PERRIN_ADAM

Just a couple points about the crank pulley we produce for the Scion xA and xB.

The factory pulley does NOT include a dampner to prevent vibration. It is made from two pieces of cast steel then pressed together with a rubber band in between. This is done to make up for the inaccuracies of this factory part and keeps costs down. Ours is precision cut from virgin 6061 aluminum to higher standards. This eliminates the two piece necessity. Your belt life will actually be longer with our pulley than with the stock pulley. (Look under your hood at the belts on the crank with the engine running. You will see the belts moving from side to side. Ours doesn't!) There is no dampner on the factory pulley!

The timing alignment for the entire rotating assembly is not at all affected by the crank pulley. A gear is placed over the end of the crank (near the pulley) this is referenced to marks on the block etc. when looping the timing set to the cam set etc. Nothing about the actual pulley has any affect on this alignment. PERIOD. Also, the direct fire ignition found on the engine eliminates any need for timing marks ont he pulley for a timing light etc. All timing changes are done electronically and not adjustable externally from the ECU or engine.

The lightened pulley will allow faster acceleration of the rotating assembly, thereby netting additional horsepower and throttle response. HP gains will vary but expect 3-4 on most applications. Aftermarket forced induction engines will see higher gains. This is an excellent, economical alternative to flywheel removal and lightening. The "do-it-yourselfer" can do this at home with basis tools. Try that with the flywheel! (NOTE: can certainly be used with upgraded flywheels for maximum HP and TRQ gains.)

As always please let me know if I can help in any way further. To order simply call us or any other authorized PERRIN™ dealer. Thanks again!

Munch

Thank you for clearing everything up PERRIN ADAM. I decided to keep my XB till next year so I ordered one of your pulleys and the fuel rail. I'll let everyone know how the car feels when I get around to putting them on .

PERRIN_ADAM

Great! Glad we could help. Keep us posted and let me know if I can help further!

Minsk99

Thanks PERRIN ADAM. Very informative! Always nice when someone shares informations in a constructive way. I'll probably be ordering one of these real soon.

Munch

No problem I'll do just that

Minsk99

Hey PERRIN ADAM. Another quick question for you regarding this pulley. This may have nothing to do with what you were referring to above, but wanted to make sure I know what's up before putting this in. I took a look at the stock pulley and it appears to have a white "timing" mark on it (see red arrow on the picture). The xB service manual says that this mark should be used to align the cam to TDC by aligning it with the "0" on the chain cover marker (see blue arrow on the picture). Anyways, I couldn't see from the picture of the Perrin pulley if it has a timing marker like the stock one. Is this different from the type of "timing alignment" that you were referring to above?

PERRIN_ADAM

There are several ways of orientating the cams to the crank. If you choose to use the crank pulley to help with this alignment you can mark the new one in the same location when installing the PERRIN one. A dial type indicator is a better way to measure and align cam to crank timing. In nearly all cases you will have the crank pulley, as well as lower cover off when doing a t-belt replacement. Most will align the lower gear to a point on the block or use the aforementioned dial indicator to find true TDC.

Thanks again! Let us know how we can help further!

Back_In_Black_xA

You don't even need any kind of timing stuff to put a timing chain on a Toyota. A new chain has 3 yellow marks on it. Every gear on the engine has a dot on one tooth of it. All you do is line up the yellow marks on the chain with the dots on the gears and that is it. It's idiot proof.

As for this lightened pulley I don't understand how weight of a pulley makes any difference. The pulley is directly attached to the crankshaft. I would think the comparatively massive weight of the pistons/rods/crankshaft would greatly offset any reduction you could make in the pulley. I can understand how a different sized pulley would create power since that is like changing gear ratios in a transmission. But same sized and just lighter I really don't get, gains in power would be very minimal.

PERRIN_ADAM

the reduction in weight on the rotating assembly. Just like any accessory on the engine the weight of the crank pulley is taxing the engine. As you reduce the weight of the crank pulley, piston, con rods, crank shaft, etc., HP and TRQ will be increased. Race engine builders take special care to remove as much weight from the rotating assembly without compromising the integrity. For the rest of the world an easy way to increase HP is to remove weight from the crank pulley and flywheel. You also get the additional benefit of improved throttle response.

If we can answer any other questions please just let us know!

Kong

Do you have the instruction of how to install it?

Thanks.

TOAST3R

ya im wondering this too. it seems easy but instructions are always good. i was thinking of just paying a shop to do it.

bdonscion

So from the sounds of it, the HP gain will not be at the engine/crank. The gain will be at the wheels. Not so much gaining engine horsepower, just letting the ponies run a little more, kind of like an exhaust doesn't increase engine/crank HP just lets the car breathe better for more wheel hp. Is that Right?

xtremeOrange

Now I'm confused... I thought that installing lighter parts of the same size was just for the purpose of reducing weight... isn't that what this pulley will do? It reduces the weight which means the power-weight ratio is higher, as there is less weight for the same amount of power to move.... When I installed the carbon fiber fenders on my '68 Bug, yet retained the 1600cc stock engine it certainly scooted a lot faster, but not because lightening it added power, there was just less weight to move. Wouldn't the principle be the same behind a lightened, yet same-sized pulley?

the_saint

In order for there to be a gain at the wheels, there has to be an even greater gain at the crank. HP is lost through the drivetrain since it uses HP to move those parts too. Now by lightening the pulley, the engine uses a little bit less HP to spin the engine, so the HP freed by the lighter crank can be moved on down the line to the ground. But ultimately, the pulley does not "generate" horsepower, it merely "frees" some up (if that makes any sense :? ).

As for personal experience, my buddy put an Unorthodox racing pulley on his impulse and it made the car "feel" quicker. We were (are) po' boys so we never had it officially dyno'd, but the un-official "butt dyno" noted an improvement.

*I can't remember if the unorthodox pulley was underdrive or not, but I do remember it being lighter than stock

Minsk99

In the coarse of doing some research on crank pulleys / dampers I came across an interesting article on the oVerboost website. They bring up the question of harmonic dampening and its importance in maintaining engine performance. In fact, if you check out the xB service manual they refer to this part as the Crank Damper (rather then a pulley). It seems like one of the reasons that OEM crank pulleys are typically heavy and have rubber either behind or between the parts is to reduce or dampen the harmonic vibrations that radiate from the crank. Perhaps this is the reason that the OEM pulley on the xB/xA has the rubber piece pressed between the two metal ones? Anyways, below is a link to the article I was referring to. Interested in what others think on this.
http://www.overboost.com/story.asp?id=1283

scionxb04

the perrin pulley does not dampen harmonic vibration...dont run it....

Back_In_Black_xA

Well the reason you have a damper on the pulley is because unless vibrations are eliminated you are shaking the hell out of your bearings which will cause them to wear faster. However a lot of the engines today are internally balanced and don't require that much from the pulley.

It sort of makes sense on the theory of unsprung weight, as in lighter weight wheels will be easier to turn so the car will be "faster." However why wouldn't it be like a flywheel and when you lighten the flywheel you get more responce and more HP but you lose torque. I wouldn't do anything that would make an engine lose any torque on a little 1.5.

rotarycolt

You dont lose torque, you lose momentum.

papi4baby

Guys the pulley does not give you horse power, it free up horse power the the engine naturally had, just was being consumed by the pulley since it is heavier it takes more energy to spin it, with the lighter pulley, the engine uses less energy thus power send to the tranny, and then to the wheels.

Munch

That is correct. The same priciple goes for the lightweight flywheel