Neumonic2002

Why does my tuner tell me NOT to get an underdrive pulley for my 2006 corvette when I do the cam swap?

I have run them on my last two cars w/o issue.

I have searched and no this is not my first rodeo either just wanting some facts not opinions on the subject.

Thanks
John

litle88

iTrader: (20)

Thats silly!
Do you have a sound system?

Neumonic2002

Running factory system and don't plan on changing it. The tuner was saying that a larger cam along with an ud pulley would complicate tuning, something about idle recovery due to the lighter mass at the front of the crank?
Bottom line is I am a little paranoid.

Nemesis350

iTrader: (11)

LOL no offense to anyone or their builder, but whoever says not to do something like that, just because it "complicates" tuning, is just being lazy

maxspeed96ct

iTrader: (3)

since it will already be off, and its only 200$ will give some kind of gain i went with it .

69LT1Bird

iTrader: (1)

Tell the tuner to man up and tune it.

Neumonic2002

Appreciate the feedback!

Did some additional research and it looks like the Powerbond is basically the same weight as the stocker but potentially more reliable.

I noticed maxspeed96ct did a 10% but the company I am looking to go with for my cam kit only has a 25% UD on there site?

I would think the power gain with a 10% is pretty mild but still upgrading to a better pulley.?.

Fb0dy0nly

iTrader: (10)

If he cant handle anything you bring to him or will not take on the challenge, I would say SEE YA! ...and find myself a new tuner!

Neumonic2002

Agreed, he will be fine. I am going to go with a powerbond or an slp and call it a day.

MikeMs01TA

iTrader: (2)

I had an ASP pulley on my new motor, until it spun. I thought it went on the crank a little too easy, compared to the stock one. Have a friend who also has an ASP pulley on his stock crank, and it's spun multiple times. I've told him it will keep happening, don't know if he went back to stock yet.

Neumonic2002

I have researched a few issues with the ASP but not the Powerbond or the SLP...wish I could afford the ATI

SShawn

iTrader: (6)

we almost always use our PowerBond UD Pulleys when we do cam swaps.

mike c.

iTrader: (1)

Get the pulley. I have a fluid damper pulley and it is WAY lighter then my stock pulley.

cam

iTrader: (9)

Wow you have to stay on top of whos stuff to buy.... When powerbonds were new and priced at 150 bucks they were the ones people were having come appart on them and ASP were looked upon as the holy grail of pulleys. Now it seems there has been a flip flop of opinions? Eeeeks scary

WADDISME

iTrader: (4)

When I was researching the build for my 402, seems like there was an issue with timing chains breaking, and the common denominator seemed to be ud pulleys. I opted not to do it. There hasn't been any new threads about the timing chain issue lately either, so not sure if that was really the cause. You can do a search on CF for some info in the C6Tech section. Good Luck.

cam

iTrader: (9)

For the couple of ponies they gain there sure is a lot of risk

Once again Bob I think Im gonna have to PASS on that one

Neumonic2002

On the timing chain breaks, I have found that easily 90% of the people that swap out the stock cam and go with something bigger or different end up changing the stock crank pulley for an underdrive pulley of various brands.
For the number of chains that have broken I would feel comfortable saying I doubt the balancer had much if anything to do with it and would point to the chain itself.
Think of valve springs, have you ever heard of a bad batch making it out to the public? the end result was valve springs breaking on many different setups - well the timing chain is no different...the bad UD pulleys came apart I thought? IDK

Thanks for the many replies as everyone has been a big help.
I feel confident in getting an UD pulley plus everyones feedback helped me dive deeper in my search to find out I needed to change the timing chain I was planning on using and spend the extra $$ to go with the Katech chain.

Larry

iTrader: (4)

Here's a before and after with an ASP underdrive and gutted cats at the same time. I have and 08 LS3 with NPP, Z06 manifolds, Airaid intake and my tuning. Same tuning on both pulls.

Larry

iTrader: (4)

Bet you didn't get it torqued down per instructions. Most don't have a torque wrench that will go to 250 lbs.

69LT1Bird

iTrader: (1)

I think the underlying issue is people think they torque them down tight enough but they don't. If you do not push the balancer up against the lower sprocket/oil pump drive tight enough and it moves, then the lower sprocket can slide forward which will bind the chain and cause problems.