First up, sorry if this is a repost, I did a search but couldn't find it.

Found this site by accident. It contains lots of information about performance mods for the Mitsu 3.0l SOHC engine (presume 6G72).

http://web.tampabay.rr.com/redroby/3liter/

Sweet site dude! Cheers!

even though i don't have one :cry: It'll hopefully be what i'll have within the next 12 months. Wicked site :thumbsup:

whats an underdrive pulley???

It's a pulley thats undersized. They're usually made of billett aluminium and much lighter than stock. Downside is that they're smaller so they can have negative effects of not spinning the alternator fast enough to adequately charge the electrical system. But this can be overcome by larger pulleys elsewhere...

I think though that would negate the effect. I would think that having a billet aluminium same size pulley would be the best bet.

Thats not the best explanation lol

hey killbilly....

This site also says that the throttle body is only 46mm.....?
I told you man!

I know it says that. In the US they used different sizes on the Montero's and things like that.

The Montero "truck" (as they call it) has a different intake setup and a different TB.

Our ones are much bigger. They're closer to 60mm.

It's a pulley thats undersized. They're usually made of billett aluminium and much lighter than stock. Downside is that they're smaller so they can have negative effects of not spinning the alternator fast enough to adequately charge the electrical system. But this can be overcome by larger pulleys elsewhere...

I think though that would negate the effect. I would think that having a billet aluminium same size pulley would be the best bet.

Thats not the best explanation lol

Undersized pullies accually spin faster then normal, but require less engine effort to spin (just like shorter gearing), you are effectivlly increasing the torque applied to that pully (and whatever it is conencted to)

This site also says that the throttle body is only 46mm.....?
I told you man!
That's because it's not an identical engine to our 2nd gens. Close, but not identical.

oh ok...my bad

Undersized pullies accually spin faster then normal, but require less engine effort to spin (just like shorter gearing), you are effectivlly increasing the torque applied to that pully (and whatever it is conencted to)

Fair enough. I've read HEAPS of reports of people suffering from underpowered systems (as in electricty) from changing to an underdrive pulley though...I mean HEAPS of them. Almost every thread on 3si.org about underdrive pulleys has a handful of people recalling their experience with them.

Fair enough. I've read HEAPS of reports of people suffering from underpowered systems (as in electricty) from changing to an underdrive pulley though...I mean HEAPS of them. Almost every thread on 3si.org about underdrive pulleys has a handful of people recalling their experience with them.

You are absolutlly right, I didn't word my post very well. The accuall pully is spinning at a faster rotation (more torque) but becuase it is smaller it is covering less belt distance. In other words the undersized pully it's self id spinning faster, but the belt is now rotation at a slower speed (hence the drop in electrical system power output).

You are absolutlly right, I didn't word my post very well. The accuall pully is spinning at a faster rotation (more torque) but becuase it is smaller it is covering less belt distance. In other words the undersized pully it's self id spinning faster, but the belt is now rotation at a slower speed (hence the drop in electrical system power output).

Ahh righteo...I thought you were saying the opposite lol I get what you mean now.

So that would be why they use a larger pulley elsewhere to compensate...and I'm guessing that it doesn't always compensate quite "right" so they tend to still have issues.

I know 3sxperformance.com do stock size billet aluminium pulleys: http://www.3sxperformance.com/engine.asp 2nd item down.