tCtuner

I know there are a ton of posts on this, but I have not found a thread that directly discusses the merits of one vs. the other from an "engineering" standpoint... and I would like some real world (read: real experience even if you don't have an engineering degree type of) answers.

First off, if this question does not belong here, I apologize!

Like I said, I have read differing views within ScionLife on 'underdrive' vs. 'lightweight' pulleys. Underdrive... meaning smaller diameter such as the NST product (less power to the accessories = more power to the wheels) vs. a lightweight, same diameter crank pulley such as the ZPIracing V.2 product (does not rob the accessories of their needed power, yet still provides gains in whp due to the shedding of weight).

It seems NST is more popular, but ZPIracing seems more logical as respects not messing with the accessories. Peoples posts seem to indicate similar gains from one product to the other.

Now to my questions: 1) Is one better than the other from a mechanical standpoint? And 2) what concern should someone have who sits in A LOT of summer commuter traffic in the Northeast? (Wouldn't the NST underdrive pulley mess with the AC and idle? Or is that why they sell the set of three... to compensate for the underdrive?)

Additionally, has anyone left on the upgraded pulley (which ever one you have purchased) and left it on for servicing other things at a dealership? Specifically, I am wondering if I get the SC in a few months, would they go balistic if they saw the pulley?

Thanks for your responses!

THansenite

I am also curious about the comparison between the two pulley options. I know NST has the 3 pulleys and a lot of people like them. However, I am a big fan of ZPI and am curious how they match up to the NST's.

ScionBandit

i had the ZPI v1 crank pulley on since it was released, started givin me trouble like a week after i installed it. just put the NST underdrive pulley in friday (waiting for other 2 to arrive), not even a close comparison. NST feels alot better
but i have not been in a car with the v2 ZPI, so icannot comment on that. I hear its good, no complaints
i am a fan of ZPI, just not happy with how they handled MY situation

tCtuner

Thanks bandit. What kind of trouble did the ZPI give you? Did it 'damage' anything?

Even though you have not had in for long, I am wondering how the NST reacts in idle (traffic jams, etc). Does the idle change?

Any other mechanical opinions? Advice?

ScionBandit

made WAY too much noise, moved around to much, just didn't seem like it should be doing any of what it did.
NST pulley seems to idle steady at 1k or so, lil higher than ZPI did

PghtC

has the ZPI issue been addressed with the v2? Anyone?

OH, and if the dealer sees the pulley added to the vehicle you can say bye bye to the engine warranty. Regardless you don't want an underdrive pulley if you get the supercharger as it will rob you of your boost. With the supercharger you will want a lighter, stock sized pulley so you still turn the supercharger at the same speed. OR you could get the underdrive pulley for the crank and a smaller pulley for the s/c to compensate.

scholarbb

NST pulley is a very solid piece. I was quite suprised when I received it. Heavy duty all the way.
Unless you spend a lot of time in traffic jams the underdrive will probably not affect you. My tc spends the majority of the time on the highway @3K plus. I've seen no ill effects so far and idle seems smoother. If you plan to supercharger you do not want the underdrive crank pulley.
If you decide not to underdrive make sure to get either a ZPI VERSION 2 or Unorthodox pulley. Agency pulleys AKA ZPI version 1 are the one that have had problems.
NST is also working on an overdrive crank pulley. If you need more alternator power NST also offers an overdrive alternator pulley. As well as overdrive water pump and supercharger. NST the only way to go IMO.

hPower

OK, so as far as engineering is concerned, this is what I have learned recently. Most of this information comes from the conversations I have had with Mike from www.NonStopTuning.com on AIM, his screen name is NSTonAIM and he is great about giving out information. I suggest you talk to him if you have questions. Strap yourself in because this is going to be a long reply!

Basically, there are several benefits to be had with aftermarket pulleys.

1. They are much lighter than stock. Less weight means more throttle responce. You slap on a pulley (or set of pulleys) that is lighter than stock and you will see your car revving up faster and easier. Both NST and ZPI pulleys are lighter than stock and their benefits can easilly be seen on the butt dyno.

2. Underdriving. Some crank pulleys underdrive accessories. Underdrive means to slow down. An underdrive crank pulley will send less power to the accessories, and thus free up some extra horsepower that can be sent to the wheels instead. This is how you see extra WHP on a dyno. Underdrive is truely the way to go if you want more power at the wheels. NST crank pulleys underdrive, ZPI crank pulleys do not.

A properly designed underdrive crank pulley will slow down accessories to a point where they will still function properly and not loose any of their power. NST spends a lot of time and money on R&D so lets give them credit, they are not going to sell you a product that will make you not want to come back to them.

3. Overdrive. Very few companies right now, NST being one of them, are building overdrive pulleys like the ones you see for our alternators. Overdrive mans to speed up. By speeding up the alternator, an NST pulley will bring the alternator up to charge faster than a stock pulley would. This means the alternator will work more efficiently and will charge easier. People with stereo systems and extra lighting mods will love a pulley like this.

So that is the engineering disscussion you wanted. If you have more questions ask me and I will help you if I can. Or go to the source and ask for youself, www.NonStopTuning.com

sensay

some people like scionbandit talk about how crappy the zpi pulley is. yeah the V1 had problems, thats why it got replaced with the V2. The bad pulley that scionbandit had was the V1, you cant even buy those anymore, so his review and negative opinions of them should not reflect the V2's which are stronger and 20% lighter than the already lightweight V1's. They were completely redone with a new company, all the quirks were worked out, and were made 100% balanced/ defect free in the proccess.

being why i just bought one an hour ago

Simplyscion

wow...that was one serious post hpower
I dont think I coulda said it any better myself. The one thing that you gotta love is mike is always on line waiting for a bombardment of questions Thanks Mike
They put out some of the best pulleys I have seen, and I dont think I have run into one company out there in my years of driving that can compare to NonStopTuning in the customer care dept. If you are rockin any of there pulleys on your car, I can almost guarantee that you dont have one complaint...I also think they have a few things up there sleeve for the upcoming months

edit: I just wanted to let everyone know that I dont work for Non Stop Tuning but I really think that customer relations is very important in this industry and flawless products will always take the cake in the end.

wc01

are there any adverse effects on having a lighter crank pull with the same circumference.does it effect idling,will it wear any bearings inside the engine,does it reduce the life of the engine.i just wanna know because im interested in getting a lighter crank pully instead of a underdrive pully. i just want to know the good and bad of having a lighter crank pully.besides freeing up some hp to the wheels

dp-_-

I will be installing the NST pulleys (all three) tomorrow....we shall see!!!

Sam_J84

yup, Mike is a cool guy. i have met him personally and talk to him frequently on AIM. he can practically answer any question about performance parts you throw at him. he definately knows what he's talking about when it come to pulley's. he's been R&D pulley's for years. I had the first underdrive crank pulley that NST ever made for the tC, and till this day i have yet to have one single problem. no flaws at all, the pulley was solid and very well made. also the first to have the overdrive alternator and the lightweight waterpump pulley. again, the pulley's were built with the same quality as the first. the 3 piece set is awesome and im glad i chose NST. i couldnt tell you anything about ZPI b/c i have never tried there pulley before. but from what i heard about there v1 pulley, i wouldnt go back to buy the v2. you can do a search on SL and a lot people will HIGHLY recommend NST. awesome customer service and perfect products. what more can you ask for?

DynomyteSW

i was informed by my mechanic that a pulley the same diameter as stock just lighter should be ok and that i should stay away from underdrive pulleys

wc01

does anyone here have just he lighter crank pully,not the underdrive.i want to see some feedback about the lighter crank pully

Typhoon

I will be getting one soon and if you are intersted pm me for details.

I know very little about pullys so take this as just my opinion. But i heard excessive underdriving will damage your accessories. Iam sure nst knows what they are doing though, lots of good reviews with them and their underdrive is not excessive. And to the people who are saying zpi pullies are bad they took action about that and got a much better pully, zpi is a top notch company as well. Id say go with w/e you think is best personaly i decided to go with zpi simply because i dont want to underdrive, and I will be turboing and def dont need the extra stress on anything in the engine.

ZPIracing

I am sure that the NST pulley and the ZPIracing pulley are both of the best quality that you can get. We are very proud of the V2.0 pulley and the quality that it represents. I can assure you that the quality is top notch and that these are in stock with same day shipping.

We have seen .4 quicker ¼ times with these pulleys and as you can see there is a lot of support with this product and hundreds of happy customers. I am sure that you will be happy with either choice I am sure that it comes down to under driven or stock sizing.

-Kenny

yamaha16bw

My ZPI V.2 was shipped today so I will give you my opinion soon.

wc01

look forward to your opinion^^^^^

sensay

mine will arrive later this week, so there are gonna be dual opinions on this one baby