Replace stock idlers when doing lower pulley swap?

[cobra940]

I couldn't find any recent threads regarding this so I thought if throw this out there.
Basically I'm swapping the lower crank pulley to a 8lb (metco lower pulley crankshaft kit) with stock upper with the 3.70" alternator pulley. (Will be tuned)
Should i be switching out the idler pulleys as well or am I ok staying with stock.
Car is weekend driver and street driven not drag.
Any advise is greatly appreciated.
Thanks!

 

[roy_1031]

I blew up a stock idler on a 2.8" upper only pulley. I recently bought some metco double bearing idlers and an aux idler. I would replace them.

 

[cobra940]

I blew up a stock idler on a 2.8" upper only pulley. I recently bought some metco double bearing idlers and an aux idler. I would replace them.

Did you go with the 90 or 100mm?
As for the aux idler it's says on the metco sites it's recommended when swapping the upper but says nothing about the lower...

 

[roy_1031]

Did you go with the 90 or 100mm?
As for the aux idler it's says on the metco sites it's recommended when swapping the upper but says nothing about the lower...

I went with what lethal had on there site. I think it's a 90mm by the blower and the rest of them are 100mm. The way I see it is doing either an upper or lower pulley, spins the blower harder which turns the idlers faster. I would do the idlers if I was throwing an 8lb lower on it. That's going to put you around somewhere around 16-17lbs of boost isn't it?

 

[cobra940]

According to this it should be just under 14psi ( I pulled it off the terminated FAQ)

I agree though, they will be spinning faster, probably should all be swapped

 

[cobra940]

Anyone else wanna put in there .02 cents

 

[b_dike]

Yes, swap them now. I blew one apart with just a 2.76 and 100mm idler. If you race at all it's bound to happen, and even if you don't. It's just good insurance.

 

[cobra940]

Looks like metco is offering 2 options
3- 100mm and one 90mm or vice versa
3- 90mm and 1 -100mm

Should I be leaning to one side more then the other?

 

[Senkak]

Definitely swap out your stock idlers for good aftermarket pieces.
The OEM idlers have been know to break and cause damage.
Your idlers are also over 10 years old.

 

[timspony]

Definitely swap out your stock idlers for good aftermarket pieces.
The OEM idlers have been know to break and cause damage.
Your idlers are also over 10 years old.

All excellent points .... I've been running Metco products for years!

 

[CobraBob]

I always recommend swapping out the stock idlers for the reasons that Rick mentioned above. It isn't worth the risk IMO of having a stock idler explode when you least want it to. The stock stamped steel idler are at best a compromise. Add in age (10 years +) and increased idler rpms and it's just a matter of time.

 

[cobra940]

Thanks everyone for your input . I'm ordering a metco set tomorrow from Rick

 

[Senkak]

Thanks everyone for your input . I'm ordering a metco set tomorrow from Rick

Wise idea.

 

[cobra940]

Wise idea.

Whoa... That's crazy! Did that go during a regular cruise?

 

[roy_1031]

Wise idea.

That's pretty much what mine looked like on a spirited uphill canyon drive. That's the reason I don't have a hood liner any more. When my stock idler gave up the ghost it shredded the belt and the hood liner. I'm still picking out pieces if shredded belt 3 years later!

 

[04sleeper]

Wise idea.

I have seen this happen so many times it should have been a recall!

Stock idlers have known to go out even in stock form. Add a lower pulley to that and you increase the speed the pulley's are spinning = quicker disaster!


I would suggest a quality set of aftermarket idlers such as Metco.

 

[Bdubbs]

One of my first mods was different idler pulleys. Stock ones look like crap too!

 

[cobra940]

Placed my order for 3 - 100mm and 1- 90mm metco set

 

[04MystiCobra]

Metco is the way to go.

 

[TRBO VNM]

You must have searched the wrong terms. Many have had issues with stock idlers no matter the situation. Poor design from the factory.