HOW TO: HOLLEY CARB TUNING TRICKS (408 STROKER SBF)
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- Опубликовано: 7 сен 2024
- STEVE BRULE DYNO TUNES THE HOLLEY XP CARB ON A 408 STROKER. WHAT HAPPENS WHEN YOU ADJUST JETS, POWER VALVES OR AIR BLEEDS ON A HOLLEY XP CARBURETOR? CHECK OUT THIS VIDEO WHERE WESTECH'S STEVE BRULE WALKS US THROUGH A TYPICAL TUNING SESSION ON A CARBURETED 408 STROKER (351W-BASED) SBF. ARE THE CARB CHANGES WORTH ANY POWER? WHAT HAPPENS WHEN WE ADJUST THE TOTAL IGNITION TIMING? FIND OUT HOW TO DIAL IN A HOLLEY CARB WITH STEVE BRULE AT THE HELM.
Great tips!...
The number ONE thing that NEEDS to be done whwn installing a new Holley carb is to get the t-slot opening correct first, and then getting the engine to idle properly, BEFORE going onto tuning.
SO many guys don't do this step. They lump the carb on, crank the idle screw up to get it to idle, proceed to tuning, and now the t-slot is all out of whack.
So much low speed, tip-in, and light cruise, performance can be lost by not making certain that the t-slot is correct very first.
Edit: I figure that I better explain what to do if your engine WON'T idle after you set the t-slot because the idle is too low...
You pretty much have to adjust the idle screw to get the t-slot opening looking correct, go install the carb, and then hope that the engine idles with the idle screw at that setting. Once the t-slot is correct, you have very LITTLE adjustment on the idle screw, in either direction from there, before the t-slot is too far out of adjustment again. IF the engine won't idle with the idle screw set to the proper T-slot setting, you can't just crank the screw up a bunch til the motor idles. You can maybe go about a half turn or so in either direction before you have the t-slot too far out of adjustment again. At that point, if the idle is too low, and IF you have a newer Holley carb with the idle air adjustment down under the air cleaner stud hole, you adjust the idle that way by turning the screw down there to pick the idle up, and then adjusting the idle mixture screws. IF you don't have a newer carb with that feature, you must drill a hole in each primary butterfly, right in the center between the throttle shaft and the outside edge of the butterfly on the side of the blade that is closest to the bottom of the carb. The side that ends up moving down towards the intake when you open the throttle. Start with a very small hole in each blade, (less than 1/8") then retest. If it idles faster, but still isn't enough, slightly enlarge the hole in the blades and retest again. Keep going larger with the holes until you have a satisfactory idle. Done. Now proceed to tuning the rest of the circuits.
If you tune your Holley carb idle like this, instead of just cranking the idle screw up until it idles, you WILL have a much better, crisper, tip-in and light cruise performance than ever before. It's WORTH the extra work to set the t-slot up properly and adjust the idle the correct way. 👍
Don't drill holes on the blades don't crank up the idle screws. Adjust idle air bleeds read up on it
It's interesting to see Richard go from the guy that knows everything to the guy that's asking all the questions. That's how we learn! 👍👍👍
I wish that Steve was more clear on what adjustments were needed. I got a small idea of what was going on, but it left me with more questions on tuning mid range/cruising conditions. As always, you did a great job of helping us all with trying to get the most outta our engines, and for that I thank you! Keep on doing what you do!!!
I was hoping to hear him say something about the results of adding a 10.5 power valve.
You adjust your power valve size according to your light cruise situation...
If during a light throttle cruise, the engine is very blubbery and rich, and is stinking like fuel, your power valve number is too large, whatever manifold vacuum your engine produces at a light cruise isn't strong enough to hold the power valve shut, and you would go down in the power valve number so that the valve takes less vacuum then what is available during light cruise to hold it shut and stave off the extra enrichment until you put your foot in it, manifold vacuum drops even more, and THEN the valve opens.
IF you are good at light throttle cruise, but the engine then starts to lean stumble when you step on it a little more, your power valve number is too small, and you would go up in size, so that the manifold vacuum that your engine normally produces and then drops a little bit when you open the throttle further than a light cruise, will now NOT be able to keep overcoming the spring tension like it did in the smaller number power valve and keep the valve shut like it did before.
It will now open a little earlier than before and add the extra fuel enrichment that the engine needs at that further than light cruise throttle position.
Little Richie at the feet of the master. The Westech guys are nice.
Mr Brulé needs to write a book just on his experiences at the dyno (if he hasn't already)
I would pay 100$ for a thorough book on his experience of dyno testing
I would love a complete carb tuning v effect of all the high and low speed air bleeds and idle fuel restrictors. Great info
@colewalker6237 The air bleeds are like a more "fine adjustment" that effects the top of the RPM band on whatever circuit that they are in. Main jets pretty much are a LARGE adjustment that affects the entire range of that circuit, while the air bleeds have a much smaller effect than a fuel jet, and the results of the bleed change happen more as more air flows through that circuit.
I learned that I love watching a master of his trade
Gotta love carb tuning. Especially when you have adjustable low and high speed air bleeds
@jaydubb71 and EVERYTHING ELSE that billet metering blocks offer.... There's MUCH more to tuning than just the 2 or 3 airbleeds (depending on whether it's a 2 or a 3 circuit) at at the top of each barrel.
The billet metering blocks introduced a MUCH easier way to tune a whole BUNCH of things to do with each circuit, than what a guy had to do before, such as drilling and enlarging holes in the blocks, or even worse, soldering them shut and redrilling them smaller, be cause there was no threaded holes in the blocks to remove a different sized jet in those positions.
Now you can play with idle restrictor jets, power valve channel jets, emulsion jets, 3rd circuit jets, and so on, MUCH easier than before. 👍
let the man do his job he knows best
I get a strong W.C. Fields vib... "go away kid, you're bothering me"
I felt the same way. Richard is such a nice guy, but you could tell that he was getting on that guy's nerves from WC. seems very rude Just because your the guru of carburetors doesn't make you any better than anybody else. Treat people the way you want to be treated.
Steve trying to pull off the Hulk Hogan hair style without the mustache. Tough to do these days.
Love this video.Thanks again.Lucky to have to guy.Give him the time and he will fine tune A carb wow.
Man these numbers make me happy!! Im building a 393w with those heads (polised up) and a 235/241 112lsa .581 howards cam and victor jr intake.
The power valve change was due to the 6.5 coming on when it shouldn’t, (Richening ) due to the mild cam having more than 13 inches of vacuum at idle.
The air bleed change was as far as I can tell , to the idle circuit to enrich the idle and be able to set it in the middle of the adjustment range on the screws.
The screws originally seemed to be all the way out or close to it.
The carb is just a tad big for it so the air bleeds needed to be made smaller.
The jets were to lean it out .
Adding two degrees made more power but not enough to warrant it due to the possibility of getting sub par gas and having knock, so they were going back to 34 degree total.
Back in the olden days a735 cfm Holley(oem 428 Cobra Jet) was$32 sold by Motorcraft.
I doubt if they were ever that cheap.
@@cjbert6790 I installed many on 351 mustangs. They really helped. I also owned a 61 Starliner with a 428 super cobra jet,top loader and 355 posi.
Donald Israel Sounds like a cool car!
So why 3/4 turns on the primary IABs and 1.5 turns on the secondary IABs ? I've always kept them squared. Explain, or did I miss that ?
10.5 power valve? This things making 21 inches of vacuum??
Now we need a tuning video for blow thru carbs!!
@dmvboxgoat9969 There's ALOT there with a blow-thru carb to master, and would take MUCH more than just a 15 minute video. It would take HOURS to go through it all, and still take much longer in reality to get comfortable with and master.
If you wish to learn about blow-thru carbs, pick yourself up a good book about the subject, and start to absorb it over days. A quick video will do nothing but leave you even more confused and dangerous than before. You only get one chance with a blow-thru setup to get it REAL close to correct, or you melt a motor down. You wanna be REAL well informed before you go to tune a blow-thru setup.
@@davelowets I have more miles on my turbo ks swap then most ppl daily driver.In it right now 3 years later.Your right it was a learning curve but I learned it and have it down packed now
WOW ...Guy's got ball's using a power tool on the bowl screws...
86 on the primary side seems really big to me. My Dart SHP 400 with 750 double pumper HP only needs 70 jets on the primary side and 82 secondaries with 6.5 power valve. Seems like they are keeping the power valve tight with that 3.5 vacuum rating and using the primaries as the only source for fuel.
Te one thing I will say, is don't hover over the guy asking nonstop questions. From experience just let the man do his job and wait for him to tell you what he thinks it needs.
Need more Steve!
Steve needs a mic lol, awesome video.
You old crusty guys need to strap a gopro to your head while you tune, us young guys need historical documents to reference.
Steve get a hair cut but not a new job because you got the real deal dream job!!! :)
34 seems like magic number for 351w. Last 3 on dyno with vastly different set ups 34 always made best power
Two turns past stripped, back off half a turn, right out of the Holley manual.
I cringe seeing that impact driver on fb bolts lol i use a 1/4inch thumb ratchet and 8mm deep socket. What cfm that carb?
950
It's difficult to hear what Steve is saying. Can you explain a little more in a cause and effect while making the changes? The jet / air bleed part had me a bit confused. Great to see Steve and a sbf on the Dyno
Is it me, or it seem that Steve B. was very annoyed at Richard constantly asking questions?
I GET THAT A LOT
@@richardholdener1727 lmao. Me too. I must know.
At the 7:00 minute mark yall were talking about adding air to stay off transfer slot.What was that could you explain.My carb idles way too low because high duration cam and if I adjust curn idle it exposes transfer slot.
Hey! I like all the questions that you’re asking, but their responses are difficult to hear. I think that this is a great podcast, but it’s still leaving me with a bunch of unanswered questions
Right on
Learned that's a lot of ci and lot of carb for what you getting out of it! But, it's a boat engine. My guess is you're concerned more about torque from 2500-5000. I'd like to see a dirt cheap stroker 393w, hyperutectic 302 pistons with big valves reliefs prepped stock Windsor rods, big hydraulic roller cam with 10 - 10.5 compression! No $1200 carb, just a 750 double pumper well tuned! You know, crap like I got stashed back! A real junk yard dog hasn't had his shots and been on a chain for 3 weeks! I actually got all that but the pistons and crank!
I'm confused on why he went up on power valve sizing...can anyone shed some light please?
to change load in fueling
@@richardholdener1727 in other words. He went up in the power valve to open sooner with the vacuum signal to richin up the off idle thru mid signal until WOT takes over.
Can you do a video of the difference in carbs. Like for street driving why get that xp carb over a brawler
GET THE BRAWLER-THAT VIDEO IS UP
Long story short.
You don't need a $900-$1000 XP carb on a mild street car.
Now if you had a 496 that liked to turn 6500+..
In my wheel house Richard. I own a high performance carb shop here in the north east.. nows the time you start tuning the emulsion and air bleed. assuming the booster is best for the application.
Pablo id love to ask you couple questions, if your able to answer would you prefer me emailing you or asking here in this?
@@brianb5779 You can ask here, or if you like I'm on FB at scs performance carburetor/fb.net
@@pablojanski.2559 Thanks alot Pablo. In the past (had a family so ive been out of it for about 5 years and am rusty now) ive done about 6 dominators for street/strip. Meaning drilled and tapped bodies for total control of idle, transition, etc.. Other than 1 ive always converted the 3 circuit carbs to 2 circuit and had very good success. Im helping a buddy now that has 500ci hemi head mopar that just got done w his 1050 quick fuel. It was pig rich so upon starting on it noticed mixture screws were @1/4 turn out on all 4, no transfer slot showing and 1 intermediate bleed at 40 (stock was 80). The ifr was .041" and felt that was way too much so put it at .031". His motor wasnt too far off my 466ci which i had .026" ifr and 46 air bleed which put my afr good at 1.6 turns out on all mixture screws. So my question is 2 parts,,,the first is do you have a particular formula when you size the ifr to the air bleed (i know some feel for every .001" move on the ifr the air bleed should be .006 to .008 change but many times ive seen that not the case). And my next question is do you have a possible thought on initial starting point for the air bleed for me putting it at .031" ifr from the .041".. I already know now his 3rd circuit will need work as well but until i get over to his house. I will be using a a/f meter just so you know. I want to say sorry for long message and hopefully everything made sense but also thank you sir very very much for your time and input.
@@brianb5779 IFR and IAB will have a relative correlation to manifold vacuum and the cams overlap.. bigger cams need more ifr and quicker circuit timing.. fuel used is also important.. generally on dominators to be used on 500+ inch engines with healthy cams that have a good amount of overlap ( ie aprox 5-8 inches hg) you will be in the .035 ifr range and around a 52-58 iab.. turns out on the idle mix isn;t a concern. set those where they are happiest.. concern is the transition.. since transition an idle share the same circuit, going to lean on the ifr can cause lean stumble in the transition.. third circuit can be trimmed right out to as lean as that part of the throttle position likes, but keep check on the wot mixture when trimming the third real lean. Third does add a little fuel at wot via pull over through the discharge tubes.. three way balancing act between ifr third and main.. wot tuning will be hsab, emulsion and jet tuning.
@@pablojanski.2559 Pablo thank you so very much for your time and info. Im in Ohio so if your anywhere close id like to stop by sometime and bring you some thank you gifts
When I give my 3fity some beans using a 600 holley should it go rich on the Air fuel gauge when accelerating?
What was the so called, " trick"? I didnt really hear an explanation of why or what was done. Made a jet change and idle adjustment change but why?
Hot rod Jesus going about doing good.
Jesus had long hair because he was under old testament law until his death, berrial and resurrection! Under old testament law Jews couldn't cut their hair or shave their beards. 1 Corinthians 11:14, it's a shame for a man to have long hair... 2 Timothy 2:15, study to show thyself approved... Acts 17:11 study scripture daily... Proverbs 25:2...
But I'm definitely not hating on Steve, at all, he's a master of his trade!
VALAINT MISSING DA POINT
Holley says power valve should be half of engine vacuum. Is this correct or do some engines like a higher number? Just confused.
half of engine vacuum when?
@Richard Holdener that's what I'm wondering, their video indicates idle vacuum but wondering how or even if that translates into real world testing.
Great video! Too bad Steve didn't have a mic. I'm deaf in one ear and I can't hear in the other. He's difficult to hear.
Carb spacer would clean up the AFR and quite possibly add a few hp’s
Possibly. No guarantee.
is this engine not going to be run without a filter or the actual air filter used in the vehicle? depending on the filter and housing, a/f could be affected.
A properly sized air filter does not affect jetting
@@8power857 yep! thats why i asked what filter would be used in the vehicle. for some reason, people love those fly eye air filters or the teeny 10x1 round filters. they murder hp output.
@@OxBlitzkriegxO im hearing ya!!
@@OxBlitzkriegxO you mean a marine flame arrestor? Cause that's not what they do on carb if you have a backfire lol
@@KingJT80 no, the cheap triangular filters with foam between two mesh areas. theyre cheap and really bad. its nothing like a flame arrestor.
I don't wanna be that guy but....here I am...and here I go... It's not a Chevy!
1:20 that looks like a righteous header burn on his arm
Building a SBF 427 for my 67 fastback right now. love when Richard does Ford stuff lol.
That did look like a nice lil header burn.
Looks like a header burn on his arm
TURBO
Watching how messy a jet change is on a holley carb makes me thankful that Weber and Dellorto's can be done by just simply removing the top cover. No need to disassemble the entire carb to access the air bleeds / emulsion tubes or jets and spill fuel everywhere.
You a v dub man? Guessing here.
@@johnsheetz6639
That, a Porsche or he has an inline 4 or 6.
Do you ever have a cat spray in the carb to check for a lean mix?
someone would call PETA on you for torturing cats.
NA you don't squeeze em. You just hold em over the carb and say Spray!
Quick scenario Richard, been tinkering with my 650 Demon (Holley-ish double pumper of course) on my 383 SBC. It's been kinda tricky to get it to idle while in gear since I put a Super Victor intake on it. This is actually the 2nd single plane intake I've had on it. Are single planes in general notorious for liking to be pig rich at idle (12.5-12.8 AFR) or might my 3200 stall Circle D just a bit tight? I heard at the end of the video it was said that locking out the distributor would improve idle quality. Ignition system is super basic as well. Gutted HEI with a 6A box and mech. and vacuum (restricted) advanced.
12.8 IS NOT PIG RICH-THAT IS FINE
Single plane manifolds with a big cam struggle to provide a carb with good signal at idle. A four hole spacer should help some. 12.8 at idle is ridiculous, sorry richard. Your running a 3200 stall? So your cam is in the 235@050 range? Your initial should be around 16-18. Need more help, shoot me a reply .
@@GG-rj4oj 230/236 It's actually a XFI Comp listing (08-467-8). Restricting the mechanical timing just to bring up the initial timing, tho putting so much in and making it hard for the starter is also in the back of my mind. How much I have now, I honestly couldn't tell you. I've really only focused on the "all in" up until this point, only because it's never much been an issue until now. I do run the vacuum advance, but is already restricted, which does seem to help, but drops off pretty quick when motor begins to bog when in gear. Sorry for the rambling, just trying to paint the whole picture. Lol Oh yeah, and I'm running a Detroit locker in the rear end, with more internal lash than the law should allow. So That's a huge contributor for maintaining a 750ish RPM idle. 🤦🏻♂️
@@n8dawg450r super victor is way to big for that cam engine combo. You would be much better off with a air gap. But if thats what you like, you need a minimum or 14 initial. A four hole spacer will help with carb idle circuit. Make sure your throttle blades are in the correct position. Not too much transition slot exposure. Set mixture screws 1 1/4 turns out and see what its like.
Another option you have is to connect your vac advance to full vavuum. This will bump initial timing up and yield a similar result. You can search this, its a common practice.
@@GG-rj4oj I'm currently at about 1 1/2-1 1/4 turns out, and also running manifold vacuum already. Will check and see what initial is set at tomorrow before work. See what's what. Thanx for the input! 👍
Do a Northstar motor
Another great video amongst all the electric, hybrid, green bullshit floating around. Thanks Richard & Steve for the unending supply of common sense.
And, BTW, I would have beaten you all for 1st reply but the signal has to travel to Melbourne, OZ......... I also blame squirrels.
Cheers to all! Steve.
First in !!!!!!
Second in… beat me by seconds 😂
Chevy distributor is in odd location…🧐
Looks Like he Got His Arm to Close to the Headers
Would have got a pretty good puff of smoke of that one.
Poor Richard. He can't get no information out of this guy. He's trying
Those aren't enforcer heads, they're the 72CC renegade 205cc www.airflowresearch.com/cart.php?suggest=9782804e-62f4-4ddd-8fd6-e5b95540731b
2+2 is ??????
4???
Lost me at using a rattle gun on a Carby
It's a drill or screw gun. It has the clutch settings
Lol. That isn’t a “rattle gun”.
But when you use one everyday like the pro’s, you get a feel for the torque you are applying
Looks like youre stealing my carb tuning content 🤔
Jk, I'm a nobody 😔
DID YOU HAVE THE ONE AND ONLY BRULE ON YOURS TOO?
I know who you are 😁
@@richardholdener1727 no but I did have the one and only @Nightwrencher on it 😎 almost as good.
@@cuzz63 lol Im happy at least 1 person knows 👌
@@NightWrencher lol...
The video was okay but I didn't learn anything
Power tools on a carburetor......
I LOVE WHEN PEOPLE DON'T KNOW
Personally I blame squirrels
Brûlé needs a haircut.
Not much explanation...
best way to tune a carb, chuck it into the recycling bin, and put on a efi system
Publicly admitting carb tuning ignorance? :)
@@rlovell383 I've tuned hundreds,
@@seancollins9745 what edelbrock?
@@karlsracing8422 you name it, carter, zenith, holley, rochester etc. Carbs, just let them go
I had an Edelbrock on a supercharged 350. It ran great out of the box! I set the idle with a vacuum gauge. Never had to open it.