4 bbl Carb for Lola Motor

[Ron Earp]

Hey Stan,

The carb arrived today safe and sound in a box. Very nice!!!! This a pretty piece and very nicely done, a testament to good work. I like watching the blades open on this 1:1 ratio but I'm a bit worried about it.....that is a lot of cam and lot of motor in a really light car......

Stan also included the progressive linkage and instructions for re-turning the accelerator pump to match. Might just do that.

I need to run an air cleaner on this, of course, what sort of air cleaner would you recommend? Space is not a huge concern.

I am planning to get the motor lined up, in, and will check the carb fit with rear deck, should be interesting! Details will show up on the build thread.

[flatchat(Chris)]

I like carbies, cause they're like me ,-- simple -but are there any similarities between this one and the "dam best" type?? basically looking for a reason to go with

[Sandy]

Ron -

Take a look at the Piper Cross filter for the Holley, X-Force, it is a well made part. Not sure if they style your looking for...

http://www.hrpworld.com/XForceAirFil...action=product

Sandy

[Big_Si]

Ron, if you're after a simple progressive linkage have a look at the linkage on the HF seires of SU carbs. These should all have a cam on the throttle which gives a nice progressive opening. It's nice and simple to remove and use elsewhere too. I've currently got one on the IDA on my classic mini! Nice and smooth at low throttle, but due to the cam allows full throttle to come in nice and easy if you wish.

[StanJ]

Originally Posted by capaci

Thanks for the post Ron

Right on the mixture.. well, please do get a 02 sensor or EGT exhaust gas temp sensor and adjust for best mixture maybe a bit rich on your engine.
This is the drag about carbs and tuning for races and best performance there is no manual mixture adjustment it is fixed for the automotive stuff.

heck get Stan to place a main mixture control on the carb that can be adjusted from the drivers seat, you sell a few of these without doubt.

The chemically optimal point at which this happens is the stoichiometric ratio (sometimes referred to as stoich), where all the fuel and all the oxygen content in the air of the combustion chamber will perfectly balance each other out during combustion.

This is what is good about EFI and digital controls you can tweak the mixture if you have the controls

On my aircraft I adjust lean to get max exhaust temp then go a bit rich on the stoich side. Best power and runs cooler then lean. This is at cruise.

best

I developed the throttle bore modifications that you see in the photos about 7 years ago during the heyday of SCCA Trans-Am road racing after Mike Lozano of Lozano Brothers Racing Engines contacted me about some part-throttle fuel distribution/drivability problems he was seeing in his customer’s engines. The “intermediate circuit” 830cfm carbs that some other racing carburetor suppliers were building in response to this issue succeeded in masking (drowning?) that original problem, but were creating others. After a bit of dyno testing it became apparent that this problem was being caused by poor-to-practically-nonexistent atomization of fuel being discharged into the air stream via the idle circuit. The radial grooves cured the fuel distribution problem practically straight away, and also allowed us to significantly reduce the total volume of fuel discharged through the curb idle and transfer-slots (and subsequently, the accelerator pump circuits as well), resulting in better mileage while maintaining the functional in-cylinder A/F ratio that Mike wanted to see. Later refinements to the concept (directed, multi-point discharge from these circuits and modifications in the metering blocks themselves to allow the idle circuits to respond more quickly to changes in the engine’s fuel demand) actually provided a nice gain in WOT power, which is hard for many people to grasp until they consider what is actually happening in the combustion chamber and why an engine needs an absolute A/F ratio slightly richer than stoichiometric in order to produce maximum power. It’s important to note here that for the most part, fuel arriving in-cylinder as a liquid (either in the form of droplets or wet film) might as well not have even gotten there at all…in fact, for several reasons the overall situation would be better if they hadn’t. Hydrocarbon molecules beneath a droplet’s surface have no access to oxygen molecules until something vaporizes the droplet…and if that “something” is compression heat -- or worse yet -- combustion heat, then the game is essentially over before those hydrocarbon molecules have a chance to participate in any beneficial way. All they can really do at that point is react (burn) while on their way out of the cylinder during the exhaust cycle…very much to the detriment of exhaust valve and header life.

All sorts of things can and do cause vaporized fuel to condense back from vapor to liquid while on its way to the cylinder. Localized pressure increases – usually due to turbulence in the intake tract – are the chief troublemakers here, but some of this is unavoidable; simply opening the throttle (and who among us is willing to give that up?) raises pressure in the intake manifold plenum sufficiently to cause a significant portion of the fuel suspended at that moment to coalesce back into liquid form…which is one of the main reasons that carburetors need accelerator pumps. All of these potential problems are compounded when any part of the carburetor fails to introduce fuel into the air stream in a way that readily allows it to be vaporized. Small numbers of large droplets not only evaporate more slowly than do large numbers of small ones, but since a droplet weighs much more than the air it is displacing in the port, it has a tendency to centrifuge each and every time it has to change direction. Obviously then, the less efficiently the carburetor atomizes the fuel it discharges into the incoming air stream, the higher the percentage of that fuel arriving at the cylinder in a liquid state…and the richer (in absolute terms) we have to start out in order to end up with a mixture that functionally approaches stoich in the combustion chamber.

(As an aside, there is a "peak to the vaporization mountain”...and it is possible to go past it and start hurting yourself power-wise. Explaining how this can happen requires a bit of longhair physics that I won't bore everyone with here; although the phrase latent heat of vaporization should be enough to get the other physicists and engineering types headed down the correct path. Anyone else interested can contact me via PM and I’ll type something up)

Regarding in-car A/F mixture adjustment capability, Holley actually offered a retrofit kit to do this back in the middle 80’s. Unfortunately, it wasn’t very well engineered and reliability issues kept it from ever becoming very popular with racers and was discontinued after a couple of years. Come to think of it I haven't seen one in decades; even on ebay. Even though the reliability problems would be easily solved today, I’m not sure just how much of a market there would be for such a system (the street muscle car guys not withstanding). Given the current movement afoot in most motorsports sanctioning bodies toward reduce the cost and complexity of the cars themselves, I don’t see any of those sanctions which currently require the use of carburetors allowing in-car mixture control these days.

Originally Posted by capaci

Flow vs Delta Pressure across the throttle plate at % throttle open, say 10, 25, 50, 75, 100 % would be good for a chart. If you could get 02 or exhaust temp this would tell us how linear the mixture is or what the curve is on a dyno so we could add engine load.

Total venturi air flow and fluid flow through the various fuel discharge circuits are both measured at 8.2 degree intervals of throttle shaft rotation as part of the final calibration process for each carburetor we build. It’s the only way I’m aware of to assure proper transition between the circuits as the engine’s demand for fuel changes. In the event that our baseline calculations are off however, the range of fuel curve adjustment on our pro-level carburetors is extremely wide and I’m happy to work with the customer to get every aspect of the carburetor’s performance as close to perfect as it can be for his application.

[Pantera1889]

Originally Posted by 2124

Ron -

How much does he get for one of these carbs?

After reading this thread, I was wondering the same thing!
Sooooooooooooo????

[StanJ]

Originally Posted by John W

Stan,

thanks for the comprehensive reply.
I guess my side oiler will be fine with LeMans bowls then, given it won't make that much power.

Cheers,
John.

Hey guys, I’m not ducking the question. I’ll post a list of products and services if Ron says it’s alright to do so. Some websites have a rule against doing that in their public forums, and I’d like to get his permission first.

[Pantera1889]

Originally Posted by StanJ

Hey guys, I’m not ducking the question. I’ll post a list of products and services if Ron says it’s alright to do so. Some websites have a rule against doing that in their public forums, and I’d like to get his permission first.

How about a PM? I am very interested in this.

[StanJ]

Sorry for taking so long to respond to the questions about pricing. We’ve been transitioning into a new facility over the last few months, and it’s taken far longer, required far more effort, and proven to be far more of a headache than I could have ever imagined.

I’ll start out by saying that while we do of course offer new, modified carburetors ready to bolt on, I also have no problem with modifying a customer-supplied core in order to reduce the customer’s final cost. The only restriction to this is that I won’t use any customer-supplied component in the build that will in any way compromise the performance or durability of the finished product. You may own it...but my name's always going to be attached to it, too.

Regarding the cost of “core” components – I maintain an N.P.A/bulk account with Holley, and normally purchase individual carburetor components rather than assembled carburetors. This saves disassembly labor, allows us to select components that are at the “optimal end” of the production tolerance range for use in our products, and it’s also somewhat less expensive for me. The portion of the final cost that our customers pay for the basic carb is always based on the lowest advertised price (usually Summit or Jegs) at the time the order is placed for the specific model Holley carburetor which would normally serve as the starting point for that build. Example: The starting point for most 750cfm based gasoline carburetors would be Holley list # 80528-1, which as of this writing is available from Summit Racing for $645.95. That would be the price the customer pays for the new carburetor itself in addition to the charges shown below for Blueprint and Pro-Prep Series modifications. For Pro-Max Series carbs, this “core” charge is actually less, with the customer receiving a “credit” for the “unused” stock metering blocks and float bowls.

Basically, the carburetor modification services we offer fit into three basic “levels”:

Blueprint Series, which includes:

Machining all of the main-body and base plate sealing surfaces square and true

Machining for screw-in air bleeds and/or transition-slot restrictions, idle circuit feed restrictions, and emulsion bleeds (if desired)

Aligning the boosters (main circuit discharge nozzles) within the factory location parameters to equalize fuel draw

Machining as necessary to assure proper (vertical) throttle plate position at W.O.T.

Secondary throttle actuation ratio as per customer requirements (or request)

Calibration of all fuel flow orifices, fuel well diameters, and emulsion area gradients, and accelerator pump discharge according to customer’s application requirements

Price $475.00


Pro-Prep Series, which includes all of the above, plus:

Venturi diameter and entry radii CNC machined to the optimum size/shape for the customer’s individual requirements

New, modified boosters installed in the optimum position within the venturi shape used

Teflon-coated throttle shafts installed, along with modifications to control throttle shaft axial movement (chief reason for “sticky” throttles and throttle bore wear)

Application-specific float and fuel bowl modifications

Dichromate finish on all zinc die-cast components

Price $970.00


Pro-Max Series, which includes all of the above, plus:

Complete venturi shape (entry, vena cava, and divergent-cone) CNC machined/optimized

Stallion Racing Components venturi extension plate (aids part-throttle fuel distribution)

Stallion Racing Components billet aluminum boosters (design depends on the application)

Stallion Racing Components billet aluminum metering blocks

Throttle shafts machined for reduce aerodynamic profile and drag

Lightweight aluminum fuel bowls

Price $1675.00


Note: Those of you who have looked closely at the posted pictures of Ron’s carb and are familiar with Holley carburetors in general will probably notice his carb is actually something of a cross between Pro-Prep and Pro-Max levels, which brings up a point I’d like to make here. Most (although not all) of the individual modifications that I’ve mentioned are “upwardly” and “downwardly” compatible with the basic levels outlined, and I’m generally happy to add additional modifications/components to a customer’s build on an “a la cart” basis…so long as those additions truly represent added value for the customer. As most any of the reputable vendors who have banners on this board will tell you, selling someone additional work that they get little or no benefit from might be good for the current month’s bottom line, but in the long term is very bad for one’s professional reputation…and for business. A big portion of the favorable reputation I enjoy in this industry is due to the fact that I believe strongly in the concept of customer service…which includes looking after my customer’s best interests. In short; if you aren’t going to see a significant gain from something, don’t expect me to get really excited about selling it to you.

I've had a couple of discussions with Ron about offering some sort of additional "GT40s.com discount" for group/multiple orders that come through this site, and I'm definitely willing to do that.

If anyone has questions or needs additional info, please feel free to ask either here or via PM.

Stan Justus
Stallion Racing Components

[CliffBeer]

Stan, beautiful work - absolutely stunning. Just wanted to pose a couple of questions:

1. Wondering if you can give a couple of rough price points just for general awareness around the forum. To be specific, what kind of price range are we speaking of to do what you did in the photos above? No need to be precise, just a rough price range would be helpful.

2. Compared to an off-the-shelf Holley (matched as best as possible) for a somewhat standardized crate performance 302, how much different/more hp would the engine make with your lovely carb? Are we talking 10hp or or more like 40hp?

I realize these are very basic, and probably oversimplied, types of questions but some basic comparative points would be helpful for us less sophisticated GT40s guys.

Thanks!

[Russ Noble]

Originally Posted by StanJ

Pro-Prep Series,
Price $970.00


Pro-Max Series, which includes all of the above, plus:


Price $1675.00


Note: Those of you who have looked closely at the posted pictures of Ron’s carb and are familiar with Holley carburetors in general will probably notice his carb is actually something of a cross between Pro-Prep and Pro-Max levels,
Stan Justus
Stallion Racing Components

Cliff, I would say Stan has already given the price points for the mods to Rons carb. Just edited it for you.

I think in another thread he said the biggest bonus was much more tractability, I think any power boost is just a nice side effect.

Cheers

[StanJ]

Russ, I think I might have been referring there to Blueprint Series modifications on carburetors that are properly sized for the application to begin with. The Pro-Prep and Pro-Max Series pieces both offer substantial increases in horsepower and torque production over unmodified Holley carburetors of similar size. For instance, Ron’s engine will likely show a gain of 20-25 horsepower and 15-20 lbs./ft. of torque using the carburetor we built for him compared to an out-of-the-box 750cfm Holley #80528 HP 4brl., along with a very noticeable increase in throttle response and smoothness. Starting with a different core (to allow a smaller finished venturi diameter) and utilizing a different booster design with higher airflow capacity would have allowed me to build a carburetor which would have made considerably more mid-range torque in this application with no sacrifice in peak horsepower, but one of Ron’s stated goals was to keep this engine from becoming a “transaxle shredder”.

For “crate engine” applications, let’s use Fords M6007-D392 as a reference point. It’s not uncommon to see everything from an “old style” Holley #4777 650 cfm 4brl all the way through a [cringe] #80509 830cfm “nascar-spec” 4brl used on these engines in street performance applications. For such an application -- and where absolute, no-compromise performance is the goal – I can build a 650 HP-based Pro-Max carburetor that will exceed both the crispness and throttle response of the 650 as well as the maximum power and torque production of the 830 by wide margins…but the practical question remains “is the customer realizing a value here for the money he’s spending?” If this is a full blown competition (or even a mostly “track-day”) car, then yes…absolutely! But if this combination is going into a car that will spend 99% of its life on the street -- where most of us already have more power under our right foot that we can safely use anyway – then no; not so much.

Now, please don’t misunderstand what I’m saying here…I don’t try to play “mother hen” to my customers. We’re all adults and – spousal opinions not withstanding -- have earned the right to spend our disposable income as we see fit. I simply believe that customers should not be treated as “marks”; if ask me in good faith for advice, I think you should receive an honest answer based first on your needs rather than mine.

[Lynn]

Originally Posted by StanJ

Starting with a different core (to allow a smaller finished venturi diameter) and utilizing a different booster design with higher airflow capacity would have allowed me to build a carburetor which would have made considerably more mid-range torque in this application with no sacrifice in peak horsepower, but one of Ron’s stated goals was to keep this engine from becoming a “transaxle shredder”.

…but the practical question remains “is the customer realizing a value here for the money he’s spending?” If this is a full blown competition (or even a mostly “track-day”) car, then yes…absolutely! But if this combination is going into a car that will spend 99% of its life on the street -- where most of us already have more power under our right foot that we can safely use anyway – then no; not so much.

Now, please don’t misunderstand what I’m saying here…I don’t try to play “mother hen” to my customers. We’re all adults and – spousal opinions not withstanding -- have earned the right to spend our disposable income as we see fit. I simply believe that customers should not be treated as “marks”; if ask me in good faith for advice, I think you should receive an honest answer based first on your needs rather than mine.

I like the way this man thinks!

It is so easy when planning a build to get into a testosterone laced pissing contest of our own making. If unabated we can easily end up with a car that is just no fun for the purpose we are going to end up using it for. It sounds like Stan has the stuff to tell it straight, if we bother to ask him, so that the finished product suits our actual purpose for the machine.

BTW, I don't know Stan, never talked to the man and haven't even discussed this with Ron. Just my $0.02 worth based on his words here.