Yeah, my MR2 belt needed to be pretty tight. I was running 12psi with a 165mm pulley on a 4A-GE, so you're going to need to run at least that ratio (from memory std SC14 pulley is 125mm, giving a ratio of 1.32:1) to get any kind of boost on a 3ltr.Originally Posted by fibrewizard
Ideally if you're getting a solid pulley made, get it made smaller, rather than a bigger crank pulley (unless you can have a dedicated belt for the SC, because otherwise you'll over-spin your alternator) but keep in mind that if you go too small you'll have trouble getting the belt to grip.
Nick had a 185mm pulley on his for a while, giving a ratio of nearly 1.5:1, which worked really well, but i think it started to run out of puff around 5500-6000rpm. If you're only going to spin to that speed, then a ratio of 1.5:1 is probably ok.
That said, you're going to want good belt coverage, and ideally I'd still go for a dedicated belt, because if you put too much tension on the belt for the alternator you'll kill the bearings, but the SC14 has a pretty solid bearing inside and can handle a bit more tension.
-RM.
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