Demon carbs experience
Thread Starter
Race Director
Joined: Jan 2002
Posts: 15,353
Likes: 2,726
From: Close to DC
C2 of the Year Finalist - Modified 2020
Demon carbs experience
I know some of you guys have the Demon carb on your motor. What are your impressions, likes, dislikes, any details. I'm giving consideration to a change to one for my motor. I have the Edelbrock 625 AFB, no problems, great power, good mileage, but I like to tinker!
....just drive 'em! Dennis, TOY-1
....just drive 'em! Dennis, TOY-1
Drifting
Joined: Oct 2000
Posts: 1,642
Likes: 0
From: Boerne Texas
Re: Demon carbs experience (Bluestripe67)
Try the archives (generally worthless, but who knows...), as there were a couple of detailed threads on this issue a few months back.
I pulled the Holley and installed a BG Speed Demon 750 vac secondary, ec on my '66, L72 a few months back. The "correct" Holley rests in a box...where it will remain for the next caretaker of the car...likely upon my death....'cause it ain't going back on this engine!! :yesnod: :lol:
The difference in the two...both nicely tuned and properly jetted...was noticeable even to someone not used to the car, or any car for that matter! Throttle response, acceleration, deceleration, and transition all are significantly smoother. And, according to the Vicom computer we used, it added about 28 ponies to the rear wheels..... :D :D
"Good milage"??? In a 427, L72 the way I drive?? :eek: That means 12 mpg rather than 9 or 10...
What can I say?? I am definitely a BG fan.
Note: You will need to build a fuel line with inline filter for the BG. You can see the one we built on my pic.
********************
********************
Jeff
Ô66. Demonized L72
ÒThe Silver BeastÓ
Keep on :flag :seeya :seeya :cheers:
[Modified by Blkblt, 4:15 PM 2/27/2002]
I pulled the Holley and installed a BG Speed Demon 750 vac secondary, ec on my '66, L72 a few months back. The "correct" Holley rests in a box...where it will remain for the next caretaker of the car...likely upon my death....'cause it ain't going back on this engine!! :yesnod: :lol:
The difference in the two...both nicely tuned and properly jetted...was noticeable even to someone not used to the car, or any car for that matter! Throttle response, acceleration, deceleration, and transition all are significantly smoother. And, according to the Vicom computer we used, it added about 28 ponies to the rear wheels..... :D :D
"Good milage"??? In a 427, L72 the way I drive?? :eek: That means 12 mpg rather than 9 or 10...
What can I say?? I am definitely a BG fan.
Note: You will need to build a fuel line with inline filter for the BG. You can see the one we built on my pic.
********************
********************
Jeff
Ô66. Demonized L72
ÒThe Silver BeastÓ
Keep on :flag :seeya :seeya :cheers:
[Modified by Blkblt, 4:15 PM 2/27/2002]
Thread Starter
Race Director
Joined: Jan 2002
Posts: 15,353
Likes: 2,726
From: Close to DC
C2 of the Year Finalist - Modified 2020
Re: Demon carbs experience (Blkblt)
When you tuned the carb did you combine seat of pants and reading the plugs to make jet changes or what? Around this area I don't worry about mileage, but on the highway, i.e. to the beach several time during the summer or on road trips/caravans I have gotten as much as 19.6 by staying around 2500-2600RPM. Then at the track, 1/4 mile, by adjusting the timing and metering rods I have run 13.6. So, if I go for the change I'm obviously hoping for equal or better based on the precision engineered changes in the design of the carb.
just drive 'em! Dennis, TOY-1
just drive 'em! Dennis, TOY-1
Pro
Joined: Jul 2001
Posts: 710
Likes: 0
From: Thornton Co
Re: Demon carbs experience (Bluestripe67)
It is the only reliable thing on my engine. Nocked .4 tenthes of my zero to 60 time. worth every penny. the car feels like it is fuel injected, the throttle response is that good. At your altitude, you may not even have to re-jet it at all. Holly is ka-ka, demon is great.
Kurt :seeya :seeya :seeya :seeya :seeya :seeya :seeya :seeya
Kurt :seeya :seeya :seeya :seeya :seeya :seeya :seeya :seeya
Pro
Joined: Jul 2001
Posts: 710
Likes: 0
From: Thornton Co
Re: Demon carbs experience (Bluestripe67)
By the way, would you go over to Jerry's and have some board walk fries and a slice of pizza for me.
My wife is from Maryland and when we go out we have to have Jerry's.
Kurt :cheers:
My wife is from Maryland and when we go out we have to have Jerry's.
Kurt :cheers:
Burning Brakes
Joined: Apr 1999
Posts: 1,162
Likes: 17
Re: Demon carbs experience (Blkblt)
Blkblt -
Why did you have to fabricate the new lines? Inlet orientation, thread size, or what?
When the air cleaner is in place, how obvious is it that you're not using the Holley?
Nice looking L72!
Thanks,
Mike
Why did you have to fabricate the new lines? Inlet orientation, thread size, or what?
When the air cleaner is in place, how obvious is it that you're not using the Holley?
Nice looking L72!
Thanks,
Mike
Melting Slicks
Joined: Jun 2001
Posts: 2,334
Likes: 2
From: San Clemente Ca.
Re: Demon carbs experience (Mike Smith)
I guess to run a fuel filter.
I use a steel Fram fuel filter off the tank
as a NOS 65 BB fuel filters are as much $$$$ as a new Demon!,
and I don't want to clog it.
That would be one way to keep your fuel lines looking stock.
There is a great spot between the tank and 3/8" steel fuel line
to sneak one in.
Or you could run a 65 BB set up. Its very sanitary, but only came on
2157 cars.
Hope this helps.
BTW, I know several street rodders/hot rodders that love 'em!
I am happy with the Holley. Sent the cars orig carb to the Holley custom shop
for a rebuild a few years ago and could not be any happier.
With 4.11's it can be scary fast as it is! Just mash the one on the right
and hold on. Have had good luck with 20-30 Holleys on different cars.
When set up correctly they are hard to beat. But it sounds as if there is finally a real competitor out there. Its about time! 40+ years at #1 is a long time!
:smash: :smash: :smash: :smash: :smash:
[Modified by 396 RAT, 7:21 PM 2/27/2002]
I use a steel Fram fuel filter off the tank
as a NOS 65 BB fuel filters are as much $$$$ as a new Demon!,
and I don't want to clog it.
That would be one way to keep your fuel lines looking stock.
There is a great spot between the tank and 3/8" steel fuel line
to sneak one in.
Or you could run a 65 BB set up. Its very sanitary, but only came on
2157 cars.
Hope this helps.
BTW, I know several street rodders/hot rodders that love 'em!
I am happy with the Holley. Sent the cars orig carb to the Holley custom shop
for a rebuild a few years ago and could not be any happier.
With 4.11's it can be scary fast as it is! Just mash the one on the right
and hold on. Have had good luck with 20-30 Holleys on different cars.
When set up correctly they are hard to beat. But it sounds as if there is finally a real competitor out there. Its about time! 40+ years at #1 is a long time!
:smash: :smash: :smash: :smash: :smash:
[Modified by 396 RAT, 7:21 PM 2/27/2002]
Pro
Joined: Jul 2001
Posts: 710
Likes: 0
From: Thornton Co
Re: Demon carbs experience (396 RAT)
I am happy with the Holley. Sent the cars orig carb to the Holley custom shop
for a rebuild a few years ago and could not be any happier. [quote]
Sorry 396, Don't mean to dog the Holly's like that, but my experiences with holly's have been less then memorable. I understand that alot of people get along with them just fine, and have great success. You know how it is , you buy a brand of t.v. that everyone says is great, but you can buy three of the things and they are dead in a week. that pretty much sums up my luck with Holly's. Carter's, rochesters, Demons, we all get along pretty well, but Holly's hate me.
Mike, the inlet's on the demon are different sizes and they have no filter in the carb. If you buy the set up from demon to go with your carb you pretty much have to build your own fuel line to go with it. And no you cannot see it under the stock air cleaner, just the fuel lines sticking out from under. Also the stock air cleaner fits over the Demon, but it does take some wiggling so that it does not impede with the choke shafts. I will let Blkblt add more, but that has been my experience.
Kurt
:cheers: :seeya
for a rebuild a few years ago and could not be any happier. [quote]
Sorry 396, Don't mean to dog the Holly's like that, but my experiences with holly's have been less then memorable. I understand that alot of people get along with them just fine, and have great success. You know how it is , you buy a brand of t.v. that everyone says is great, but you can buy three of the things and they are dead in a week. that pretty much sums up my luck with Holly's. Carter's, rochesters, Demons, we all get along pretty well, but Holly's hate me.
Mike, the inlet's on the demon are different sizes and they have no filter in the carb. If you buy the set up from demon to go with your carb you pretty much have to build your own fuel line to go with it. And no you cannot see it under the stock air cleaner, just the fuel lines sticking out from under. Also the stock air cleaner fits over the Demon, but it does take some wiggling so that it does not impede with the choke shafts. I will let Blkblt add more, but that has been my experience.
Kurt
:cheers: :seeya
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Race Director
Joined: Jan 2002
Posts: 15,353
Likes: 2,726
From: Close to DC
C2 of the Year Finalist - Modified 2020
Re: Demon carbs experience (Milehigh66)
I'd be glad to have some eats, but the pizza HAS to be Grotto, ooooooh so good! Got a trivia question for your wife. Where were the two original Jerry's Sub shops located in the Wash. metro area?
Well, so far I hearing good things on the Demon carb, it just may find it's way onto the car, or should I say onto the list of other things for the spring. Keep the thoughts coming.
....just drive 'em! Dennis, TOY-1
Well, so far I hearing good things on the Demon carb, it just may find it's way onto the car, or should I say onto the list of other things for the spring. Keep the thoughts coming.
....just drive 'em! Dennis, TOY-1
Drifting
Joined: Oct 2000
Posts: 1,642
Likes: 0
From: Boerne Texas
Re: Demon carbs experience (Mike Smith)
Mike:
Nice looking L72 back to you!!! :cheers:
The Holly has the small internal filters, but the BG has none. The line fittings are ANs and are a different thread size. Lars (Lars Grimsrud) built a custom line with a C4 FI inline filter (very efficient), and we put together a tech article on it (he did...I did the photos). If you want a copy, let me know and I will e-mail it to you. It is full of pictures.
To answer your question regarding looks, with the air filter cap on, it is difficult to tell from the Holley...as per my pic. However, the fuel lines and filter are a quick giveaway. This set-up is super easy to change out if one wished the car to be judged (I choose not to). Lars uses my engine as a test bed for his carb and distributor rebuilds, so we have changed it out and back a couple dozen times. It is a VERY quick change. :yesnod:
Here is a pic of the look without the air cleaner.
***************
Jeff
:cheers: :seeya
[Modified by Blkblt, 6:48 PM 2/27/2002]
Nice looking L72 back to you!!! :cheers:
The Holly has the small internal filters, but the BG has none. The line fittings are ANs and are a different thread size. Lars (Lars Grimsrud) built a custom line with a C4 FI inline filter (very efficient), and we put together a tech article on it (he did...I did the photos). If you want a copy, let me know and I will e-mail it to you. It is full of pictures.
To answer your question regarding looks, with the air filter cap on, it is difficult to tell from the Holley...as per my pic. However, the fuel lines and filter are a quick giveaway. This set-up is super easy to change out if one wished the car to be judged (I choose not to). Lars uses my engine as a test bed for his carb and distributor rebuilds, so we have changed it out and back a couple dozen times. It is a VERY quick change. :yesnod:
Here is a pic of the look without the air cleaner.
***************
Jeff
:cheers: :seeya
[Modified by Blkblt, 6:48 PM 2/27/2002]
Melting Slicks
Joined: Jun 2001
Posts: 2,334
Likes: 2
From: San Clemente Ca.
Re: Demon carbs experience (396 RAT)
"the fuel lines and filter are a quick giveaway"
That's all I was trying to say. You could build a new fuel
line set up to match a stocker by using a steel inline filter
off the tank. It would take a keen eye to detect the Demon
under the filter. My orig. carb came with my car in a box.
It was torn down to its smallest element. Sent it to Holley
and it came back like new. If I didn't have the orig. carb that my
car rolled off the assembly line with I would try a Demon!
But for now it runs and looks too good to mess with.
I hate to say it, but I have bent hundreds
of miles of 3/8" tubing (at work) . Mainly heavy wall SS, with Swedglok -5 sp
or parker fittings. Have flared my fair share as well.
Buy a bit extra and you will be fine! Its really not that difficult.
Racer
Joined: Sep 2001
Posts: 371
Likes: 1
From: Nashville TN
Re: Demon carbs experience (Bluestripe67)
I am very happy with my Speed Demon 650; double pumper, mechanical secondaries. It replaced a new model Carter AFB 600. Like someone posted earlier, it is like fuel injection. It really improved the throttle response and power. It could be felt by the seat of the pants. In fairness to the Carter, I never attempted to tune it. But still, it suprised me that a carb swap made such a difference. I'm going to Beech Bend, in Bowling Green KY, March 3rd for a trip down the quarter. I'll see what it does. :D
Racer
Joined: Sep 2001
Posts: 371
Likes: 1
From: Nashville TN
Re: Demon carbs experience (Marshall Bissett)
I have an Edelbrock Performer RPM. I'm not sure but the I believe that the Performer is a little lower. I'm using a drop base open element air cleaner with a 14X2" filter that clears the stock '63 hood by a 1/4". A 3" tall filter will not fit my application. The base is a K&N with an unknown drop. They come in different drops. Not all brands of drop base will fit the Demon. Also, I'm not using a choke. My foot is the high speed idle for about 20 seconds after start-up. I went to the local speed shop and tried combos until I found one that fit. I pulled a plain lid from another old air cleaner that I have because I didn't want the very big K&N logo on top of the engine.
