Hey All,

My friend recently introduced me to the world of underdrive pulleys as he has had them installed in his focus. Well in the end I noticed a decent difference in how his car pulled around over the stock pulleys.

I did some searching around and noticed that Thunder Racing sells them for our cars. Is this a good mod to do to gain a bit more power out of the car?

 

i wanted to install them on my car then i heard they dont do much to our cars, but hey i might have been told wrong...my friend did them on his stang and there was a difference.

 

You lose something to gain a bit of power, ie less current from the alt, or less power steering, less water flow from the water pump, etc. All to gain a very slight amount of power.
My personal opinion is the money is better spent elsewhere...

 

I like mine and got them for pretty cheap from another member.
Every little bit counts plus its an easy mod. I have no charging problems either.

 

https://www.thirdgen.org/techbb2/sho...hreadid=310616

Power and Amp series, won't affect your charging system.

 

I wish i didnt even buy mine, I have a noticeable difference in power steering and my alternator cannot even charge my battery at idle. Dont waste the money. At least dont buy the ones from MOTORVATION through Summit.

 

Is the powersteering harder to turn? If it is, without any detrimental effects. I might install a bigger pulley to increase steering effort.

 

I kinda like the fact its harder to turn on mine, the quick ratio, 13" wheel and underdrive pulleys give it a pretty nice feel..
if your at like 1000rpm or under and it downshifts you feel a change though, thats a little weird going around turns :P

 

I put a set on my dirt car, it kept throwing belts off at about 6800rpm's. I don't notice any power difference (not running alternator or ac pump) but steering is fine and cooling is fine. If cooling became a problem a more aggressive fan may help, there is a ford truck fan out there that a local race engine shop uses, they say it is good for a 20 degree drop by itself.

 

When I built my 355 for my 88 camaro I done before/after testing. Sat down and figured out all the pulley sizes I wanted/needed. Bought them (no kit deal)

I ran stock pulleys. 4 runs, avg. together.

Swapped to new underdrive pulleys. 4 runs, avg. together..

I lowered my ET by a solid .2 second.

IMO worth every bit of the money.

Now I'm running some pretty high % under drive though.

I have a CS-130 105 amp alt., mildon high flow water pump, ford taurus 2 speed elec fan, and 31" x 19" alum rad.

At a 700 rpm idle with fan on low I have 12.3 volts, but at 900 rpm I have 13.1 volts.. Cruzing down the road at 2700-3000 rpm I'm at 14.8 volts

Water temp runs on avg. in summer 193* on a long 40+ mile drive.


Mine is a V belt setup, and I mixed and matched my after market pulleys.

All polished alum.
Crank pully is a 5.5" 2 groove march pulley,
water pump is a 6.6" single groove summit pulley
ALT. is a 2.812" single groove summit pulley
Power steering is a 5.75" single groove summit pulley