Demon vs. Quick Fuel??

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Beef97

Member

Dec 24, 2004

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Corpus Christi, Texas

Dec 9, 2006

#1

• Dec 9, 2006

• #1

I realize that the Demon and Holley debate has gone on for years but I haven't seen much about the quick fuels. I have a speed demon 650 on my stang now but im not too crazy about it. Lots of tuning issues. I know the basic design of the quick fuels is a basic holley design but so is the demon. its crazy to think how many different opinions and results can come from the same basic design. Any info would be awesome guys! Also, does quick fuel make anything smaller than the 650 (in a 4 barrel?) i think their website isn't complete right now. Thanks again.

 

dolfan87

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Dec 28, 2000

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Lake Havasu, AZ

Dec 9, 2006

#2

• Dec 9, 2006

• #2

I have a 750 Mighty Demon on my Mach, and the thing is impossible. I have been fighting it for a month. I always used Holleys in the past, and never had a problem. Now I "step up" and get the Demon, only to find out it's crap.

I took the thing apart to see if there was anything blocked in the carb, and guess what? Every port has aluminum in it! The CNC machine left these little "tags" in every port. I called Demon, and they couldn't of been less helpful. Did NOT apologize, could of cared less actually.

So needless to say I am about to buy a Holley, and send this POS Demon back to Barry Grant and tell them where they can shove it.

I know this didn't help your quick fuels question, but I had to vent...back to topic.

87

 

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Beef97

Member

Dec 24, 2004

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Corpus Christi, Texas

Dec 9, 2006

#3

• Dec 9, 2006

• #3

yeah i've been reading that everywhere also. its a shame also because it is such a cool looking and SEEMINGLY well built carb. Nearly everything is billet and it just looks so cool. My car really just doesn't run as well with it. I'll keep looking into these quick fuel ones though. thanks for the reply

 

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5.0ina66

Member

Jun 6, 2003

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Ohio

Dec 9, 2006

#4

• Dec 9, 2006

• #4

The early Demons were incredible, but a while back Summit stopped carrying them due to quality issues. I've heard so many horror stories since then, the only demon I'd buy would be used.

 

thehueypilot

Active Member

Feb 25, 2004

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Medina,Tennessee

Dec 9, 2006

#5

• Dec 9, 2006

• #5

Quick fuel is the best carb I have ever bought. Very high quality but their web site has been broke for years but they have good customer service. I have a 850 Vac sec. that I have been racing for the last four years and it has worked very well and I really like the billet aluminum parts instead of the cast junk base plates. I would buy another one w/o hesitation. I think both Summit and Jegs carry them.

 

washMO66

Founding Member

Oct 30, 2001

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Washington, MO

Dec 9, 2006

#6

• Dec 9, 2006

• #6

Can't comment on quick fuel other than I have heard that they are a nice carb.

I must be the only one who has had three different demons on my car and have been more than happy with each one. 650 mighty demon (still have it) was the first, once I got it tuned it was perfect, tuning was just as basic as any holley I had touched in the past, had to re-jet and change the squirter to add some fuel... Second was a 750MD that I borrowed, worked great.

Third was my current carb, Race Demon 775RS DR, bolted it on, set the floats and took it to the dyno. We changed nothing from the factory settings, jets, squirters, all were good for my set up. I may lean it down a bit to see what I can pick up but for now it is very safe and is crisp as can be...

Not sure of your set up but Patrick James with Pro Systems is probably the route I will go next engine build....NEVER heard anything but positives out of him.

 

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Beef97

Member

Dec 24, 2004

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Corpus Christi, Texas

Dec 9, 2006

#7

• Dec 9, 2006

• #7

yeah thanks for the replies. I'm thinking that i simply have too much carb anyways for my setup. Maybe i'll get a 600 or something.

 

S-Car-Go

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Mar 25, 2003

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San Jose, CA

Dec 9, 2006

#8

• Dec 9, 2006

• #8

What IS your set up? I too have only heard good about Pro-systems. They only build for 400+hp though. At the time I was under that window, but Patrick was still very helpful.

http://www.pro-system.com/

Another option is Jesse at Bigs.
http://www.bigsperformance.com/index.htm

No experience with Quick Fuel and the last Demon I had was ~10 years ago. It worked fine.

 

fvike

Member

Aug 24, 2004

335

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Mosjøen, Norway

Dec 9, 2006

#9

• Dec 9, 2006

• #9

I had some tuning issues with my 750 Speed Demon too. Pulled it apart, brake-clean and pressured air everywhere, in all the holes to blow out CNC shavings, which I've read is a problem for Demons.
Then I jetted it down 2 sizes on the primarys.
Never had a problem since, but I've noticed it's touchy on the floats.
Demons works, but they just need a little TLC first.

 

1

10secgoal

Active Member

Dec 1, 2003

2,801

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San Diego

Dec 10, 2006

#10

• Dec 10, 2006

• #10

QF has been becoming big over the past few years. Might have something to do with all the Holley employees going to work for them.

 

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BlwnGazkit

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Nov 3, 2006

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Richmond, VA

Dec 10, 2006

#11

• Dec 10, 2006

• #11

The Demon Carbs are NOT easy to tune.

You MUST know what you're doing or you will never get the thing to run correctly on your car. They're also rather finicky about matching them to the engine, a 650 would be fine for a 351 but too big for a 302...

I've had a Road Demon and never had any problems with it but it did take awhile to get the tuning correct.

 

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Beef97

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Dec 24, 2004

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Corpus Christi, Texas

Dec 10, 2006

#12

• Dec 10, 2006

• #12

would a road demon 525 be too small for my application? The only other option i was thinking about was a 600 holley. Also, one other thing i was wondering.....due to height restrictions i'm using a drop base air cleaner so i don't think that it will fit with the vacuum secondaries. the housing for the vacuum sec. will hit the air cleaner i think. I'm probably going to have to use a double pumper so i was thinking the holley 600 dp would be my best option? Thanks for the reply!

 

1

10secgoal

Active Member

Dec 1, 2003

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San Diego

Dec 10, 2006

#13

• Dec 10, 2006

• #13

BlwnGazkit said:

You MUST know what you're doing or you will never get the thing to run correctly on your car. They're also rather finicky about matching them to the engine, a 650 would be fine for a 351 but too big for a 302...

I did notice this while reading on them a few times. They use some junk about an average rating. They had a 575 on a 347. I think they rate thier carbs differently than everyone else. Most everyone use the 3in vac method. If they don't use it, then it's not apples to apples and kinda hard to determine what you need.

Click to expand...

Click to expand...

 

washMO66

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Oct 30, 2001

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Washington, MO

Dec 10, 2006

#14

• Dec 10, 2006

• #14

My Mighty Demon 650 supposedly, according to BG, flowed 753CFM and was comparable to a Holley 750DP.

I have no clue what my 775 race demon flows but my 347ci seems to like it

Beef97 - What is your engine ci and build?

 

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BlwnGazkit

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Nov 3, 2006

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Richmond, VA

Dec 10, 2006

#15

• Dec 10, 2006

• #15

BG recommends the 525 Road Demon for engines up to an unmodified 350. Personally I got better performance from a properly jetted 625 on my 302, and I have a 725 on my mod'd 351...

 

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FullRace

New Member

Dec 10, 2006

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Dec 10, 2006

#16

• Dec 10, 2006

• #16

Me being biased to Holley, I think those Demons are really aimed at being "stylish" as well as performing decent. I think that a good Holley double pumper is better than a Demon. Especially with a few modifications. If the holley was garbage, who would copy it?

 

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Beef97

Member

Dec 24, 2004

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Corpus Christi, Texas

Dec 10, 2006

#17

• Dec 10, 2006

• #17

True true, im definately leaning towards the holley. Will a drop base air cleaner clear the vacuum secondary housing? My setup is a mildly built up 289, new heads, cam, headers, msd, rpm manifold. Lots of other mods but still a 289. Im thinking of a vac. sed. holley 600. I can get a good deal from ebay on a custom built 600. http://cgi.ebay.com/ebaymotors/HOLL...tegoryZ50068QQihZ015QQitemZ250059457356QQrdZ1


i think that link will take you there check it out! Thanks so much guys!!!

 

1

10secgoal

Active Member

Dec 1, 2003

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San Diego

Dec 11, 2006

#18

• Dec 11, 2006

• #18

washMO66 said:

My Mighty Demon 650 supposedly, according to BG, flowed 753CFM and was comparable to a Holley 750DP.

I have no clue what my 775 race demon flows but my 347ci seems to like it

Beef97 - What is your engine ci and build?

Click to expand...

That's what I mean. It's a 750 then. A carb CFm rating is not made by the measurements of the bores. Its' measured at vacuum. If a carb flows 645 cfm @ 3in of vacuum, it's a 650. If Demon measurs them @ 1.5 in of Vac, then everything will be different. If it flows 650 @ 1.5 in, it migh flow 753. Kinda see where I'm going with this ?
This is how you tell if you carb is too big for you motor, or too small. 3in at redline is street carbed. Less in more towards racing. So If you are pulling 9 in vac on a motor at redline, it's way too small. And that 600cfm, is not flowing 600 cfm anymore.