I am trying to buy an underdrive crank pulley for my 2.4 ld9, but I dont want my 1000 watt stereo going bizzerk! So, my ? is, does aem or any manufacturer make an oversized alt. pulley to compensate for the underdrive crank pulley? If so, where do I get one? And what is involved in removing the alt. pulley? Just remove the bolt, slide the old pulley off and put the new one on? Thanks!
98z24, lowered 2", aem intake, cat-back striaght pipes!, cop ligths in the front and rear, 18" liquid metal's, primer black, tint, full audio and video.
just turn the tensioner and it puts slack in the belt...then i believe you need a alllen wrench(not positive, cant remember) and you have to use one ratched to keep tension, and use the other ratchet to turn it and break it lloose, then the pulley slides right off
AEM sells an UNDER DRIVE pulley. With the AEM under drive pulley and an under driven crank pulley you will have major charging issues...especially at idle. At this time no one offers an over driven alternator pulley. The alternator pulley comes off with an open end wrench and t-50 or t-55 torx drive. See picture below.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
there is no such thing as an "over driven alt pulley" the only real solution to that are, upgrade the alt to a 180-220A unit, OR, don't under drive it. use a lightened one instead. I'm going the second route for my car, only because, I like having that extra charging power when I use my system (which is hardly ever as is).
isnt the larger alt pulley just going to slow down your alt even more??
I would say get some lightened pulleys, from say.....MD_LD9, the gentleman who was nice enough to already give you info
You get all the benefits of the underdrive set, without the problems that accompany them.
Brad wrote:there is no such thing as an "over driven alt pulley" the only real solution to that are, upgrade the alt to a 180-220A unit, OR, don't under drive it. use a lightened one instead. I'm going the second route for my car, only because, I like having that extra charging power when I use my system (which is hardly ever as is).
upgrading the alt will NOT solve the problem. Ive even talke to some people that say it might be worse (depending on the alt) becuase they still need to spin at a certain speed to put out the 180 amps.
I have problems charging at idle with NO stereo system. underdriving is simply not for those who want a big stereo.
well, I have talked to md ld9 and he is no longer making the darn pulleys!!!!! It sucks too! I really want one and no one wants to get rid of there used one's and he isnt making anymore, just my luck huh? But thanks for the info. I guess my crank will have to do with the stock crank pulley until I can get someone to give up one of mikes pulley's...
98z24, lowered 2", aem intake, cat-back striaght pipes!, cop ligths in the front and rear, 18" liquid metal's, primer black, tint, full audio and video.
When I bought a 200 amp HO alternator from
Motor City Remanufucturing, it came with an overdrive (undersize) pulley. I eventually contacted them over getting an even smaller pulley, which they delivered for just the cost of shipping.
I'm not sure what the diameter of the stock pulley is, but this one is 1.75". They told me that there were no "perfect match" pulleys available for the Cavy in smaller sizes than stock, but that this kind (that has an extra rib) work fine with the belt running on the inner ribs. The tensioner took out all the slack, even with the stock belt.
It probably reduces the life of the alt, seeing as how it really screams at high rpms, but it gives me solid idle output, even with the stereo pounding. It's been running fine for the past two months.
Shop Manuals, Brochures:
www.kenmcgeeautobooks.com
matthew christian wrote:well, I have talked to md ld9 and he is no longer making the darn pulleys!!!!! It sucks too! I really want one and no one wants to get rid of there used one's and he isnt making anymore, just my luck huh? But thanks for the info. I guess my crank will have to do with the stock crank pulley until I can get someone to give up one of mikes pulley's...
I just do not have any LD9 cranks. I'll probably run another LD9 pulley GP next summer. I do however have some alternator pulleys. I never said I'm not making them anymore, just that I currently have none, and will not be having any more made till next summer.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
^^^^thats what I was hoping he meant.....
my experience's have told me that having a
higher then stock output alternator (180 amps vs 105 amps) means you simply cannot run an AEM alternator pulley (yes, thats the LARGER one, that SLOWS down the alternator, thus freeing up the parasitic loss the alternator creates) on a j-body with every single option under the sun when used in conjunction with an underdrive crank pulley (smaller then stock, actually works reverse, it slows down ALL the accessories freeing up yet more parasitic loss).
the higher output alternator's do not put out as much as a stocker AT IDLE. idle is where the charging issues reside.
my fix - stock sized crank and alternator pullies and raised idle via HPT. car charges AMAZING at idle now.
moral of the story...
lots of options, auto, and any kind of aftermarket stereo (ie amp) -LEAVE THE FREAKING PULLEY SIZES ALONE.
5spd car, few options, no stereo- run em all underdrive and see if your car will charge at idle, if not, take one off and put a stock sized back on and see.
In the end, we're all just chalk lines on the concrete.. drawn only to be washed away.
I have a stock crank pulley, overdriven alternator, and HPT adjusted idle speed. It took this in combination to get acceptable output from my HO alt at an idle. I had problems with the stock alternator as well. I think the auto-trans cars are even worse for this with their lower idle rpm speeds.
Shop Manuals, Brochures:
www.kenmcgeeautobooks.com
hmmm thats real odd man. it should be doing its job now.
my car just loves its new found power. i can even leave it sit for weeks without having to rev the engine to like 3000 for 5 mins before i park now. starts right up.
In the end, we're all just chalk lines on the concrete.. drawn only to be washed away.
stock output at idle for the alt is 60-80A. output at idle for the alts that I BUILD is between 100-120A. and this was with a 2 3/4 inch pulley on it. I have done a few now for people who have under drive pulleys on their cars who need more output. maximum output that one of mine has hit was 230A at 3500 RPM Engine speed. this is with a 220 stator and the 2 3/4 inch pulley for the one customer. so yes, it is possible to have over drive pulleys on the car and still have enough output from the alt to run the big stereo.
interesting...
id like to hear more.
In the end, we're all just chalk lines on the concrete.. drawn only to be washed away.
z yaaaa wrote:interesting...
id like to hear more.
Me too!
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
ask away and I shall answer.
well considering you just solved all of everyone's charging issues AND we can still run underdrive pulleys...
id say you can pretty much spill your guts, no questions from us needed, just tell us EVERYTHING!! lol
In the end, we're all just chalk lines on the concrete.. drawn only to be washed away.
i couldnt care less what it puts out at 3500rpms.
what i DO care about is what it puts out at 650rpms
He already claimed an idle output of 100-120 amps. Sounds like a time for you guys to PM him for prices.
Shop Manuals, Brochures:
www.kenmcgeeautobooks.com
I already did.....waiting to hear back about turn around time.....
Geeky wrote:He already claimed an idle output of 100-120 amps. Sounds like a time for you guys to PM him for prices.
he didnt specify auto or manual.....most of the manuals are idling around 900
my auto idles at a commanded 920
In the end, we're all just chalk lines on the concrete.. drawn only to be washed away.
my manual idles at a commanded 1050.......damn cam
but i <3 it
