edz968s

The bearing that is 'failing' has no belt tension on it, it`s the bearing the impeller is running in that is overheating and letting go.
Don`t know why yet, maybe a bad batch as Carl mentioned, but with turbo bearings running higher temps and surviving; it`s an unknown as to why at the moment they are overheating, but it is seriously being looked into.

Lemming

That is not true, they said that they would no longer warranty mine because it was being used for racing!

Carl Fausett

I disagree. They did honor your warranty and we did rebuild your supercharger without charge even though it was used for racing. But they also said they would not do it again.... See post 1038 and 1040.

Generally speaking - Raptor is now instituting a "warranty void if racing" policy just like Vortech and Paxton do.

But Tim, we did rebuild yours anyway under the warranty.

Carl Fausett

The new Stage II crank pulleys have arrived, and I have test-fit them to the 968 sprocket and they are good.

Now they are off to be hard-coated.

The matching 2.55" supercharger pulley for the Stage II kit is in manufacturing right now. (Review details in post 1066)

They both (the SC pulley and the Crank pulley) should be ready at about the same time.

Here are some pics of the crank pulley fresh from the mill...

mikey_audiogeek

Different application, I know, and possibly OT. But we had a problem with a big industrial fan that was killing belts and finally killing bearings, always the axial thrust bearing. Turned out to be an air column resonance interacting with the torsional resonance of the drive, causing a cyclic thrust load as the rotor vibrated torsionally.

Once we tuned away from the resonance, we stopped killing belts AND thrust bearings.
Adding some flow resistance was a quick and dirty way to kill the resonance.
Thrust bearings showed signs of roller skidding and smeared raceways as a consequence of the incredibly high torsional accelerations.

Ok, we return you to your usual programming...

Pulleys look great, Carl!

Cheers,
Mike

Carl Fausett

Yes a big industrial air mover can produce quite a "chop" - but the torsional oscillations of a 6" impeller with 20 vanes is so smooth as to be hard to measure. Thanks for the note, but I dont think torsional oscillation of the shaft is an issue in this application. Interesting note, tho.

However: the larger pulleys on both the crank and supercharger will meen that the user does not have to tighten the belt so much, reducing side load on the bearings and lowering temps, extending bearing life.

Crazy Canuck

That international buyer is my friend who is still waiting on the upgraded crank pulley despite paying for it back in May and a promise it was shipped a month ago.

We want to install the SC in the car but want the upgraded crank pully and we have track days scheduled for the weekend 17-18-19 of Aug.

Carl Fausett

I have the 968 Crank pulleys in my hands. Photos attached.

I am only waiting on the matching supercharger pulley to come back from the hard-coat process, so I can ship the two pulleys together in the same box.

I expect them here this week.

Carl Fausett

The matched sets of pulleys (crank and supercharger) were shipped yesterday, 08/11/2011 to everyone that prepaid for them.

Thank you for your patience.

The only thing I do not know is what belt length you will need for these as I do not have a 968 here at the moment.

Once you find out which belt length fits, please let me know.
Buy the belt locally from NAPA or whatever and send me the receipt and I will refund you the purchase price.

Belt tip: use a seamstress cloth measuring tape, run it around the pulleys and walk into NAPA with the length you find. Put the tensioner in the middle of its travel when you measure. They will hand you a 6-rib belt based on that length, and you should be all set.

edz968s

My unit has now been rebuilt in Australia and is winging it`s way back to you Carl.
Let me know when it`s on the way back here
Then we can get it back together and running

Carl Fausett

Yes, we are expecting it. You are getting a completly new unit, so I have to drill and tapp oour mounting holes into it for you.

Condis

Hi

I´m a new reader here. This topic has been very interesting. I own allso 968. I´ve thought get some extra power allso to my car. I´ve noticed that there had been many problems with this kit. How many kits Carl you´ve sold? Is there anyone who is totally satisfied this kit without technical problems. I´m looking reliable system. I would be grateful yours honest answers.

Carl Fausett

There have not been many problems with this kit. The Stage 1 kit has been remarkably problem free.

However, the Stage II kit was taken racing and found not to have enough belt wrap, so belt slippage occured.

That has now been addressed with the new Stage II pulleys.

Condis

Thank´s Carl your quick answer. I want to raise my virtual thumb up for you. You´ve done never giving up development work. Hopely you´ll get solve those little technical problems.

Carl Fausett

Who has installed these new Stage II pulleys? I need to get the belt length from you...