Tuning Secondaries: Holley Style Vacuum Secondary Carbs (Extra HP)
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- Опубликовано: 27 мар 2021
- A lot of folks never touch this stuff, but it really does make a big difference.
Secondary spring kit: amzn.to/31rYTQ0
quick change diaphragm: amzn.to/3sxzujs
replacement diaphragm: amzn.to/3cukRrJ 
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Like I said guys, this is very much so tied to the "seat of the pants" feel - if you know what to look for, you can really make a big difference on a vacuum secondary carb.
Links to tuning bits are listed in the video description. thanks for watching guys - more importantly, I hope the video was helpful.
Is that a 302 in that Maverick? I have a Holley 600 on mine. Do you recommend I use a smaller cfm carb? I was thinking of ordering a 4150 to put on.
these are great tips man. really appreciate the videos.
I normally have a 600 on the mav 👍
This 390cfm is for a dual quad intake, only on the mav for post rebuild testing
Good video!
Appreciated the tach view. You could see it.
Cool tip with the paperclip.
@@ThunderHead289 Thanks.
Glad you are un-retired!
Excellent description concerning vacuum. I learned and gained my information from shop manuals and I still have those manuals. I'm soon to be 74. Learned a lot in the 60s and 70s. Keep up the good work.
Everyone needs a little extra street torque. Love the music in the beginning.
I think it was Alice in Chains. Good band.
@@shawnmay7264 right right
I love dem carbinators.
That was one of the cleanest 2nd gen rams I've ever seen.
Wow, I’m dreaming! I had a ‘72 Maverick,4 dr, with a 302/5.0 and that , even stock was quick. I did a good manifold cleaning and had true dual exhaust put on, along with rebuilt transmission/shift kit. Pretty good runner. The one thing I never got around to was the diff, it had a 2.74 pumpkin, not enough to scare the big boys, but solid enough for me and good highway mileage.
I'm glad you are back on videos. I may not catch everything you say in one viewing but I actually learn a lot from you. Carbs were always a mystery to me and I believe that if I need to work on one I can go back through your videos and find a solution to my problems. Keep on doing what you do.
Brother your videos have helped me so much over the years ! Thanks again for sharing .
Truly glad to see you back absolutely enjoy watching your videos just goes to show you can teach this old man new tricks thanks
Sooooooooooo happy to have you back. I squeal a little when I see you've posted a new episode.
Thanks for explaining the carbonator and sharing another informative video.
Glad your back..your knowledge of carburetors is impressive..
Thank you for the great knowledge Luke and for all your help working great videos
Good stuff! Uncle Tony did a similar video on this also. I love my 4100 Carb on my 64 Galaxie with the 352. It was your video that finally got me to tune mine correct and she can spin the two tires with my posi unit in the rear.
Hey man. Great job! Nobody else on RUclips speaks as much about carburetors on old fords as much as you.
Great information on Secondaries Luke
I love the info, you are amazing, you have me all excited about working on My 1968 Dodge Truck with 340 , thanks for inspiration
You rock. Love to see younger people like yourself who just are gearheads. Don’t worry about the paint job or what the interior looks like. Just so it hauls ass.! Just like we did it back in there 60s and 70s. All your money goes into engine and transmission and go fast. Who cares about how it looks. Also I got the same beer bottle opener ring.
Another useful tidbit of great information.
Hello uncle luke 👋 glad you are back buddy 👍 it makes my day with your notification
Thanks for the video and information. Have a great day!
Great choice of intro tune 🤘🏻
Luke, Thank you for that explanation! As an older guy who grew up with '70's GM 350's, Chrysler 318/360, etc..that 'bogggg' then ' 4 bbl howl (yeah, flipped breather lid lol) we thought that was normal.. Now in my 50's, I realize how much faster my old school big body Lemans, Cutlass, Caprice, Fury etc, could have been. I still love the early/mid 70's boats, (84 hs grad lol) but man, a 4bbl, shift kit and duals with glasspacks, hrs of cruisin fun with under 300hp!
Thx for this video Luke. This helps alot.
appreciate you teaching me this stuff
Thanks for the video Luke.
Been my expierence that the best way to cure vaccum secondary stumble is to install a double pumper, problems solved , great videos luke 👍
Seen an old Maverick run an 11.60 quarter mile in San Antonio, Texas in 1983. Here’s the part you may not believe, it had a two barrel 289! This was before the days of the huge 5.0 aftermarket, all old school technology. I thought it was bad ass because my ‘62 Ranchero ran 11.80’s with a 650 DP. Being real my Ranchero had a C4 and the Maverick had a five speed Doug Nash tranny and would get 12” of air at launch!
That appears to be a fancy trailer park, the ones in AR usually have gravel drives.
Another good video for new car people love it
When I get my Mustang done this spring, I'm making a road trip to see you for a tune ;-)
I’ll be around I’m sure lol
Always informative my friend
Carb vids are brilliant.
Well done, Luke.
Always informative
I have a 460 running that same carb yet new to all of this. I was recommended using a purple or yellow spring. I don’t known the gearing as well. Previous owner dropped the engine in my 69 cougar from a 72 grand marquis D2VE-AA heads.
Candy blue. Nice video, thanks!
Thanks. My engine would go very lean as soon as the secondary opened and then go back to rich. I was getting ready to richen/drill the secondary idle/transfer slot orifice. Now I am just going to use a heavier spring.
Oh boy. Now that he said “minty”, i hope it wasn’t your peg leg you got the gas on!!! 😂
any friend of pegs isa friend of mine!!
👌
minty
5:40 VTEC kicked in yo! I'm just here to relax to the sound of Luke's voice; so chill, haha.
I hear Foreigner " Rev On The Redline " Playing in my head when I hear that Maverick grab some Horseseys
Luke; that Alice:
I can't take it! Soo good!
I'm gonna spam to every comment saying it's AIC: it's not. It's Skorned - Psychosis. Spooky actually how it sounds AIC...
the Maverick would love a locker, good show info
The song is psychosis by skorned. It's scary how much that guy sounds like Layne, the guitarist could even pass for Jerry Cantrell. Had me completely fooled
Yep, got it !
Well explained. them some bernoulli's for the masses!
Luke getting fancy with the music.
you made the video !!!!! whoop whoop must stil watch it but it will be awesome
Man that 4 door Maverick sounds badass brother.
Mavericks don't seem to get as much attention as the more "obvious" muscle cars. This wee beastie doesn't 𝑙𝑜𝑜𝑘 anything special but it sure "brings the thunder" when you ask it to.
I never got the "4-doors aren't cool" thing and it comes as no surprise that Luke runs a 4-door; who cares about these stupid "rules"? She looks, and sounds, pretty damn cool to me.👍👌😁
@@2H80vids She sure does like look at the new Charger its a 4-door muscle sedan and it looks badass.
Love that old maverick
Awesome, thanks man!
Secondaries kicking in like vtec!
Luke! Skorned! What's it been like 6 years since they released this? Nice intro. There is another band that sounds like them. Cant think of the name.............LOL.
I bought an adjustable vacuum secondary canister that can be easily tuned by turning a screw to make it open sooner or later. I just make it open sooner until i get a bog and then back off until it has no bog. I have a 780 Holley on a 350 sbc that is probably only opening to 650 cfm thanks to the vacuum secondaries.
COOL THUNDERHEAD!!!
Quaker City Nighthawks, great taste in music!
Great to see you still around been awhile Luke @Thunderhead289
Yeah Alice n Chains!
What song is that I’ve listened to like everything by them and don’t recognize it
@@THECREATOR1099 Skorned - Psychosis
@@dolor1983 thanks bro, if you didn't say I'd think that was for sure an alice n chains song
@@dolor1983 thank you!
I knew it couldn’t be them haha Ive heard and regularly listen to copious amounts of Alice In Chains
Interesting, thanks to share.
I love that truck
The size and design of the engine makes a difference. A small engine will be much more sensitive to secondary opening rate, moving the power range up in RPM with cam timing (longer duration specs and opening/closing event changes) will also make it more sensitive to the secondary opening rate. The larger the engine the more it can tolerate or wants, same with cam timing/duration. For instance the Pontiac 455s I run in my cars make 500ftlbs at 2000rpm, and they are still making 500ftlbs at 4500, they are pulling 15 to 19 inches of vacuum at idle. Mechanical secondary 850cfm carbs do not bog on them even when they have a 2.93 gear and a 1900 stall behind them, in a 4100lb GTO. Up to 45mph you can smoke the tires by simply whacking the throttle in 1st gear. Not some 205 70 14s, but 275 65 15 or even the 295 60 15s I run under those cars. Yes that is a mid 12 second 4100lb car with 8.8:1 compression, and those gears/stall, using a 224/228-110LSA hydraulic flat cam.
I used to help the chevy and small ford guys go faster, one of the first things I would do was changing the secondary spring, going with the lightest one that did not bog. The factory spring opens kinda slowly, usually you can't tell at all. I have my own way of setting up the timing, because I like my engines to drive around nice, start easy, but make as much power as they can. So I never used manifold vacuum to the advance. I would curve the weights and springs so the mechanical advance would be all in by 3000rpm, a really fast curve. Then I would give the engine however much total timing it wanted, and the vacuum advance could be used to both advance and retard the timing depending on how much vacuum the engine has at various RPMs and loads. I would drop anywhere up to a full second off the ETs for the chevy guys and improve drivability for them, and then they'd take it to someone else and run slower than they had it running before I saw it. I do not take much stock in what most chevy guys say, if they are a builder with a dyno then they usually know what different combinations do, so I will start where they leave it. The average guy, man its all over the place.
I throw out everything the chevy guys say when tuning my Pontiacs and my 4V Cleveland engines. There is quite a bit of difference in the chevy and those engines. The 351W seems to work ok with the typical chevy thinking, but a Pontiac will go slower almost every time you try to use chevy thinking on it. From timing and secondary opening, to gear ratios and stall, torque monsters and huge port Clevelands want different things. I never had a problem with a 4V 351C and a lack of bottom end either, they will fry tires from idle by mashing the throttle unless you get over 235@.050 duration. Then they need more gear/stall. Seriously fun engine if you can find one, no need for a bunch of aftermarket parts like heads, throw a cam, springs, roller rockers and headers at it, maybe an intake depending on how much cam you are running, and they are freakish monsters.
If the sbc was in a light vehicle with 3.55 or deeper gears with more than 3000 stall, it usually worked great with the lightest spring Holley makes and a fast advance curve as long as it doesn't rattle. Those things are prone to rattles, so they can only take just so much timing before they try to tear themselves apart. If the vehicle was over 3300lbs and had less than 3.55 gears it was usually one of the two springs between the plain stock one and the lightest. Compression ratios change how much vacuum an engine has too, high compression engines pull more vacuum than low compression provided the cam timing and port design, shape, and size are all the same. Its usually not a big change, but it is noticeable on a gauge.
With the small Fords like your 289/302, a fast advance and a tailored opening rate on a somewhat smaller carb worked best. A mechanical secondary carb will make the SBF drink a ton of gas. I had a 600 double pumper on a 302 in an F150 4x4, the mileage is abysmal like that. Swap it for a vacuum secondary 650 or a QJet and it picked up a bunch of mileage and some power down low. Two pumps always shooting fuel in can make a big difference. Adjusting the Qjet secondary opening rate is super simple,. All you need is a small Allen wrench and a small flat blade screwdriver. FYI Fords really like the Qjet, they came on some 351 4V Clevelands and 429/460s for a few years. Its worth learning how to build and tune them if you want a great street carb. Fords never seemed to be too prone to ping/knock, but they would surge at cruise if you had the timing advanced too far, and also they run hotter if its advanced too much or too retarded.
The best way to learn how to do all of this is to go out and try different things, make notes of what the timing is at various RPM with what spring in the carb, and see how it runs. A Dragy is worth the investment since it is more accurate than the butt dyno. I run wideband O2s and a Dragy to tune the carbs I build for E85, reading plugs on ethanol is difficult because the stuff burns so clean. A wideband make it so much easier to dial in part throttle, cruise and WOT.
You have to find what the engine wants and likes, the only way to do that is test test test test and then test some more while keeping track of what changes you made, and only one change at a time. Eventually you will learn what it wants. You'll find that changing the timing will result in you needing to change the idle, and if you increase the vacuum you might need to lower the float level too. Change one thing, see what it affects and then make that right. Its how you do it.
I have quite a bit of variance between 455s, usually based on compression ratio and chamber shape in the heads, since the Pontiac changed compression ratio with different size chambers, and all the shortblocks have flat top slugs (save for certain 428s that had a slight dish) The machining variances can stack up one way or another, and casting shift also changes things, so no two engines are the same. They can be quite close, but probably not the same. Go find out what your engine wants.
Great info
Glasses?
Love the informative videos.
What is the make and model on your cool glasses?
Smartest guy in the park
Was it Alice In Chains at the beginning?
Skorned - Psychosis
@@dolor1983 I didn't know this group, thanks a lot, it very looks like!
Maverick sounding nice there bud. You doing to switch to the two 4 barrels on the channel? Like to see that going on :-) Nice!
Third place to get vacuum for advance or secondaries when running a shitlumpy cam could from the brake booster if you run power brakes. It acts like a vacuum reservoir.
My 89 Caprice wagon with the 307 was slow as a dog till one day I romped on it and the secondary's opened up and finally the thing had some power. They must have been stuck or something. I think the Qaudrajunk has vac secondary's
Love your videos, what your thoughts on tuning a 04 Chevy vortex 4.3 ?
Well that solves the mystery why my 1964 Comet 289 with holley 600cfm 4br stumbles when I floor it off the line. When ever I get around to driving it again I'll change out that spring. I alway thought it was the accelerator pump sized wrong.... thanx
Modern day Isky/Smokey/MT my friend. You ever want to watch some 410's rip around Knoxville let me know; I'm buying!
I don't get it. Didn't you have small screw to lock the secondary's in about 50% throttle, we used to force them open. I cut the secondary advance spring so much it was gone on my 427 Tri Power then went to progressive linkage adjusted to open about 3,000 RPM. What a flipping mistake, the car was like idling or ripping your head off. Very hard to cruise around and be cool that way. Great Video Luke, You have learned some extremely useful lessons, thank you for sharing. Dennis in Virginia
Very interesting.
Hey Luke, i hope to have around 545 hp or better in my ldo maverick coupe using a holley hi rise and 347 stroker. Love mavericks. 🇦🇺
Hi Luke just curious hope you can clarify please? I’ve learnt a lot now about setting the transition slots to a square and how to adjust the idle, now one video says adjust the idle from the secondary blades via the hidden screw and another says adjust idle with initial timing while having a buddy assist inside the car having it in drive ( automatic ) to desired rpm?
Great tutorials only started watching them hope you can help muchly appreciated 👍
Do you plan to have an all Maverick playlist?
Carbonator tuning at its finest.
👌
minty!!
What is the tablet running ?
I must have missed the video of that
Sweet
You tease on your app!
Good explanation but my engine is still hesitating when the secondary opens can you tell me why?
Love your videos! How is it trying to work around Mook? I’d go nuts
I don’t work around mook to my knowledge - unless you meant the safety intern from a couple of my videos back.
Them halo headlights look like headlights I see a lot on Jeep wranglers Around me
You gotta keep em carburated..
😆🤣
Good to have another ford guy out there
So, I've never heard a good explanation why vac secondary carbs are listed at a higher cfm than double pumpers. 780 vs 750, etc. could you shed some light on that? Much appreciated! 🤘
Last summer i got my dad's 59 fairlane running after sitting since 1990. Alas, it's got a 223 with a 2 speed fordomatic. I'm looking for a rebuildable 390 and a transmission. There are no ford guys around here (eastern iowa). You have one sitting around for sale, or know someone who does? Or a good place to look?
I want to know where to get the mask with the biohazard symbol on it like the one you have hanging on the mirror, please?
So on an edlebrock I would just tighten the spring for secondaries correct. Basicly making a "heavier" spring. When I floor it I hear the change sounds like it wants to go but. Slowly picks up speed. 87 silverado long bed 650cfm edlebrock asv2. Damn thing driving me crazy. Like it tries to open up under light throttle cruise. Out of no where sounds like it bout to take flight but press gas peddle just a tad and goes away. Like what do you want to do woman. Ugh. 😅😅😅😅
How can I get more power out of a 93 F150 300 with EFI ?
My dad had a Maverick they called it a grabber 302 boss
A in C!!
Easiest fix is to throw the vac secondary away and go to a good old mechanical secondary carb. Vac secondarys are good for heavy vehicles or large trucks but in a lightweight street car you cant beat the response of a double pumper.
Yep light cars or very low gearing will benefit better from a mechanical secondary over a vacuum secondary. In many cases you can never properly tune a vacuum secondary to work right if you are too light or have too low a gearing. I actually ran into this issue with a 3500 lb passenger car that I built a hotrod 292 for but I swapped the stock 3.20 gearing for 4.56 gearing to bring the cam into the 3500 - 7500 rpm power band which just made vacuum secondaries pretty much impossible to adjust properly for a steady strong pull.
It all depends on what your doing, the 600 double pumper in my hands is actually what I run on the maverick normally. With a double pumper, you have to “drive it” on the bottom end. It’s all about pedal control which is very hard to explain to folks, especially those used to fuel injection, hard concept for them to wrap their head around.
@@ThunderHead289, but you have to be more careful with a double pumper as they are not as forgiving when oversized like a vacuum secondary. The 600 cfm vac secondary was too small in fact for the rpm my built 292 ran I switched to a double pumper but got the 670 holley at the time and it was a better fit.
My street build for my truck that 306 is getting 800 cfm in the form of holleys stealth EFI for better tunability for a wide range of conditions.
You know, you have reliable car when a screwdriver is a part of the dash equipment :D
That’s what holds my glovebox shut 😂😂😂😂😂
Yes to Alice in chains
Skorned - Psychosis
Any chance you might explain tuning secondaries on a Holley mechanical secondary setup? I have a 302 swapped pinto with a mechanical secondary carb. I've always heard on lightweight vehicles mechanical secondary setups tend to work the best.
Ah. So you must be one of those chaps that understands how to control your throttle for maximum acceleration.
Mechanical secondaries are always actually better, IF you can regulate your foot feed.
Biggest thing with tuning is just getting the secondary accelerator pump right
How can monitor your speed when the speedo isn't working??? Also interesting that it's a sedan with a manual shift.... I usually monitor the pickup by the exhaust tone sounds... Assbackwards but I'm not ASE certified.....
It’s easy to know what speed your going after you get familiar with the rpm and a gps.
Someone put the toploader in, which is one of the reasons I bought the car, was supposed to be a parts car that I ended up driving.
And you can 1000 percent hear when secondaries open as the entire exhaust note changes - weather it accelerates at that point or not tells the tale.
Love the video. Love all of the videos. Love AIC, but must admit I don't know this song, and Shazam won't id it. Need to know what this is.
Skorned - Psychosis
@@dolor1983 Interesting. Thank you.
Did I get this right? Is the secondary there to get more air in the intake at higher rpm, when vacuum is higher anyway , while a bigger Carburetor would decrease the vacuum (air speed/ fuel draw) at lower rpm? So its the best compromise for both rpm ranges? Thanks for your How tos, they help a lot. 👍👍👍
The benefit to a vacuum secondary in theory is that it’s much more dynamic based on load if set up correctly - it can much more easily match the volume supplied to the volume required by the engine always maintaining good booster signal.
This is also possible with a double pumper, but you have to be good at pedal control and understanding exactly what to give the engine.
@@ThunderHead289 So when I hit the gas and vacuum is increasing above the springload of the secondary, it opens and more air flows in, right?
That is correct - but it’s not vacuum you would see on a gauge plumbed to a typical carb port. Venturi vacuum is the one vacuum signal that actually increases as the throttle is open - all other vacuum sources will actually drop out.