Underdrive Pulley

I've just ordered one of those, along with the 2ZZ water pump, the associated underdrive pulley for that and the longer belt.

MWR's site shows an independent dyno run that indicates a 3HP gain from using both of these pulleys.  I'm looking forward to that, should be noticeable.

I don't think 2% will be noticeable.

@pwnzor

The waterpump pulley is not a good idea on the 1ZZ nor does it bring any power.

The alternator pulley does not give ány hp. It onñy emasures more in a Dyno because those are acceleration banks. On a braked bank it would score zílch.

The positive effects are:

- less revs = less load/wear of the alternator

- larger diameter = more torque = less effort to turn the rotor

- less revs means quite a lot of less intertia. It calculates to about 2 kg. off the flywheel without the price in less smooth engine

In driving it is not really noticeable. The engine blips a bit more responsive and shifts quicker but it is best seen as marginal gains in that area.

Marginal gains though dó add up. It´s the same with a kilo here, two there; a bit of less turbulence here, less lift there; a horse here, two there. In all you end up with a lót livelier car. 

+or-3 is the margin of error of most dyno machines.  MWR have been know to publish dyno specs for their products that did not add up when actual users had them on a dyno.
They are like most speed shops where they will try to up sell you.  

@dev

make that every commercial enterprise, bar the exception.

Underdrive, overdrive pullies have their effect in gearing up or down.  That is nothing subjective. Whether the effect it x, y or ?? is not complicated either and for the rest it is caveat emptor. In other words; keep it OEM unless you know what you do.

regardless of the horsepower gain (or non-gain, depending who you listen to), I'd have made this switch.

Bottom line is it will require less energy to turn those pulleys, and it will increase the life of the components due to spinning them at lower RPM.  

These are very cheap modifications, and I don't see any possible downside to them.  Plus... shiny pulleys!

@petrus

"The waterpump pulley is not a good idea on the 1ZZ nor does it bring any power."

It's going on a 2ZZ water pump, not the stock pump.

Point is that the 1ZZ does not make the revs the 2ZZ does so there is not much if any issue with cavitation and slowing the pump down further reduces cooling capacity which is the not so good idea bit imo.

I think any negative effect will have to be measured and its very simple to do so.  If there isn't any then by all means keep it.

I personally do not like to under drive anything for a street application  with the rational that the engineers know what they are doing and a marginal increase or decrease might actually have some unknown long term consequence that I may not be aware of.  

 This holds true for a lot of modifications were a minor details can cause collateral damage somewhere else like the bearings of the component because it may not be balanced as well.   No doubt I am guilty with my own mods like my header wrap and some other stuff but when we go off the Toyota plantation nothing is risk free. 

What I am getting at is simply this.  If I were to take a chance on something It would have to have some decent gains where the risk would be salvageable, isolated to just the component and certainly not something  from MWR as they have a history of cutting costs when it comes to quality.  

@dev

I don´t disagree. OEM is the way it is for millions of yens of research reasons. Any improvent at whichever point will have a greater price somewhere else.  Now, as we and our uses, priorities, preferences are all different we will weigh the prices differently aganst the gains.  Another point to take into account is that Toyota engineers design for a wide fool proof band width of average users. On the issue of alternator output, even hálf the max amps would still be more than I need. Me getting away with a 0.8 kg. LiFe battery is an example. No way that battery would do for any commercially sold car. 

Oh, and I have weighed the pros & cons of wrapping and opted not to. 

Another biggie is my suspension choice (for the moment). Did a huge NoNo; cut some off the OEM springs.  But hey, I díd decide not to delete the ABS 😉

Right, now the TRD Sportivo kit ´dog bones´. Can´t figure out why Toyota though that só important. 

@dev

Posted by: @dev

not something  from MWR as they have a history of cutting costs when it comes to quality.  

 

Please elaborate on this.  I bought the cat pipe from them because Toyota wanted almost $1800 for it, and my mechanic found the same thing MWR offers at other distributors - only for at least $100 more.  So, in perusing the site, I found there are a lot of things available and decided on these pulleys, water pump and belt.  Can you cite any instances of low quality output from MWR?  I'd love to hear all about it before I have these parts installed.

Thanks in advance

Posted by: @pwnzor

@dev

Posted by: @dev

not something  from MWR as they have a history of cutting costs when it comes to quality.  

 

Please elaborate on this.  I bought the cat pipe from them because Toyota wanted almost $1800 for it, and my mechanic found the same thing MWR offers at other distributors - only for at least $100 more.  So, in perusing the site, I found there are a lot of things available and decided on these pulleys, water pump and belt.  Can you cite any instances of low quality output from MWR?  I'd love to hear all about it before I have these parts installed.

 

Thanks in advance

Can you post a link to the cat pipe.  

@dev

https://www.monkeywrenchracing.com/product/magnaflow-cat-pipe-mr2-spyder-49-state/

You should be fine with that. MWR will most probably have the retailer drop ship it to you.  
Magnaflow did have an issue with those but I believe it’s rectified now. Just hope it’s not old stock.  
Keep in mind that most parts from MWR is not their own and sold elsewhere. The stuff they get made that is sold by them is all ways suspect. Their used engines are suspect and so is their built performance engines including their workmanship. I know local members that were burned and many SC members by their workmanship and the parts that they get manufactured that carries their name.  
At some point it’s less about incompetence which has been their excuse and more or less cutting corners. They also tend to up sell like  80s high fi sales people.