Demon 850 stock jets. There are no numbers,.
Demon 850 stock jets. The richness comes from the idle circuit and the transfer slots. 050 580 lift with 1. it has the baseline jetting printed on it. Jun 6, 2009 · Another carb question. I have a Mighty Demon 750 with Annular legs and mechanical secondaries. - Mopar Muscle Magazine JETTING (MAIN JETS): Due to varied applications that a universal performance carburetor will work with, a few tips on jetting are provided to help you understand their purpose. Oh by the way, are carb jets universal? Thanks! Life isn't simple but the simplest answer first is universal jets, NO. Thx, sorry for the stupid questions. Dart block. in 63 nova , 350 trans. Page 2 of 3 < 1 2 3 > Show 40 post (s) from this thread on one page INTRODUCTION Demon CarburetorsTM have many unique features that make them the ultimate choice for performance enthusiasts, like yourself. Re: Demon Carb ?s update - 05/01/1102:52 PM ok i finally got back to tuning this 850 demon carb here is a list of what has been done since last post . For the most part, the jets delivered with the carburetor should suffice as your tune-up "baseline". 4 inches on the Superflow 600 bench. This is 99% a street car that my 18 year old grandson drives. Jul 10, 2007 · Just bought a nice used BG Speed Demon 850 carb from a guy off the internet. JETTING: Out of the box jetting will be extremely close for most single four-barrel applications. Feb 15, 2012 · Speed and Mighty Demon carbs also benefit from the exclusive Idle-Eze™ base plate, an ingenious device that allows quick and easy idle speed adjustment. Tried to drill out the outside air bleeds and the bleed came out with the drill bit. I seem to be running a bit rich and was thinking going down on the jets but not sure how much. 028" size jets in these holes with various ones blocked etc. Jun 13, 2006 · 454, cam just replaced with a Lunati 60202 mild+ cam for oval ports, oval port - stock head and components, exhaust 3 inch dual glass packs (stock exhaust manifold - hedders on order) Intake is a edlebrock air-gap. Jun 27, 2019 · I looked up stock jetting for the various Demon 850 models in the Demon Carb Tuning Manual I've got that gives all the specs along with carb function diagrams and tuning parameters ("How to Tune and Win with Demon Carburetion" by Ray Bohacz: S-A Design book #SA68, ISBN #1-884089-9 from CarTech, Inc). Stock Sizing was 470 cfm, however the carb may not be way too large for this engine to handle afterall for trial purposes. Apr 30, 2014 · Hesitation when moving the throttle open is a accelerator pump adjustment change, pump cam change, or pump nozzle change, not a jet change. An 850 cfm "double Nov 18, 2007 · Is there a previous thread on instructions of re-jetting a Mighty Demon 750 cfm carb or can someone advise me on what needs to be done. It has a set of mildly ported 781 oval port heads, an airgap2 rpm intake, headers, 10. If I compare to the smaller carb, this thing is way too lean. The Demon 850 carb provides multiple performance benefits compared to most stock or street replacement carbs: Greater airflow – The large venturi design flows up to 850 CFM, supporting over 650 HP. The comments are for the Mar 27, 2008 · When I flowed an 850 Demon on my flow bench with my carburetor flow setup. As good as this is, it was not all that Damon observed. Great! Jan 15, 2006 · I have a 383 stroker and I had a 750 single pumper holley on it and it ran rich. Edelbrock usually run great out of the box with a few minor tweaks. Then if the engine is still lean increase jet size in front then back, until you are in the ball park. All times are GMT -5. Send your blocks 4150 E85 kit--for 4-barrel 650, 700, 750, 850, 950, and 1050 double-pumper carbs: Demon, Holley, Proform and QuickFuel. Sep 23, 2002 · Engine Mods - What size jets are you using in your Holley's - Presenty have a 750 dp mech with 72 primary and 78 secondary. Jul 23, 2021 · Current setup is close to stock jetting (85/93 - two up on the primaries) with a 8. 5 PV on a motor with ported 061 heads and a healthy hyd cam (251@. . 1. The only numbers on it Sep 25, 2003 · I compared my Road Demon 625 to my Holley 650 Double pumper. The power valve seemed like the right one - 6. Nov 1, 2001 · We provide dyno results for Demon's full line of carburetors to find out which is the best for your Mopar. . I'll get the jet kit tomorrow. For every 2000 foot increase in altitude, you can reduce the jet size by one size. Start with the stock #80 jets in front and go 8 or 10 sizes larger in back (88's would be where I'd start). The goal is to help you understand the Oct 26, 2010 · Even using the stock jetting when it was a downleg carb the numbers tell me a 10 jet split brings it even front to back. 2 mpg (Imperial) on the highway. TH400 w/ 3000 Holley 4 Barrel Carburater Information List Numbers and Stock Jetting One of the things we noticed over the years is the lack of information concerning Holley List numbers and the specifications for individual carburetors and their stock jetting. I got out yesterday for the first time this season. Oct 24, 2003 · -Speed Demon 850AD/850ADV comes with 80/85 jets. 5 PV and 93 Jets in the secondary with no PV. And Every Holley book and YOUtube i have watched say if it stumble at the first of the full throttle stomp. Carburetor Air Bleeds and Jets are a must when track-tuning your carburetor for maximum performance! Aug 16, 2023 · I have what I believe is a new Race Demon RS. Working on tuning a 302 at this time that I ported the heads for with a VrJr, 650 Demon carb jetting is 74 front 76 rear not finished yet but was a big improvement over stock jetting. Dec 4, 2012 · Just for reference, years ago I was speaking to UDHarold about a cam for a fairly stout 468, and he reccomended running a pair of Holley Blues (110GPH), one for each bowl on the 850 Demon, with 3/8" lines and a separate regulators, it worked well. Does anyone else have this size carb on a windsor? Apr 3, 2004 · I have used my 350 as a testbed for Carter AFBs (less than 600cfm), Rochester Q-Jets (750 and 800 cfm versions), Holley 390, 590, 600, 650, and 750s (both vacuum and mechanical secondary), Edelbrock Performers (600-800 cfm), BG Speed Demon 650 & 750 (I use a BG Speed Demon 750 double pumper as my standard setup), and BG Mighty Demons (650 & 750). Demon air bleeds stink, too small, the Holley air bleeds screw right in and are much nicer, only thing I found thats better. Model specific subject matter experts, classified ads and more. Jan 9, 2008 · Stock jetting for an 850 carb is, Prim. I’ve got my combo just about dialed in but was wondering what jet sizes you all are running. , 5. Jul 13, 2007 · So today I decided to do some carburetor surgery and got a new jet kit to hopefully lean this bad boy out. The time now is 08:57 AM. And check for debris inside if it's brand new. wondering what size jets woulb be a good starting point to get it running right. 021" jet in their billet blocks as stock size. The Demon ET'ed the Holley by 2 tenths and 3 mph. Dec 14, 2002 · I run an 825 Demon Race carb on top of my Whipple. I had rich carb issues from the beginning and ended up getting gas in the oil which washed out the bearings. As usual - Joe's right ! Barry Grant's Mighty Demon line of carburetors is highly regarded for its quality, power-making ability and great value. 020" idle transfer slot opening recommendations. Its got 80 in the primary and 80 in the secondary. 5PV. On a chassis dyno, these are pretty good out of the box as far as response and fuel curve. 4200 stall and 4. The video explains the various jet sizes, and how they affect engine performance. As I bring up revs to 2500 or so notceable amounts of fuel come out of the primary annular boosters and black smoke starts coming out of the tailpipe. The brand offers carburetors for a wide range of vehicles, including the 750 and 650 carburetors for motorcycles. Whether it be circle track, drag racing, or getting the most out of your hot rod, these products will give you the added edge over other competitors. How small can I go? I felt more power with the 750 just ran poor. I am thinking of pouring some nitrous down my engines throat can I do this with the q-jet?Or will I have to come up on a holley or demon 850?Also is there much of a horsepower gain with a 1" carb spacer?I had one under the holley 650 but I bolted the q-jet just straight on the manifold. May 15, 2003 · The 850 double pumper comes stock with 80's in both. Jun 12, 2024 · Demon Carburetor is a leading manufacturer of high performance carburetors for street, strip and race applications. Jul 4, 2010 · carb. Whether it is everyday driving or just getting the most out of your hot rod, Road DemonTM will give you the necessary edge over others. intake, street strip car_ need input for primary and secondary jet sizes, am using power valve on primary Apr 8, 2001 · My notes show a Motorcraft 4V carb to be original equipment on the '72-'73 351 Cobra Jet. It was on my buddies shelf in the garage for 20 years or so. Mar 27, 2011 · If your mighty demon has screw in IFR's in the high location I suggest you place them down low in liquid fuel like an old Holley block and drill them . Nov 8, 2002 · i just got an 850 speed demon and the as delivered jets are WAY to big(85/92's). Jun 4, 2012 · Just got an 850 Mighty Demon carb and it comes with 85 jets in the Primary with a 6. If you're a carb wizard like Jeff Swisher they can work great. Jul 23, 2021 · I've baselined the carbs per Demon's instructions. There are no numbers, Jul 10, 2007 · Help Just bought a nice used BG Speed Demon 850 carb from a guy off the internet. Using the formula May 31, 2020 · Went racing yesterday, used an 850 Holley and my 850 Mighty Demon for testing. According to BG's literature, the 750cfm Mighty Demon comes from the factory with a #75 primary jet and a #83 secondary jet. It has totally different metering blocks and air bleeds from a Jun 9, 2019 · Anyone have any experience, or have any knowledge of the new "Street Demon" carbs since the Holley take over of the brand, ??. If you have a decent cam you need to work on both these circuit's and the power valve. 050 w/ . 036" Airbleeds can be recailbrated as you suggested to and . Not sure where it was A/F ratio wise with the factory tune up in it as it hasn't run yet. With downleg boosters in my speed demon 750dp my car wanted 80p/88s to be happy. 421 CI. We dont have any track here to run and tune with so i want to get a good starting point and then go back to chasis dyno. With over 40 years of racing heritage, Demon has continuously innovated and engineered carburetors that deliver maximum power and performance. I have a holley 800 double pumper Feb 6, 2022 · Assuming you don't have access to Mighty Demon carbs and if you find Mark Whitener is pretty busy as usual, I suggest you check out AED brand 750 or 850 carbs. Victor Jr, No spacer, (Vette hood clearence). If it's an Annular Booster carburetor it would have had 80 & 88 Main Jets. Jul 31, 2002 · I found this at summit. When in doubt, jet larger to start. Oct 15, 2013 · I think the stagger jetting hurtI am either going to go with 80 square and a rear p/v (box stock calibration) or go with 80 primary/88 secondary w/no rear p/v and give it another try. The 750 rating is just their for comparison to the Sep 1, 2013 · MP electronic ignition with chrome ECU New wires and plugs. Your 72/80 is almost what a 650 Speed Demon comes stock with. The BG carbs have too large main air bleeds and too large main well bleeds and this makes them rich at cruise but lean at WOT with the same Apr 29, 2017 · The 625 cfm version should run really nice on a mild 318, I would highly recommend tuning it though. The fuel pressure is set at 4. Barry Grant Speed Demon 850 VS carb w/o choke. The QFT SQ-850, Holley Race Brawler 850, and Proform 850 all come with the same air bleed and jet package. PS. I am putting it on a 468BBC and am having problems with part throttle richness. It was running rich but that may have been due to other carb issues. With its precision craftsmanship and ability to optimize airflow, this carb can provide a significant boost in horsepower and throttle response. Demon’s carburetors Feb 1, 2018 · Hello everyone. Stock jetting for the 4781 is 80/80 with a secondary power valve. So far the jets are #66 from #72. Demon Carburetors sells innovative carburetors, such as the Street Demon, for four-barrel applications. I now have Jan 26, 2018 · If anyone has one of these carbs, did it come with jets installed in the metering block emulsion tube holes? Some guys recommend sticking anywhere from 0. I used 84/90 on the 4781 with the secondary power valve removed. comp 08-432-8 roller cam vortec heads 9. Jetting may be necessary with the Demon, but the 351 CJ still had a few goodies left even in '73, my notes show the Cleveland Oct 24, 2008 · Can an 850 demon carb,im guessing speed demon,not sure,be jetted down to work with a modified 318 temporarily,or will it just be way too much?I ask,because i have the chance to get a nice one in a trade deal,and since i plan to go with a highly modded 360,or stroker for serious street/strip action. 5 LB. I broke in the cam last week. Any ideas on what jets come in a Demon 850? BGI-230001-2 Jet Sets (65-82 Jet Range) 2 Of Each Jet Size w/Divided Plastic Tray Jul 21, 2006 · The engine comes with a BG Speed Demon 850 (#1563010 - mech secondaries). I took the carb off the engine and brought it to work and reset all of the specs. The time now is 03:27 PM. Plugs are also wet and black when pulled with only tips being correct colour. In that carb (750) I ran 78/81 jets with a 2. I am thinking of going with a 625 CFM Street Demon, on my up comming LA 360 build. 040-over 440/9. Mar 8, 2019 · Your car will go and run fine with the 750 Demon carb. InductionAll times are GMT -4. 574/0. (front bowel only) & jets. This manual will discuss the special points and unique features of The engine comes with a BG Speed Demon 850 (#1563010 - mech secondaries). They left out jetting specifications stating that “We purposely left out jetting specifics, as jetting depends so much upon specific usage, gearing, transmission type as well as the characteristics of the individual engine. Just put this all together, bottom end seems a bit froggy - top end ok Dec 19, 2010 · Hi together, i got a question about jetting. Dont have a 6AL yet. The annular raises the signal for street driving and costs very little flow on the top end. It's in great shape - seems ok. Read more, at Sport Truck Magazine. Stock jetting is 85,93. Many folks buy a used carburetor at a swap meet or from an ad and find out that it wasn't what they thought they were buying. Mar 1, 2008 · Sport Truck garage tests Demon carburetors on a small block Chevy engine and proves that bigger carburetors aren't necessarily better. Had it converted to annular and so far I am at 71p/75s and going down on the primary side till it complains. Aug 27, 2011 · The stock 502 carb is not an 850 DP and it's jet sizes are not really relevant to your situation. Mar 3, 2010 · C3 Tech/Performance - mighty demon jetting - some input would be great. At cruising speed the idle circuit, the transfer slots and the main jet are all contributing to the mixture not just the jets. - I have been fighting some idle/part throttle issues with my Mighty Demon 750 and after many phone calls to BG and 3 carbs later they finally fill me in on a little info. They also give instructions on changing the jets for increased performance. The time now is 01:30 AM. Secondary is 93 and I have 97's. OOTB jetting is pretty rich, depending on your elevation and the stock jet size it might be worth it to change jets before you install the carb to spare the hassle. 5 pv. 85/93 jets stock with 6. Now this stumble started show it ugly head the first of this year. The engine ran hot during the first 15 minutes of run time, so I shut down and let it cool. I'd like to make sure that was the stock settings, or if it's been Apr 23, 2017 · I have an early Barry Grant Demon Carburetor on a 350 chevy motor in my coupe. 0- 11. It has the gold sleeves in it with 2 pv's and 85 square jets. stock power valve 3. In a Holley carb, the jets are located in the metering block (behind the fuel bowl). I would like to put the 750 back on. 750 Holley should never need more than 4 steps leaner or 6 steps richer jetting, unless it is a blow-through turbo or supercharged application. 5 lbs fuel pressure (Mighty Demon 850 down-leg boosters). Jul 2, 2018 · 825 Mighty Demon reduced IDF jets low speed air bleeds increased slightly to delay transisiton to main float level, set slighty below 1/2 level in window 74 main jets ( 72 is lean, 76 is rich) Transition slot completely covered Butterflys have 1/16" ish holes drilled low speed 4 corner mixture screws approx. 050)/1-7/8 Lengthy video on tuning the jets on your holley carb. 5-13:1 is optimal for max HP I called Barry Grant today and the tech stated Jul 12, 2013 · Here, the air-fuel mixture is drawn and atomized in the fast-moving air stream to the cylinders. I have now pulled the motor, which only had 350 miles on it and after replacing the main bearings, rings and polishing Sep 10, 2002 · C3 Tech/Performance - Jet size for 850dp - Going to put the Holley 850dp, 4 corner idle on my car this week, was wondering if the jets are the right size. That is supposed to be the same as Holleys at 1. Mar 22, 2013 · 406 SBC, dart heads, with an untouched box stock Barry Grant 850 on it, 80 jets front and back with power valves front and back. Apr 4, 2022 · Hey guys I'm trying to identify this demon carb that came on my 454 in my Chevelle when I bought it. How to install & tune a Mighty Demon 750 double pumper 4 barrel carburetor with mechanical secondaries. she's running really rich right now with #89 and #85 jets in it. Anyone think I should bump it up to 83 in the back before the dyno session…. A vacuum secondary would probably be a better setup. If a 5 gas analizer and dyno is not availible to you just do ur plug readings as usual. Carb is a mighty demon 850 with drop leg? boosters, & four corner idle. Oct 12, 2009 · I'm running a demon 850 on my 351w. 8:1 compression HYd roller cam 408. Oct 11, 2011 · Alum big port heads (More info coming). 64IIGolf lover your spot on, my eyes burn when I stand anywhere near the engine at idle. 85 and I have 89's. Timing might be a bit over 18 at the moment. I found that the idle linkage screw as it just touches the throttle linkage only needs 1/2 turn in to meet the . In other words, if you attempt to match “normal” brake specific numbers, you may be left with a sluggish Demon that is operating well below its potential. Jul 15, 2010 · Hi i have a 850 mighty demon carb on my 393ci cleveland, it is currently stock out of the box 850, i have heard of them needing some fine tuning from the way they are for maximum power, i realise a dyno is the best place to sort this outg but i do not have access to one in my area so i'm just after a little guidance in this area. Jul 14, 2017 · The "as delivered" jetting from Holley is very close to optimum for the majority of high performance applications. Across the range of sizes, from 650 cfm to 850 cfm, the Speed Demons deliver balanced, high-velocity airflow and exceptional fuel metering capacity to match the fuel requirements most street engines. The Mighty Demon 850 is designed for racing and high-output street engines and boasts billet aluminum baseplates and metering blocks, large-capacity fuel bowls with sight glasses, and streamlined air entires - features typically found only on high-dollar modified carburetors Jun 8, 2018 · Just thought I'd throw this info out thereNow, I know not a lot of you run demon carbs and even less have the older BG-made unitsI use a 2007-vintage 850 speed demon/mech secondary carb on my . This rod fits through the center of the main jet, and the diameter of the metering rod and the jet size both play a role in fuel delivery. 80 fronts & rears. Have you checked your plugs to see if you are lean? Aug 25, 2009 · Gentlemen, I need some starting point recommendations for Jetting the Big block. Same will apply to 4150 style Holley carburetors. Next, I dropped the jetting back to stock, damn car slowed down 3 mph. carb. :Do No: My combo is listed in sgnature. Running 10. 5:1), unknown cam, with a complete MSD Ignition, Barry Grant Mighty Demon 850, on top of an Offenhasuer 360 Tunnel Ram with a single carburetor top plate, breathing through Basset Classic, long collector headers with a Holley Carburetor Jet Size Conversions Nov 29, 2024 · My rule of thumb is: Stock or mostly stock = Q-jet Mildly modified cruiser = Edelbrock Going racing = Holley Q-jet is great, but complicated and hard to tune. Apr 23, 2010 · I have a Holley 850 Double Pumper with annulars, model number 0-9380 going on my 454 cu Big Block. 5 in the primary,the rear is blocked. 578. 56 gears out back. Nothing else changed, just annulars. After you make a jet size change and run the car for a while. Jun 9, 2008 · I'm looking for some help with tuning my mighty demon 850. Yes it does use Holley jets, etc. Seems like too much jet to Sep 25, 2023 · The general consensus is that these things need about four jet sizes richer, primary and secondary, to run safely (stock jetting is 85P/93S - I'm at 85/94 now). 1st thing is to make sure your engine is Dec 31, 2006 · I've never been inside a carb before, where are the jets located in the speed demon, im assuming i take off the fuel bowls and i should see them? I picked up a holley jet kit from summit today and need to jet down from 86/93 to i think 78/79. INTRODUCTION Demon CarburetorsTM, the first new design in racing carburetion in 40 years, have many unique features that make them the ultimate choice for racers, like yourself. Ive heard of folks jetting a carb down and Dec 29, 2013 · The BG 750 as manufactured has too large main air bleeds and will run lean at WOT with the same 70P (w/PV) and 80S (no/PV) jetting which is close for a Holley. The only thing i have done to carb is change power valve to 3. BILLET MTR BLK & CAST MTR BLK & BILLET MTR CAST MTR BLK & ROAD DEMON BASE PLATE CAST BASE PLATE BLK & BASE PLATE BILLET BASE PLATE Mar 2, 2010 · So, you say the 850 didn't generate as much signal strength as the 650 or the 750 therefore, it requires a bigger jet to deliver the same amount of fuel. I cant identify what type it is or how many CFM . That comparison could be apples to lemons. Jun 10, 2019 · Its a 850 double pumper carb running on a 12. 3000 stall, 391 rear end gears, headers, victer jr. I took it apart to check the jets, power valve, gaskets, etc. The Street Demon is ready-to-run out of the box and features many innovations including the Goggle Valve Secondary (GVS™), Aerospace Composite fuel bowls, and much more. Jan 17, 2009 · I found a great deal on a mighty demon 850 carb. Stay away from the performer rpm- too large for a stock engine. Mar 6, 2010 · I was running 6 jet sizes richer to get a nice AFR. Looks like a 750 to me, throttle plates and venturi don't look big enough to be 850. Based on what I've read regarding the Mighty Demon 850 I went ahead and increased jets to 88 primary and 96 secondary with a 4. Dec 6, 2002 · ThermoQuads 101: the basics. 6 pump gas mtr. 5 Dec 2, 2009 · Holley explains how the main jets on a four-barrel carburetor operate. If you’re considering upgrading your ride with a Demon 850, this […] Sep 12, 2010 · Ok, I built a 502 and put on a Barry Grant rebuilt Mighty Demon 850. I have a 1976 Hawaiian Jet Boat, powered by a Ford 460, (8. Re: Stumble from my 850 Mighty Demon? - 06/07/0811:49 PM I just checked the Demon web sight and found that a stock 850 MD comes with 85/93 jets. pop out a plug on each Head and see what it looks like. 5 mph faster than my 1000 Mighty Demon, 850 A/D Mighty Demon and it was 4 tenths quicker and 3 mph faster then my Holley 750 HP vs carburetor. Nov 7, 2013 · Have 400 pontiac, headers, 342 posi, XE268-280, 2000 stall and have a 600 and 750 edlebrock performer that im considering to replace a 750 holley 3310 for better tuneability and gas mileage and automatic choke. Jul 24, 2002 · Factory Jet Sizes on my Speed Demon 850, dp, mech secs, annular booster model are : 80 primaries and 85 secondaries. The car seems to run fine with that. Carb has dual feed center hung fuel bowls. This is just a street cruiser. 021" to 0. Apr 22, 2011 · Re: jet size question on a 454 ho with an 850 dp I would start with 78-78 being a street car, possibly change pump cams to delay secondary openings, if you're concerned about better mileage. Larger jetting may be necessary with unusually large manifold volume, stack of spacers or such. I have run an 850 A/D booster Mighty Demon on my 358 in the past and the car went the best at the track with it. May 5, 2019 · No amount of jet change will will fix a stinky idle as that circuit is not active at that low of rpm. Even with it giving me fits for tuning it (ie needing way bigger jets than I would have considered in the Holley), I'd rather work on it than the Holley. Aug 31, 2011 · With our 4. installed smaller IFR down to 28 from 35 in attempt to lean out transition circuit . 5 May 24, 2010 · What is the car telling you? Too many variables to set your jetting on someone else's combo IMHO. 10 geared L78 and the stock 4346 780 Holley and headers, I run 6. For sure go mech. 8-1 compression on L31 block professional products cross-wind intake 1 5/8 semi-long Demon 850/1000 body, downleg boosters, QFT 850-1000 throttle plate (the BG plate tore when I was adding PV protector), Holley billet blocks. 5 PV in the front. Will be putting in a 68 primary in next couple of days to lean it out a bit. Aug 23, 2009 · Greetings. MSD street HEI. Other than the obvious of a vacuum secondary to mechanical, I like the Demon way better. The Demon tech line did tell me the carb was calibrated for performance and might get better mileage with some tuning adjustments. But the Demon is a clone of the Holley and uses the same jets. Jun 30, 2024 · Once you figure out the size, i can give you air/fuel bleeds, jetting, etc stock spec for every orifice in the carb if you need it. even running as rich as it is the throttle response is like night and day over the holley. 067" IAB &. Looking for some recommended jet sizes for my combo. Jun 4, 2002 · Demon Carb Jetting help!!!! Pontiac - RaceI just did a major makeover on my intire driveline including a new demon 850. 1-1/4 turn out idle speed 1100 rpm INTRODUCTION Demon CarburetorsTM, the first new design in racing carburetion in 40 years, have many unique features that make them the ultimate choice for performance enthusiasts, like your-self. At WOT I am running between 14-14. 5 PV). you are already in dangerously lean jetting territory with the 10 sizes smaller #64 jet. Jan 7, 2020 · A Demon with an overly rich tune-up may act excessively sluggish compared to other style carburetors. Also, 30 cc pump in the front and 50cc pump in the rear, J tubes. I was just wondering what your opinions were on them. It’s basically the same physical size as the original HP950, which is a much better carb for the application than a MD850 Dec 31, 2003 · If you keep the 850 Holley plug only the rear PV and install about a #4. they will flow 1015 CFM at 20. Demon Carburetion’s Mighty Demon carburetors are a step up from the Speed Demons. 5 PV on the primary side (originals are 80/88 and 6. Tunnel ram manifolds (dual-quad applications) might require jets as much as five sizes larger than stock. Look at the small print on the box label. We would like to show you a description here but the site won’t allow us. Mar 24, 2004 · C3 Tech/Performance - Very interesting talk with Barry Grant about the flow of their carbs. 624 lift cam. Feb 14, 2009 · ok, this is my first build, just rebuilt my holley and am wondering what would be a good initial jet setting for it for my build. But the fatter jets in, she came back around. this info can translate to any holley 4150 and 4160 style carbs. Much happier with a Bill Mitchel modified holley 850 ANNULAR. also if spacer would be recomended. May 31, 2021 · There is a chance one of these jets are off by some, but the car runs hard. Holley recommends a 0. 5 @ cruise, tried jetting down from 90 primary to 85, no change then went 82 still fat as hell, no change, Thought the PV was blown, changed it still fat as hell. Mar 6, 2006 · Recommendation for maximum performance was to switch the low rise for the 427 high rise and the 780/800 Holley for the 850. 5:1 on my A/F I have been under the impression that about 12. 33/33 hsab, 76/84 jets. With that venturi diameter, I think the Proform tune should be a safe place to start. Chevy Forums FREE technical assistance for your restoration and repair. Jetting and power valve tuning aside, just be prepared to play with secondary springs. I swapped on a Vic jr, and ran it with the same jettingcar ran the same as the dual plane. Jul 10, 2007 · If it's a Downleg Booster carburetor it would have had 85 & 93 Main Jets. Just keep an 8-10 jet size spread. YOU Jun 12, 2024 · Demon Carburetion Mighty Demon Carburetors MAD-850-AN Are you running an over-the-top street/strip engine combo with a high compression ratio, big cam profiles, large cylinder heads, etc. The carb idles fine (900-1000rpm) and when you're "on the gas" it runs strong and smooth all the way to 6000rpm. Nov 24, 2009 · I'm running the 825 demon on my 472 w/ cobra jet heads, . Now I have a 600 holley single pumper on it. It came with 85/93 jets and 6. So I picked up a set of #70/78 jets from the local speed shop. It has . The same thing happened on the second run. The problem is when I'm trying to "cruise" or hold the throttle still for a constant mph. thoughts? experience? thanks for reading Discussion on jet sizing differences between primary and secondary jets in carburetors for automotive enthusiasts. I have been running 74 and 80 in my 780 vac carb, seems to like the extra fuel, but runs out of top end at about Description NEW 850 CFM HOLLEY MARINE carburetor, model 4150, List number 80443. You are right if the carburetor is box stock or only slightly / conventionally modified. They feature billet base plates […] Feb 27, 2005 · demon carb too rich? Performance TalkAll times are GMT -4. I love it and it has worked flawlessly for two seasons now. 5 Power Valve. May 14, 2007 · For a 502 cast iron head stock crate motor. 1 454, air gap intake, elderbrock oval port heads, 1 7/8" full length headers, roller rockers, and most important comp XE284H with 240/246 duration @ 0. ? If so, then you need a radical street/strip carb to match. Best thing to do is look up your carb by it's list number at the Holley web site and install the jets and power valves called for. This manual will discuss the special points and unique features of the Demon carburetors, and the correct procedures for their proper installation and tuning. Once you know the correct stock jetting for your particular Holley carb, you can determine whether you live or race at an altitude above sea level. What do you think? Get the Inside Scoop on this High Performance Carburetor The Demon 850 carburetor has become one of the most popular performance carburetors on the market. This manual will discuss the special points and unique features of the carburetor, and the correct procedures for their 4-Barrel Double Pumper 4150 Stock DIY E85 Kit. 5 power valves front and back, #72 primary jets, #76 secondary jets. The Speed Demon™ line offers a wide range of sizes with vacuum and mechanical secondary designs. 5 inches. I started off with 73 jets on my 650 Demon. So, lots of reading - it has been recommended that in order to fix these, they need to be recalibrated to a more standard Holley double pumper setup. Oct 3, 2012 · Holley Jet Sizes - Street Driven Small Block Discussion in ' The Hokey Ass Message Board ' started by BOSTONCAMARO, Oct 3, 2012. 5ish compression/edelbrock rpm heads and intake/comp XE 274 cam (230°@. Dec 24, 2007 · if i get a demon 850 ,can i use the typical holley jets ? does a demon carb come with the same sizing of jets as the holley ? thanks jason Feb 18, 2005 · Hi all, I have a question about where I should start on jet sizes for my Holley 750? I'm getting ready to rebuild this double pump carb (mechanical secondaries) that came off of a SBC. 65). is on 383sbc , 9. Demon engineers took these features and packed them into three distinct models—Street: Road Demon, Street/Strip: Speed Demon, and Race: Mighty Demon. Power Valve On powerful engines at high speed or under high load, main jets cannot provide sufficient fuel without adversely affecting the carburetor’s performance at lower engine speeds, and power valves were introduced to resolve this difficulty. I was gonna try it on my street car and see how it works. Large plenum manifolds will require larger jetting (3 to 4 numbers larger). today i opened up a Mighty Demon 850 i bought as "new" and discovered that the carb had been gutted! No floats, no jets, no powervalve and Mar 20, 2006 · Carb Size for 454? The 1967 - 1972 Chevrolet & GMC Pickups Message Board Jun 14, 2024 · Chris, I played with 850 vac sec carbs (both Holley and Demon), never got them to run great as street/strip carb with high stall converter. Too many people have no idea how jetti Feb 25, 2016 · A smaller orifice will restrict fuel, and result in a leaner mixture. can i jet this like my 750 vac holley or will i need to jet larger than the vac? this is the first dp carb for me. Sep 30, 2023 · The general consensus is that these things need about four jet sizes richer, primary and secondary, to run safely (stock jetting is 85P/93S - I'm at 85/94 now). Just build on the Speed Demon 850 Carb and heared from Jan 20, 2015 · Success in Tuning Street Demon 625 Carb for Better Mileage Last February I posted on my initial experience with a Street Demon 625 carb and noted the gas mileage was significantly worse than on the QJet it replaced. Jan 9, 2003 · Replacing the stock 795 cfm Q-Jet with our 750 Speed Demon resulted in a 25 hp increase along with 11 lbs-ft more torque. You can look up the Lars papers and it will also tell you how to setup a Demon carb, that's where I learned how to do it. 025" HSAB is a good place to start w/ 80/88 jets with no rear PV. Personally, I wonder if there is much difference between an 830 and an 850? I bought the Demon mostly because they build it at the factory to specifically be used in a blower application. Sep 12, 2021 · This FST carb was over a tenth and a half quicker and 1. Make sure float Jun 27, 2002 · I tried a 850 mech speed demon on my 454 71 4spd and it needed bleed restrictors and a bunch of labor, put it on my BB T-bucket that could use the flow better. The Street Demon also uses jets for its primary metering, however, a metering rod is used to control fuel flow in conjunction with the jet. I havn't found much comment on them being used on SB mopars. Don would definately be able to tell you what series of carb and what jets you should start with in your application. 14. I was using a 750DP prior to all the changes and using it now for start-up, checking, etc. Oval Track CarburetorsQuick Fuel Technology | #424XP4412A Quick Fuel XP-4412-A XP-Series Carburetor, 500 CFM, CT Alcohol Jan 9, 2008 · If it does there is a idle jet adjustment under the air cleanner stud. How good or bad is this for a mild 408bb? How hard are these to tune? Here are the features: Features: Billet Baseplate with new Idle-Eze Billet Metering Blocks Patented Concentric Venturi Apr 5, 2015 · The stock factory Q-jet manifold will give you the best mileage, followed by the Edelbrock performer. 5 However, the primary jets were # 72 and the secondary jets were # Jul 27, 2012 · Holley Jet Sizes (850) D/P Guys thanks for all the useful replies. The carb is a mighty demon 850 with downleg boosters. is airhorn delete, choke delete, metering block kit on secondaries. Idle mixture is pretty good and jet sizes have been proven with the same carb on engine builder's dyno Apr 15, 2008 · But doesn't a blower increase the air going in-which would need larger jets-can't hurt to try. The previous owner believes it's an 850 C FM but after doing the numerous research which seems to be quite an issue with these carbs I can't find anything to identify it. 5-1 aries aluminum forged pistons and a Lunati full roller setup 241/248 @. Generally set the idle mixture screws and they run fine. 602", 244 dur comp cam and it's perfect, so i would say the 850 might be a little big for you,,,,,JMO Oct 13, 2009 · I slapped on the 850 Demon DP and reading my wide band it is <11. DEMON CARBURETION – NEW PRODUCT Demon CarburetionTM warrants its new Speed Demon products to be free from defects in material and workmanship for a period of 90 days from date of purchase. prgka vtlq ncqd uqmgdvma ltcpo mig qyi ajkcl jlt lvhmq