Im trying to figure out if i want to buy underdrive pulleys and was wondering if anyone on here used them and noticed any gains. If so could you tell me also if you think the pulleys are a bad idea or anything please say so i heard they are not always good or something.

 

Can cause undercharging if used on Alt.

 

Run the march power and amp series. They have a smaller pulley for the alternator so you dont lose charging ability

Thats what i run and its just fine. Gains?? i didnt notice much at all tho except in the throttle response and engine free reving ability. power gains showed minimal

in fact, i gained 8 whp when i added 1.6 rockers and underdrive pullies. I was running very lean tho, so i think with a better tune i may have been near 260whp or so, its hard to say. but still, 14whp between the two mods, and i bet the rockers made the most of it. you may pick up some power but its probly gonna be less than 5whp

but the motor free reved much quicker and throttle response went up..so in that sense it was worth it to me

 

I have been woundering this too. Tpis's set clames their setup only drops the alt by two persent.

 

without the alternator pulley, the voltage drops for sure at night with lights on. I ran my underdrive crank pulley before swapping the alternator one on. It did lower voltage at night.

during the day however it ran pretty good unless i idled along time then it drained alittle

 

there are better ways to make horspepower, u run the risk of overheating and undercharging

 

Ive had them on a S10, Dodge Dakota, my v6 camaro.

Didnt give much SOP feel. However, it made them spin the tires easier.

On the s10 with a very large stereo system, it gave me charging problems.

IMO, if you have a fully loaded car, or large stereo. Do not do them.
If you have a base model car, no stereo, go for it.

 

I have one on my bird and noticed a little differnce. The thing I did notice is that you really need a better alt that the factory crap CS series alt. Even before I changed it out and with new alt and battery( regardless of make) at night sitting in drive at a traffic lt it did almost the same. There's an article on SE 3rd gen thats pretty cool(one day I will get around to doin it), that imo, remedies the problem with the CS series by gettin rid of them all together. hth

 

So dose that mean if i get them to make sure theres a alt pulley to what about air conditioning pulley? I was looking into the BBK set on summit so should i not and just get the march set?

these http://store.summitracing.com/partdetail.asp?autofilter=1∂=MCH%2D4410&N=700+4294908216+4294908198+4294924928+4294925232+4294839035+115&autoview=sku
or these http://store.summitracing.com/partdetail.asp?autofilter=1∂=BBK%2D1620&N=700+4294908216+4294908198+4294924928+4294925232+4294839035+115&autoview=sku

 

cant beat the power and amp series... its designed so you dont lose voltage. If the pulley kit you get has an alternator pulley and its NOT smaller than the factory one, then it will not overdrive the alternator to make up for the underdriven crank pulley, and you may experience charging problems.

voltage drop not only effects charging and your headlights but also your motor's performance as the ecm does have fuel related tables based on battery voltage. Fuel pump also wont pump as much fuel with low voltage but on a stock or mild motor, this may not effect you.


you dont need an air condition pulley. as far as water pump pulley i'm not sure. my kit was a 2 pulley system, and i have no problems with keeping cool. I have stock radiator with a low temp fan switch and 170 degree T-stat. you dont want to underdrive the waterpump too much since cooling can become an issue. But it will make hp. Water pump is probly the biggest restriction on the motor as far as accessories go.

Those kits are nice...polished and light weight aluminum so they are gonna help your rotating mass which will help it free rev quicker, giving you good throttle response. Abit more expensive but they look nice my 2 pulley kit was unpolished and 99 bucks. the power and amp series will eliminate charging issues, but i'm unsure of the waterpump size pulley. Same with bbk i'm not sure of their water pump pulley size. i'm not sure if they alternator pulley is any smaller either so you may have charging issues. i wish they would give dimensions

You could always bump the idle speed up 100 rpms to cure the charging issue tho

 

ight so i think ima try the power and amp set thanks for all the answers. what belt would i need it didnt say anywhere on there about the belt?

 

thats gonna depend on how big the pulleys are and how you route the belt

You can take some string, wrap it around all the pulleys and then measure that length. Go to autopart store and order a belt of that length.

on my 89 with smog delete and march power and amp crank/alternator pully i used a 94inch belt. its just alittle shorter than factory since i deleted smog pump and routed it different so i didnt have to use a smog pulley. with smog pump you will have a longer belt than what i used but should be shorter than stock unless the water pump pulley is larger to underdrive that pump

just install them and measure it with string

 

what about the width of the belt would i just say i have a camaro and i put underdrive pulleys on it and i need a belt 95 lets say inchs and they should have it right?

 

yeah the part numbers are generally the lengths

dayco belts that most stores carry are like that. you need 6 rib belt. my 94 inch belt is dayco 5060940. the last 3 digits are the length. 94.5 inch is 5060945.

 

ight sweet thanks ill have to remember this when i get the stuff.