Intlcutlass Posted January 15, 2003 Report Share Posted January 15, 2003 If so who's did you use, and did it help or hinder? Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 16, 2003 Report Share Posted January 16, 2003 Do they even make them for 2.8 and 3.1???? Quote Link to comment Share on other sites More sharing options...
ismellrealbad Posted January 16, 2003 Report Share Posted January 16, 2003 who wants to explain to me what that is and what it does/where it goes etc? Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 16, 2003 Report Share Posted January 16, 2003 someone told me before that we can use the ASP underdrive pulley for the 2.8/3.1 Berretas I believe, I have no clue if anyone has confirmed this or not though.....go to ASP's site http://www.aspracing.com/import.htm and check it out, I'll search for my previous post(s) on the GMF board and see what exactly the person who recommended it to me said....I think you have to change something I believe...not sure Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 16, 2003 Report Share Posted January 16, 2003 an underdrive pulley just replaces your standard pulleys, depending on what car/engine you have you can get alternator, water pump, etc....the concept behind it from what I understand is that they reduce the speed at which your accesories turn, therefore making them need less power to operate and giving you a slight performance boost from this. I'm not sure this is a good explanation although it covers the basics I guess, someone else please chime in and fully explain...thanks...hehe Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 16, 2003 Report Share Posted January 16, 2003 I know pullies are good for HP and that for a Mustnag they reduce about .2 of a second on a 1/4 mile. Quote Link to comment Share on other sites More sharing options...
ismellrealbad Posted January 16, 2003 Report Share Posted January 16, 2003 well before that link somoene gave i never even saw a pic of this thing. when i saw the pic i realised it went somewhere on the accessory line, but where and how that helps was what i was wondering. So do you get this pully for every accessory on the line, or is it just one? I would prefer not to reduce the speed at which my alternator turns, if anything id like a smaller pulley to increase that. im guessing there are no adverse effects on the power steering and water pumps? AC wont blow warmer than usual from a slower speed? Quote Link to comment Share on other sites More sharing options...
NORBI Posted January 16, 2003 Report Share Posted January 16, 2003 do u think that Beretta 3.1 pulley would work on a 2.8 since its almost same engine Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 16, 2003 Report Share Posted January 16, 2003 It should, the accessories are probably identical since the motors are basically identical also......as I stated before, I really don't know if the underdrive pulley for the Beretta will work though, I'd find out ASP's return policy and see if they'd let you return it if it doesn't work. Quote Link to comment Share on other sites More sharing options...
SuperBuick Posted January 16, 2003 Report Share Posted January 16, 2003 http://www.fastforwardperformance.com Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 16, 2003 Report Share Posted January 16, 2003 The underdrive pulley replaces the crank pulley. Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted January 16, 2003 Report Share Posted January 16, 2003 Good discussion. I used to have to figure this stuff in my job. Here's an old spread sheet that figures the RPM's for you. It used pitch diameter but the od of most serpentine belt pulleys will be close enough.  The smaller the driving pulley (crank shaft Pulley) the slower the driven will spin. The larger the accessories pullies the slower the accessories will spin. To overdrive a supercharger you use a smaller pulley.  Smaller crank pulleys do increase useable motor hp. Can't go to small or the belt won't drive your accessories. I don't think a 3" crank pulley would work. Keep in mind that the crank pulley is also a vibration damper so weight is also important. You may have to get a shorter belt also.  Pulley Sizes and RPM's  RPM 5000 Crank Pulley Dia 7  Pulley Belt Ft Motor Belt Ft Pulley Dia Per Rev RPM Per RPM RPM Crank 7.00 1.83 5000 9163 5000 Alt 2.25 0.59 5000 2945 15556 PS 4.00 1.05 5000 5236 8750  Crank 5.00 1.31 5000 6545 5000 Alt 2.25 0.59 5000 2945 11111 PS 4.00 1.05 5000 5236 6250  If you want the file let me know.  Alt really cranks dosen't it.  Dimensions from 90 TGP If anybody knows of smaller ones i would like to know. The 5" pulley is just an example of how much you can slow things down.  Why does program compress tables. Sorry Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 17, 2003 Report Share Posted January 17, 2003 Tom, did you mean to put a link to here http://www.fastfwdperformance.com/ Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 17, 2003 Report Share Posted January 17, 2003 :withstupid: Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 17, 2003 Report Share Posted January 17, 2003 if superbuick meant to post a link to that.....then what were we supposed to be looking at on that site? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 17, 2003 Report Share Posted January 17, 2003 They sell underdrive pullies. Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 17, 2003 Report Share Posted January 17, 2003 where are the pullies on the site Tom posted? I looked all over the site and couldn't find em.....also it looks like that crap is for Porsches, did you even bother clicking on the link that Tom posted......find the underdrive pullers on http://WWW.FASTFORWARDPERFORMANCE.COM and post a link to THEM please!!!...the site(s) I posted sell them, I think that Superbuick meant to put a link to http://www.fastfwdperformance.com, if I am WRONG about this..then sorry I'm such an idiot, but I couldn't find any pulleys on that site Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted January 17, 2003 Report Share Posted January 17, 2003 I thought you meant the corrected link. Sorry. My bad. Quote Link to comment Share on other sites More sharing options...
mfewtrail Posted January 17, 2003 Report Share Posted January 17, 2003 no problem Quote Link to comment Share on other sites More sharing options...
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