Barry Grant Speed Demon

[Dennis Kelley]

Hey Guys,

I really like your site. I may be checking a quote on a new 4150 style carb in the spring, but I wonder if you perform Demon rebuild and upgrades.

Later Dennis

[PRO-SYSTEMS]

HI Dennis,

Unfortunately we no longer work on Demon carburetors.

To get a quote on your design simply fill out our online quote/order form and I'll review your program and E you back with a quote on a design for your program. We don't have part numbers and don't offer any off the rack. Everything i custom built for your application. There may be a lot of questions on the tech sheet that you won't know. Just fill it out as best you cna and E it in when you're ready.

Thanks for the inquiry Dennis.

Patrick James

PRO-SYSTEMS

[chrispy]

Patrick,

I would be interested in your reasoning for not working on the Demons anymore?????

Care to share?

Thanks in advance,
Chris

[PRO-SYSTEMS]

Our performance programs don't transfer into them as they have restrictions in design that won't allow our modifications or programs to be installed in them.


Thanks.

[chrispy]

Patrick,

Thanks for the info. Good to know.

Chris

[lovehamr]

Patrick,

I'm no pro but I have used/worked on/ built and rebuilt Holleys for about 25 years and now have my first Demon. As of right now my Race Demon RS seems more adjustable in every fashion than any other carb I messed with. So this statement;

"Our performance programs don't transfer into them as they have restrictions in design that won't allow our modifications or programs to be installed in them."

doesn't seem to make any sense. Are your carbs electronically controlled? What mods do you perform on Holleys that you can't perform on Demons due to design constraints?

Thanks, Steve

[PRO-SYSTEMS]

A couple of many things: With the removable booster deal, you have to use BG boosters as ours won't fit. So you're limited to them.

Some passages I prefer to be smaller to keep velocity and shift recovery up for some applications and putting the drill bit or end mill in reverse doesn't make the hole smaller.

Theres more, but you get the idea.

[lovehamr]

Patrick,

Thanks for the reply. But here we go again.
"With the removable booster deal, you have to use BG boosters as ours won't fit. So you're limited to them."
Is there some sort of problem with BG boosters? If so please enlighten us. As an owner of one of these carbs I'd like to know all I can.

"Some passages I prefer to be smaller to keep velocity and shift recovery up for some applications and putting the drill bit or end mill in reverse doesn't make the hole smaller."

What passages, for instance, would you want to leave smaller than are in the Demon? Do tell. I know of using PVCRs but all of the other passages that I know of are already adjustable on the Demon. Like changeable emulsion tubes and air bleeds for instance. But other than that it kind of leaves me in the dark.

Thanks, Steve

[StanJ]

Steve, I understand what Pat is saying. It isn't so much that any particular change is impossible...just that changing some very important things...such as decreasing the cross-sectional area of some tapered passages in the metering block main wells for example...is more work than a significant percentage of customers are willing to pay for. Yeah, it can be done...even the booster issue is pretty straightforward to solve (there are a couple of ways to handle it; the more "involved" of the two allows one to swap any 4150 Holley-based booster into a race Demon at will). The difference in performance from these (and subsequent) changes can be pretty dramatic in some applications, but we're talking about an extra $1500 worth of work here over-and-above whatever else needed to be done. A select few "street" guys can handle that; most can't...if they could, they'd have likely gone the EFI route to begin with.

Having said all this, the Demon carburetor isn't a bad basic design; in fact, in stock form it offers several advantages over a Holley HP of comparable size. The "problems" with the Demon line are the same ones that Holley faces: covering a practically unlimited number of applications with a manageable number of products means that no product can be "razors edge" perfect for any one application, and -- as with any business -- production costs increase exponentially the closer you get to building large numbers of anything absolutely right. I know Barry Grant personally, and I can tell you with absolute certainty that he will not offer any product or service unless it is profitable for his company to do so...and I do not say that in criticism.

In addition to around 150 Holley carbs, we prepared 22 Demons for a variety of racing and road applications in 2005 and will do even more of them this year. If the market continues to grow, I'll look at building components for them (such as billet boosters and redesigned metering blocks) that address these shortcomings.

Stan Justus
Stallion Racing Components

[lovehamr]

Stan,

Thanks for the reply. Did you happen to notice the date on my last post? It was almost a year ago exactly! I was kind of confused when I saw it. That's the oldest response that I've ever gotten. Thanks for bringing it back up! Now some questions for you, if you don't mind. You said the one of the Demon shortcomings was "decreasing the cross-sectional area of some tapered passages in the metering block main wells." How does this manifest its self in the performance of the carb? Remember, I'm a layman. And again with the booster venturies; what does Holley have in this arena that BG doesn't?

Thanks again, Steve

[StanJ]

Ooops...I didn't even think about looking to see how old this thread was before posting to it...and actually, I committed another gaff by posting as I did in Pat's thread...considering that I'm technically in competition with him, business-wise. My apologies Pat; I dropped the "professional courtesy" ball here.

Now to Steve's comments...

Actually, I mentioned decreasing the cross-sectional area of some passages (main wells in particular) in the metering block as an example of a modification that is sometimes necessary in order to tailor the fuel conditioning/delivery curve as perfectly as possible for some applications; I didn't mean it as a wholesale damning of the Demon metering block design; they work quite well for a broad range of applications. The point here is that while most of us in the performance carburetor preperation industry have had access to raw, unmachined metering block, venturi body, and baseplate castings from Holley for several years, Barry has elected not to sell such "unfinished" components for the Demon line. So, something like changing the emulsion area/cross-section gradient the right way (I won't bore everyone with the long-hair physics involved, but there's a lot more to this than just air corrector and emulsion orifice sizes) in a Demon requires quite a bit of fabrication and machining.

Regarding boosters, BG does have several different designs available for the Demon, but what if your particular application requires something outside the norm...say, 358 cu. in., professionally ported heads and manifold, 12.5 to 1 compression, any camshaft profile and practically any carburetor modifications...just so long as the venturi diameter doesn't exceed 1.252" and the throttle bore diameter doesn't exceed 1.562"? (Grand American Challange guys know all about this) If you're running a Ford (and hey, if you're not...what are you doing here?), then any of the Demon booster offerings from BG are going to have a performance compromise somewhere in the RPM range; their signal curves for the range of venturi air speed this application presents are simply outside the parameters of what this engine will want and there is no real way to "tune" out of the problem (and heaven help you -- and your pistons -- should you decide to get creative with oxygenated fuel).

Actually, the same holds true with any "stock" Holley booster in this application, but at least with the Holley 45R-312 "severe duty" booster, you have a workable starting point to get where you need to go airflow and signal-response wise, and just as importantly, we have access to them at a reasonable price. Barry will never tool up to cast Demon boosters of the design that I use for such an application simply because he could never sell enough of them to recover his investment, much less make a resonable profit. This type of thing best falls to people like Pat...or me.

[lovehamr]

Stan, thanks for taking the time to explain that. I do appreciate it.

Steve