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#1 |
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Who said Yaris was slow?
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[QUOTE=ChinoCharles;57109]You guys just won't get off this specific weight thing, will you? QUOTE]
No we won't!!! The porpouse of this mod is weight reduction... ain't that right?
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#2 |
![]() ![]() ![]() Drives: Black 2007 Yaris Liftback 1.5 Join Date: Jan 2007
Location: Memphis, TN USA
Posts: 252
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#3 |
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Banned
Drives: LB Join Date: Jul 2006
Location: OH
Posts: 7,787
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As I've stated before, in-hand estimation had me guessing the NST pulley is about 80% lighter than stock. If you guys want numbers, though, then numbers you will get.
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#4 |
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#5 |
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Gangsta
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#6 |
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Super Moderator
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#7 |
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Banned
Drives: LB Join Date: Jul 2006
Location: OH
Posts: 7,787
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OEM Toyota Pulley - 50.00 oz
ZPI pulley - 14.4 oz NST pulley - 12.5 oz The DIY has been edited to include this information. Thanks for your PATIENCE.
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#8 |
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Super Moderator
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#9 |
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Who said Yaris was slow?
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75% reduction
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#10 |
![]() ![]() ![]() Drives: Scion FRS Join Date: Aug 2006
Location: Arizona
Posts: 179
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i smell harmonic balance thread whatever coming around .___.
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#11 |
![]() ![]() ![]() Drives: 03 Toyota Corolla S modded, Join Date: Jan 2007
Location: LAS VEGAS, NV
Posts: 221
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can it improve fuel economy?
__________________
THE YARIS: TINY BUT PRICEY! BUT YOU JUST GOTTA LOVE IT....
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#12 |
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Any weight removed from the vehicle improves MPG. Simple fact.
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#13 |
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Banned
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#14 |
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Though I do agree with you that less weight is better for MPG, when were talking rotating mass, this is not true.
A crude explanation: as you start to decrease rotating mass by lightening things like the pulleys and the flywheel, MPG may suffer. The engine revs faster and once spun up it takes more gas to keep things going. Lower mass will take less time to dissapate the energy put into it. Toyota knows this and has designed certain portions of the drivetrain to take advantage of rotating mass for optimal mpg. The pullys are one of these portions. Gains or losses in mpg will be most noticeable on the highway. Around-town should remain the same or maybe get better. Maybe. The main reason for a possible decrease on the highway is that the RPM at which the engine wants to 'cruise' will likely be eliminated. This is due to a less efficient energy storage system. Anyway, wtf do I know. With only the pulley changed out and the flywheel the same, there likely wont be much change.
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#15 |
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Hey Chino... how is the idle? Notice any difference or have to make any adjustments?
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#16 |
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Banned
Drives: LB Join Date: Jul 2006
Location: OH
Posts: 7,787
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#17 |
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Good to know. Now where's my damn pully!!!
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#18 | |
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vroom vroom
Drives: lil red 5-door Join Date: Sep 2006
Location: Bangkok, Thailand
Posts: 7,744
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Quote:
BUT! In order to get the rotation up to speed, there is more inertia to be overcome (think of how much effort you spend spinning a small, light top vs spinning a larger heavy one), which is where more fuel is required. So, in this kind of stop-and-go traffic situation, less rotational mass can have a good effect on performance and mileage. Of course, the disadvantage of removing rotational mass in a 4-cylinder daily driver is the idle quality. The engine needs the heavy weight of the flywheel to keep it going during the 3 non-power strokes. So, when you reduce this mass, the engine will slow down between rotations, and at a lower engine speed (idling), this can make things very rough, even stall the engine. But, as I mentioned before, 80% (if not more) of the rotational mass in our engine/transmission would be from the flywheel, so a ligher crank pulley should not be such a big difference that it can cause problems. At least that's what my physics education tells me, I can't wait to see the effects for myself
__________________
The price of freedom of religion, or of speech, or of the press, is that we must put up with a good deal of rubbish. - Robert Jackson ![]() Bye bye 1NZ... |
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