Well i've been reading up on underdrive pulleys and i've come up with the fact that you can install the '93 water pump pulley and gain hp without comprimising cooling because the pulley is smaller which makes it spin faster. Do i need to install a crank pulley or can i just install the water pump and be good? Also if you know of any kits that are good let me know. This is a street stang so i'm not touching the alt pulley. THanks guys
Can i just install the '93 Cobra water pump pulley for more hp? Or change crank?
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cenok is family
15 Year Member
you can run just the water pump pulley if you want without having to get a crank pulley. i have a crank and waterpump ud pulley on my car.
93tealstang
Founding Member
I'm not understanding how you're gaining anything by installing just a water pump pulley. The idea is to slow down accessories which allow the crank to spin faster. The cobra water pump pulley and it's counterpart, the cobra underdrive crank pulley are a factory underdrive setup. It's a "mild" underdrive setup which compare to a March or BBK "street" setup, doesn't yield much gain.
I have a mustang performance book where it runs over a bunch of different projects. And it says in it for street stangs you should run a 93 cobra water pump pulley with a larger crank pulley. I'm not saying thats right. Thats why i'm asking. I would like a 2 piece kit i dont want to mess with the alt pulley.
jtfairlane
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- Mar 5, 2006
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I am always amazed at the confusion over underdrive pullies.
If you theoretically only installed an "underdrive" water pump pulley, and if the 93 Cobra water pump pulley is smaller than your factory pulley, than by installing the Cobra water pump pulley in place of your factory water pump pulley it would become an overdrive pulley and not an underdrive, because it would be smaller and spinning faster. As such, you wouldn't gain any power and would most likely lose a couple hp.
Running a larger crank pulley also is not going to increase performance. The idea is to run a SMALLER crank pulley and LARGER accessory pulleys to decrease parasitic loss from spinning the accessories and thus gaining back a little power that was used to spin the stock pulleys.
If you're going to run the Cobra "underdrive" pulleys, don't run just one or the other, run both.
If you want to do underdrive pulleys WITHOUT any headache, get the March #1015 kit. You get a crank and water pump pulley, and in addition you get an alternator pulley that is EVEN SMALLER than an overdrive alternator pulley, which will keep your alternator amps high even at idle in drive (even with an A/T).
Do it right the first time. Alternator will charge right, and you will gain a few hp.
If you theoretically only installed an "underdrive" water pump pulley, and if the 93 Cobra water pump pulley is smaller than your factory pulley, than by installing the Cobra water pump pulley in place of your factory water pump pulley it would become an overdrive pulley and not an underdrive, because it would be smaller and spinning faster. As such, you wouldn't gain any power and would most likely lose a couple hp.
Running a larger crank pulley also is not going to increase performance. The idea is to run a SMALLER crank pulley and LARGER accessory pulleys to decrease parasitic loss from spinning the accessories and thus gaining back a little power that was used to spin the stock pulleys.
If you're going to run the Cobra "underdrive" pulleys, don't run just one or the other, run both.
If you want to do underdrive pulleys WITHOUT any headache, get the March #1015 kit. You get a crank and water pump pulley, and in addition you get an alternator pulley that is EVEN SMALLER than an overdrive alternator pulley, which will keep your alternator amps high even at idle in drive (even with an A/T).
Do it right the first time. Alternator will charge right, and you will gain a few hp.
93tealstang
Founding Member
^^^
I completely agree. Most underdrive kits use the larger alternator pulley because that will in theory gives you the maximum gain. I've even seen track cars with larger power steering pulleys. Small crank, everything else bigger is what nets the most gain. But, like stated above, March and ASP offer a more "street friendly" kit that gives you an overdrive alternator pulley to help with charging. This really is the only way to run underdrives on a city driven stang. Keep in mind, a 3G 130 amp alternator is also recommended with underdrives. The stock alternator is
. It will get weak and die out with underdives, I learned from experience.
I completely agree. Most underdrive kits use the larger alternator pulley because that will in theory gives you the maximum gain. I've even seen track cars with larger power steering pulleys. Small crank, everything else bigger is what nets the most gain. But, like stated above, March and ASP offer a more "street friendly" kit that gives you an overdrive alternator pulley to help with charging. This really is the only way to run underdrives on a city driven stang. Keep in mind, a 3G 130 amp alternator is also recommended with underdrives. The stock alternator is
. It will get weak and die out with underdives, I learned from experience.^^^
I completely agree. Most underdrive kits use the larger alternator pulley because that will in theory gives you the maximum gain. I've even seen track cars with larger power steering pulleys. Small crank, everything else bigger is what nets the most gain. But, like stated above, March and ASP offer a more "street friendly" kit that gives you an overdrive alternator pulley to help with charging. This really is the only way to run underdrives on a city driven stang. Keep in mind, a 3G 130 amp alternator is also recommended with underdrives. The stock alternator is
Will keeping the stock alternator pulley with underdrive crank and water pulley help with the alternator problem?
i had a small crank pulley on which is what gives u the gain in HP and used stock for the rest i had no charging problems or any problems at all the only problem u will have is picking the right size belt and i got lucky on that guessed it right on the first try
93tealstang
Founding Member
When changing to underdrives, it's better off changing in pairs. Just the crank isn't going to do much for you since your not slowing down any accessories. Plus, you'll have to play around to find the correct belt size. Change the crank and water pump, leave the alternator alone, and re-use the stock belt.
Save your money on the underdrive pulleys and use it to make the power somewhere else, they are not worth the hassle of killing your alternator and robbing amperage to the things that are a neccesity... like your fuel pump, ignition, computer
93tealstang
Founding Member
Opinions vary, I say they are one of the best bangs for the buck. Underdrives paired with a 3G should give no problems electrically. If they do, the problems lie somewhere else in the electrical system. That's been proven.
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