under drive crank pully

[gtvibe]

i have an unorthodox racing crank pully and i have been unsuccesful installing it. i have taken it to a couple of shops with no succses. apperantly i need a speacial tool to loosin the tensioner. i asked a snap on tool guy and he had never heard of the tool...if there is any advice on where to go to get it installed or how to get my hands on the tool, it would be much appriciated. if any one knows of a place to take it around des moines iowa, that would be great

[BlueCrush]

Welcome to GenVibe! First, the guys at the places you are goingt to are idiots. releasing the belt tensioner is so simple a cavemen could do it. lol. I wouldn't trust a shop that didn't know how to do that. Your asking for trouble before they even start.Second, if you do have a Vibe GT as your username suggests, DO NOT install that underdrive crank pulley. Your engine may be good for a little while but eventually your oil pump will blow destroying your engine. The underdrive crank pulleys are a NO, NO for the 2ZZ engine.There have been people here on GenVibe, MatrixOwners.com, NewCelica.org and 9thGenCorolla that have tried the underdrive crank pulley on their 2zz engines. Most have had to replace the engine after 5,000-15,000 miles. Basically, by making the crank pulley smaller you are speeding up all the other pulleys. The oil pump just cannot keep up with the increased speed on the 2ZZ because it revs to 8000+/- rpm to begin with, and by increasing that speed even more, it WILL give out in a short amount of time. It's your car and you can do what you want, but I would seriously reconsider putting that on your GT. Good Luck with whatever you choose. As a side note: There have been no reported problems of using a underdrive crank pulley on a 1ZZ engine (Vibe Base & AWD). So, it is safe to use on that engine as far as we know.

[gtvibe]

hey thanks alot for that heads up you probably just saved me lots of money. im 18 and an aspireing auto technician and any info on how to get that tensioner loos would be much aprieciated. i tried a couple time but couldnt figure it out.

[micbarric]

Quote, originally posted by BlueCrush »Welcome to GenVibe! First, the guys at the places you are goingt to are idiots. releasing the belt tensioner is so simple a cavemen could do it. lol... "We protest that remark!!!"

[BlueCrush]

LOL! I was waiting for someone to post that.

[djb383]

I'm confused, which isn't hard to do, but wouldn't a smaller crank pulley slow the other pulleys down?

[Pablo1669]

Quote, originally posted by gtvibe »hey thanks alot for that heads up you probably just saved me lots of money. im 18 and an aspireing auto technician and any info on how to get that tensioner loos would be much aprieciated. i tried a couple time but couldnt figure it out.Yeah man, stay the heck away from those things.I was fortunate enough to know the right people at the dealership, otherwise it would have been nearly $9,000 in repairs.Can we make a warning on this page somewhere for those who are thinking of doing this?

[djb383]

More info on underdrive pulleys.http://www.stewartcomponents.c...1.htm

[joatmon]

I had no problem with the tensioner, it is just an idler wheel on a spring loaded arm. Find a socket that fits the nut in the center of the wheel, put it on a big breaker bar or ratchet, and either push or pull, I forget which. It will move the arm, and thereby move the wheel, and take the tension off the belt.and since several peole, can't remember if it was vibe or matrix, or both, had sudden engine death from oil pump malfunction attributed to aftermarket underdrive pulley on the 2ZZ, I really don't think the token HP increase is worth the risk

[Lancer]

Yeah, your right. I think Bluecrush had a brain fart (can we say fart?) The underdrive pulley is a tad larger and lighter then the stock crank pulley. And will cause the other accesory pulleys to run a little bit slower. They will also give better throttle response and let the engine rev faster (less rotational mass to get moving).But, that link is about water pumps and their pulleys. Underdrive CRAnk pulleys free up around 5-10 hp.Pulleys and a 2ZZ engine = BAD MOJO!Pulleys and a 1ZZ engine = little tiny bit more zoom zoom.

[djb383]

I think the point that Stewart Components was trying to make is they don't recommend under-drive pulleys for daily driven street vehicles.

[djb383]

Quote, originally posted by Lancer »Yeah, your right. I think Bluecrush had a brain fart (can we say fart?) The underdrive pulley is a tad larger and lighter then the stock crank pulley. And will cause the other accesory pulleys to run a little bit slower. They will also give better throttle response and let the engine rev faster (less rotational mass to get moving). Again, Im easily confused......you say the under-drive pulley is a tad larger than stock. Do you mean larger, as in diameter, and if that is the case, wouldn't a larger diameter pulley spin the other pulleys faster and act like an over-drive pulley rather than an under-drive?

[joatmon]

I would think that to underdrive the accessories, you want a smaller diameter pulley. At a given engine speed, the belt speed will be proportional to the pulley diameter.Say the pulley is spinning at 1000 RPMs, and has a diameter of seven inches. The circumference of the pulley is then 7 * pi, (because a rough approximation of pi is 22/7, and I want math to be easy, so that's what I'll use)That means that the full circumference of the pulley cycles around 1000 times a minute, so the linear belt speed is 1000/minute * 7" * 22/7 = 22,000 inches/minute.A 14 inch pulley would give you a belt speed of 1000 * 14* 22/7, or 44,000 inches/minute.So a bigger pulley would move the belt faster. To save power, you want to move the belt slower., so use a smaller pulley. It's like a ten speed bike. It';s a lot easier to pedal if you shift to the smaller gear up front, the larger gear in back.

[djb383]

Thanks joat, that's kinda what I was thinking but you said it much better.

[BlueCrush]

Quote, originally posted by Lancer »Yeah, your right. I think Bluecrush had a brain fart (can we say fart?) The underdrive pulley is a tad larger and lighter then the stock crank pulley. And will cause the other accesory pulleys to run a little bit slower. They will also give better throttle response and let the engine rev faster (less rotational mass to get moving). Really? Why does UR reccomend a belt that is the same length or smaller than stock with their pulleys when their alternator pulley is 5mm larger diameter than stock. The crank pulley would have to be smaller in diameter.

[goodvibe]

The stock GT pulley has a vibration damper that the aftermarket units lack. It's a needed component for the crank bearings and oil pump to last. Don't change it but if you want to reduce the size of the accessory pulleys, you'll accomplish the same thing without risk.

[kevera]

Underdriving/underdrive is slowing the speed of the accessories, or the driven component, from their original factory speed. Underdriving can be done in two ways. First is by increasing the diameter of the accessory pulley/s. The problem with this method is it increases the size of the accessory pulley/s which increases their weight. Weight reduction is the most important key to increasing engine performance and response. This method also eliminates the ability to underdrive the a/c, which is a tremendous robber of horsepower. The second, which we use, is reducing the diameter of the crank pulley. This allows us to achieve the best ratio of underdriving, and most importantly maximizes the reduction of weight on the crankshaft. This reduction in weight reduces the moment of inertia allowing your engine to respond faster to throttle inputs and perform better at all RPM's. This method also allows underdriving of the a/c we can maximize the performance of our kits by not leaving any accessories to rob precious horsepower from your engine.I would take BlueCrush's advice and knowledge on this subject.The crank pulley is smaller,So it spins FASTER.When you install a larger alt pulley,it rotates slower compensating for the crank underdrive.EDIT:Brian,you were right the first time.

[BlueCrush]

Quote, originally posted by joatmon »So a bigger pulley would move the belt faster. To save power, you want to move the belt slower., so use a smaller pulley.No wonder I didn't do so well in physics. lol. I was thinking the smaller crank pulley would move everything faster.None the less it is not recommended for the 2ZZ but ok for the 1ZZ as far as we know.

[djb383]

That's why they're called an under-drive pulley.......a smaller diameter crank pulley 'under-drives' or spins the accessories (other pulleys) slower for less load on the engine.

[goodvibe]

Oops, that right, larger accessory pulleys.

[TRD1zz00gt]

So are there any 1zz'ers out there that have a UR crank pulley bolted on for a decent amount of time that haven't experienced detonation???

[Lancer]

!Quote, originally posted by 13Vibe03 »Removing a few pounds from the flywheel or installing a lightweight flywheel would be a better choice!JessAutomatics don't have that option. So I went with the pulleys, crank and alternator. Loved them both until I got boosted!Sorry, couldn't find a pic of the stock crank pulley. But here's the UO crank pulley on a 1zz engine.

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[kevera]

That oil pan is sweet .How many quarts is it.

[BlueCrush]

Kev, Here is the Moroso oil pan info: http://monkeywrenchracing.com/....html

[Lancer]

Yeah, it looks nice but it's a leaky P.O.S.! Paid too much for it ($300). Was a pain in the booty to install (the flange is like 1/4" thick!) . And it's leaked through ALL of the plugs. The main oil drain plug got striped out and now still leaks oil (albet much slower with the self tapping plug). I go though about half a quart every 2-3 weeks.I'll get it fixed in the spring sometime when it's warmer. Only good thing is that, that side of the underbody and suspension aer well lubricated and don't have hardly any rust on it! Oh, yeah, it only holds one more quart over the stock oil pan.S'pose we should get back on topic before we get spanked!

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[djb383]

Are you running an oil pressure gauge and if so, what is your pressure @ idle and +/-3000 rpm? Thanks.

[Lancer]

Sorry, no oil pressure guage.