Is anyone using a Demon? Speed Demon Carb. I'm thinking about the Speed Demon 850 for the BB.

I would like to have a clean burning machine. Just about every Holley I have ever had seemed to be a little rich. Even if you adjust it, after a while it just has that Holley smell and richness.

 

Yep 650 mech secondary no choke... Very nice and responsive...Dave...

 

I run an 850 mech secondary on my '66 427 L72. The correct numbered Holly has been in the parts box for about 5 years now, and never will see service again under my management. All of the CCC in Colorado run Demons simply because we have found with correct set-up out of the box (don't slap on any carb and expect miracles... ), these carbs just run better. Lars has tuned all of them on a dyno out here, and runs a 750 on his built 350 '64. Even in colder Colorado conditions, it fires with a pump or two, and acts like there is a choke on it.....there isn't. Its just a matter of being set up properly from the get-go, and many folks just buy these things and slap them on.



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Jeff; Charter CCC
1966. Modified L72
The Silver Beast

 

blkblt,

I assume you can have an Elec choke with the mech secondary style... on the Demon...right?

Tim

 

Hey, Tim -

I also run a Demon 750 MS on my 409 SB, but if I had it to do again, I'd go w/ the 850 MS, but that's another discussion.

The Demons are great. These things have instant response and run like a fuel-injection car once setup properly as Jeff has stated.

As far as the choke, I don't believe the double-pumpers ship w/ a choke, but you can order the choke kit separately from Summit as I did. Although, Lars ended-up ripping it off of my car and tuning it so well that it didn't need the choke.

From CCC experience, you really can't go wrong w/ the Demons.

 

thanks for the info guys. why would you remove the choke...though?

Is there performance issues?

 

Personally, its just something else that requires maintenance and set up and can go bad. I have used vac sec and mech sec, choke and no choke, Demons, and just find that I need nothing more than a mec sec/no choke set-up for great performance. However, if the carb isn't set up properly, or is "tuned 'til its broke", a choke probably can help in starting and warm-up. I always thought that a choke was the way to go until the current set-up. If this little group out here (the CCC) has nothing else, we have great beer, and finely tuned carbs and ignition systems, thanks to Lars and the Viking Lounge! . Those two items make a huge difference in performance anywhere, as you know. I highly recommend an 850 Demon for your BB!!

Jeff

 

tdelph -
The BG Speed Demons provide an outstanding level of performance once set up right. I have a couple of BG carb papers for setup and installation that you may find useful - drop me an e-mail request and I'll send them out to you:
V8FastCars@msn.com
The 850 mechanical sec carb is an outstanding choice for your BB - it will perform very well through all modes of operation. I'm running a 750 mechanical carb on my 357, but I have also test-run and set up 850s on my 350. Don't let a segment of enthusiasts scare you with "Over-Carbo-Phobia". Big carbs have a very good level of performance, and do not produce off-idle stumbles, poor low end response, over-rich conditions, or the other problems you may hear about. I run 750s and 850s on my small block (and we're running a 1050 on a small block strip car) with an incredible level of performance.
You can also ship the carb directly to me and I will set it up for you for a very small beer fee.
You don't need a choke. All the BG carbs we have had with chokes have produced an over-rich condition when using the choke (even when set up very lean), and perform much better and cleaner without it. The car will be just a little balky for the fist 4 minutes of operation, but initial start and performance is no problem. The choke will cause you more frustration that not using one.
Finally, don't use a vac sec carb on a light car like a Vette. The mech sec carb will produce a vastly superior level of performance at WOT, and will really improve your fun factor.

 

Thanks again to everyone responding to my questions. I feel a lot better about getting one.

I will let you know how it does.

Thanks lars, looking forward to receiving the setup info.

Tim

 

Take the carb you have and send it to chuck nuytten in texas. He specializes in bench flowing carbs. I sent him a carb for a engine i own that made 1080 hp and the car will sit and idle by itself! He will modify your carb for your application.

 

Vette Rod,

I will keep that in mind for future reference. I need an 850 anyway. I am runnung a DP 750 right now and that isnt enough for the motor I have. I knew this when I built this motor but now the time is right to change it out and I have some good information about the Demons.

Thanks for the reply,

Tim

 

A demon will not compare to one of chucks carbs. If you want instant throttle response and the best performance I would look into it. www.chucknuytten.com