Underdrive pulley

[Petrus]

I mean not output a higher voltage than the battery, so the car will be running off the the battery not the alternator at idle and the battery light will come on, no?

Ok, I understand now.

Because I have a silly light mini battery that is sensitive to overcharging, I fitted a Volt-meter:



As such I have had an eye on the voltage for the best part of a year.
Even immediately after starting, with the revs at normal idle it is at 14.2 Volt without any users and with main lights on 13.9 - 14.0.
Lowering/raising the windows with the light on does not drop it under 13.8 at idle.
The thing is that it needs only charge very little and the regulator can simply put more current through the stator.
I don´t expect any issue and íf I would be at a traffic light in the dark with blower on, or what; too much drain from electrical users, I can simply raise ´idle´ with the right foot.
But.... we will see soon enough ;-)

[Petrus]

The pulley is in.
Will do it at the garage as an air tool will make light work of what manually can be herculean, so next week.

[shnazzle]

I mean not output a higher voltage than the battery, so the car will be running off the the battery not the alternator at idle and the battery light will come on, no?

Ok, I understand now.

Because I have a silly light mini battery that is sensitive to overcharging, I fitted a Volt-meter:



As such I have had an eye on the voltage for the best part of a year.
Even immediately after starting, with the revs at normal idle it is at 14.2 Volt without any users and with main lights on 13.9 - 14.0.
Lowering/raising the windows with the light on does not drop it under 13.8 at idle.
The thing is that it needs only charge very little and the regulator can simply put more current through the stator.
I don´t expect any issue and íf I would be at a traffic light in the dark with blower on, or what; too much drain from electrical users, I can simply raise ´idle´ with the right foot.
But.... we will see soon enough ;-)

I can tell you what REALLY pulls power; a subwoofer  


It's hilarious watching my volt meter in my clock and then playing a song that has random bassy moments. I can get it to drop as low as 9v with high bass and volume. If I turn on my seat heating on both seats, all lights, fan on full, and activate windows while playing loud bass music, I managed to get the battery light to come on hahaha.
Good times.

[Petrus]

It's hilarious watching my volt meter in my clock and then playing a song that has random bassy moments. I can get it to drop as low as 9v with high bass and volume. If I turn on my seat heating on both seats, all lights, fan on full, and activate windows while playing loud bass music, I managed to get the battery light to come on hahaha.
Good times.

Seen mý head unit?





and no woofers nor yeppers in the doors either (got four running around)    :-)

[Petrus]

Fitted. Sofar no difference seen on the Volt meter.
Idle; fan on, lights on, window up/down; no effect, stable as a rock.

[shnazzle]

So, conclusion? 
Something we should do or not? 
Guess it puts less strain on the alternator if yoy rev it a lot (i.e. Me)

[Petrus]

So, conclusion?
Something we should do or not?
Guess it puts less strain on the alternator if yoy rev it a lot (i.e. Me)

Í have done it and would do it again.
Depends entirely on whether you nééd the maximum output. If not, go for it.
If you rev it a lot, it is a no brainer imo as above 3K the alternator is spinning more than it needs as max output is reached on the standard pulley.

Changing is a job not worth that name íf, big IF, you use an air tool.
And you need a 5cm longer belt.

[shnazzle]

So, conclusion?
Something we should do or not?
Guess it puts less strain on the alternator if yoy rev it a lot (i.e. Me)

Í have done it and would do it again.
Depends entirely on whether you nééd the maximum output. If not, go for it.
If you rev it a lot, it is a no brainer imo as above 3K the alternator is spinning more than it needs as max output is reached on the standard pulley.

Changing is a job not worth that name íf, big IF, you use an air tool.
And you need a 5cm longer belt.

I've already destroyed one alternator, just wondering if I should spare this one a bit. 

As for install;
Just a case of belt off, carbon canister out, undo bolt on pulley and replace? I can see how an impact gun would be required here unless you remove the right motor mount which wasn't fun last time I did it

[jonbill]

Fitted. Sofar no difference seen on the Volt meter.
Idle; fan on, lights on, window up/down; no effect, stable as a rock.

Surprised, but win! Even if its a small one

[Petrus]

I've already destroyed one alternator, just wondering if I should spare this one a bit.

As for install;
Just a case of belt off, carbon canister out, undo bolt on pulley and replace? I can see how an impact gun would be required here unless you remove the right motor mount which wasn't fun last time I did it

It is a véry good idea for making life easier on the alternator indeed.

Yes, correct. As simple as that. In my case even simpler as I have the canister out.
The impact gun also undoes the nut like a treat which by hand may be not even póssible with the alternator mounted.

I

[Petrus]

Fitted the 130/90 headlight bulbs.

Started up. Let the idle settle.
Voltmeter reading 14.2V
Switched on lights. Voltage drops to 14.1 and resettles at 14.2.
Switch on mains dipped. Voltage drops to 13.9 and settles at 14.2.
Now large. Voltage to 13.6, settles at 14.1 then 14.2.

I had roughly worked out that it would work,  but it still is tense butt till it does.
I mean;  0.8 kg mini battery, high wattage bulbs, underdrive alternator pulley...

[Petrus]

Done some night distance with the 100 Watt lights on and there is no issue.

Did notice a difference now. The smt blipping the throttle on the downshift is noatably more brisk.

All in all still a thumbs up!

[shnazzle]

I feel I should. But... That's a lot of money for a pulley. Too much.

[Petrus]

I feel I should. But... That's a lot of money for a pulley. Too much.

Well, I agree but... it is not for the pulley; it´s for the effects: Forget about the difference when shifting, just think about the reduction of the load on the alternator.

[tom256]

https://www.ebay.co.uk/itm/VMS-Racing-Light-Weight-Aluminum-Crankshaft-Crank-Pulley-1-8-Corolla-Celica-MR2/292765028911?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D225076%26meid%3D50f99fb17f7a4a61852f86b96bac17d0%26pid%3D100970%26rk%3D6%26rkt%3D15%26mehot%3Dnone%26sd%3D362126773729%26itm%3D292765028911%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100970.m5481&_trkparms=pageci%3A59ce9f1b-53e9-11ea-b263-74dbd180ae39%7Cparentrq%3A62e65b231700a128ed37fa1bffcf15ec%7Ciid%3A1


What about this lightweight aluminum crankshaft pulley?

[shnazzle]

Dangerous territory there. 
That's one of those mods where you'll enjoy some quick revving, until the off-balance finally screws things.

The lads at High Performance Academy did a whole seminar on it. 
It's one of those things where if you do it you have to do it right. And right = expensive

[tom256]

Dangerous territory there.
That's one of those mods where you'll enjoy some quick revving, until the off-balance finally screws things.

The lads at High Performance Academy did a whole seminar on it.
It's one of those things where if you do it you have to do it right. And right = expensive

I just found this thread, but I'm still looking for Yours opinions.

https://www.toyotanation.com/threads/2005-corolla-1zz-fe-light-weight-crankshaft-pulley.1571482/

I'm going to stay with MR2 for a long time.


@edit

Official site:
https://www.vmsracing.com/products/copy-of-subaru-impreza-wrx-sti-light-weight-aluminum-crankshaft-crank-pulley-oem-size

[Petrus]

As with an underdrive alternator pulley it does nót increase engine output one bit.

Unlike an underdrive pulley the OEM crank pulley also has a balancing function.

It must however be noted that the word on the more knowledgable fora is that the 1ZZ can be fitted with a lighweight one whereas the 2ZZ can not. Personally I find the ´data´ under the latter conclusion even softer than the pre-cat damage info.

I checked the thing on mine being a harmonic damper or not and it is not much of one. The thin rubber bonding layer is thin and the outer righ rather light. It will do very little if anything at all on the 1ZZ.
Here a clear illustration shamelessly nicked from the interweb




Anyway, I have not gone this route, yet. Need more info.
Any pointer to the HP Academy info Patrick?

[Petrus]

Just as a footnote: I think lighter/underdrive pulleys rather cool ´tuning´ gadgets by principle.
They do not generate/liberate any more power from the engine. Ok, the water pump impeller going slower meets less water resistance but that is negligeable.
Yet on the Dyno is does register more power.
Same thing on the drag strip.

Both the Dyno and the drag strip are accelero-´meters´ and in that the reduction in rotational mass doés count.

So no they do not do anything to add power, they do however the equivalent by reducing rotational mass. Reducing say 1,5 is that ánd that times engine rev ´delta´ 

[Petrus]

Anyone with more data on the balancer or damper aspect?

Read about several pulleys going wobbly because of the rubber bond layer starting to go. Nothing odd as it is 15 year plus old rubber now.

Both the VMS one in OEM size and Cosmo underdrive version are still availeble.

Still cool ´tuning´.

[Petrus]

Meanwhile ordered the VMS pulley.

For explantion see also https://www.mr2roc.org/forum/index.php?topic=69358.0

[Petrus]

For those, or the one, interested in the plus or minus of the harmonic pulley there is another thing to take into account:
There is a whole lot of weight being pushed and pulled around by the pulley by means of a belt. How´s that for a harmonic damper ;-)
Now switch on the a/c and bear in mind the force it takes to drive it.
Ditto a lighter underdrive alternator pulley or a twice as heave decoupling one.
All in all, when we start modding the car, the harmonic argument becomes a moot one.

[Petrus]

The lightweight crank pulley looks véry well made and is some 1.2 kg lighter.

You cannot view this attachment.

[shnazzle]

https://youtu.be/J1BGsgIZ_Ek

And the associated blurb.
http://www.atiracing.com/products/dampers/101/index.htm

Now, grain of salt of course because of who wrote this but the reason I knew where to look is because of the sheer amount of random engine builds I've seen online and how many of those use this specific damper.

Funnily enough, they make one for 2zz.
Might be one for the track peeps

[Petrus]

Funnily enough, they make one for 2zz.

Also informative. The 2ZZ already hás one so they are basically underlining that tuning shifts/cahnges the requirement. The Toyota one is a wide band design so íf it would need replacing than the shift is considerable.
With the 2ZZ though, it is a bit mwah as the engine will not be asked to run at the same revs for long and rushing up/down through the revs does not require such a rev specific damper.

Going down to the coast in a moment.  Good comparative trip.