10% Overdrive Crank Pulley

I am considering manufacturing a 10% overdrive crank pulley for the Super Coupe and would like to know if there is interest in it. As you all know the small 10% blower pulleys tends to slip because the surface area is reduced when the pulley diameter is reduced. If the crank pulley is instead made larger in diameter by 10% you will realize more blower overdrive without any of the pulleys being made smaller and thus reduce the tendency to slip.

Let me know if you like the idea.

Charles
Magnum Powers, LLC

That would make for an awesome new product. You might even think about making a 5% overdrive crank pulley for people who just want 5% or for those people who already have something on their car but want to step up to 10%.

Oh, how about a bigger blower.

I cannot see the advantage of a larger crank pulley since it will increase weight and at the worse point in the system, the outer diameter of the pulley which sees the highest stress. With the troubles some have had with keeping a crank in the SC, that is one point I would look to reduce weight at, not increase it.

The 10% jackshaft pulley has already been proven to increase blower speed while reducing weight without belt slip.

Paul

Light weight Aluminum 10% overdrive crank pulley

BT Motorsports said:

I cannot see the advantage of a larger crank pulley since it will increase weight and at the worse point in the system, the outer diameter of the pulley which sees the highest stress. With the troubles some have had with keeping a crank in the SC, that is one point I would look to reduce weight at, not increase it.

The 10% jackshaft pulley has already been proven to increase blower speed while reducing weight without belt slip.

Paul

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Hi Paul,
The stock Ford pulley is made of steel and weighs 6.2lbs. The pulley I've designed is made of aluminum and weighs 2.2lbs.

BT Motorsports said:

I cannot see the advantage of a larger crank pulley since it will increase weight and at the worse point in the system, the outer diameter of the pulley which sees the highest stress. With the troubles some have had with keeping a crank in the SC, that is one point I would look to reduce weight at, not increase it.

The 10% jackshaft pulley has already been proven to increase blower speed while reducing weight without belt slip.

Paul

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people that are snapping cranks is due to an improper tune, advancing the timing too much just to try to find more horsepower without getting greasy. I personally think a 10% crank would de ideal. the couple more ounces is not going to make a bit of difference!

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Sounds like a great idea. I would like to see it produced.

Magnum Powers said:

Hi Paul,
The stock Ford pulley is made of steel and weighs 6.2lbs. The pulley I've designed is made of aluminum and weighs 2.2lbs.

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Well, if it is truly 2.2lbs, yet larger than the stock crank pulley, that is certainly impressive and I would like to see it. From the measurements George Davenport has taken, the stock crank pulley weighs 7.03125lbs and the aluminum underdrive ASP crank pulley which is smaller than stock weighs 2.84375lbs. How did you get a larger pulley than stock to weigh around 1/2lb less than the smaller ASP underdrive pulley and still maintain enough strength?

Kevin Leitem said:

people that are snapping cranks is due to an improper tune, advancing the timing too much just to try to find more horsepower without getting greasy.

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Kevin, I personally recall off the top of my head two people (know both of them personally in fact) who had issues with breaking crankshafts on more than one occasion in reference to my comment. One of them was running a relatively stock vehicle with no timing changes and the other had a dyno tune by Brian Herron. In both of these instances, timing advance was not an issue.

the couple more ounces is not going to make a bit of difference!

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I would agree if the few ounces were added at or very near the center of the pulley, however, weight added at the outer portion of the pulley is very significant to changes in stress on the crank. Granted, an aluminum pulley of less weight than stock will reduce the stress the crank sees, however, that information was not provided prior to my response. I still ask though, why produce such a part when the same goal has already been accomplished with the jack pulley..... "why try to reinvent the pulley"?

Charles, if anything, it would seem the biggest benefit would be to produce the lightest crank pulley possible to work with a 10% jack pulley. This would combine the greastest amount of weight savings while still allowing 10% overdrive for those who want it.

Kevin, I personally recall off the top of my head two people (know both of them personally in fact) who had issues with breaking crankshafts on more than one occasion in reference to my comment. One of them was running a relatively stock vehicle with no timing changes and the other had a dyno tune by Brian Herron. In both of these instances, timing advance was not an issue

was the balancer correct? weight sould not be an issue if it is balance properly!! When i got my 5% jackshaft i was dissapointed that the side of the pully for the crank was made smaller and the supercharger side was left alone. i hoped the supercharger side would be bigger. And please don't tell me that would add weight! I don't want to make it sound like i know everything, but most people try too hard to make these engines run better. all it take is work at the places where it counts

I think Charles is headed in the right direction. One of the most effective ways of increasing the boost in a Cobra, Lightning or Harley Truck is by a larger aluminum crank pulley. So, I can see where Charles is headed since it's already being done with the above mentioned car and trucks. They don't seem to have any problem with the larger and lighter crank pulley. Ha, maybe it's one of those companies that will be making them for Charles.

Charles, I think you have a winner on your hands, especially, if you produce a 5% crank pulley for those people who already have a 5% supercharger pulley or one of the new 5% SCP jackshaft pulleys. I would make a 5% and 10% and capture all of the market. Heck, I would start now and setup a group buy within the group buy forum.

Last, but not least, a lot of people will buy from you because you have a trusted name within our community and you support our cars and events.

I like the idea of it. Some people will mod their cars in stages and this will fit in well with some of those types of approaches. Take my example for instance:

I have a 5% pulley installed
Lightweight jackshaft pulley installed

I'd rather keep the parts I've already spent my hard earned money on and overdrive the supercharger via the crank pulley. I don't have the exhaust (today) to go faster with the supercharger, so that's why I went only with the 5%. This just will give another option to those of us whose budgets are a bit tighter than others. I like the idea and would very much like the option when I am ready to address the pulleys on my SC.

Nettlesd said:

I think Charles is headed in the right direction. One of the most effective ways of increasing the boost in a Cobra, Lightning or Harley Truck is by a larger aluminum crank pulley. So, I can see where Charles is headed since it's already being done with the above mentioned car and trucks. They don't seem to have any problem with the larger and lighter crank pulley. Ha, maybe it's one of those companies that will be making them for Charles.

Charles, I think you have a winner on your hands, especially, if you produce a 5% crank pulley for those people who already have a 5% supercharger pulley or one of the new 5% SCP jackshaft pulleys. I would make a 5% and 10% and capture all of the market. Heck, I would start now and setup a group buy within the group buy forum.

Last, but not least, a lot of people will buy from you because you have a trusted name within our community and you support our cars and events.

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OK, it sounds like there is some interest out there for this product. I have both a 5% and a 10% pulley design that I will send out for quotes. These pulleys must be surfaced treated for good wear qualities and long life. They can be black, some other color (red, blue, etc) or clear. What color would you like to see? Since quanities are limited we need to decide on one. I think Black or Clear. What say you? Oh, yea I could make matching jackshaft and blower pulleys as well if there is interest in them.
Charles

Magnum Powers said:

OK, it sounds like there is some interest out there for this product. I have both a 5% and a 10% pulley design that I will send out for quotes. These pulleys must be surfaced treated for good wear qualities and long life. They can be black, some other color (red, blue, etc) or clear. What color would you like to see? Since quanities are limited we need to decide on one. I think Black or Clear. What say you? Oh, yea I could make matching jackshaft and blower pulleys as well if there is interest in them.
Charles

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Charles,

I'm not sure how far along you are in the design, but, I would look into making them a 2-piece design, where as, someone could swap between the 5% and 10% portion of the pulley. This way, people could have the best of both worlds. I believe you probably follow what I'm trying to say so I won't elaborate on the actual design.

Also, as you can see, 007_SuperCoupe is the market segment I'm talking about in my previous post.

What kind of Aluminum will be used? What kind of testing will used to make sure the pulley doesn't fail after it goes out to the public?

I think this is good idea. Giving more options for the SC's owners to OD the blower. I'm not going to doubt it, or bad mouth it, I'd like to see it before I'd pass my judgement on it.

Keep up the good work.

Ryan A Harris said:

What kind of Aluminum will be used? What kind of testing will used to make sure the pulley doesn't fail after it goes out to the public?

I think this is good idea. Giving more options for the SC's owners to OD the blower. I'm not going to doubt it, or bad mouth it, I'd like to see it before I'd pass my judgement on it.

Keep up the good work.

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Yup, I agree with what Ryan said. Charles, I am still waiting for a response to how you are going to make a larger than stock pulley lighter than the smaller underdrive ASP offers from the same material while retaining strength and reliability?

Paul

BT Motorsports said:

Yup, I agree with what Ryan said. Charles, I am still waiting for a response to how you are going to make a larger than stock pulley lighter than the smaller underdrive ASP offers from the same material while retaining strength and reliability?

Paul

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These kinds of things are made of 6061 T6 aluminum billet. If there are people interested in testing a few prototypes I can work something out. Then again it is not a problem to beef it up a bit and come out with a 3 pound pulley that’s a very conservative design, what the heck, it would still be half the weight of the stock one.

I may be interested in an OD Crank pulley, but price is a factor, as far as bang for the buck. I would love to see it done in red to match my 'Bird, but if I had to vote - I'd go with either a polished finish or black.

Depending on what your look for for a test vehicle, I would offer mine as a "guinea pig" to test the pulley.

-Andy "Melon"

Charles,

It sounds good except, I don't want to give up my polished underdrives. I'm also a little concerned about spinning the jackshaft pulley faster, because if the bearings fail you can't replace them.

How about making a better flowing intake manifold adaptor (casting that connects lower IC tube to intake manifold). I like the one Randy Baker was making, but I don't want to rework the opening on my intake manifold. The stock casting seems to be very restrictive near the bend by the fuel rail and after seeing what you did on the inlet plenum, I know you could make similar improvements to the intake adaptor.

David

PS: It would also be nice if you could polish it to match all my other MP parts.

David Neibert said:

Charles,

It sounds good except, I don't want to give up my polished underdrives. I'm also a little concerned about spinning the jackshaft pulley faster, because if the bearings fail you can't replace them.

How about making a better flowing intake manifold adaptor (casting that connects lower IC tube to intake manifold). I like the one Randy Baker was making, but I don't want to rework the opening on my intake manifold. The stock casting seems to be very restrictive near the bend by the fuel rail and after seeing what you did on the inlet plenum, I know you could make similar improvements to the intake adaptor.

David

PS: It would also be nice if you could polish it to match all my other MP parts.

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David, are the bearings failing becoming a "big" issue now days? I could look into it and see if there is anything I could do to help. I could design and cast a new intake manifold adaptor but I'm not sure what the demand would be. Getting something like that into production costs a lot so I would need a lot of sales just to break even. Let me know.

Charles

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How about a whole new manifold and intake adapter? Big gains could be made with the right design.

David, are the bearings failing becoming a "big" issue now days? I could look into it and see if there is anything I could do to help. I could design and cast a new intake manifold adaptor but I'm not sure what the demand would be. Getting something like that into production costs a lot so I would need a lot of sales just to break even. Let me know.

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Charles,

No I don't think the jackshaft bearings are failing very often. It's just one of those things that if it does go, your pretty much screwed and you have to locate a used accesory bracket to get going again. I don't think spinning it 10% faster really makes a whole lot of difference, but thought it was worth considering.

I don't want to hi jack this thread talking about other parts, but I'll bet you could sell alot of intake adaptors if you could improve the airflow 25-30% and keep the price around $250. Might be worth looking into, if you haven't already.

David