered my own question. Does it really do justice I guess is what I'm asking.

 

My car revs a bit quicker, nothing earth shattering, but it servs its purpose.

I got mine for $75 shipped from an old GD so it was worth it since I had to change my belts anyway.

 

A question about underpulleys. Assuming you get the smaller than OEM pulley you will be underdriving the A/C the alternator and the power steering. Is there a noticeable difference when driving? Is there a noticeable drop in the summer when you turn on the A/C? I'd prefer not to underdrive anything if it is noticeably harder to steer the car. And I definately want my A/C running at peak because of the nasty humidity in Toronto during the summer. Will I notice a difference on the smaller lighter UDP?

 

I didnt notice any diff in a/c, alt., or power steering but deff in power. A BIG plus in my book.

 

This has always been debated and will always be debated.... we've seen a 2002 6MT dyno a 9 whp gain with UDP, but yet there are many with UDP experiences that say otherwise. It doesn't hurt to have one, but just don't be disappointed if there isn't a significant difference.

GregP's UDP dyno can be found in here somewhere: www.greghome.com

 

Which UDP is recomended? I talked to my dealer about ordering the unorthodox, he didn't recomend it because he said they have had numerous problems removing them from vq35's. Although that is the 350Z version. He says the aluminum is too soft and they have major problems removing the pulley because the bolt tears into it. I would prefer to keep it stock diameter. I thought i read somewhere about one that had a bronze bushing it which would be stronger than the aluminum at the crank hole. I am a tool and diemaker/ machinist and I could probably make my own brass bushing for the unorthodox version. Opinions on manufacturers or my dealer's comments are welcome. Difference in weight between stock and smaller diameter is only a few ounces.

 

Unorthodox makes a pulley that is lighter than stock but the same diameter.

 

I'd rather spend my money on something else.

 

well... up to 9 horse for about 200 bucks or 20 horse for a new y pipe at around 1000 cdn.

UDP = $22/horse
cattman y-pipe = $50/horse.

Methinks the UDP is the best bang for the buck until my suspension is installed.

I will eventually get the y-pipe, just trying to figure out how to get one without giving UPS a bucket full of customs fees.

 

GAB is free and gives a PROVEN 9whp... $00/whp

 

FTW...

Btw, once again for those interested in the UDP... only ONE person has done a dyno comparison with and w/o UDP and the BEST run was a 9 whp gain and that was using his WORST stock baseline as comparison. I vaguely recall one other person saying that the UDP reduced their 1/4 mile by 0.1 sec or thereabouts. Just something to think about.

 

In that case I'll keep saving up for the cattman y

 

Save for headers if you're wanting increased performance.

 

Just noticed that you have a 2003. Gains from a y-pipe are about 8-10 whp tops, not 20. Most people with intake, y-pipe, cat-back have dynoed around 212-218 whp with stock being around 205.

 

great work with the #'s there buddy, except you forgot one thing, youre comparing CND$/hp with US$/hp....super smart. to put it in perspective the RIGHT way, i got my y-pipe for 175 US$, thats less than $17.50/hp. and if you get the 20 that you say you will, thats $8.75/hp. i LOVE your calculations

 

i dunno, i dyno'd my automatic with intake and y-pipe and made 195 whp on a mustang which translates to upwards of 220 on a dynojet. if you figure for the 12% lower its 222 whp, and thats an automatic.

 

Until you actually put your car on a dynojet, I would stop throwing those #'s out.

A 6th gen dynod 260 whp on a Msutang dyno.. so does that mean he has 300+ fwhp on a Dynojet...

 

no, that means they guy that set up the dyno machine screwed up pretty bad.

 

Sure as hell did.

 

The thing about numbers is they'll never be the same. Engines are always going to run different and perform in their own unique way. That's why upgrades are a game, you have to play with different things to get the best gains. A UD pulley, as said can't hurt, but it may not be the best for a 80k mile car that has a struggling camshaft anyways. Same with the GAB, just b/c it was mentioned above. I did the ported hanger option and the original, to tell you the truth, I was disspointed in the NOTICABLE loss of acceleration while I've heard people say there is no loss.

 

is that supposed to mean?

 

esp if you are trying to compare with other Dynojet numbers.

Dynojet > Guesstimated Mustang dyno conversion

I'm sure a somewhat accurate estimate can be done, but in this case it looks like pure speculation to me.

 

A UDP doesn't create HP so you can't measure it.... it free's up HP that the engine was using to rotate that heavy azz stock pulley. Imagine pedaling a bike with a heavy azz rear tire.... then think about the same with a lighweight wheel.... same goes for you engine; you can only generate so much energy to pedal the tire, it's easier to pedal a lighter tire. I put one on about 3k mile ago, didn't notice this HUGE difference but I did notice that the engine revs a lot more freely when moving up through the RPM range. Haven't had any issues at all with the pully other than having to re-tighten the power steering pully after the belt streched a little. My .02 for what it's not worth...

 

I'm still pretty sure that if it really does "free up" hp, you will see it on a dyno assuming that hp makes it to the wheels. Whether or not it does is another thing altogether, since it seems that with our 32 lb flywheel, anything you gain at the crank with be lost there anyway. I could see a UDP making more sense if one had a 15 lb flywheel or something. Just my opinion of course.

 

Well what do you expect ? It would cost me 1000 CDN to buy a cattman. I can get a UDP for 200 CDN . I don't like it but that's the way it is. I'm not going to buy some mild steel piece of junk. I want stainless to last. And if you can find me stainless y pipe for 175 US please point me in the right direction. And sorry I said 20 horse for the y pipe should have been about 15. That's according to maxmods.dyndns.org So 12 -15 horse for 1000 bucks is still way more than the UDP.

 

Well, if it is the same diameter, wouldn't it NOT be underdriving? Thus, it'd be called a LDP or "Light Drive Pulley"?

 

I was thinking about getting this one since I will have a system in my car, and I don't want to underdrive that, just use it for the less weight.

 

There are 2 diameters and the smaller diameter is not stock so it underdrives the power steering

 

Actually, the power steering pulley is the same diameter as stock while the other pulley is reduced in diameter (for the Unorthodox pulley, 2001 model)...and the pulley is very light compared to stock. I have had absolutely no problems with this pulley. As an added note, you can order this pulley directly from Unothodox (Long Island, NY) and save money. I got mine for $95.

 

uhhh, thats what he said. the power steering is underdriven because the other pulley is smaller diameter.

couldnt you just find other smaller pullies for the a/c, p/s and everything if youre that worried?

 

I can notice the biggest change in the fan motor. When I have the fan on sitting still at a light and then start to move giving the car some gas I can hear the fan motor rev up too. Some people have claimed that the headlights dim with these but that hasn't been my experience. I don't have a system in or anything so I can't comment on that situation. I'd go for it, I got mine from Motostorm, installed it myself and haven't had any problem with the pulley itself. Had to re-tighten the PS belt, but no big deal.

 

A couple of things. Weight is miss leading. As most may or may not know less weight can hurt on some rotating things, and help on others. When it comes to pulleys it’s not the weight so much as the diameter of the pulley that helps. You don’t want to lighten up your crank pulley but so much because of crank harmonics. Beside a pulley couldn’t weight but so much (crank will weight more). So by cutting 1-3LBs you will see little effect. It’s the Dia. Of the pulley that makes a UPD effective. It’s like gearing. Think of your pulley system as a bike. As you switch gears the sprockets are changing in Dia. Same thing with a UPD. You are simple making it easier for the engine to turn the item with the new Dia. Pulley, thus freeing up energy needed to turn it.

The only problem some people run into with UDP is that they turn the A/C and alt. To slow. Which is why as mentioned, you see the lights get brighter when the engine is reved. It’s been my experience that the crank UPD is the only one that really helps. The rest do little, and can cause more issues then anything.

I only type this because everyone seems to be focused on w

 

Then why does Unorthodox state that 85% of the gains are as a result of weight reduction?

I would hope that they know more about their product than you do.

 

How did you order this? I just looked at their website and they were listed for $200.90. Did you call them directly?

 

the effect of weight isnt that its dead weight is less, its that the rotating mass is less. just like wheels, the difference is that because there is less weight being turned, less effort is needed to turn it. it takes less power to turn it which in turn makes more power to the wheels.

 

I don't know what to tell you other than the word under drive means Dia. not weight. It it was all abou the weight then why call them UDP, why not light weight pulleys? I went to their homepage and they say just what I said but a little different, so I'm not sure why you mention this knowing more than them thing? Right from their page...

"This version of our crank pulleys increases performance because they underdrive all the accessories (15-20% more power), unlike accessory only kits out there that do not include the crank pulley. This means one you air conditioning is on our crank pulleys give you more power back to the wheels by not letting the air conditioning compressor rob as much power. However, we do not push the amount or percentage of underdrive too far for two main reasons. First, it is important to keep charging systems, air conditioning, power steering, and water pumps moving fast enough for every day driving. Second, not much horsepower is gained from extreme underdriving. We always keep our underdrive percentage under 20% which is what allows us to maintain factory specified outputs for all your accessories."

This is just what I said. This whole article is about the underdrive (i.e. dia.) percentage, and how they are careful not to effect the speed of the alt. and other items so they function correctly, but they are reduced. Again you are changing the amount of energy needed to turn your accessories by way of Dia. Not so much weight. You are dealing with such little weight change it's really not sig. Now if your pulleys weight was 13Lbs and you went down to 2LBs then yes you may see something.

"For most applications all of the underdriving is done at the crank pulley, not the accessory pulleys..."

Like I said this is really the only place that is effective in my experience.

"This is done so maximum weight loss can be achieved at the crank..."

I don’t think they mean physical weight. I think they mean rotating mass weight generated by it simply being a different dia.

"where most of the horsepower gains are realized."

They are are saying that the weight cut is the reason for all power gain; they are just restating what they said earlier, that the crank underdrive is the only pulley that really matters, and is best.

I read “the stock dia. Pulley” article. They only reduce the weight and yes what little HP you may gain from those pulleys are in fact only from the weight cut because that's the only change. I assure you that the amount you again is very little if even measurable. Trust me, been around it for 10+ years.

If you don’t believe me than do this. Jack the front of your car up and put it in “N” Of course make sure the “P” brake is on. Now grab your tire and spin it. Take note of the force it takes to spin the wheel. Now take your tire off and put the lugs back on so the rotor is firm, and not loose. Now do the same thing, grab the rotor and spin it. Which is easier? As you can see the dia. Makes a huge difference, and the rim/tire is heavier making it easier once going. That’s momentum. Keep this is mind when thinking about pulleys. Just because a place sells something as gold doesn’t mean it is.

http://www.thunderracing.com/catalog...d=251&pcid=111

http://www.lgmotorsports.com/catalog...e9f1ada3323982

 

No that's not what he said. He said the power steering is underdriven. I said the power steering is the same as stock....

 

If I remember correctly, I saw it on EBay and called them directly. It was brand new.

 

Here is where I got mine. Installed for about 6k miles with NO issues.

www.motostorm.com

"The lightest Aluminum underdrive pulley made for the 1995-2004 Nissan Maxima,1996-2002 Infiniti I30/I35, 2002-2004 Nissan Altima 3.5 liter. The concept here is rather simple, your stock pulley weighs close to 6 lbs and these pulleys weigh in near 1 lb. This reduction in weight allows your engine and crank to become more productive once the huge, heavy stock pulley is replaced by one of these. Expect anywhere from 6-11 horsepower just by bolting on one of these pulleys. Just because these pulleys are extremely light doesn't mean they aren't strong, each pulley is carefully machined from a solid mass of 6061 T6 aluminum which is well known for it's strength and lightweight. These pulleys are 3D computer designed, tested and manufactured by Motostorm Inc. They are 100% american made. The completed design has been street and track tested for a total of two years before the release of these pulleys. Each pulley is hand inspected and computer balanced before final packaging. Not only are these pulleys the lightest but each pulley has a bronze oil seal bushing located on the back side for added safety and wear. There have been no oil leak issues with this pulley. These Pulleys are smaller than the stock pulley and require two different size belts. All belt sizes are included with the instructions. $109"

 

I got one of those forever ago and its still sitting on my desk.