After my engine dyno I was able to get better performance out of a Holley 750 DP 4779. Since I need to get another Carburetor how would a SPEED DEMON 750 BARRY GRANT Mechanical Secondary part# 1402010 compare to the Holley 750 DP #4779?

Have anyone done any apples to apples testing of Barry Grant vs Holley Carburetors?

This will be on a 95% Street Car.....

Originally posted by DEEBOO:
After my engine dyno I was able to get better performance out of a Holley 750 DP 4779. Since I need to get another Carburetor how would a SPEED DEMON 750 BARRY GRANT Mechanical Secondary part# 1402010 compare to the Holley 750 DP #4779?

Have anyone done any apples to apples testing of Barry Grant vs Holley Carburetors?

This will be on a 95% Street Car..... =
Sorry, not exactly an apples to apples comparison but on a 489 the 850 speed demon was worth about 20HP over a ugly old 4779 that I use as kind of a breakin / baseline carb.
The Demon also had outstanding BSFC numbers compared to the Holley but the Holley was probably going pretty rich in the top end as it was too small.
Actually so was the Demon ;)

Just got done with a blown 392 Hemi with two mighty demon 650's & they were flawless.
I basically needed to adjust the idle graemlins/thumbsup.gif

One of my all time favorite carbs is the 950HP Holley but I have used about 6 Demons now with zero problems.

BTW the 750 Demon will,, according to Demon outflow the 750 Holley because they wetflow them.

love my 650 mighty
shane

If I'm not mistaken, the Holley mentioned has straight leg boosters. It's not really fair to compare straight legs with down legs for power output, if the BG has DL boosters. That said, the straight leg booster should help low rpm torque but be more restrictive at higher rpm.

Looking at the dyno result, which carb do you think I should use.
1. 3310- Change jets and Sec. Spring
2. 4779- I had good results on the dyno w/70-80 jets and plus 20ft lbs torque over the stock 3310
3. Demon 750 - I know Wolfplace have had excellent results with these carbs, but other has said the Holley is easier to tune! Any truth to this?
Since Demon's are rated for "wet flow" instead of the dry flow like others "Holley". Do you think I can benefit from the extra cfm or will the bigger carb be a waste! Some say a 750 Demon will flow more than 850 Holley. What part would that play in having good manners on the street, or do I need to be conservative and use a Demon 650?
I would really like to get to 500hp/tq on the street without any majors changes.

Here's an opinion on demons. (http://board.moparts.org/ubbthreads/showflat.php?Cat=&Board=Racer&Number=999981&Forum=Racer&Words=demon&Match=Entire%20Phrase&Searchpage=0&Limit=25&Old=1week&Main=999981&Search=true#Post999981)

my demon jr works well.

Thanks for the info guys,Yes I have also learned to tear down new parts and go over them, never trust anything out of the box. My Afr Heads had all kind of metal shaving so its pretty easy to find left over machining work inside new parts.
I also found this camparison of differnt size carbs.
Demon Carbs (http://www.classictrucksweb.com/tech/cl_0312_carb/)

I found this very interesting in the article about Vac Sec Carbs:
Due to the way a dyno loads an engine versus how a car loads an engine, vacuum secondary carbs rarely work well on dynos. We usually have to wire the secondaries wide open for the tests, as we did here. This does not mean the carbs won't work well on the street, it's just that dynos don't allow enough time during an acceleration test for the secondaries to fully open.
Maybe I might not need to change carbs to pickup a little extra hp/tq the 4779 carb made over the 3310... graemlins/hurray.gif

Interesting article.

Just today I actually read a review of the 3310 on a Ford 302 and it made almost 30hp(339hp to 369hp) less on the dyno than a mech sec. 650 demon. I would have liked to see the difference in his 1/4mi times as well to see how much of a diff vac. secondaries actually are in the real world. Maybe WolfPlace or someone else with alot of Dyno time experience can chime in on this...

I think you and I both are worrying a little much about the performance of the 3310s. It's a vac. secondary street/strip carb designed specially for the street primarily. It's not going to perform as well as an all out race setup carb that costs more, HOWEVER those road demons(which barely cost anytying more) sure do have a good rep.

Originally posted by RegaMaro:
Interesting article.

Just today I actually read a review of the 3310 on a Ford 302 and it made almost 30hp(339hp to 369hp) less on the dyno than a mech sec. 650 demon. I would have liked to see the difference in his 1/4mi times as well to see how much of a diff vac. secondaries actually are in the real world. Maybe WolfPlace or someone else with alot of Dyno time experience can chime in on this...

I think you and I both are worrying a little much about the performance of the 3310s. It's a vac. secondary street/strip carb designed specially for the street primarily. It's not going to perform as well as an all out race setup carb that costs more, HOWEVER those road demons(which barely cost anytying more) sure do have a good rep. =
If they were tested properly I would tend to doubt a 30HP gain with the Demon.
Who sponsored the test,, it seems to have an impact on the outcome on occasion :D

With any vacuum secondary I have a bolt & nut I keep on the dyno we install on the carb to pull the secondaries open otherwise the dyno will drive the carb nuts on an acceleration test

As for the post, while I am not defending demon or BG as anyone can screw up,, of the last 6 Demons I have used there were no problems & 6 out of 6 in my opinion ain't too bad ;)

I have had many holley carbs and there has been metal shavings in them-I agree with mike I think the demon carbs make more power they were able to work off the holley design and make a better carb anyways just my 2 cents...

Originally posted by DEEBOO:
I found this very interesting in the article about Vac Sec Carbs:
Due to the way a dyno loads an engine versus how a car loads an engine, vacuum secondary carbs rarely work well on dynos.would different gear ratios have different effects on secondary opening rates? :confused:

I think Demons are good carbs (I run one) but I hate Barry Grant as a company. Their quality control seems to be on the bad side... I know quite a few people who have gotten bad carbs from BG right out of the box and everyone I know who runs a BG electric pump has had it fail on them. Then BG tries to charge you $150+ to replace a defective o-ring that cost $0.00002. While I'm on my BG-hatred rant, don't ever try to deal with their customer service or tech line, you'll get nothing but cockyness. This is all just my experience though.

If I'd have to chose Holley or Demon I'd probably pick Holley... Even if the Demon is a slightly superior design, the Holley is a tried and true performer and I've never had any quality issues with one.

Well I have had my BG 250 GPH pump working fine for three years now.

When I got my Demon carbuerator I knew nothing about adjusting one and the idle circuit was very rich. Their tech guy spent a least an hour with me going step by step with how to drill out the idle circuit air bleeds and then how to get the proper jets into the carbuerator. I found their tech line to be the best I have ever used.

In fact their tech help was so good I felt fine with taking my Holly 3310 apart to replace the metering block with one that has jets so that I could tune it better too.

Now both my corvette and chevelle run with a perfect air fuel mix for street driving with nice light tan plugs and perfect idles.

I prefer the Demon now as it is easier for me to work on but both the BG and Holley are performing great.

go to www.competitionplus.com (http://www.competitionplus.com) there is a good article about demon carbs there

You know I am a Demon fan! I love holley because they are the pioneers of the carburetors but I have nothing to complain about with my Demon and unfortnetly some people have had problems with them and then you have people like me who had problems with Holley then switch over to Demon. I am favor Demon for my application because the drivability and performance gain was easier to track.

I think its wrong when people down Demon without using them, and vice versa people downing Holley without using them. This is my .01 cent I can't afford two cents!

I'm a loyal Holley user and have also used older model Demon carbs. I always had problems with the idle circuits when using Demon carbs, but in all fairness I think my carb tuning skills are better now than they were 5 years ago when I was using the Demon stuff. I think the newer Demon carbs sport some really nice features, including fuel level eye sight, heli-coil bowl screws and billet base plate. I think if you're tuning on a carb much (rejetting, changing power valves, etc...) it's just a matter of time before you strip a fuel bowl screw. I've done it on my HP-950 and had to buy a nearly $60 (from memory) Holley kit to fix it ( I checked at local hardware stores and the screw Holley uses in the fuel bowl is some oddball size. I'm not sure I buy into the usefulness of changable venturi's for a street/strip ride, but I'm sure I don't understand all there is to know about the benefits this feature offers. Same for the additional fuel circuit on the higher end Demon pieces. That brings us to price. The price for a Holley HP1000 is $699. The price for a 1000 CFM Race Demon is $725. One stripped fuel bowl on the Holley and that differnece becomes a moot point. I've never over torqued a carb and broken the base plate, but I'm sure it's happened to someone. How about the performance of those Demon carbs? Who on here runs a Demon and can share their setup/track times? I wouldn't be opposed to trying one on my car, but I wouldn't run out and drop the cash for one with the expectations that it would provide noticable gains over my HP-950 smile.gif

I run a King Demon, annular boosters, presently in the 995 cfm comfiguration.
It gives me MUCH more tune ability (street driven) than the #8896 Holley 1050 cfm Dominator it replaced.
As a plus, for me anyhow, the venturi sleeves can be replaced as the motor's future requirements increase. The Demon can easily become up to a 1295 cfm if need be.

Originally posted by BillsCamino:
I run a King Demon, annular boosters, presently in the 995 cfm comfiguration.
It gives me MUCH more tune ability (street driven) than the #8896 Holley 1050 cfm Dominator it replaced.
As a plus, for me anyhow, the venturi sleeves can be replaced as the motor's future requirements increase. The Demon can easily become up to a 1295 cfm if need be. Bill, are those interchangeable boosters included in the price for the carb?

Originally posted by kjett:
I wouldn't be opposed to trying one on my car, but I wouldn't run out and drop the cash for one with the expectations that it would provide noticable gains over my HP-950 smile.gif Ken, I've actually tested both a BG and HP950 back to back and the performance diff is a wash. I've got the BG 750 SilverClaw (predecessor to the Race Demon w/o removable sleeves). With the HP950 I ran 10.61 with a 1.46 60ft. With the BG I ran 10.60 with a 1.48 60ft. Now for the caveat, the hp950 was box stock with no jet changes or power valve changes. The BG had been "dialed" a bit but on the BG pass I inadvertantly loaded up the chassis too much on the starting line and lost my weight transfer. With a proper launch the BG would have been probably .03-.04 quicker but with a jet change the hp could have done just as good. So, to me both carbs are about the same as far as et goes. I do like the fact that the BG comes with the secondary idle adj screw which is much better that messing with an allen wrench and trying to adjust the Holley from underneath the base plate.

Originally posted by kjett:
Bill, are those interchangeable boosters included in the price for the carb? You mean the venturi sleeves? One set comes with the carb, of course. I believe additional sets run around $80 a set and are color coded. The 995 cfm set is black. ;)
I LOVE this carb and you know I'm a big fan of the HP series.

Just a question about all this? Performance aside, can anyone compare quality or problems experienced so to speak between the 2 makers? I personally think the performance isn't an issue, as everyone in here is at diffrent levels of tuning experience, so I don't think we are getting truely accurate tests, but what about quality, as an example stripped screws-parts missing-breaking base plates? anything like that
Just wondering as im about to make this purchase as well. Thanks Jeff