ATI Damper - 25% U/D
Thread Starter
Racer
Joined: Feb 2005
Posts: 280
Likes: 2
From: Houston TX
ATI Damper - 25% U/D
Does anyone have experience with the ATI 25% underdrive damper P/N 918661? I was going to pick up one they have on sale on "the auction site" (is that how it's referred to?).
I talked to them about it this morning and they said they're new, they just weren't advertised in print. Not sure why they can't just sell them like normal, but whatever. He said it works for an LS6 as well as LS1, is that right? Another wierd thing I noticed - when you scroll over the P/N on the ATI site, it says you need a special seal, but the guy said it doesn't.
Is there any draw back to an aluminum shell? Does anyone know the belt lengths needed for 25% underdrive accessory pulley and 10% A/C pulley? The guy said he'd never put one on and doesn't know.
I thought talking to him would make me feel better but it did the opposite, that's why I wanted to see if anyone had experience with these. Thanks!
I talked to them about it this morning and they said they're new, they just weren't advertised in print. Not sure why they can't just sell them like normal, but whatever. He said it works for an LS6 as well as LS1, is that right? Another wierd thing I noticed - when you scroll over the P/N on the ATI site, it says you need a special seal, but the guy said it doesn't.
Is there any draw back to an aluminum shell? Does anyone know the belt lengths needed for 25% underdrive accessory pulley and 10% A/C pulley? The guy said he'd never put one on and doesn't know.
I thought talking to him would make me feel better but it did the opposite, that's why I wanted to see if anyone had experience with these. Thanks!
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
http://www.atiperformanceproducts.co...ts/damserp.htm
They listed on thier website it comes under serpentime dampners, but nohing said about seal or belt length, infact summitracing did not list belt size either.
So hope somebody chime in here who had first hand exp.
I assume 78" length for main accessory belt and dont know about A/C tho. I guess whatever belt size fits ASP UD will fit same on this one but this ATI UD is 5.5" in dia which is smaller than ASP too.
They listed on thier website it comes under serpentime dampners, but nohing said about seal or belt length, infact summitracing did not list belt size either.
So hope somebody chime in here who had first hand exp.
I assume 78" length for main accessory belt and dont know about A/C tho. I guess whatever belt size fits ASP UD will fit same on this one but this ATI UD is 5.5" in dia which is smaller than ASP too.
Melting Slicks
Joined: Oct 2007
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From: Cedarburg, WI
Thread Starter
Racer
Joined: Feb 2005
Posts: 280
Likes: 2
From: Houston TX
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Melting Slicks
Joined: Oct 2007
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From: Cedarburg, WI
Tech Contributor
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From: Dyer, IN
Melting Slicks
Joined: Oct 2007
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From: Cedarburg, WI
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
I find this interesting because I spoke to one of their technical guys a few years ago and he told me there was an internal discussion at ATI about whether or not to produce a 25% under drive. The primary issue was it wouldn't dampen the crankshaft harmonics to a level they felt was required, but it was needed to compete with other companies. Looks like the bean counters may have won out on this one.
Melting Slicks
Joined: Oct 2007
Posts: 2,464
Likes: 2
From: Cedarburg, WI
I find this interesting because I spoke to one of their technical guys a few years ago and he told me there was an internal discussion at ATI about whether or not to produce a 25% under drive. The primary issue was it wouldn't dampen the crankshaft harmonics to a level they felt was required, but it was needed to compete with other companies. Looks like the bean counters may have won out on this one.
Melting Slicks
Joined: Oct 2007
Posts: 2,464
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From: Cedarburg, WI
Well after looking further at all my parts I have collected I may have to sell both the Powerbond 25% & ATI 25% Underdrives..
I bought a used QTP two piece timing cover and their site says it won't work with underdrive A/C!
Looks like I will be looking for the ATI 917278 instead..
I bought a used QTP two piece timing cover and their site says it won't work with underdrive A/C!
Looks like I will be looking for the ATI 917278 instead..
Thread Starter
Racer
Joined: Feb 2005
Posts: 280
Likes: 2
From: Houston TX
Nope, still don't know what belts to use and it's not installed yet. I bought a GMPP extended warranty a few years ago so the dealer is covering the leaking front crankshaft seal and is going to install the ATI tomorrow when they fix that. They do have belts there so unless I find out the right length tonight, all I can hope is that they can find one that works. ATI didn't even know what the correct length was.
I got mine on EbXX as well. It was nice to find the price break for the ATI!
Thread Starter
Racer
Joined: Feb 2005
Posts: 280
Likes: 2
From: Houston TX
About your conversaton with the ATI tech - if it was a few years ago and their 25% underdrive damper is only a few months old (from what I understood), isn't that enough time to develop one that does dampen vibrations properly? I hope that a company like ATI wouldn't sell a sub-par product just to appease the "bean-counters" and to compete with other proven products, but of course time will tell... Seems like a big risk on their part to me.
Just curious to know as much as I can about all this, sounds like you're much more in the loop than I am but just wanted to bring up that point to see what you think. I actually wasn't even planning on this mod at all until the crank seal started leaking and I read about it. Seems like a new balancer is a good idea if it comes off for whatever reason so may as well pick up a few ponies while the work is being done!
Drifting
Joined: Jan 2005
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I'm not having any problems with my 25% ud.. The Powerbond pulley seems to work great. The AC has no underdrive though (I'm assuming not, anyway, same length belt.. ) I'm not sure that would make much of a difference.
Truth be told, I wasn't going to get one either, but when doing a cam swap, might as well, right? So I tossed in last min and so far so good!
) I'm not sure that would make much of a difference. Truth be told, I wasn't going to get one either, but when doing a cam swap, might as well, right? So I tossed in last min and so far so good!
Thread Starter
Racer
Joined: Feb 2005
Posts: 280
Likes: 2
From: Houston TX
I'm not having any problems with my 25% ud.. The Powerbond pulley seems to work great. The AC has no underdrive though (I'm assuming not, anyway, same length belt.. ) I'm not sure that would make much of a difference.
Truth be told, I wasn't going to get one either, but when doing a cam swap, might as well, right? So I tossed in last min and so far so good!
) I'm not sure that would make much of a difference. Truth be told, I wasn't going to get one either, but when doing a cam swap, might as well, right? So I tossed in last min and so far so good!
Do you happen to know what length belt you're using? I imagine they'd be the same or close between the different pulley manufacturers. Worth a shot anyway. Thanks.