Underdrive Pulley or Harmonic Balancer
Thread Starter
Instructor
Joined: Jan 2007
Posts: 100
Likes: 0
From: Grand Junction Colorado
Underdrive Pulley or Harmonic Balancer
A couple months back I rebuilt my whole top end. Trickflow heads, LG 1-3/4 headers, yella terra ultra lites, FAST 90/90, Cadillac lifters etc. From Vengence Racing. I never had the right installer for the ASP underdrive pulley so I reinstalled the factory pulleyand now it has a slight wobble. I talked to some people and they say they wouldn't even bother running the underdrive because it runs everything else slower too. I recently moved to McAllen,TX and now in the heat my car runs around 225-230 F in stop and go traffic so I am going to be installing a DeWitts radiator to help with cooling and am wondering if I should install the underdrive now when i have the radiator out or should I leave out the underdrive and use a harmonic balancer. Also, what are some websites or names of some good harmonic balancers. I will be planning a trip to England Green's shop in the near future to have this work done. Thanks
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Top shelf is ATI, and if you speak with them (at least a couple of years ago) they didn't offer a 25% under drive because it was less effective damping the crankshaft harmonics.
Le Mans Master
Joined: Sep 2004
Posts: 6,019
Likes: 567
From: Conroe Texas
i installed, and pinned, a fluidamper last year with the stock size pully as i didn't want the headache of slower water pump and alternator ( on the recomendation of a vette tech ). here in the houston area, my temps run 192-194 consistently and very rarely getting to 198 sitting in traffic.
Burning Brakes
Joined: Sep 2007
Posts: 1,048
Likes: 300
From: FL
From my understanding the underdrive pulley was really used for road racers that would stay up in the high rev range for long periods of time. Racers were having problem with over spinning the power steering pumps and having fluid leaks, etc. So they used underdrive pulleys to slow the whole system down in the high rev range. The 25% underdrive pulley is good for about 8rwhp.
I don't have one yet but I keep mixed reponses regarding charger and cooling issues. I may just save the $250 and stick with the factory balancer when I do my cam swap.
I don't have one yet but I keep mixed reponses regarding charger and cooling issues. I may just save the $250 and stick with the factory balancer when I do my cam swap.
Team Owner
Joined: Mar 2001
Posts: 25,889
Likes: 7
From: Virginia Beach
CI 3-5-6-7-8 Veteran
I wanted the best, so I put an ATI superdamper in when I did my cam swap. They only come in 10% underdrive because ATI couldnt achieve their level of dampening with anything more.
I have zero, I mean zero pulley wobble with it.
Some pics:
I have zero, I mean zero pulley wobble with it.
Some pics:
Thread Starter
Instructor
Joined: Jan 2007
Posts: 100
Likes: 0
From: Grand Junction Colorado
Than ks alot guys, looks like I am going to be running the ATI dampner since I already have a feeling like I will be going bigger and badderrin the future! Anybody know a forum vendor that supplies them?
