I found out what has been robbing some of my power.
07-16-2018, 11:26 PM
#1
Burning Brakes
Thread Starter
I found out what has been robbing some of my power.
WTF. When I had my motor rebuilt I decided to replace the balancer. At the time, there were plenty of posts about failing ATI balancers so I decided to go with a Powerbond balancer. I was going back through the parts on my car tonight and I noticed that I purchased a 10% Overdrive balancer instead of a 10% Underdrive balancer. It has an outside Diameter of 8.2" instead of 6.75" for an underdrive pulley. It is also made out of steel and weighs more than 12lbs, whereas the ATI weighs 8lbs. I cannot believe that I made this mistake.
Last edited by lamboworld; 07-16-2018 at 11:30 PM.
07-17-2018, 08:41 AM
#4
Burning Brakes
Thread Starter
07-17-2018, 08:49 AM
#5
Melting Slicks
Member Since: Jun 2005
Location: Rochester NY
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St. Jude Donor '10, '17
That sucks. Good news is that since you have decided to swap cams (again) that the balancer will be off anyhow. Replace with ATI 10% underdrive or Innovators West standard diameter. Don't ever put an OEM balancer back on your car. Don't even think of it. And grab an ARP balancer bolt while you are at it. ATI has allegedly rectified some of the issues they were having with poor heat treatment on their balancers.
ATI:
https://www.texas-speed.com/p-1193-a...ncer-w-ac.aspx
IW:
https://innovatorswest.com/850-LS7-Damper.html
ARP Bolt:
https://www.texas-speed.com/p-2802-a...it-gm-ls7.aspx
ATI:
https://www.texas-speed.com/p-1193-a...ncer-w-ac.aspx
IW:
https://innovatorswest.com/850-LS7-Damper.html
ARP Bolt:
https://www.texas-speed.com/p-2802-a...it-gm-ls7.aspx
07-17-2018, 09:24 AM
#7
I doubt that 10% overdrive is costing you more than 5-7 wheel as thats about all the 10% under drives give you
07-17-2018, 09:25 AM
#8
Yep:
https://www.corvetteforum.com/forums...questions.html
https://www.corvetteforum.com/forums...questions.html
Originally Posted by Grand Sport Man 
I have used them on others cars but not the vette. I have a 2010 LS3.
1) What is the percentage of underdrive and are there different percentages offered for the vette.
10% and 25% are your 2 choices
2) Average HP gain; any dyno or track results from just adding a pulley.
I don't know of anyone who has done a back to back test, but 7-10whp is the norm for a 25% UDP. The car doesn't make any extra power, but power is freed up as a result of the slower spinning accessories.
3) Does it affect the cooling or charging system, if so how much.
This is a highly debated topic when it comes to an UDP. Some people have issues, but from the research I did before buying one myself, the increased idle speed makes up for the slower spinning alternator at idle and no adverse effects are present. I have a 25% UDP in my car and also a tiny 17lb motorcycle battery in my car and have yet to experience any issues with charging or starting after the car has sat for over a week. I do not use a trickle charger. The deka battery just plain works.
4) Best brand to use and price range.
After reading of multiple people snapping timing chains with a particular UDP, I would go with either a Powerbond or ATI. I have a good buddy(taken19) who road races often and snapped a C5R timing chain within a year. There have been a few different threads about this and road race+that brand of UDP=bad harmonics and a broken timing chain.
If I do one, I would like to get the right one. Thanks
I have used them on others cars but not the vette. I have a 2010 LS3.
1) What is the percentage of underdrive and are there different percentages offered for the vette.
10% and 25% are your 2 choices
2) Average HP gain; any dyno or track results from just adding a pulley.
I don't know of anyone who has done a back to back test, but 7-10whp is the norm for a 25% UDP. The car doesn't make any extra power, but power is freed up as a result of the slower spinning accessories.
3) Does it affect the cooling or charging system, if so how much.
This is a highly debated topic when it comes to an UDP. Some people have issues, but from the research I did before buying one myself, the increased idle speed makes up for the slower spinning alternator at idle and no adverse effects are present. I have a 25% UDP in my car and also a tiny 17lb motorcycle battery in my car and have yet to experience any issues with charging or starting after the car has sat for over a week. I do not use a trickle charger. The deka battery just plain works.
4) Best brand to use and price range.
After reading of multiple people snapping timing chains with a particular UDP, I would go with either a Powerbond or ATI. I have a good buddy(taken19) who road races often and snapped a C5R timing chain within a year. There have been a few different threads about this and road race+that brand of UDP=bad harmonics and a broken timing chain.
If I do one, I would like to get the right one. Thanks
07-17-2018, 09:47 AM
#9
Le Mans Master
I have an oem one if you need it. No issues, just went ATI (stock diameter) when I did my cam swap
07-17-2018, 09:48 AM
#10
Burning Brakes
Thread Starter
Yes I agree. I think that I am giving up 5 to 7whp because I am using a 10% overdrive and I am probably also giving up 5 to 7 by not using a 10% underdrive. I also don't know if I am giving up any power because of the weight difference. My current balancer weighs more than 12lbs and I think that the ATI is quite a bit lighter.
07-17-2018, 09:54 AM
#11
Burning Brakes
Thread Starter
07-17-2018, 01:03 PM
#12
Drifting
I will apologize in advance if this has been covered before but I have been off the forum for a long time. You guys report that several of the ATI balancers have failed. What were the failures and causes and how frequent do you guys think it happened? Did they fail in the housing, inertia ring or the steel or aluminum hubs? Under what circumstances did they fail? Thanks a lot if you guys can give me some insight.
Gary
Gary
07-17-2018, 06:13 PM
#13
Melting Slicks
That sucks. Good news is that since you have decided to swap cams (again) that the balancer will be off anyhow. Replace with ATI 10% underdrive or Innovators West standard diameter. Don't ever put an OEM balancer back on your car. Don't even think of it. And grab an ARP balancer bolt while you are at it. ATI has allegedly rectified some of the issues they were having with poor heat treatment on their balancers.
ATI:
https://www.texas-speed.com/p-1193-a...ncer-w-ac.aspx
IW:
https://innovatorswest.com/850-LS7-Damper.html
ARP Bolt:
https://www.texas-speed.com/p-2802-a...it-gm-ls7.aspx
ATI:
https://www.texas-speed.com/p-1193-a...ncer-w-ac.aspx
IW:
https://innovatorswest.com/850-LS7-Damper.html
ARP Bolt:
https://www.texas-speed.com/p-2802-a...it-gm-ls7.aspx