Coy Miller's cog pullies

Ryan A Harris

Registered User
Ok, I am not saying I am going to make these, but I would know what they are? I would like to see, can anyone send me a pm or email. I am VERY interested in these.
 
If it where me, I think I would go to Coy Miller for that info.
He has done all the research.

Kurt Sr
 
Coy Miller Cogged Pulleys

Coy Miller Cogged Pulleys.
Coy Miller and myself are the only two cars running his special pulleys he is number 1 and I am number 2

His pulleys are proven performance ;)
 
Cogged supercharger drives are no hidden secret. I'm sure most of you have seen them and did not realize what they are. I know I have seen a couple of pictures of Coy's setup.

They are simply pulleys that are not flat or grooved, but have slots cut in the pulleys to allow the teeth of belt to grip the pulley. Big advantage is that they do not slip! They are also noisey.

Additional issues on the SC is the jackshaft. To have a really good setup you would need cog drives all the way down to the crank. This would actually involved making three pulleys (sc, jackshaft and crank) to get the most holding power. This can get a little expensive!

You also must size the pulleys for proper rotor speed and find (or have made) a cogged belt that fits around the pulleys.

I couldn't find a pic of Coy's engine (I'm sure someone will post it), but here are some other cogged sc pullies:

pull_top_v.jpg


blower5.jpg


BLN355SideMed.jpg
 
But wasn't Rich Thompson www.mn12performance.com the first to have a cog pulley system. I believe ASP made one set for him. Initial cost was something like $450. He was going to offer them but no one bought any at that price so he dropped it.
 
Yes Rich Thomson had ASP do the first set of cog pulleys. They were a combo type deal that used a rib belt from the crankshaft to the jackshaft and a cog belt from the jackshaft to the supercharger. That design also used the factory spring loaded tensioner. In other words it was a cog supercharger pulley and a rib/cog jackshaft pulley for the $450.00 or whatever is was, I've tried to forget the dollar part of this deal.

We ran it on the dyno and found out that the belt still sliped at the crankshaft side and the factory tensioner would not hold the cog type belt. ASP used what is known as a Hobb tool to cut the cog slots and that tool will not work on the small side of a step pulley like the jackshaft pulley, so we did that opration with a CNC mill. We also fabricated mechanical tensioners to work with the cog belts. The revised design is coged all the way.

So yes the origanel idea started out as a $450.00 pulley set but like more often than not it turned into a lot more. The only pulley from that deal that we were able to use in the end was the supercharger pulley itself.

Don't take me wrong I am not saying what ASP and Rich did was all wrong, that is just a part of development , it had to start some where. I guess the point I am trying to make is we did not buy a set of $450.00 pulleys and make a $1,050.00 profit from retailing them.

Also just to clear the air so to speak I don't think a cog pulley set in it self would put any one in the elevens, this is nothin' fancy. If you are on the edge and your supercharger belt is sliping then it would be one more part towards helping you hang on to that last bit of boost. For most people there are better places to invest your money, in other words this would be one of the later components you would need in a all out Supercoupe build up.

I am not a good salesman so I won't try to sale everyone on cog pulleys but if anyone thinks they are at the point of needing a cog set call us and we will be glad to help.

Thank's Coy Miller.
 
Noise and cogs.....made eazy

There is a way to get some of the noise to go away. This was talked about some time ago. The reason that a cog system makes noise is that the air get traped under the belt as it turns. This can be helped by drilling small holes in the flats of the pulleys. These work as a bleed off valve for this trapped air. On a 671 blower setup the noise level was greatly reduced by doing this. The guys at Blower Dirve were really happy with this trick and it has been used by some of us street racers to help hide that whistle that comes with their cog setup.. Just some helpful tips from the old guys who like to surprise their racing friends....Rich
 
When Coy brought his SC to Carlysle a couple years back, Eric gave me a quick ride around town. That sure put a smile on my face. Part of the enjoyment came from hearing the sweet sound of that cogged setup, a real head-turner. And to help clear up any misconceptions, I could have driven that car back to STL, it was completely streetable. Anyone that remembers it having a hard time starting should keep in mind that it occurred only after the EEC tuner was installed. I think the sounds a cogged setup makes are part of the reason to get them, but also expect to be replacing belts more frequently.

Mendola
 
Coy,

Good to see you post on here. I was just providing information and giving credit where credit was due. I wasn't trying to knock what you had done but just give Rich some credit on a first. I figured it was configured the way you described it because Rich said it would still allow the belt to slip. That's the only way I could see it being done.

Anyway, you are the first to break 11's and no one can take that away.
 
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