Overrunning alternator pulley? - NewCelica.org Forum
Install Guides Parts Catalog Gallery Tech Info

Go Back   NewCelica.org Forum > Celica Discussion > Fabrication Forum

Fabrication Forum Welding, metal working, and general engineering of parts

Support NCO
Thread Tools Display Modes
Prev Previous Post   Next Post Next
Old 08-23-2014, 09:55 AM   #1
Join Date: May 2009
Location: Chicago-south
Posts: 8,246
iTrader: (10)
Overrunning alternator pulley?

Does anyone know the shaft and thread dimensions (length and diameter) for a GTS alternator? Letting the alternator freewheel when it's not driven is very beneficial to belt and tensioner life, it's also a small boost to engine efficiency, and best yet reduces spinning mass on engine deceleration. The alternator rotor and shaft is typically about 90% of the weight of the alternator, so for ours it would be about 8-10 lbs of mass spinning at roughly 3x crank speed due to pulley ratio! That's a lot of energy to slow down each time you want to change gear. I'm a little light on math to figure the moment of inertia and how many lb/ft of stored energy that is,but if you've ever spun an alternator by hand and then stopped it by hand you can feel it's got some serious heft just at 100rpm, now imagine at 20,000 RPM!

I'm trying to figure out if there's a cross from a commonly available pulley to fit our alternator, I'm hoping maybe a later model Camry/Corolla uses the same alternator innards and shaft size so it's just a direct swap over. The pulleys for a 2010 Corolla are about $50. I have no idea if it would make any appreciable difference however EVERY new car is using them so there must be some benefit to offset the cost and enough for the bean counters across the industry.

From the rebuild procedure outlined in Alldata the shaft of a 2010 Corolla alternator looks like it's externally threaded and tapered like a standard alternator shaft. If anyone knows the dimensions of ours I can get the dimensions of the 2010 Corolla or other models from one of my suppliers at work as they'll be likely to have that stock on hand, but unlikely to have on hand the stock for a 10yr old sporty coupe/rare corolla model.
2000 Celica GT-S 'slowest GT-S evar'
1998 Mazda 626 FS-DE/CD4E 'mom-mobile'
Originally Posted by JCMiller View Post
I'm gay
Originally Posted by soundman98
no, don't even waste your time. if you want a honest sticker, at least get one that says "objects in mirror aren't really racing, so quit trying"...
Bitter is offline   View this Members' Photo Gallery Reply With Quote


Thread Tools
Display Modes

Go Back   NewCelica.org Forum > Celica Discussion > Fabrication Forum

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

All times are GMT -7. The time now is 07:15 AM.

vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.