So ... I have a leaking water pump gasket and decided to do a little "overhaul" and replace the drive belts, timing belt, etc.

With that being said, I was thinking about upgrading to T3's lightweight alternator pulley, waterpump pulley, and crank pulley.

Does anyone here have any experience with them?

I know there's always some debate about crank pulleys and being balanced and what not but 4ag's are balanced internally, my motor is bone stock, and will most likely never see the track and/or be built to any kind of race applications. T3 claims they're balanced and tested the pulleys up to 11k rpms

My thought process is, if I have to take that stuff off anyways, surely shedding some weight would be a quick and easy way to gain a little extra power, right? I still have AC and PS, but the AC doesn't work so I might take off the compressor too.

I have their single row crank pulley and it is great. I think NST was having a really good deal on pulley sets recently too though.

I seem to remember a debate longgg ago from another chassis forum about lightweight pulleys. The obvious claim was that a lighter pulley would in theory mean that the rotational mass, and thus friction from the pulley would be reduced, and less of a load on a pulley and less of a load transferred would mean an increase in power as the final result (I guess the opposite of running your A/C in comparison of load-bearing).

However I also seem to recall that there were in fact negative results when installing lighter pulleys. I can't remember exactly why, and this was not T3 or a 4AGE, and that had dealt with harmonic balancers; but I'd do a little research. T3 is a good company and they test their stuff personally, so that alone would probably be a good indicator, but ~150 USD plus shipping per pulley is a huge chunk a change in my eyes for something that isn't really that much of a gain.

I'd start by testing your alternator, looking at current draw and loss, and going from there. If you're alt. is stock, it'd be better and more practical to replace and upgrade it to a higher amp..

Just my two cents

I remember seeing a discussion similar to that. I also heard that you would want to reduce weight at the flywheel equal to the amount you reduce your crank pulley for symmetry. If one is heavier than the other you might increase wear or something like that.

CloudStrife wrote:I seem to remember a debate longgg ago from another chassis forum about lightweight pulleys. The obvious claim was that a lighter pulley would in theory mean that the rotational mass, and thus friction from the pulley would be reduced, and less of a load on a pulley and less of a load transferred would mean an increase in power as the final result (I guess the opposite of running your A/C in comparison of load-bearing).

However I also seem to recall that there were in fact negative results when installing lighter pulleys. I can't remember exactly why, and this was not T3 or a 4AGE, and that had dealt with harmonic balancers; but I'd do a little research. T3 is a good company and they test their stuff personally, so that alone would probably be a good indicator, but ~150 USD plus shipping per pulley is a huge chunk a change in my eyes for something that isn't really that much of a gain.

I think that is geared towards American V8 motors. Most v8 crank pulleys are referred as harmonic balancers, because that is what helps balance the crank and all that. Everything is balanced individually and internally with our motors, I think. Our crank pulleys dont have weights on them like v8 motors. Regardless, like you said T3 is a good company and I highly doubt they would sell something that's not proven to work.

I see where you're coming from on the price though, that's why I'm posting on here asking for feedback haha the main attraction to me is everything will already be exposed when i change the water pump and the belts.

aukword1 wrote:I remember seeing a discussion similar to that. I also heard that you would want to reduce weight at the flywheel equal to the amount you reduce your crank pulley for symmetry. If one is heavier than the other you might increase wear or something like that.

I can see theoretically how that would be an issue, but on the flip side mine isn't a race car Lol. I don't imagine cruising around town on the weekend or an occasional late-night tofu delivery run would do too much damage haha

Yeah, no worries. If I'm doing a bunch of labour pulling parts, I like to replace as much as possible too.

I'd just look for second-hand lightweight pulleys. Damn things are always for sale, people build up the stock 16v and then ditch the motor for a swap. Usually the powder coating or anodized finish will come off a little, but it'll be much cheaper for the same hunk o' metal.

Oem crank pulley does have rubber so there is prob some damper affect. This has been much debated and is prob negligible. Its down to the end user using a solid pulley.

Other than that t3 uses and underdriven (larger) water pump pulley than stock, iirc. Good at the track but may not be ideal on street. Again fairly negligible.

I've looked into the lightweight crank and accessory pulleys also, I decided against it in the end based on some horror stories I read on the 4G63 mitsu forums about having a lack of damping in the aluminum crank pulley wreaking all sorts of havoc on their highly tuned interference turbo engines. Granted the 4A is not anything close to a 4G63, I still decided to play it safe. Although I believe Manon Racing Products, out of NZ or Aus I forget which, has a stock style dampened aluminum crank pulley. I'd lean towards that option over just solid metal personally. Toyota engineered the crank pulley with a rubber damper for a reason is my thinking.

Some great info/discussion here. I agree with both Deuce and GZE, however I would say that since we can't really test the OEM pulley vs T3 light pulley as a control and variable (without some weird centrifugal force machine that records NVH), I'd say on merit alone what they sell is good enough. Those guys I'm pretty sure daily their cars and go back and forth between hard driving and daily routine.

The only way to know for certain however, is that you could always set up a test on your own, but like I said before the cost is not worth it IMHO. You talked about getting all three pulleys, which would be around 6-750 new. That is a lot of cash!!

Also, I used to be one who not only replaced everything when an extensive labour job came up, but I would find a reason to try certain or experimental mods. I've learned it's better to give the car what it needs first, and then try and fit mods on. You need a baseline of how the car performed before "upgrading" IMHO. It's kind of like when people have 30-year old rubber brake hoses, fit SS on, and then shout in joy, never have experienced the rubber hoses just being replaced. That's a whole different argument lol, but you see where I'm coming from?

Thanks for the responses fellas! All very good points and stuff definitely worth considering.

Deuce Cam wrote:Oem crank pulley does have rubber so there is prob some damper affect. This has been much debated and is prob negligible. Its down to the end user using a solid pulley.

Other than that t3 uses and underdriven (larger) water pump pulley than stock, iirc. Good at the track but may not be ideal on street. Again fairly negligible.

Good call! I didn't know that the crank had rubber. And yes, you are correct. The T3 water pump pulley is 18% bigger.



A little side note, I'm looking on NST's website right now and it looks like you can get a full 4 piece kit (two-row crank, WP, ALT, and PS pulley) for only $246, and 3 piece kits (no PS) for only $186. T3 is more expensive at $265 and its equivalent to NST's 3 piece kit, no PS pulley. Im leaning towards T3. Even though they're more expensive, they gave me the hookup on my Watanabe wheels so I gotta stay loyal.

Regardless, when rounding the numbers you're getting the whole pulley upgrade for less than $300, which isn't too bad.
Thats only like, 25 large roast beef max combos from Arby's Lol.

I have the T3 light weight pulleys on my BT 20v 4age. I also have the fidanza light weight flywheel as well. I have not had a problem with any of the parts so far. Alternator charges everything just fine and water temps stay in range. I will admit that my car does not have all the accessories that a stock GTS AE86 has. Other than that, the engine revs great!