Demon carbs

[OldFoggey]

I was reviewing some magazine articles from back in the 2007 - 2009 time frame concerning BDR Cobras and from what I gathered they use to use Demon carbs. I have been looking at switching back to a Demon because of the glass site glasses for float adjustment and the Ez-Idle adjustment they have. But I was wondering why BDR moved over to Holley to start with. Anybody have any idea or better yet is anybody now running a Demon?

Thanks.....Don

[DAVID GAGNARD]

Have had a Demon on my race car (331 stroker) since day 1 (2005) and have only one complaint...the base plate is CNC'd out of soft aluminum and where the 2 throttle shafts go thru the baseplate there is no metal bushing like in a Holley and after time,in my case 2.5 years, the metal throttle shafts eat out the soft aluminum and you get a major vacuum leak.......had to replace the baseplate........

Other than that,I like Demon carbs, all other workmanship was first class and everything from a Holley will pretty much interchange on a Demon....easy to tune and once tuned properly I didn't touch the carb except for the baseplate replacement.......

David

[Gaz64]

A Holley Ultra HP has equivalent of "Idle-eze" and more new features than a Demon.

[Rick Parker]

Didn't Demon go out of Business?

[DAVID GAGNARD]

Originally Posted by Rick Parker

Didn't Demon go out of Business?

At one time, yes,but you can still buy a new Demon carb form Jegs/Summit and most other mail order high performance places........

David

[jwd]

Originally Posted by Rick Parker

Didn't Demon go out of Business?

Barry Grant went out of business years ago because of poor quality control. It was so bad that Summit, Jegs etc. quit selling his stuff because of the high return rate. In early 2012, Holley bought out Barry Grant and now produces the Demon line but with a higher quality and they are now being carried again by the big name stores.

[6t8stang]

jwd nailed it - they're back in business and doing well again I believe. I didn't know Holley bought them out - I thought ex employees took over from Barry, but I could be wrong.

I'm running a Demon for years and love it.

It's really nothing specific to Backdraft - rather the dealer, engine builder and/or owners choice.

[OldFoggey]

Thanks for all the replies. I've looked at the Holley Ultra but didn't see any mention of anything equivalent to Demon's "Idle-Eze". Barry Grant did go bankrupt and was bought out by Holley's parent company High Performance Industries. From what I've read on many sites is that due to the light weight of the BRD mechanical secondaries are the recommended way to go. But very few of the Demon carbs with mechanical secondaries have electric chokes if any choke at all. Does that present an issue in the colder season? Even though I'm in Florida it's not uncommon for temps to be in the high 20's to low 30's at night in the winter. With no choke I don't believe there's a fast idle function. Anybody had any issues in the winter with a Demon without a choke? Thanks......Don

[Gaz64]

Ultra HP does have "Idle-Eze" as stated above.

Here is a link to all of it's features:

http://www.holley.com/data/types/pic...umHP_Intro.jpg

Holley has certainly picked up their game, more features than anybody now.

[DAVID GAGNARD]

Originally Posted by OldFoggey

Thanks for all the replies. I've looked at the Holley Ultra but didn't see any mention of anything equivalent to Demon's "Idle-Eze". Barry Grant did go bankrupt and was bought out by Holley's parent company High Performance Industries. From what I've read on many sites is that due to the light weight of the BRD mechanical secondaries are the recommended way to go. But very few of the Demon carbs with mechanical secondaries have electric chokes if any choke at all. Does that present an issue in the colder season? Even though I'm in Florida it's not uncommon for temps to be in the high 20's to low 30's at night in the winter. With no choke I don't believe there's a fast idle function. Anybody had any issues in the winter with a Demon without a choke? Thanks......Don

I'm in Louisiana and I don't think you'll have a problem with no choke....My Demon and the Holley on my street car do not have chokes,in the dead of winter when I crank them up all I have do to is feather the throttle for 30 seconds, then put it in gear and roll the car forward about one car length,putting a slight load on the engine and then they will idle fine............

[Clois Harlan]

Originally Posted by DAVID GAGNARD

I'm in Louisiana and I don't think you'll have a problem with no choke....My Demon and the Holley on my street car do not have chokes,in the dead of winter when I crank them up all I have do to is feather the throttle for 30 seconds, then put it in gear and roll the car forward about one car length,putting a slight load on the engine and then they will idle fine............

That is exactly what I do David, my ole 427 FE runs an earlier version of the Holley HP and it does get cold her and it may spin slowly for a few revs but it has always started and as you stated a 30 sec rev at 1500 RPM and a slight movement in gear and all is well.

Clois

I also have a couple Demons on the shelf because of the baseplate. Demons are great for racing but not so great on the street IMO.

[*13*]

Had one years ago. I really liked it. Only changed because it was too big & I had a smaller Holley on the shelf.

[Rickd]

I've got one if you want it. Never installed. Bought it when I had a 302 Hipo that I put trick flow heads on .. but it ran super sweet with the old holley so we just left it that way. Been in a box in the closet for 6 years or so.

[OldFoggey]

I just ordered the all black Holley 4150 (part number 0-76750hb) double pumper from SummitRacing since it does have an electric choke, mechanical secondaries plus 4 vacuum ports so I can eliminate the spacer I'm using to get the second port. I've read several reviews and it seems to be pretty much an out of the box bolt on accessory.Hopefully this will end the idle quirkiness I've had since purchasing the car last July.

Don

[Texasdoc]

Originally Posted by OldFoggey

I just ordered the all black Holley 4150 (part number 0-76750hb) double pumper from SummitRacing since it does have an electric choke, mechanical secondaries plus 4 vacuum ports so I can eliminate the spacer I'm using to get the second port. I've read several reviews and it seems to be pretty much an out of the box bolt on accessory.Hopefully this will end the idle quirkiness I've had since purchasing the car last July.

Don

Don't be fooled with Holley's "Out of the box and go" rhetoric. Especially if you purchase from someone other than Holley directly. I have heard many horror stories of carbs that didn't work. Like mine. I suspect that someone else bought this carb, messed with the settings, and sent it back. The store just re-boxed it and sold it to me.

I bought a Street Avenger (non-ultra) 670 with vacuum secondaries. Put it on expecting it to run perfectly. It was anything but perfect. Idled at 2000. No adjustment on the idle (hot or cold idle). Eventually figured out how to get it tuned right.

My suggestion is to get a book and learn how to tune the Holley. Another option is to search Youtube or purchase the Holley DVD from Boxwrench (highly recommended for a Holley learner).

Here is my $0.02 on setting up a Holley carb. Not sure it if works with any other brand, but will likely work on carbs based on the Holley design. I fiddled with this carb until I finally did it this way. Not sure where I got the final piece of the puzzle from, but it worked.

Originally Posted by Texasdoc;

1. Make sure there are no air leaks.
2. Warm up the car.
3. Set the float levels per Holley's instructions.
4. Set the idle mixture screws per Holley's instructions to best vacuum.
5. For those with vacuum secondaries, remove the line that runs to the distributor and cap the hole on the carb to prevent vacuum leak.
6. Make sure the choke is off - for manual, just use the lever. For electric, push the choke (fast idle) cam down.
7. With the carb off the car, set the PRIMARY blades by using the curb idle screw so the idle transfer slots as viewed from the bottom of the throttle blades are square (really just a dot). Again, make sure the choke is off!
8. Now put the carb back on the car and adjust the idle by turning the SECONDARY throttle blades adjusting screw. This is hard because Holley puts this screw underneath the throttle plate. I have an airgap intake, so I found a small screwdriver that fit and I didn't have to take the carb off repeatedly to make this adjustment.
9. Go back and attach the vacuum line to the distributor (if applicable), recheck your timing, and adjust your electric choke (if needed).

The biggest problem I had was that my Secondary blades were open way too far when I got it new. I had the curb idle screw all the way out, and it was still idling way too fast since the secondaries were so far open. Setting the PRIMARIES with the transfer slot just visible, then adjusting the IDLE by adjusting the SECONDARIES sets them both where you want them to be. Now, if you need to adjust the idle, you can use the curb idle screw for small changes.

Also, attaching the vacuum advance distributor to a manifold vacuum, not a ported vacuum really helped smooth out my idle. There is alot of debate on this subject - too long and off-topic for this post.

Good luck with the new Holley! I've thought about switching to a mechanical secondary 750, but I'm running so well with the vacuum 670, I don't want to mess it up.

[DAVID GAGNARD]

Don't be fooled with Holley's "Out of the box and go" rhetoric.

X 1000.......

There IS virtually NOTHING you can buy and bolt on "out of the box and go"...everything especially carbs will need some adjustment....the Holley carbs are jetted slightly rich form the factory as they have no idea if they are going on a basically stock engine or highly modified engine,the carb will have to be tuned to each individual engine for the best performance.....

Although the Holley should be close,I doubt if will be perfect out of the box....as Texasdoc said,it's not hard to tune a Holley and if you follow his instructions you should be fine.......

David