underdrive pullies

[chevyracing55]

does any one use underdrive pullies, are they a waste of money, and do they give noticable power gains? thanks

[droopy89]

Not exactly sure, but the throttle response is a little snappier

[Hammer Head]

I've run them in other cars & trucks. They give about 10-15hp. You won't really feel anything but it may save a little on gas.

[rentedmule]

noticable but nothing crazy. for the price I think they were worth the money

[droopy89]

but wont the alt. pulley lower the recharge of the battery, thus shortening the engine-off life of the battery?

[1993blazerlt]

most of the kits use a different size pulley combo to keep the alt at the same rpm but allow other components to be under driven

[droopy89]

so which one of these would be the best?


http://www.performancecenter.com/product/Engine/Pulleys/0/6/0/CHEVROLET/1997/S-10+Pickup/Vehicle+Specific/4.3L/Complete+Pulley+Kits


by the way, this site is cheaper than most others that i find

[Hammer Head]

The ones that I've had made alt output lower at idle making the idiot light pop on. Upper RPMs it was fine though.

[rentedmule]

so which one of these would be the best?
http://www.performancecenter.com/product/Engine/Pulleys/0/6/0/CHEVROLET/1997/S-10+Pickup/Vehicle+Specific/4.3L/Complete+Pulley+Kits
by the way, this site is cheaper than most others that i find

Those still seem expensive, I thought they were cheaper at Summit? I paid about the same price for mine in Canadian $'s with taxes at a local shop. I have the march power and amp series and didn't notice any change at all in charging. just make sure you get the ones for an internal alternator fan.

[Hammer Head]

I think Summit's cheaper too. Maybe by at least $10-20.

[nomaboy]

i got the jet pullys and the crank was smaller and the alternator was bigger. a bad design because the smaller crank pully will slow everything down and the bigger alt. pully will slow the alt. down even more. so i used the crank pully and left the stock alt. pully on there. i got about .2 10ths when i put the pully and e-fan on it.

[j894]

^ you didn't get the "power & amp" type, series. you have normal underdrive pullies.
Which don't compensate for the slower speed of the alternator

[04silveradomykk]

I've got March power & amp series steel pullies. I like them, before I did e-fans my truck would heat up pretty good idling at a light with the pullies but it never threw it into the red. Once I did e-fans it's never climbed over the 180 preset.... I noticed on the test drive after doing the pullies it would break the tires loose easier. I don't have drag E.T. numbers. just my seat-o-pants dyno. A good mod.

[droopy89]

on the power and amp series pulleys, does it matter if its an auto or a manual, cause on the march website, it says "Recommended for Automatic Transmission Vehicles"

[04silveradomykk]

I couldn't see why it should matter what kind of pullies you've got with either an Automatic or Standard.... maybe it makes so much horespower on a manual trans they had to say that as a disclamer in case somebody hurts themselves with all the power they opened up..... Hmm, nah.

[Sparky2263]

The big alt., small crank pulley set-up isn't usually a big deal. No, it doesn't charge at idle and takes 12-1500 rpms to start charging. Those of us old enough to remember the pre-1980 Chrysler products don't worry about it.

Now, lot's of low speed driving, stop and go, weak battery, big-ass amps, maybe you run into a problem.

Spinning that alternator is the hardest thing the belt does (unless the A/C compressor is engaged) so why miss out on the gains?

[droopy89]

alright its settled, im getting the March kit soon, maybe when i get back taxes, and i dont have any amp or something that would take alot of power draw, all i have is door speakers and a H/U


But what length belt would i need?

[04silveradomykk]

it probably depends on year anda few other factors, I found a 91 inch fits best.

[droopy89]

any specific brand?

[Sparky2263]

Wait until you get the pulleys. Lot of time you use the same belt and if not, they give you a belt size.

[droopy89]

alright, thanks

[Mikz86TA]

If you do the March Power/Amp Series charging wont be an issue. ASP, older Hypertech and others you will have an idle charge issue. PowerMaster sells a nice alt. that has higher AMP output and a low-RPM charge turn on. You can do an alternator that has a regulator that will charge at low RPM (Alt. RPM) if you have issues. I know the Hypertech set has a larger than stock alt pulley, which will affect charge. I am just going to leave the stock alt. pulley on, since it is smaller. I also have an even smaller alt. pulley lying around from my Trans Am set(s). I might try it if I still have issues. You will need an Impact to get the alt pulley off. Also keep in mind a new belt size. You will notice snappier throttle resp. and definately worth the $ for the gain. 10-15HP sounds small but is quite a lot considering other mods HP per dollar. I personally cut advertised HP by 25% myself. If you do that and add all mods together, you will still have significant gains. 250HP at the flywheel can be done to a 4.3 with just bolt ons.

[Mikz86TA]

The reason why Auto/Manual disclaimer is for the idle drop off of the alt. At idle ,at say a red light, an Auto has a load on the motor which causes a drag in the idle. And the manual there is no drag until you shift into gear and release the clutch. On my T/A, I did underdrives back when all I had were bolt-ons and a 305. At night with the lights on, music on a bit, maybe A/C too and at a light, you would notice the lights dim. If I stalled it up a bit they would get brighter. Or same if I just put it in neutral. Same reason why some cams are recommended for manuals only. Thats due to low-vaccum characteristics at low-idle on the cam which will affect power brakes. =)
on the power and amp series pulleys, does it matter if its an auto or a manual, cause on the march website, it says "Recommended for Automatic Transmission Vehicles"

[LowSDime97]

i have heard that if u have a system in ur truck that u would only want to use the crank pulley, or is it fine to use both? and in conclusion should i get me some underdrive pulleys?

[Mikz86TA]

My Hypertech kit came with a small crank and a larger alt. I kept the stock alt pulley on. Ironically I used the belt size that Hypertech recomended. If you use a larger alt pulley, you will slow down the alt. Alts have a regulator that 'turns on' ar a specific RPM. And they usually dont put out full volts until even higher. If you put a larger pulley on it, you slow it down and result is a poor charging system. Some aftermarket alt companies make a model that has a low-RPM 'turn-on' regulator. Powermaster used to have some. IDK if they still do. Those were designed primarily for cars that have lopey cams and turn low RPMs...especially in an auto car. There is a site that carries stock GM pulleys for the alts of various sizes. If you have issues...measure yours and then compare it to what is available. Ill try to find the link.

[j894]

I have the power & amp series on mine & noticed no charging problems. I have a small "system" & stock 100amp alt.

Someone was saying you can use a 120amp alt from a suburban as a factory like upgrade, with almost no modification.

[Mikz86TA]

Yeah, there is a thread with the swapping of a CS130D (late model 4.3 100A alt) to the larger case CS144 which bolts in with almost no problem. Those are on big trucks up to 8.1L and are quite a bit more amps =) And the March P&A you have is definately the better set of pulleys to get if these are concerns. But I got the Hypertechs ,which they dont make anymore, 2nd hand for CHEAP off e-bay =) From experiencs with underdrives on the TA, I noticed the larger alt pulley that thay came with and chose not to put it on. Charging didnt change a bit for me. I actually have an even smaller bonus pulley that will work as well. Just waiting to do the CS144 upgrade 1st

[Slaymanic]

Hmm so ya'll say the problem with charging shouldn't be a big deal but I'm pulling 400amps to my subs and then my head unit pulling 70amps my lights dim when the subs hit going 65mph so I donno any ideas? I only got a 105amp alt duracrap that is =]

[Auto-x]

Hmm so ya'll say the problem with charging shouldn't be a big deal but I'm pulling 400amps to my subs and then my head unit pulling 70amps my lights dim when the subs hit going 65mph so I donno any ideas? I only got a 105amp alt duracrap that is =]

Here's an idea, Get a system built for the audio range humans can hear without bleeding from the ears.

[Mikz86TA]

400 amps to your subs????? You mean 400 watts? And I am definately not saying the OEM charging system is adequate. In fact most of the time its inadequate for even the stock electronics. Headlamps usually draw the most current (amps), then add electric fans, AC, Ignition, other lamps when headlights are on, ABS motor, PCM, BCM, short-draw current like power seat/windows/locks/map lights/etc, and so on. Definately more is drawn on the charging system than its capable of providing. But also you got to think that everything isnt drawing what its rated to at all times. Thats just its max capability. For instance, the fan motor say has a 30amp fuse. That means 30amps is its max rated current draw. But if you have it blowing on the 1st 3 settings, its no where near 30amps. In fact it is possible that on high its not there yet either. Same with all that aftermarket stereo you got. The radios generally draw the same amount of current as a stock one. Additional amps, vary. And likewise do not always draw full potential. Subs require more power to perform, therefore a sub amp at the same setting/volume/output as a mids-highs amp is drawing much more current to play. LED lights dont draw hardly any current by nature. So cby hanging to LEDs in various lighting, you are actually saving current draw off the charging ststem. (think of that as a free mod. kinda like doing the TB restrictor mod....no HP gains come from it but you get better response) IMO the 100Amp alt on the s-series is about 85% effecient at what it needs to be on the stock setup. Add amps, neons and other additional stuff and you reduce its effeciency. IMO, with stock stuff, e-fan(s), ignition upgrades, small system.....a 200A alt is perfect to be 100% adequate. Still by upgrading like Silvy did, is better and pretty reasonable in cost than nothing. Hope this helps:D
Hmm so ya'll say the problem with charging shouldn't be a big deal but I'm pulling 400amps to my subs and then my head unit pulling 70amps my lights dim when the subs hit going 65mph so I donno any ideas? I only got a 105amp alt duracrap that is =]

[Mikz86TA]

You mean the decibel level. The audio systems ARE designed for the audio range of human ears. 20Hz to 20kHZ (20,000Hz). Only a few test CDs are going below or above that range. And very little studio recorded music isnt going to the ends of the range. Excessive dB's and constantly listening for a period of time to the excessive dB's are what cause hearing problems. BTW, I am a SQ (sound quality) guy. I still like to 'drop tha beat' every once in a while though:D hehehe
Here's an idea, Get a system built for the audio range humans can hear without bleeding from the ears.

[Slaymanic]

Auto X:
400watts my bad heres the offical correction and I can hear it without bleeding from the ears at full blast infact I am concidered one of the loudest non-show trucks around here =] I make the air pressure around my truck change and no my hearing hasn't shifted negative either.

Mikz86TA:
Well it's all Infinity since that is what I prefer but its drawing 60watts through the head unit pushing 4 speakers and the amp is pushing 400watts through the two 12"s in the back. I'm still just wondering if the pulleys would be a bad idea because I keep it cranked up 24/7 for the last year with no hearing difficulites and no voltage issues just a 7 year old alternator going out. So I'm still wondering if it will work or not.

[01blzxtreme]

Auto X:
400watts my bad heres the offical correction and I can hear it without bleeding from the ears at full blast infact I am concidered one of the loudest non-show trucks around here =] I make the air pressure around my truck change and no my hearing hasn't shifted negative either.

Mikz86TA:
Well it's all Infinity since that is what I prefer but its drawing 60watts through the head unit pushing 4 speakers and the amp is pushing 400watts through the two 12"s in the back. I'm still just wondering if the pulleys would be a bad idea because I keep it cranked up 24/7 for the last year with no hearing difficulites and no voltage issues just a 7 year old alternator going out. So I'm still wondering if it will work or not.

nahh dont get scuurred bro hahah....400 watts is close to what my brother has on his blazers mids and highs amp 350 watts that is....and a memphis monoblock 1000 watt amp powering 2 12" kicker solobaric subs..all with just the original alt adn an optima battery also has a capacitor to help...but when at idle you or even driving and you crank that bishh up the needle from the battery goes up and down...and it doesnt just shake it actually goes down alot....its had that system for about 3 years and havent had any problems with the alternator it just screws up the battery thats all lol...

[oldS10dude]

Horsepower TV just had a show where they installed underdrive pulleys
on a little mustang and got about 5 more hp with them ..

[01blzxtreme]

and about the alt pulley been smaller...i dont think itll fu** up your alternator....because they made the crank pulley smaller to slow down all the accesories so if they slow everything down the alternator wont charge the battery and wont give the correct amperage so they had to make the alt pulley smaller to speed it up a lil for what they had sowed everything down....ahh hope it made sense