Crank/Underdrive pulley
Registered User
Joined: May 2008
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From: SoCal -818-
and a post ***** lol
i got more posts on socalG than driver and i joined socalg in november haha
Registered User
Joined: Jul 2007
Posts: 495
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From: ATX, TX
bump, any updates on the underdrive crank pulley?
I had a civic and had the AEM alternator and crank pulley, it def made a difference, pulled hard and rev'd up faster, especially when vtec kicked in
on the civic it was probably the best bang for the buck mod to increase power.
i talked to Stillen, they said it produces 10hp at the wheels, no dyno sheet avail.
but will reduce other acc. (steering, alternator...) by 20%, i have a big system (JLw7 & 1000 watt amp) kinda makes me worry about alternator strain, i guess i need to get some type of cap for the sub.
the guys that have the underdrive pulley, what do ya'll think about it?
I had a civic and had the AEM alternator and crank pulley, it def made a difference, pulled hard and rev'd up faster, especially when vtec kicked in
on the civic it was probably the best bang for the buck mod to increase power.
i talked to Stillen, they said it produces 10hp at the wheels, no dyno sheet avail.
but will reduce other acc. (steering, alternator...) by 20%, i have a big system (JLw7 & 1000 watt amp) kinda makes me worry about alternator strain, i guess i need to get some type of cap for the sub.
the guys that have the underdrive pulley, what do ya'll think about it?
Registered User
Joined: Jul 2007
Posts: 495
Likes: 0
From: ATX, TX
Unorthodox Racing makes stock diameter pulleys as well.
check out this page, looks like they have a dyno sheet
http://www.unorthodoxracing.com/Item...ke=20&Model=66
check out this page, looks like they have a dyno sheet
http://www.unorthodoxracing.com/Item...ke=20&Model=66
^ i would search for and read subys thread first where he had his engine replaced due to the AF pulley, i know it does not happen to every car and is a rare occurrence as many have had their pulleys for years with no issues, but its best to see both sides of the picture before making your decision.
I am not going this route because, the possible downsides outweigh the possible gains from the pulley IMO.
I am not going this route because, the possible downsides outweigh the possible gains from the pulley IMO.
well depends on what your looking for. pulley is a performance mod. however does not give horsepower gains. and noone besides you will know you have it. and system is a completly different mod, where people who notice it and it will make your car stand out but also make your car slower because of the weight.
so what are you looking for fast and quiet or slow and loud.
so what are you looking for fast and quiet or slow and loud.
""""Usage Concerns
Be careful if your car is driven on the street to not have more than 15-20% underdrive. Some companies also offer stock diameter crankshaft and accessory pulleys. Poorly designed cheap pulleys or copies and knock-offs of major brands can have severe side effects because of too much underdrive of the alternator, power steering, and/or air conditioning units, which are not spinning fast enough. These lead to dips in alternator voltage, power assist, and air conditioning effectiveness may be noticeable, especially at idle. The headlights may dim when coming to a stop, or the stereo may lower in volume, for instance. Too much underdrive for a race car, this is not of concern, but for a daily driven vehicle it can be a major annoyance.
Changing the original crankshaft pulley can have negative effects if the replacement pulley is not manufactured properly. A crankshaft or accessory pulley that is not machined or balanced properly can cause severe damage. For most domestic V8s a harmonic damper is necessary to absorb crankshaft vibrations. Early to mid-year V8's kept the pulley and damper as separate components. Most late model V8s now integrate the damper and the pulley into one part. For small displacement engines found in many import and domestic vehicles (4.0L and under) the original crankshaft pulley only serves to quiet noise vibration and harshness (NVH) you hear in the occupant compartment. Although it may look like a damper on V8's engines it serves no protection function to the engine. It is the same as the baffles and resonators found in the intakes and exhausts systems of most cars today that serve to make the engine as quiet as feasibly possible. The first things most enthusiasts do is install high flow intakes and exhausts; the quieting function is eliminated."""
simple terms will strain your alternator, and in my case may cause crankshaft damage causing engine failure. good luck.
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Joined: Jun 2009
Posts: 273
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wikipedia quote for you....
""""Usage Concerns
Be careful if your car is driven on the street to not have more than 15-20% underdrive. Some companies also offer stock diameter crankshaft and accessory pulleys. Poorly designed cheap pulleys or copies and knock-offs of major brands can have severe side effects because of too much underdrive of the alternator, power steering, and/or air conditioning units, which are not spinning fast enough. These lead to dips in alternator voltage, power assist, and air conditioning effectiveness may be noticeable, especially at idle. The headlights may dim when coming to a stop, or the stereo may lower in volume, for instance. Too much underdrive for a race car, this is not of concern, but for a daily driven vehicle it can be a major annoyance.
Changing the original crankshaft pulley can have negative effects if the replacement pulley is not manufactured properly. A crankshaft or accessory pulley that is not machined or balanced properly can cause severe damage. For most domestic V8s a harmonic damper is necessary to absorb crankshaft vibrations. Early to mid-year V8's kept the pulley and damper as separate components. Most late model V8s now integrate the damper and the pulley into one part. For small displacement engines found in many import and domestic vehicles (4.0L and under) the original crankshaft pulley only serves to quiet noise vibration and harshness (NVH) you hear in the occupant compartment. Although it may look like a damper on V8's engines it serves no protection function to the engine. It is the same as the baffles and resonators found in the intakes and exhausts systems of most cars today that serve to make the engine as quiet as feasibly possible. The first things most enthusiasts do is install high flow intakes and exhausts; the quieting function is eliminated."""
simple terms will strain your alternator, and in my case may cause crankshaft damage causing engine failure. good luck.
""""Usage Concerns
Be careful if your car is driven on the street to not have more than 15-20% underdrive. Some companies also offer stock diameter crankshaft and accessory pulleys. Poorly designed cheap pulleys or copies and knock-offs of major brands can have severe side effects because of too much underdrive of the alternator, power steering, and/or air conditioning units, which are not spinning fast enough. These lead to dips in alternator voltage, power assist, and air conditioning effectiveness may be noticeable, especially at idle. The headlights may dim when coming to a stop, or the stereo may lower in volume, for instance. Too much underdrive for a race car, this is not of concern, but for a daily driven vehicle it can be a major annoyance.
Changing the original crankshaft pulley can have negative effects if the replacement pulley is not manufactured properly. A crankshaft or accessory pulley that is not machined or balanced properly can cause severe damage. For most domestic V8s a harmonic damper is necessary to absorb crankshaft vibrations. Early to mid-year V8's kept the pulley and damper as separate components. Most late model V8s now integrate the damper and the pulley into one part. For small displacement engines found in many import and domestic vehicles (4.0L and under) the original crankshaft pulley only serves to quiet noise vibration and harshness (NVH) you hear in the occupant compartment. Although it may look like a damper on V8's engines it serves no protection function to the engine. It is the same as the baffles and resonators found in the intakes and exhausts systems of most cars today that serve to make the engine as quiet as feasibly possible. The first things most enthusiasts do is install high flow intakes and exhausts; the quieting function is eliminated."""
simple terms will strain your alternator, and in my case may cause crankshaft damage causing engine failure. good luck.
first off a couple pics.. as you can see compared to the mag this thing is huge, weight difference is stock is a little over 8 lbs and this one is 2 lbs so im losing 6lbs off of the turning ratio.
and now the quick review...didnt do the dyno after the install because per UR that results will show after 5-7 days or 200miles where maximum hp will be gained.
IT WAS A BISHH AND A HALF TO INSTALL nut was on so hard on, it says only 30 ft of tq thats less than a wheel nut. that was not the case. took like 2 hours and three broken tools until it was loose.
it was snowy out and still icy so i never got on it until i put about 50 miles on the car and just now coming home highway ramp was all salted and dried out. stopped vdc off shifted first. slip light hasnt been blinking this bad since idn. almost went sideways.
second pulled and third was like with boost. i dont know i still need clean stretchway and for it to breakin but so far. super power gains.
and now the quick review...didnt do the dyno after the install because per UR that results will show after 5-7 days or 200miles where maximum hp will be gained.
IT WAS A BISHH AND A HALF TO INSTALL nut was on so hard on, it says only 30 ft of tq thats less than a wheel nut. that was not the case. took like 2 hours and three broken tools until it was loose.
it was snowy out and still icy so i never got on it until i put about 50 miles on the car and just now coming home highway ramp was all salted and dried out. stopped vdc off shifted first. slip light hasnt been blinking this bad since idn. almost went sideways.
second pulled and third was like with boost. i dont know i still need clean stretchway and for it to breakin but so far. super power gains.
