The idler pulley that come off is a HKS pulley (I believe). The GTM one is a different pulley altogeter--the one that is right on top of the blower and is smaller.

 

So your referring to this pulley?

 

or this one?

 

^^^Yes, this one--the biggest one--furthest to the left

 

wow that's strange man. I can only think that it has been overstressed with the extra boost the GTM pulley is producing. I'm sure HKS would have seen this on their kit after all the testing they did if it was a common problem.
Has the pulley itself been damaged? If not, you should be able to remove the broken bolts, and replace them and be on your way again in no time.

 

That makes no sense, that pulley is not affected at all by going to a smaller pulley.

That pulley's speed is directly related to the RPM of the motor, regardless of the pulley on the blower.

Give us a call at the shop johnnylaw so we can see what we can do for you.

-George
GT Motorsports

 

that is the one that HKS replaced under the recall.

+1 on George..

 

Well surely it is. The more boost your trying to push, the more load your trying to put on the motor end, and the idler pulley is the link between the engine and the supercharger right? I'm talking about load, not speed.

 

It's a fixed idler pulley, it doesn't see load just speed. The blower will see load, and so would the engine, but not that pulley.

-George
GT Motorsports

 

The 1 to the far left is a drive pulley. the belt goes from the crank and then from the crank to the blower. Its at least seeing the most load, load pulling down (crank belt being tightened) and a perpendicular load from the belt to the blower.

Either way, sucks that it broke. I guess you need some 'mad JDM yo' patience now.

 

Right, so how does the engine transmit its power to the blower?!?!?

The crank transmits the power to the idler pulley, and the idler pulley transmits the power to the supercharger, and vice versa, the supercharger load is sent to the idler pulley which in turn sends the load to the engine. The idler pulley is the middle man, so really it's the one that is seing the most load.
The load from the supercharger has to be transmitted somehow, it can't just leap across to the engine.

 

My lamens thinking.

The belt is a fixed length and does not change hence the static load on the pulley does not change.

Where you may see additional load/strain on the pulley is when you actually give the car a hit like taken off from the lights. The smaller pulley on the SC creates more power initially therefore at this point there may be more load on the pulley. Once everything is moving in unison then the load would reduce.

Have no idea if this thinking is true.

Keep in mind we do not know how tight the belts were and if the pulley in the picture is the new version of the item.

If the belts were too tight this would contribute to additional strain.

 

Its pointless for me to continue to further explain, just think about it longer

-George

 

Instead of just undermining someone why don't you try and help them understand with your explanation. Here's mine.

Imagine the crank and idler pulley as one system, and the supercharger as another system. Two separate systems.
The crank and idler pulley are connected via a belt. When the crank is turning, so is the idler pulley, but the idler pulley is spinning freely and putting no load on the engine, right? Now imagine trying to grab the idler pulley and trying to stop it. Now you have put load on that pulley right? Well, the supercharger system is the same as you trying to grab that pulley. Increasing the boost on the supercharger is the same as trying to squeeze the idler pulley harder.

P.S. I'm not arguing with you, i'm just hungry for knowledge and would like to understand your theory.

 

Stronger bolts were used to replace the ones that come with the HKS kit that were broken. The idler pulley has been secure, even under high load. I still have some occasional belt issues on cold start (screeching/burning smell coming from belts) for ~20 seconds, but hope to get that resolved shorty. The car has felt really good, especially with my Volks and re050a pole positions mounted.

 

What sort of bolts did you replace them with, and what bolts came with it originally? I ask because i might just upgrade the bolts straight away when i get the kit.