The 80 amp alternator with stock pulley from my 90 model NA weighs just under 5 kg.

Not dry sump no (that would be nice though), vac pump is going on. I have more ancillaries on the engine than anyone else has ever had i think :(
 
If you're not running power steering you could definitely run something as small as James said. Especially if you are using some good dry cell batteries as well.
 
Being a street car i want it all and it costs you in weight thats for sure! this car still has a/c too (thats a whole other thread that one)
 
If even the non power steer car has a 5kg alternator then there are a few kg gone in alternator itself using aftermarket the same capacity, or even more if i dropped to a 90A for instance. But also the alternator bracket being thrown in the bin too.

Yeah biggest saving will be the bracket for sure. 
 
I will be running a smaller alternator then the 100 yes.
 
From factory, can the 80 and 100 be swapped? or do they have different thickness mounting?
 
Ian are you able to measure the thickness of the bottom mounting tab/bolt location? The 100A i have is 58mm.
 
Suppose smaller output will be same or smaller if anything, can always shim it out with some washers.
 
BTW the same manufacturer/design/technology alternator ect on the same car, the 100A wont have any more load on the motor then the 80A
 
Another trick is to turn off the alternator (cut the ign wire to it) to stop the load on the motor when required (during short runs or TPS over 95% ect) and gain a few KW's, but thats a different topic.
 
Ill be keeping the alt in the factory location, no vac or dry sump pump, dry sump would be nice but alot of weight, more connections and parts mean more things to fail ect, ill test the car, if i dont need it i dont need it.
Only spot to relocate is AC location i guess, but much hotter and higher COG.

Hmm ill see if the various celica alts I have a dfferent amps. If so ill weigh them.

I think ill start a thread is on vac pumps. I was just looking at them this week but no idea on the gains are to be had.

What sizes did SW20s come with? was 80 the smallest or was there a 70 or 60?
 
Having a look, theres a few models that have the same mountings, thread size, pulley size ect, some just have diff plug, no big deal, so can easy get 60 and 70A, wounder how much they weigh

I think one of the US SW20 models came with a 70A alt. The lightweight alt bracket racerx makes comes with a washer/shim so you can use the smaller alt.

That would have been on a 5sfe i guess.
 
If only this ebay store had weights next to all these alternators:- http://stores.ebay.com.au...0.m14.l1513&_pgn=2
 

WIDEMR
Yeah biggest saving will be the bracket for sure. 
 
I will be running a smaller alternator then the 100 yes.
 
From factory, can the 80 and 100 be swapped? or do they have different thickness mounting?
 
Ian are you able to measure the thickness of the bottom mounting tab/bolt location? The 100A i have is 58mm.
 
Suppose smaller output will be same or smaller if anything, can always shim it out with some washers.
 
BTW the same manufacturer/design/technology alternator ect on the same car, the 100A wont have any more load on the motor then the 80A
 
Another trick is to turn off the alternator (cut the ign wire to it) to stop the load on the motor when required (during short runs or TPS over 95% ect) and gain a few KW's, but thats a different topic.
 
Ill be keeping the alt in the factory location, no vac or dry sump pump, dry sump would be nice but alot of weight, more connections and parts mean more things to fail ect, ill test the car, if i dont need it i dont need it.
Only spot to relocate is AC location i guess, but much hotter and higher COG.

Given the same loading the alternator will not load the motor any more.  If you are going to turn the alternator 'off' by disconnecting the excitation current you'll certainly want to make sure sure all your trims are tuned correctly.   Fuel pumps and injectors do not operate the same at the reduced voltage, even if it is only a few volts.

For factory size options for guys Ill have a look at some alternator catalogues when im down at dads old shop soon, see what has weights, altho doubt they will be accurate. Just had a look at one site i know i have a cat for, it does show weights, but again single digits weights, hard to compare, prob just shipping weights. 
 
Looking at Denso, factory size specs, shows a 70A at 5kg (Ians says his 80 was less then 5kg) and a 100A at 6KG. 
 
like very very common Sv21 camry http://www.pinpoint.aea.com.au/Guest_pc_alt.aspx?pn=ALT1091&id=5072&ptbl=Alternator 
Hole centres i think are 1mm out, shouldnt matter on factory bracket, deff wont matter with racer x light bracket which has rose joints and threaded rod. Battery stud is on the side (boot side)
 
Need to get a 80, or camry 70 and a 100 or other alt and put them on the same scale, not different ones all around the world. 
 

Also a smaller output alternator will have smaller and, generally, lighter rotor, meaning less reciprocating mass, light weight fly wheel lovers will be all over this, so will spool up faster.

 
Under load tho i dunno how its affected.