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Thread: 6G74 ACC belt size for A/C delete using timing tensioner pulley.....

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    Forum User Not Verified Feedback Score 4 (100%) TUFFTR's Avatar
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    6G74 ACC belt size for A/C delete using timing tensioner pulley.....

    As the title say's....to save me some work.....does anyone know the size of a belt to drive the Alternator, when doing an A/C delet kit that deletes the A/C, bracket, and both tensioners, just using a spare Timing belt tensioner in place of it all?

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    Forum User Feedback Score 0 GTwizard's Avatar
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    Dude,
    Don't use that tentioner pulley. Feet per second (or minute) on that pulley is not even close to the belt speeds you are having to deal with. Acc belts run at about 6 xs that of a timing belt speed.
    Just use the stock tensioner up there as it should be. It is close to 3 " and was made to handle those FPM required. I know you were using the excentric pulley so you can have some way to tension the belt. No Need to.
    I can send you my belt lenth, but than it will depend on if you are using a first gen, or second Gen revised pelley as ths diam are not the same. Even the diam from upper to lower are not the same.
    To install belt. you just need to remove 2 upper alt bolts, remove the upper of the 2 lower bolts and let the alt Pivet on bolt 4.(the lowest). Rotateing the alt down loosens the belt. Pulling the alt back into place tightens it. I did duttch's this way and My own. Belt replacement is even faster that stock. LOL. That little damn pulley that you are using will blow apart in no time at all. I have seen it used so many times and is not at all a good idea. Jackson racing uses those pullies as well for the Miata supper charger kits. I saw them in place on a cusomers car and through them in the trash. I replace them with the 3" mitsu and boost went up from 8 to 12 lbs boost. So that gives you an idea just how much drag an under rated pulley will hurt you. It robs power and will ware the belts early. Thought you should know. I also run the unorthodocs under drive crank pulley. I don't recomend under drives for anyone and for good reason. But again all other pulley diam are going to effect the total length of the belt. Cut a peace of string the exact legth that you need. Now measure it and get a belt 10 MM shorter.
    This will give you the tesion you need or get you damn close anyways. That's what i did. WEll, I lied. I cut a perfectly good belt. LOL.
    Last edited by GTwizard; 06-03-2011 at 02:38 AM.

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    Forum User Not Verified Feedback Score 4 (100%) TUFFTR's Avatar
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    :O Interesting and valid point you use.
    For reference, my crank pulley is 100% standard! Used a lightweight one, felt not one bit of different. CBF using an underdrive one as I'd need new belts.

    So are you saying to keep the upper idler pulley or just keep the lower tensioner pulley?
    I want to piss off the A/C bracket aswell which is why I wanted to piss off the lower pulley.....In the upcoming holiday's though I'll need to get re-acquainted with my lower end and see what needs doing first hand.
    I predict one too many trips BACK to the local parts store.

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    Forum User Feedback Score 0 GTwizard's Avatar
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    Yes, get ride of all that lower crap. Now you only need to clear the Alt braket. Some will grind the bracket. Grrrr I don't like that idea at all. So just leave the origenal one in it's place and save lower and set it aside.
    The upper and lower pulleys are of 2 different sizes. Use both (one at a time) (LOL) to take your belt length. Get the length of the shortter of the 2. If the belt is not tight enough, go back to the larger pulley. Just too easy.
    other post seen to want to make this way to involved. All I did was the use the Alt as the tensioner for belt on and off. Think of it that way.
    Last edited by GTwizard; 06-03-2011 at 10:29 AM.

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    Forum User Not Verified Feedback Score 4 (100%) TUFFTR's Avatar
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    GTWizard - is there the possibility of overloading the alternator bearings using it as the tensioning device? This is what I'm most scared of...I've rebuilt the alt myself about 2 years back but now I'm not in the auto-elec game anymore to get it rebuilt will cost me a bit more then just parts lol This is why I wanted to use some sort of swing tensioner system in place of the upper pulley...
    And I agree, Didn't want to grind away my alternator bracket 1 bit. Trying to find a 3.5L alt bracket is like....well..........cant think of anything to compare it with but its NOT easy!

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    Forum User Feedback Score 0 GTwizard's Avatar
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    Belt load and tension is the same, wether you tighten with adjuster or alt. So there for over tightenwith ether method is not good. The only reason most all over tightening take place is because Mitsu never had enough belt wrap going around the AC compressure and was required to be over tight just so the belt would not slip and squeel. The meth you are now using has NO more AC to be driven so there fore belts will work a bit looser and beaing friendly. That Alt is getting a full 180 degrees worth of belt wrap. When you llok at my dyno, you will see a puff of smoke belch out the side for a brief moment. That was iether tire slip on the dyno or belt slip as I am not supper tight. I think was belt slip but Dunno.

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    Done and Done. Thanks GTWizard!

    Using a 6PK1035 belt. Seems to fit almost perfectly! A 1040 might be better but might be too loose.

    Much better way to do it IMO, saves grinding the bracket..

    Also holy hell that's a bit of weight to save! Didnt take me long either...Just take out the Alt first and the drivers side rad fan.
    Shoulda done this a long time ago...
    Last edited by TUFFTR; 07-06-2011 at 03:37 AM.

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    Sorry for the thread resurrection...

    I cant get an answer anywhere

    I'm going to be removing a/c (gen2 gto tt)

    Now I know most people use a 1035mm or 1038mm belt when using the stock lower pulley but mine has a UD crank pulley

    The aux belt I'm running now is 1080mm (previous owner) but a few people I've seen running UD pulleys WITH a/c are using 1100

    So going by my calculations with belt length, to remove AC using stock tensioner with UD pulley, I need either

    6PK985 OR 6PK965

    Dont know what length to go with, can anyone help?

    Cheers lads

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