Don Terrill’s Speed-Talk

Anyone have experience with demon carbs good or bad? Thinking about trying one on my footbrake bracket big block chevy.Just wondering if anyone uses them and the good or bad. I dont see many at the track.It would be a 4150 style carb not a dominator.Thanks in advance

8-10 years ago they were good carbs.i won't even work on one for anybody now.i have seen things on new out of the box demons that just make me shake my head.the last one i bought would only run 5.21 on my car.i purchased a qft carb and got it to run 4.95,Alan

I havent used one in many years, do you still need to take them apart to get rid of all the shrapnel inside of them? I much prefer 4150's

I am the one guy who never has got a bad one.. I use them all the time, and I like them very much.. I allways need to run a much bigger jet than the way they come out of the box. If you are going to run the engine on an engine dyno, it is easy to get the jetting perfect. I never get calls from engine customers that I have put the Demon carbs on, so that is a good sign. They always make more HP than the HOlleys


JOE SHERMAN RACING ENGINES

I used to use them and would suggest them to everyone.....they do flow nicely and power can be made with the larger venturi if tuned properly.

However, I have like others, stepped out of the dark and into the light and seen the errors of my ways.

I will not or would never suggest a Demon to anyone ever again.

why?

1. to replace the boosters you need to go to BG as nothing else will fit the mainbody. and the over priced boosters to me are just a rip off....$80+ for BG vs $10 for holley....yeah im talking 4150 style.
2. the dowl pins that are in the meteringblocks will not work on a holley without mods.
3. the over jet, over emulsify way of tuning just doesnt suit my way of tuning a carburetor.
4.I have heard too many complaints about the customer service.
5.I swore that when I could get a holley to replace the Demon it was coming off and not going back on....its in about 30 pieces under my bench in a box as a reminder not to go there ever again....

now i did find a way to use holley boosters in the BG mainbody....i may try that with all holley parts.

They look nice. If that's what you're after you'll be fine with one, just look it over closely inside. If you're looking for more, it's NO problem getting more power out of a reworked Holley over the cheap/shiny stuff. If you're looking for good bang for the buck, call the number below and we'll talk about what you've got and what would work well. There are ways to spend a little less and get a lot more.

I have had very good luck running them. I use the race demons. I have two demons both identical models one is older than the other. The thing I dont understand is the older one has drilled holes in the throttle blades the other has none but has a big jet in the center of the carb under the air cleaner stud. If you leave the air cleaner stud out it runs badly. I don't understand the logic of this but both run good.

Machining simple sleeves let's you install Holley boosters into a demon body. I do it regularly. I like the demon 4150 core. My 1.640 Venturi flows more in a demon body than it does in any other. If I could get bare demon centre sections I would be using them over anything . The king demon main body is a different kettle of fish. The Venturi is too short.
You have to remember that all these carbs are mass produced and built to a price.
I would like to know how someone can say that there is no problem getting more power out of a Holley when the mechanics and design is the same.

I bought a 750 annular mighty demon(general competition) a little over a yr. Since then (351 windsor) ported 1970 heads with large vlvs. , scavenge collectors with a nice 2.5'' exhaust. The cam is small (.500 and 218 @ .050) stealth intake matched to the head, not the gsk. Before all these changes (motor already with cam and intake) the carb seemed to be better than what was on the car. After the porting and 2.5 exhaust, that demon was a demon ( severe surging, would not idle).Called BG tech line(what an _______ I got hooked up with) and asked for the simple jett sizing. The carb was 2 sizes smaller than BG said.I'm no expert but I knew it was going to take more than 2 sizes to cure a severe lean condition.Went 7 sizes larger than what the carb came with( found a chevy site where they dyno tuned the same carb)! Mine is a mild street build. Went to a .060'' IAB (from .070'').This helped the idle and part throttle cruise. Drilled the pump shooter from .031 to .040.That also has helped when you step on the gas, but still can go bigger. Would I Buy another...probably not. This carb was a new ebay purchase. When recieved, I took it apart(curious with the new toy) and on the main body where the metering block goes, that machined surface when machined had about an .080'' step! Something in the cnc program (glitch) went ''haywire''. Sent it back and got another.The booster(banjo fittings) were not on the same plane, mine are now thanks to a mill and a tender touch.I'm still playing with it. Will get an A/F meter to continue for the fine tune along with a trip to Maryland International Raceway.Gonna feel good to run that stang through the gear box!

I've have very bad experiances with their products and customer service.

I personally will never buy another BG product in my lifetime.

I wonder if the same d-bag customer service guy still works there from when I had to put up with him in 2004. Kind of sounds like it. If I remember right, I think his name started with a C

Bigjoe
is it possible they cherry pick their best carbs for u and send flawed carbs to others?

The main thing I see on the Demons that I don't like is the size of the booster legs. Probably one reason why they need more jet, a 750 Race Demon uses a .160 booster leg, the same as my 1250... I would suggest a Holley 1000 HP annular 80514, if you have a sufficient amount of stall the downleg version 80513 will work. Be ready to tune ANY carb to work for your combo if you want the best out of it.

I like the metal parts, center sections, metering blocks and so forth fine. In the beginning they claimed so much power increase due to the design of the center section - that was laughable. They since under rate the flow to create the appearance of superior design with the unknowledgeable. As a complete carb they are trying to give a better tune out of the box with little or no sophistication in approach, sort of the misstep Brad Urban made when he made the Speed Blocks.

Troy Patterson TMPCarbs.net TMP Carbs

What that means is that the emulsion port layout, air bleed sizing, booster channel sizing, etc. isn't optimal, not to mention that you only have a few venturi/throttle bore combinations to choose from. A custom built Holley will make more power with a better graph if it's done right. The mechanics are the same, but the calibration is not.

RayJE Carburetors wrote:Machining simple sleeves let's you install Holley boosters into a demon body. I do it regularly. I like the demon 4150 core. My 1.640 Venturi flows more in a demon body than it does in any other. If I could get bare demon centre sections I would be using them over anything . The king demon main body is a different kettle of fish. The Venturi is too short.
You have to remember that all these carbs are mass produced and built to a price.
I would like to know how someone can say that there is no problem getting more power out of a Holley when the mechanics and design is the same.