CorvetteForum - Chevrolet Corvette Forum Discussion

C6 Tech/Performance LS2, LS3, LS7, LS9 Corvette Technical Info, Internal Engine, External Engine, Tech Topics, Basic Tech, Maintenance, How to Remove & Replace
Sponsored by:
Sponsored by:

Underdrive pulley

Thread Tools
 
Search this Thread
 
Old Apr 30, 2008 | 08:26 PM
Share
  #1  
Bad06vette's Avatar
Bad06vette
Thread Starter
Burning Brakes
15 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Jan 2007
Posts: 1,093
Likes: 0
From: Dallas TX
Default Underdrive pulley
I tried searching but didn't see much information on an underdrive pulley. Are these worth it? Will I see any significant gain? What exactly is the purpose of them?

I don't see many people talking about getting these or people listing them on their mods list... I figured that might be a sign. I had one on my SS, so I was just wondering if it would be worth it on the vette, I think they are around 250-300...

Any info would help. I don't want to be buying anything in the future that isnt worth it. Thanks!
Reply
0
Old Apr 30, 2008 | 08:32 PM
Share
  #2  
dennis50nj's Avatar
dennis50nj
Race Director
10 Year Member
 
Joined: Mar 2005
Posts: 11,549
Likes: 27
From: Southampton NJ
Default
yes the pully is worth it. 5-8 hp also you get to pin the crank
Reply
0
Old Apr 30, 2008 | 08:36 PM
Share
  #3  
Bad06vette's Avatar
Bad06vette
Thread Starter
Burning Brakes
15 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Jan 2007
Posts: 1,093
Likes: 0
From: Dallas TX
Default
Originally Posted by dennis50nj
yes the pully is worth it. 5-8 hp also you get to pin the crank
What do you mean by pin the crank? How come most people dont have/dont talk about the underdrive pulley?

Also, where is the best place to order one? How easy is the install?
Reply
0
Old Apr 30, 2008 | 08:43 PM
Share
  #4  
C6400hp's Avatar
C6400hp
Safety Car
 
Joined: Jun 2005
Posts: 3,989
Likes: 5
From: DFW This user does not support or recommend the product or service displayed in the ad to the right
Default
Originally Posted by Bad06vette
What do you mean by pin the crank? How come most people dont have/dont talk about the underdrive pulley?

Also, where is the best place to order one? How easy is the install?
You have answered your own question, almost. Most people don't talk much about them because they are usually only added in the process of a cam swap. The reason they are only usually added with a cam swap is because it will cost you nearly the same labor to install an underdrive as it would the cam and underdrive. Its fairly labor intensive. If you are going to do one, I would make sure you have it checked for balance, I have heard of some that have been as far as 18 grams out of balance. Not very good for a balancer to be out of balance , eh.

Pinning the ccrank is just as it sounds, putting a pin through the balancer and into the crank to eliminate the possibility of of the balancer coming loose from the crankshaft.
Reply
0
Old Apr 30, 2008 | 09:23 PM
Share
  #5  
dennis50nj's Avatar
dennis50nj
Race Director
10 Year Member
 
Joined: Mar 2005
Posts: 11,549
Likes: 27
From: Southampton NJ
Default
lots of labor most wait since the pully comes off anyway on a cam swap but if you are trying to get every ounce of power in bolt/on mode every little bolt/on counts
Reply
0
Old Apr 30, 2008 | 09:25 PM
Share
  #6  
Bad06vette's Avatar
Bad06vette
Thread Starter
Burning Brakes
15 Year Member
Conversation Starter
All Eyes On Me
 
Joined: Jan 2007
Posts: 1,093
Likes: 0
From: Dallas TX
Default
Originally Posted by dennis50nj
lots of labor most wait since the pully comes off anyway on a cam swap but if you are trying to get every ounce of power in bolt/on mode every little bolt/on counts
Yeah... I'll probably just pass on the pulley... unless I get a cam in the future.
Reply
0
Old May 1, 2008 | 06:43 PM
Share
  #7  
sea six's Avatar
sea six
Burning Brakes
15 Year Member
 
Joined: Oct 2006
Posts: 752
Likes: 0
From: Lebanon CT.
Default
It is not necessary to access the pulley from the top, you can do it from the bottom and it takes 2 / 3 hours. Do a search! Spin had a DIY on this very subject!

Reply
0
Old May 1, 2008 | 08:51 PM
Share
  #8  
Ragtop 99's Avatar
Ragtop 99
Safety Car
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Nov 2007
Posts: 4,537
Likes: 1,403
From: Bethesda MD
Default
IIRC, even using Spin's method, it was much more involved than doing an F-body.
Reply
0
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old May 1, 2008 | 09:32 PM
Share
  #9  
huckleberrydude's Avatar
huckleberrydude
Pro
 
Joined: Oct 2003
Posts: 639
Likes: 0
From: springfield missouri
Default
Originally Posted by sea six
It is not necessary to access the pulley from the top, you can do it from the bottom and it takes 2 / 3 hours. Do a search! Spin had a DIY on this very subject!

I agree with you but it is still a pain in the butt. Havent read the DYI, but it is pretty straight forward.
Reply
0

Get notified of new replies

To Underdrive pulley

Tags
Back to Subforum
C6 Tech/Performance
View Next Unread
NPP dyno question??




Click for Advanced Search
Reply Closed Thread Share
Forum Jump
Trending Topics

All times are GMT -4. The time now is 06:12 AM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE