Pulley Bros 4AGZE supercharger pulley

[Pimpin_1JZ]

Anyone had any luck with these? I have just bought one and reading through the instructions, it says to machine the front clutch of original pulley. But from my understanding it is a whole replacement, or am I wrong?

Please halp.

[TERRA Operative]

The clutch is reused, but the pulley is replaced with the Pulley Bros. one.

You using this in a GZE? Good luck hitting 10PSI before it starts slipping.......

[Pimpin_1JZ]

You mean the belt slips or the clutch?

[TERRA Operative]

The clutch slips due to the lack of friction material in the pulley contact face.

The pulley was designed for use on Commodores with the SC supercharger fitted, and hence was never designed for more than 8PSI or so.

[Q-Authority]

The clutch slips due to the lack of friction material in the pulley contact face.

The pulley was designed for use on Commodores with the SC supercharger fitted, and hence was never designed for more than 8PSI or so.

That's not really true, not that I am defending the way this pulley was designed, but its pulley face is virtually no different in design or size from the Speedchaser pulley, which was also designed to be used with the oem sc12 clutch. There were definitely no problems with the Speedchaser pulley attaining proper increased boost levels, and avoiding clutch slippage.

Speedchaser, however, took advantage of the very long splines that the oem sc12 has on its input shaft, on which the oem clutch shaft engages. Because the splines are so long the oem clutch could be spaced outward a significant distance by using a very wide spacer, instead of the typical oem washer sized type. This allowed Speedchaser to extend the correct number of pulley ribs outwards, and have them correctly aligned with the other drive pulleys. If Pulleybro had done the same thing they would never have had the complaints about their pulley that they currently do.

Because PulleyBro did not do this, only 3 ribs of the pulley can therefore be aligned properly with the other pulleys, and that forced them to have to use an undersized 3-rib belt with it. I contacted them early on in the design of their pulley, and was told that their manufacturer had screwed up the design. PulleyBro just never bothered to have them correct it, which was a really bad decision, otherwise they would have no problem selling these things left and right.

FYI: the jdm 120mm pulley clutch is pretty near the same exact size as the PulleyBro pulley face, and is in fact used with the quite good, but very rare TBS 106mm sc12 clutched pulley assembly, which is completely plug 'n play with the sc12.

[TERRA Operative]

Here we go again...

As quoted from another post I made on this very subject:

Yea, Joe passed while testing a new pulley design and it appeared as though he lost control of his car. RIP.

You will find that most of their sales go to the Commodore crowd (Joe was involved with Commodores and designed the pulley to suit those engines) and as such only had to hold a few PSI boost. The pulley won't hold more than 9PSI, and as the Commodores don't run near this, the pulleys work fine.
Stick it on a 4AGZE, and you *will* have slip.
I know all about it, as I have done extensive testing, and provided tech support for Pulley Bros for the more curly questions regarding the SC superchargers etc from their clients.
I'm also mates with and helped the guy who was testing the new 92mm SC12 pulley that was in development (Who is friends with the Pulley Bros family), which also exhibited slip at higher boost (that one was able to peak at 13PSI during our tests). Through a few modifications I was able to lift the boost before it slipped by a few PSI, but it still did end up slipping.

Trust me, I know what I'm talking about.

These pulleys are fantastic for low boost applications and are very well made for that purpose, but they are not suited at all to high boost due to their lack of friction material on the pulley mating face.

With my tests we did machine in the extra ribs into the pulley so as to be able to use a 5 rib belt (it cost us $20 odd to get that mod done) and it made no difference to the slippage of the pulley.
We also tried pumping almost 30 volts into the coil and could only get about 10-11 PSI boost intermittently on the SC14 with the 103mm pulley.

And unfortunately, due to the untimely death of Joe, the Pulley Bros endeavour will be wrapped up by the family once all stock is sold unless a buyer for the business is found. Hence no further research and development is being or will be done until new owners are found etc.

[Q-Authority]

Well, this discussion could probably go on for quite some time, but it is not really worth it. I can only wonder at how Speedchaser managed to make theirs work, while PulleyBro could not. Additionally, since the TBS 106mm clutched pulley also works quite well, it doesn't seem as though it is the size of the pulley face that is the problem. My guess would be that unresurfaced clutches were used for the testing. That alone would reduce the useable contact surfaces significantly. Whatever the issue was it is too bad that it did not work out better, and of course a shame that Joe passed on.

[TERRA Operative]

Yep, we resurfaced both faces, twice during testing. We even used two different machine shops, to eliminate the possibility of mis-machining. Plus we tested with two independent pulley sets and an extra coil sent from Pulley Bros to rule out possible coil failure.

We (dave_101 on these forums and I) covered all bases possible, and the only thing that the Pulley Bros pulley doesn't have that is on the stock pulley is the metallic clutch material.
We actually had the metal on the contact faces 'smearing' and starting to turn blue from the slip.

It sucks, but the 103mm pulleys on an SC14 just won't work over 9-10 PSI. In the end dave_101 opted for a damped 165-something mm crank pulley instead.

[stepan117]

i have used this and had the same slip problem but then found using the old type clutch plate gave more pressure to the pulley and managed to et 16psi with an oversized crank pulley. Must admit it was a bit of a mess around getting it done plus tightening up a 3 ribbed belt tighter than normal , but finally got it going good

[Q-Authority]

i have used this and had the same slip problem but then found using the old type clutch plate gave more pressure to the pulley and managed to et 16psi with an oversized crank pulley. Must admit it was a bit of a mess around getting it done plus tightening up a 3 ribbed belt tighter than normal , but finally got it going good

Would you clarify just what it was you were using before the old type clutch hub that caused issues, and what was the difference between it and the old type? That might actually help others.

[stepan117]

ye sorry about that,

I have an 176mm alumimium oversized crank pulley and two undersized tensioner pulleys from Fensport in the uk. I used a Bosch 3PK950 3 ribbed belt and at first i had (i bileve ) the newer type clutch plate (looks pretty flat on the face) and found it too flimsy to sustain the presure on the metal faced Pulley Bros Pulley (boost dropped off at 10psi approx) so i turned to a more robust solid clutch ( i bileve the older type which has the cross shaped design on the face of it and thicker in construction) and found it to keep the pressure for the friction. I had to toghten the belt a bit more than usual to prevent slippage but it worked good
I also did an abv mod by plumbing a connection from the outlet manifold pipe to the abv valve to snap it shut quicker

[Q-Authority]

It sounds like you were using a clutch hub for the jdm 120mm sc pulley to start with, and then switched to the larger/older one afterwards. Interesting why the older/larger one worked better, as the newer/smaller one is used with the Japanese TBS 106mm clutched pulley and it works fine. Also, lots of people have used the smaller/newer 120mm clutch hub/pulley assembly with 175-180mm crank pulleys without any problems. They all manage well over 10psi, and I have known several that have have run them for quite some time. Wonder if your smaller/newer clutch hub could have just been a bit too worn. Hard to imagine the clutch itself being too flimsy, but you always have to wonder at these things.

[shrike]

so what would you have to do in order to run 1bar on a sc14?

[stepan117]

never used the sc14 but i guess a similar set up i.e. AVB mod (so it does'nt bleed off at 8psi ) and big crank pulley would raise the boost and i guess if you want more then a smaller pulley like the Pulley Bros sell , they do one for the sc14 which i bileve is a better design than the sc12 one with respect to the fact you can use a normal width belt rather then a 3 ribb

[shrike]

I know people that use the sc12 pulley on the sc14 to gain 1bar would this still allow the clutch to be used? or if say I got a custom pulley made in the same size would the clutch be able to be used I need to be able to disengage the sc at certain rpm points