Billet Carb Circuits Tune-up

[Troy Patterson]

I'd still be willing to test it for ya!

I'd be willing to give you a good deal on a remanufactured / modified carb as a sale so that I at least get cost covered, then if it destroys your carb you can pay the regular price How's that for a deal

Troy Patterson tmpcarbs.blogspot TMP Carbs TMPCarbs.net

[Alaskaracer]

Once I finish my build, we might just have to talk.............. Another thought would be to rework the one I have...........King Demon............That is, if you would rework one anyway.........I'll be up and running this season, so I'll keep it in mind for sure..........Pretty good deal though.

[John R]

Jon;
The design looks good!

Not trying to be smart here. I don't see a transition slot in your pictures? Did you omit it for clarity? If not, how were you planning to deal with the transition between the idle @ main circuits?

[SchmidtMotorWorks]

I don't see a transition slot in your pictures? Did you omit it for clarity? If not, how were you planning to deal with the transition between the idle @ main circuits?

It doesn't have one, does anyone know how those slots are machined? And what the circuit should be?

[jmarkaudio]

Mile Laws will have some insight in how they cut the slots, BLP has to replace the slot to correct the size and position when doing big Dominators. You could also use a series of holes in a line tied to the idle feed passage and get the same effect. The slot on a Holley is tied to the idle circuit, the combination of idle air bleed, idle feed restriction, and the size and position of the slot have to be balanced to work together to get the correct metering and duration of operation for the transition circuit. Then you use the mixture screws to lean the idle discharge further, the load at idle is less than driving on the transition circuit and as a result needs less fuel. On a Dominator the slot tends to be too long, and to get the metering back in order rather than plug it and re-machine the slot we use a t-slot restrictor. Her is a quote from Tuner on an old post, might help understand the operation of the transfer circuit better.

Tuner wrote:
On the Dominator the T-slots are too long. Slot area exposed above the throttle blade is air bleed, at the blade edge and below is fuel feed. As the blade moves the proportion of bleed to feed changes. To have the correct mixture when the blade is near the bottom of the slot, the large amount of slot acting as bleed requires that the upper (screw in) bleed be relatively small. As the throttle opens and more of the slot becomes fuel feed and the slot’s bleed function diminishes, the small upper bleed then causes richness. With the small upper air bleed, the relatively small IJ size that gives the correct AFR at moderate throttle openings when the slot is all below the butterfly is too small to give the correct AFR at almost closed throttle when the slot is nearly all air bleed. The relationship of the various orifices is out of proportion.

The bleed from the slot affects the action of the mixture screw also. Because there is a relatively large amount of air bleed in the over-all circuit a relatively larger idle jet is necessary to get curb-idle screw sensitivity as desired. Example of this is your carb with .040” IAB and .030” IJ. In a 4150 like a 750 with a 3/16” T-slot that would give a very rich mixture screw. Your 4500 likely has a 5/16” T-slot which is the equivalent of another .065” diameter bleed in the idle circuit when the throttle is low on the slot.

A solution is to put a restriction in the passage to the T-slot sufficient to prevent over-richness the necessary .040” (or so – single carb application) idle jet would otherwise cause. The usual range is .052” to .059”. Use a .040” IJ and .078” IAB and .052” T-slot jet. If it’s too lean at small throttle openings just above idle go smaller on the IAB. If you have to go below about .063” on the IAB go up a drill bit size on the TSJ and go back to .078” IAB and come down again. These suggestions aren’t cast in stone abut they should be close, whatever makes it run good is what to do. The object is to be just rich enough to run well when the engine is warm. The correct mixture will be too lean on a cold engine and require some help to stay running for the first couple of minutes. It’s easiest to tune this part of the carb by making it so stupid lean it’s gasping for fuel at low part-throttle (on the T-slot) and then just coming back richer to where it runs good.

[SchmidtMotorWorks]

Sounds like it would be nice to have some adjustment like a trasnfer jet (or jets) to control it.

[Troy Patterson]

Sounds like it would be nice to have some adjustment like a trasnfer jet (or jets) to control it.

That's what an off-idle circuit restriction does. Not that you aren't capable of it, but it's a big undertaking for someone not carburetor savy to manufacture a carburetor. I'm interested, but honestly my interest isn't in manufacturing a shiny box, but something groundbreaking based on what I've already developed and knowledge. We're talking patents and stuff like that. I'm looking to either take on a venture capitalist or fund it myself in time.

Troy Patterson tmpcarbs.blogspot TMP Carbs TMPCarbs.net

[SchmidtMotorWorks]

We're talking patents and stuff like that.

We won't live long enough to profit from a patent case and the money returned wouldn't be enough to pay for the lawyers.
Even if you were infringed and could prove it, it would be a waste of time and money to defend because if you do finally win they can just file BK and walk away, happens every day.

An invention I designed for a medical company was patented 15 years ago is still in litigation surely millions had been spent on lawyers.
http://www.icumed.com/clc2000.asp

[ijames]

Jon is probably right about patents not being worth it for a small business, but in terms of going to venture capitalists for funding and eventually being bought out by a bigger company having IP locked up in patents can be worth a lot. Think of them as an investment for the future, not as something you'll use right away .

[jmarkaudio]

Jon, if the slot size is machined correctly it will not be an issue, balancing the idle jet and idle feed restriction will set the proper fuel amount for the transfer circuit. The idle circuit then falls in line as it then uses the mixture screw to further lean it. If you made it a little larger as in the case of the Dominator you could add a replaceable jet as I do, but better to size it right to begin with.

[SchmidtMotorWorks]

having IP locked up in patents can be worth a lot.

Who has $$ that would pay $$ for for carb IP? Holly? Edelbrock? Why would they? For them the business is about saving pennies on production cost and marketing, very little else.

Venture capitalist? No way, having worked for a company that was turned over by one I can't imagine that anything carb related would even get a meeting. These guys look for 50% returns yearly not business that barely scrapes buy in the automotive aftermarket.

[Troy Patterson]

I'm well aware of the value of patents. Holley and Demon would love a fool like me to dump a bunch of hard work and ideas in their lap and save them from the future, but I'm not that guy. I'd rather die with it in my head than give it to people who care give a sh#t less weather I lived or died. Truthfully Jon, if you aren't playing for real, you're just f#cking around. The years and money I spent developing my knowledge and understanding wasn't play time or money.

The way to make it work with patents and all and the inevitable battle with the Holley / Demon food chain is to come to the party with pockets deep enough to pull it off.

Sure, it'd be fun to just dabble, but I feel what I can do is basically obsolete the existing Holley carburetor in most ways. I'm thinking not in terms of a few dozen units a year, but thousands.

Troy Patterson tmpcarbs.blogspot TMP Carbs TMPCarbs.net

[Troy Patterson]

having IP locked up in patents can be worth a lot.

Who has $$ that would pay $$ for for carb IP? Holly? Edelbrock? Why would they? For them the business is about saving pennies on production cost and marketing, very little else.

Venture capitalist? No way, having worked for a company that was turned over by one I can't imagine that anything carb related would even get a meeting. These guys look for 50% returns yearly not business that barely scrapes buy in the automotive aftermarket.

Say, is Holley scraping by?

Troy Patterson tmpcarbs.blogspot TMP Carbs TMPCarbs.net

[SchmidtMotorWorks]

Say, is Holley scraping by?

In venture capitalsit view no not even that good.

Aftermarket parts maker Holley files for bankruptcy
Feb 12th 2008 at 11:37AM

http://www.autoblog.com/2008/02/12/afte ... ankruptcy/

The fact that Holley and Crane weren't picked up by any kind of investors tells you what the automotive aftermarket looks like to them.

[Troy Patterson]

Say, is Holley scraping by?

In venture capitalsit view no not even that good.

Aftermarket parts maker Holley files for bankruptcy
Feb 12th 2008 at 11:37AM

http://www.autoblog.com/2008/02/12/afte ... ankruptcy/

The fact that Holley and Crane weren't picked up by any kind of investors tells you what the automotive aftermarket looks like to them.

Well, looks like the future caught up to them - LOL Not sure it really means a lot though, in many cases what they are doing is wiping a debt liability off the books. Kmart filed bankruptcy a few times in the 1990's shortly thereafter purchased the much larger Sears Roebuck & Co.

I'd say that Holley is nothing more than a cash cow for the parent company(s), it's a company sorely neglected manufacturing a 60 year old product. How Holley has managed not to have any major competitors come along is both (in part) explainable and surprising. I can only speculate on the how, assuming my experiences with corruption in SoCal has anything to do with it, they've paid off dirty politicians, public employees and criminals to stifle competition - as any long established buiness with few to no competitors in LA has, you can be sure of it.

The issue of carburetion is much broader 'now days' than it would seem with implications for a "greener" future, emissions and so forth. It's not just an issue of horsepower any longer

Troy Patterson tmpcarbs.blogspot TMP Carbs TMPCarbs.net