Under Drive Pulley Kit Question

k00ksta · Mar 25, 2009

I am looking to finally ditch my stock pulleys and go with a set of Aluminum Blue Anodized pulleys. But I have a question about the 25% under drive. Will this cause me to have any alternator charging or cooling issues with my setup? I do have a Hypertech thermostate 160 degree I believe is the rating in it now. I also have my fans wired to a relay and a switch and do not have any cooling issues as of now. I have never seen the car raise really above the 190 mark when warmed up. So I just want to be darn sure before I put these on my car. Thanks for any suggestions

wytstang · Mar 25, 2009

If you have charging or cooling issues after a pulley swap it's most likely the problem was already there just not noticeable. If both are up to par there should be no issues after the swap. I've had my ASP pulleys going on 3 yrs or more and zero issues thus far. Hell I had more cooling issues when I lost my air dam under the bumper then the pulley swap.

k00ksta · Mar 25, 2009

Ya I am going to agree with you and just pull the trigger. You know this only comes with a Water Pump Pulley, Crankshaft Pulley and Alternator pulley. Can I get one to match the power steering, idler pulley, any others? All I find is black ones and if I go with a set of Chrome or Blue ones it all wont match haha any suggestions

toyman · Mar 25, 2009

k00ksta said:
Ya I am going to agree with you and just pull the trigger. You know this only comes with a Water Pump Pulley, Crankshaft Pulley and Alternator pulley. Can I get one to match the power steering, idler pulley, any others? All I find is black ones and if I go with a set of Chrome or Blue ones it all wont match haha any suggestions

Just so that you are aware. When you reduce the crank pulley size all other pulleys are rotating at a slower pace. The UD pulleys for the water pump and alternator are larger than stock and therefore are even turning slower again. I had no problem with UD's when the engine was stock.

wytstang · Mar 25, 2009

Pretty sure you'll need to powder coat your other pulleys if you want them to match.

R.A.T.M. · Mar 28, 2009

toyman said:
Just so that you are aware. When you reduce the crank pulley size all other pulleys are rotating at a slower pace. The UD pulleys for the water pump and alternator are larger than stock and therefore are even turning slower again. I had no problem with UD's when the engine was stock.

I don't think this is quite correct. When you reduce the crank pulley size, everything spins faster - this is why they give you larger accessory pulley's - to slow them down again.

final5-0 · Mar 28, 2009

I love pulleys

You get a torque gain ALL ACROSS the rpm range

Now ... consider these 2 radically different applications

1) My h/c/i GT

2) A Stocker or Bolt-on Stang

The focus here will be on idle issues

I idle at around 900 rpm

The other examples will be way down there around 650 rpm

At rpm as low as that ...
At night .. You might see a dimming of the h lights during idle

Also ... If you got a mega watt hungry sound system .....

Might not have enough juice at idle to feed the hungry beast

As Always

Application has a lot to do with what is good for one and bad for another

Grady

tstang21 · Mar 28, 2009

i have a march pulley set and i love them. i havent had any cooling/electrical problems for about a year now.

toyman · Mar 28, 2009

R.A.T.M. said:
I don't think this is quite correct. When you reduce the crank pulley size, everything spins faster - this is why they give you larger accessory pulley's - to slow them down again.

Nope. Think of it this way. Using a 6" crank with every revolution the belt will move (pi x d) about 18.85 inches. With a 5" crank the belt moves only 15.7". So it follows that at any given rpm the driven pulleys are slowing down. The accessory pulleys are larger to slow them further. From above if an accessory pulley were 2" diameter it would take 6.3 " of belt movement to turn the assessory once. So, the 6 inch crank turns the accessory pulley (18.85/6.3) 3 times for every revolution of the crank. With the 5" crank it's 2.5 revolutions with every turn of the crank. A larger accessory pulley slows it further. If it was increased from the 2" above to 3" it will rotate (15.7/9.4) 1.67 times for every turn of the smaller crank.

Venom351R · Mar 28, 2009

I just bought a set of BBK UD Aluminum pulleys from summit that came to my door yesterday. I cant belive how light the aluminum ones are compared to the steel set that I had an a previous Mustang. I tried to weigh them on the bathroom scale but they would not register.

R.A.T.M. · Mar 29, 2009

Does any brand offer an advantage over another? Steel versus aluminum?

Adam95GT · Mar 29, 2009

R.A.T.M. said:
Does any brand offer an advantage over another? Steel versus aluminum?

Ive noticed slightly different sizes among brands... My FRPP set is a different size then the MACs that were on an engine i purchased

Under Drive Pulley Kit Question

k00ksta

Member

wytstang

Mustang Master

k00ksta

Member

toyman

wytstang

Mustang Master

R.A.T.M.

Member

final5-0

Mustang Master

tstang21

Member

toyman

Venom351R

R.A.T.M.

Member

Adam95GT

New Member

Similar threads

Under Drive Pulley Kit Question

Member

Mustang Master

Member

Mustang Master

Member

Mustang Master

Member

Member

New Member

Similar threads

Privacy & Transparency

Privacy & Transparency