Corsa-B.uk - Vauxhall, Opel and Holden Corsa B Owners Club

after some advice and help as i hant really been into the corsas that long. ive got a 1.4 8v corsa sri and its basicly built for audio, so as u can imagine theres alot of strain on the alternator.
its got a 100a alt on it but runs on the thin V shaped alt belt and is, i think, slipping.it only slips when the voltage is dropping down to low 13v/12v's. is there an easy fix for this or a way of running a wider and perhaps sturdier belt.?

is it tentioned properly? there should be about 13mm of play in the middle of the belt ( the longest section of belt between pulleys ).

as for fitting a bigger better belt the only way to do this i think would be to change the pulleys the belt goes round to puleys that would fit a belt you want but whether that would be possible i dont know.