90mm and 100mm aux idler ups and downs?

[FreddyFingers]

So I have a 100mm Steeda on my car and just ordered the metco 4 piece that comes with a 90. Besides the obvious size difference, what would be advantages and disadvantages of both?

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[bigmoose]

The only disadvantage of the 100 is it won't fit with a 3.1" pulley or larger. If yours is smaller than that then stick with the 100.

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[FreddyFingers]

Ok, yes, right now I'm using the 100 with stock idlers (changing to metco) with a 2.8 upper. I also am running a #2 lower and changing my alt pulley to a 3.2. Would the 90mm still give me the wrap I need?

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[cj428mach]

You should always run the larger idler because it slows down bearing speed and will increase bearing life. A 100mm idler doesn't work on larger upper pulleys if using a billet flow idler bracket as it put the pulley up closer to the blower.

 

[FreddyFingers]

Yeah more belt rap is def understood. Was really hoping there was going to be a more of an up somewhere for the 90mm considering it's whats coming with the metco 4 piece I just bought lol.

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[cmac29]

Yeah I had to switch my 100 to a 90 with the KB and a 3.5 on it. I also had to switch one of my Metco 90s to a metco 76 (i believe) when I put the 8lb lower and 3.5 alternator pulley. The belt kept walking fwd on the lower pulley.

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[FreddyFingers]

What I really can't believe is I've owned my car since 2008 and just now doing some of these upgrades. New alternator and clutch and rear gears all coming soon.

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[FreddyFingers]

Does anyone know if I can still use the 90 with success?

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[cj428mach]

Did you buy 4 90mm pulleys? or a set of 4 pulleys with 3 100mm and 1 90mm?

If you bought a kit with 100mm idlers and 1 90mm then the 90mm goes here.

 

[FreddyFingers]

Ahhh okay lolol. Now I feel like a terd lol. Yeah I got the 3 100s with the 1 90 and just assumed the 90 went closest to the supercharger.

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[Rambro]

I had to run a 90mm snub idler in place of the 100mm and no problems so far. The 100 would not fit with my RR 2.70 upper.

 

[FreddyFingers]

Knowing what I know now (thnx gents) what are your opinions on alternator amperage; I've been thinking changing to a mechmans but not sure whether to do the 170 amp or 240? Is the 240 overkill and would it get too hot under regular driving loads?

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[FreddyFingers]

Disregard last! I found a couple things in regards to that same question

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