Never Connect Your Vacuum Advance to Ported Vacuum! 

Yep!

Agreed,mine runs like a dog on manifold and awesome on ported

​@@whiteboyfromernulfor your vacuum advance to work it has to be vacuumed open with throttle. At idol you don't have vacuum advance if you're using a ported vacuum. With a ported vacuum you get advanced timing when you give it throttle. With a manifold vacuum you have already advanced your timing all the way so when you give it throttle it's slower to get speed then if you use a ported vacuum.

Probably have a stock engine. Or already enough initial

more than likely you are tuned rich at idle/part which would explain why it does.

I was gonna comment, but i saw your reply, and i cudnt agree more, it all depends on the specifix combo your workin with, my shop uses ported for most apps, but we HAVE used manifold in a few cases......all depends on combo.....nicely written comment!!!

@timothyarnott3584 Ya ported works good. Having a tunable pot is good to dial it in. Best thing is to figure out what your engine wants for timing under different operating conditions and dial it in for your specific combo 👍

this ends the entire discussion. but its a great clickbait video

You are right. I described the mixture density as lean and rich when I should have used less dense and more dense. I'm going to put this all to the test in my follow up! I'd love to pick your brain on your tuning methods at some point so I don't misrepresent them in the follow up.

Well well well 😂 This sounds extremely similar to a video SOMEONE made as a response to yours dosnt it Junkyard 😏 ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wfzXmBKkxVQ.html Me and Junkyard have been going back and forth on this topic lol, we are good buds though 😁

@@newguysgarage6802 I'll prove you wrong! Although, I will be the bigger man and admit if I prove myself wrong. XD

​@thejunkyardnecromancer I'm not here to fight back and forth with like minded folks, but you can't post a video with a thumbnail of my or uncle Tony's face stating we're wrong without one of us rolling in 🙂

Haha. Thanks man!

Exactly!

Thanks for watching!

Thanks!

Since you experimented with both, what was your experience with each as far as throttle response and driveability?

@@thejunkyardnecromancer On ported vacuum it ran a lower idle speed and you could feel it pull into the advance more, but seemed to require a little more throttle to get goin, whereas on manifold it felt more driveable using slightly less throttle for the same results. This is a bone stock 350 with 2.02/1.71 valves. It very rarely hits 200 degrees and while towing up the pass over 90 only ever hit 210 maintaining 55mph at 2800 rpm. it is easier getting over hills as well. I do need a different carb as the 600 is choking it out a bit, but otherwise drives perfectly fine. The old timer that owned it had it on manifold and he's been around the block more than I have so I trust his judgment on the matter more than what standard is

Definitely! I think hotroding and building old vehicles requires some experimentation to find the right combo for you!

Thanks!

Very interesting

Your distributor probably didn't have enough mechanical advance or a lazy mechanical advance curve so the ported advance helped fill in the gap off idle til your mech adv kicked in 👍

@@MarcBchannelyeah you’re probably right. It’s an 80’s “smog” distributor…. I really should get one with a more aggressive mechanical advance but what I have is working so I haven’t spent the money yet.

Yeah I had the same issue you did. Same engine even! I hooked the vacuum to the carb, and it was mint!

Same here. 73 318. Vacuum advance connected to manifold vacuum and it ran terrible. This may work for some vehicles but not mine.

Yup. I noticed that as well. As for idle I usually use ported. It makes a more throaty low idle without the manifold advance. And as many pointed out... as soon as you barely crack the throttle blades the ported connection has the same vacuum as manifold. The blades just block the ported connection at idle stop. Pull the hose and set your base advance... engine performance is exactly the same no matter which port you use. Only idle is altered.

@@PsalmFourteenOneno engine performance isn’t exactly the same! Most vehicles with a distributor will have a stumble and possibly be hard to start when vacuum advance is hooked to manifold vacuum! Fixed many vehicles over the years that had those issues!

Thank you , you saved me quite a bit of typing

Yes sir, efficiency goes hand in hand with pollution.

Well said good sir.

Exactly!

Thanks!

and which map is that on a stock 65 mustang?

I'll see if I can find those text books! I understand that ported vacuum is the same as manifold vacuum except at idle. My argument is that you need that extra advance at idle. I'm going to do a follow up and test both ways. I'm willing to be wrong, but I'm going to put it to the test.

Is for trying to educate theese youngsters. He just doesn't understand the original design.

@@thejunkyardnecromanceryou ask about ported and manifold vacuum being the same except at idle. Thunder289 actually has a video showing this correlation. No one has yet described why! High vacuum means lower cylinder pressure slower burn. This means more ignition advance to have the main burn at the correct degrees just after TDC to get the most power. Open the throttle plates and the mixture goes rich as well as cylinder pressure goes way up. Going rich and high cylinder pressure means faster burn. Fast burn means you need later timing to keep the burn at the correct degrees just after TDC for max power. If you advance the timing at this point you risk pinging and poor performance, burn hits before TDC. Ported vacuum does exactly that, advances timing. Manifold vacuum retards timing at this point preventing pinging and deliver max power. It can take some time to get the mechanical advance in sync with vacuum advance for the most power, best fuel economy and best tune. Of course you can detune, richen up the idle, set your mechanical timing at idle for best idle and use ported vacuum.

That's what some other people have said too. I'm going to test both configurations in my follow up video.

Thanks for watching and interacting! Glad you are enjoying it!

You can definitely time your engine to run on either one, but I would argue manifold vacuum is the better option.

Your almost right in the money, just one key difference though. When you hit the gas with manifold vaccum it takes timing away When you hit the gas with ported it will add timing So if you want to run 22° initial advice, with manifold when you punch it it will drop the timing down when you need it the most If you run 22° initial machanical, then when you punch it it will add timing or keep it the same at WOT so you can keep your timing giving you the grunt you need off the line 😉

@@newguysgarage6802 I explained that exact thing in the video. When you punch it, you actually don't need as much timing as you think!

@@newguysgarage6802Revving an engine in neutral isnt even remotely the same as an engine under load. An engine under load make very little vacuum and at wide open throttle there is no vacuum. Ported vacuum is nothing but manifold vacuum that is switched through the throttle blades, once you are off idle, the ported and manifold are the same. And guess what happens if you are running low initial with your vacuum advance hooked to manifold? All that timing that was pulled in at idle manifold vacuum instantly disappears. As I said, it is simply a difference in the way the engine is tuned.

@@richardbeals1403 I think you would bennefit by honing your comprehension skills. Dont just ignore the facts. Maybe watch the video again. Try to understand what he's saying.

That is very interesting. It would be an interesting experiment to track the signal from the two different sides to see the difference.

Thunderhead289 agrees with you. His Carb Cheater (Very Cool) instructions recommend similar idea.

Exactly! Thanks!

Thanks!

I have worked on and owned a LOT of pre 68 vehicles and worked at a dealership and NEVER saw one vehicle from the factory using MV. I am still waiting for someone to show all the factory service manuals and vacuum diagrams that show it connected to MV. Been crickets on that for years now!

Thank you!

Thank you sir!

This is all very true! As for the lean/rich explanation, I should have described that as more dense vs less dense. My description as lean vs rich has caused a lot of confusion, and I've realized it was an incorrect way of describing it. I'm testing all these configurations right now for a follow up. It will be interesting to see as my 68 f250 (with an engine from 1975) definitely would fall into that "ported from the factory" group. I also plan on doing a demonstration with two vacuum gauges (one on ported, the other on manifold) while driving to show exactly what you said. They are exactly the same off idle. Do you have any suggestions of things to test or things to monitor while in testing to get the most complete answer I can? Thanks for your comment and your wisdom. PS - Those late 70s square body Chevys are great trucks!

@@thejunkyardnecromancerYeah, I can see how some people would misunderstand the whole rich/lean - dense/less dense ideas, so you're right, it might be a good idea to clarify that in the follow up video. As for actual experimentation, the only thing I can suggest is to compare the vacuum can on the distributor to a pre-emissions model, as well as the carburetor if you can find a similar one. I'm not very familiar with Fords, but I know some Chryslers from that era used an odd way of supplying vacuum to the distributor. They had an orifice built into the throttle body of the carburetor (thermoquads, perhaps others) that actually connected manifold vacuum to the ported vacuum port that fed the vac advance. I don't really know why they did that, perhaps they were trying to get the best of both worlds... but it would be very interesting to see how Ford plumbed their carburetors or if they tinkered with the vacuum pot on the dist.

Absolutely perfect explanation!! Subscribed!!

...and for that reason alone your engine can have a stumble that connecting to ported vacuum will fix.

So I have a stumble at 45mph. 351w HEI dizzy Manifold vacuum connected 2bbl Holley Stock internals If I pull the vacuum advance line and plug it, It runs better? I wanted to connect it to ported vacuum but after watching this maybe my timing is off ?

How does vacuum retard timing? don't it pull to advance but does not push to retard? hmmmmmm Glad I got mechanical advance MSD dizzy. lol

That is a very good point. A lot of other people are saying it depends on your setup as well. Thank you for sharing your experience.

Thanks!

Thanks!

Thanks!

I don't know where you worked as a mechanic, but I NEVER saw a factory car prior to 68 that used MV. I would love to see the service manual that shows connection to MV direct to the dist.

That sounds like a cool old truck! Must have been from the 20s or 30s to have a manual spark advance like that!

Thanks!

Definitely!

I don't think compression is what matters. I have high compression motors that work better with manifold vacuum advance. It might have more to do with cam timing 🤷‍♂️

@@KC9UDX yeah a high commission engine with a big cam probably would work well that way. An engine with 10:1 and a mild factory cam doesn’t tend to respond the same to the timing at idle. Pretty sure it’s the cylinder pressure that’s the factor.

Yup! Or if you have a lumpy cam. More timing=happy idle👍

​@@MarcBchannel Until you drop your automatic trans in gear and lose that manifold vacuum.

Thank you!

Thanks!

You are right! I have shop repair manuals for all my vehicles and reference them religiously. A problem does arise however when you modify something, especially removing emissions equipment like EGR, or installing better flowing intake, exhaust, and carb.

It depends on what the engine wants for idle timing and combustion stability. Sometimes the timing retard is required to raise the cylinder pressures at idle especially if the mixture is not overly diluted from overlap-induced internal EGR. Retarding the timing using ported vacuum means you need more throttle opening at idle which allows a bit more air when compared with residual gas. I’d say pick whichever the engine wants. Also one other thing, the more retarded timing will pull less a bit less oil through the valve guides at idle since the manifold vacuum will be a bit lower. For EFI engines timing at idle is often a bit retarded, but there is effectively an inverted ‘mechanical’ advance below idle speed. This will advance the timing if you lug the engine a bit without moving the throttle, the timing advances, engine torque goes up, and the engine is nice and stable while lugging. The timing retards as RPM picks up, giving a nice smooth lugging response, even without moving the throttle. Think of the mechanical timing with a ‘V’ advance curve with the tip of retard just above the desired idle speed.

Not when the engineers were concerned about emissions and you’re concerned about power and efficiency.

I think I agree, except regarding power brakes. Boosters are connected to base, after Venturi. There is always vacuum present.

@stuckinmygarage6220 Yes, brake boosters are connected to full manifold vacuum, but you are thinking about it the wrong way. When you add the extra timing at idle from vacuum advance being connected manifold vac, your engine produces noticeably more vacuum while idling. Even at the same idle speed as before. Now you have more vaccum assist to all your vacuum powered functions. My engine went from 15in vac at idle to 21in. Same idle rpm

Very well said 👏 It always amazed me how many people got their knickers in a twist for something that follows literally the exact same curve apart from idle. I've personally always ran manifold because in both my stocker and my bigger cam weekend cruiser they enjoy the ease of starting at such a nice 'starter-motor friendly' 6deg BTDC before the engine fires and manifold vac adv shoots that up to a steady ~20deg BTDC and I enjoy all the benefits of nice idle characteristics, cooler running temps and sharp throttle response.

@edwardpurks3883 Thank you, Mr. Purks, for your comment. However, I did not 'think about it the wrong way'. I agree with everything you said, except that there is no comma between "carb and power brakes". There is no 'better' vacuum for power brakes. It's constant manifold. Ported has no effect on brake boosters. [Off topic, unless talking about leaking diaphragm or something.] Again, I agree with your well written comments. Best regards

@stuckinmygarage6220 Hmm. You still don't understand how increased engine vacuum improves vaccum powered brake assist. More timing at idle doesn't just increase vacuum single to the carb, but it increases vacuum signal to the entire intake manifold. Including the line feeding the brake booster. Everything will see a higher vacuum signal with the increased timing. You can also feel increased brake booster assit just from your engine decelerating(which increases vacuum temporarily). The brake pedal goes noticeably further down if you Rev your engine, then let it decelerate. You can witness this sitting still in Park or neutral. I appreciate the comment. Running more timing at idle helps booster signal too. Especially just idling around a parking lot or driveway

Glad I could help!

Great videos

The MN accent and Canadian accent are similar kinda haha. #manifoldvacuum!

I also detected a little Slymo slipping in there😀

Indeed! Thanks for the sub!

Thanks for watching!

Thanks!

Power IS economy!! Hot rodders have been arguing this for decades. But the fact is, squeezing the most bang out of each and every droplett of fuel is what economy and power both are all about. And FINALLY, our government has seen the light in that regard. But what did we get for all of our efforts except for higher prices of everything. Bureaucratic fat-cat pocket lining programs, fills me with an urge to defecate.

@@petesmith5092 you are right! Power is economy!!! That should be put on a shirt!

@@thejunkyardnecromancer you are welcome to use that. Just cut me in for 5%....🤣🍺🍺

This is the way!

You don’t know how the system works! Buy the book PERFORMANCE IGNITIONS written by Dr Christopher Jacobs and get up to speed! Quit spewing BS! Dr Christopher Jacobs was the premiere ignition expert and consulted to many NHRA and NASCAR teams and built his own ignition company that MSD bought out because they couldn’t compete with him. That’s after he made his fortune developing electronic devices for the medical community and making millions on his patents..... You, uncle tony and thunderhead289 don’t have his credentials....

Thanks! However, both Dan and Tony do know a lot, and do give good advice quite often! They just happen to be wrong about this one thing.

Thanks!

I've never tuned timing with a vacuum gauge, but I've heard similar things about the quicker throttle response from other people. I'm hoping to test this theory in my follow up.

Quicker than what? Theres more to it than switching the rubber hose… carb adjustment, timing adjustment.

@@Trobertsdsgmach1 this is very true! Dan and TH289 claim that running your vacuum advance off of manifold vacuum requires you to close your throttle blades so much that your transfer slots are completely closed off in order to get a proper idle speed. They claim this causes a delay in the transfer circuit of the carburetor, which will in turn cause a delay in throttle response when you stomp it. Their solution is a higher initial timing like 18-22 degrees BTDC, and ported vacuum to control the vacuum advance for part throttle driving. In theory it does make sense, but I think it might not work as well in practice. I'm testing all this right now, and I'll be uploading my findings in another video to come!

@@thejunkyardnecromancer I do not have any distributors with vac advance, all billet msd with light springs and custom weights (rather then full lock out) for street use. All trucks and cars in my garage have full mechanical advance and a curve designed to make the most “power” not the best “power and mileage “. Vac advance has to many things to go wrong in my opinion

Also i do not tune the idle speed with the curb idle screw or any else, advancing and regarding the idle timing is the only way to adjust idle.

Did you check your initial timing timing and mechanical advance? You can tune an engine to run on either ported or mailed vacuum. In my opinion, manifold vacuum has the most benefits. My plan is to test this theory in my follow up video on the topic.

@@thejunkyardnecromancer Yeah, we tried to optimize the initial timing and the mechanical the best we could to the manifold vacuum but no matter what we couldn't get it to work right, always had problems.

I tuned my engine to run on manifold vacuum because I didn't know any better. It ran awesome and used different mechanical timing springs etc and had an adjustable vacuum canister diaphragm on a ACCEL blueprint series distributor. I made sure to check total timing too. I now run off ported because I heard I've been doing it wrong the whole time. I have not tuned my engine to run off ported vacuum and I have some pretty bad dead spots and bogging at full throttle. So I believe I can tune my engine to run off ported as well.

@@junkyyarddawg Hell, try it. I'm still new to this timing stuff so i cant tell you right from wrong, only what works for me and what doesn't. I likely don't have a setup like yours and that may be why neither me nor my grandfather could tune my engine to run off manifold vacuum. We were only able to get it to run halfway decent on manifold before switching it to ported without changing anything else, it feels better than a brand new car.

@@sebkhailer7374 yeah I'm currently running off ported on my new Demon. I just haven't tuned it or changed jets etc to see what the problem is. I just used a vacuum gauge etc and adjusted the air fuel mixture. Might be it's lean or too much fuel when the secondaries open up. Not sure but I need to put in a little time to find out. I haven't checked timing either.

That is a good way to go about it for sure. That's my mentality going into the testing for my follow up video. Unfortunately, I don't have access to an infrared gas analyzer or anything to test emissions. Do you have any tips or alternative methods I could use during my testing? I want to do this as objectively and as scientifically as possible. Gathering the most data as possible in the process.

You can definitely tune your engine to run well on ported vacuum, and it might be easier to do so if that's the way it came from the factory. You do you man!

I also have a 59 352FE. Ported 2100 and runs great!

Thanks!

Hmm... I've never heard of a lean mixture causing pinging. Only ever heard of too much advance (maybe from too much initial timing or mechanical/vacuum advances tuned incorrectly), or heat soak causing pre-ignition and pinging. Time for me to do some research!!!

Thanks! And excellent story!

Well, the way I was taught to check timing was Step #1, ‘Disconnect vacuum advance’ so that meant manifold vacuum and the fact that the weak idle mixture NEEDS more advance than the mechanical initial timing.

You're absolutely correct... watching on a scan tool how modern engines change their timing can give us a good idea how to tune older engines, and they do all run higher advance at idle, indicating that analog distributors should run on manifold vacuum... HOWEVER... you have to keep in mind that most (if not all) vehicles from the late '60s to the early '80s were DESIGNED to run on ported vacuum operated vacuum advance, so they'll run better that way if they're still in stock configuration. I have no doubt that the hot rod you mentioned ran better on man vac, but that's because you were able to tune it to run best that way. Yes, stock engines can be tuned to run better on man vac as well, but if they haven't been professionally tuned, they should be run on ported vac the way they were intended, to get the best drivability out of them.

@@livewire2759you clearly aren’t grasping that “ported” vacuum was a shitty attempt to reduce emissions and had no performance or efficiency benefits whatsoever. Just look at what the manufacturers did to neuter engines in the early 70s in the name of “clean air”, ported vacuum was a key player in that BS. It was all trial and error, because they had no way of simulating combustion and no real understanding of how to produce reasonable power and lower emissions with mechanical/analog fuel control. Take a look at a stock 1985 Mustang GT 5.0L HO 5-speed some time. The distributor was connected to a thermal vacuum switch that used ported vacuum warm and manifold vacuum cold. The problem with ported cold was the engine didn’t have enough advance for the lean mixture when there was no heat in the engine to aid fuel in becoming a vapor. As soon as the engine warmed up, the engineers killed off the vacuum advance to slow the idle speed and limit emissions. Manifold vacuum produced higher CO and HC numbers at the slower idle speeds that were not compatible with catalysts. But that it in a nutshell, ported is an emissions technology, and offers no realized performance advantages. It can and does however provide timing later than needed and can put the engine into knock if you aren’t running EGR or your carburetor is not calibrated properly. It is also not compatible with higher compression combinations using larger cams which is why so many people simply switch to a mechanical advance only system, attempting to run ported advance doesn’t work on the more aggressive combinations, however, manifold vacuum does when applied correctly and can be a huge benefit to idle stability and operating temperature.

@@TheGT350Garage "You clearly aren’t grasping that “ported” vacuum was a shitty attempt to reduce emissions..." Ok, if you want to be that way, I can be a jerk as well... You "clearly aren't grasping" why vacuum advance was invented in the first place. You clearly aren't grasping that it's not a power adder or performance device. You clearly aren't aware that it's sole intention was to RETARD timing under part throttle to heavy throttle acceleration in order to help reduce or eliminate knocking. You don't seem to understand that they retarded the base timing on those engines to make up for the advance caused by using manifold vacuum at idle. You also don't seem to be aware that the reason why they used manifold vacuum for this up through the mid '60s is simply because nobody had come up with the concept of "ported" vacuum yet... they didn't need to because manifold vacuum worked "well enough". That doesn't mean that has always been ideal. Yes, the concept of ported vacuum came from attempts to reduce emissions at idle, and it works to do exactly that... when the engine is warm. You seem to be ignoring the fact that man vac/port vac makes no difference when a carbureted engine is cold because they run on a fast idle when they're cold... that's right, while warming up the throttle is open to the ported vacuum port which, if connected, sends vacuum (the exact same amount of vacuum that a manifold port would send) to the vacuum advance, advancing the timing at "idle" during the warm up cycle. Again, if you watch data on a scan tool, you'll see that modern engines do this same basic thing... increasing idle speed and advancing timing until the engine is warm. Now, most of all, what you don't seem to be grasping, is that when car makers started using ported vacuum to run the vacuum advance, they also re-tuned and re-engineered some things. These things included using different weights and springs to tune the mechanical advance to work better with the ported vacuum advance, as well as changing the vacuum pots themselves to work better with ported vacuum. Not only did they start recommending more advance for base timing to make up for the lack of vacuum advance at idle when using ported vacuum, most manufacturers used some sort of restricting orifice in the vacuum advance system to optimise it for use with ported vacuum to eliminate the problems with suddenly going from no advance at idle to near full advance at off-idle. When they did this, they found a happy surprise that they could actually get better throttle response from closed throttle to off-idle than the old manifold vacuum operated systems did. This is why, when you just switch one of these emissions era engines from ported vacuum to manifold without making any other changes, they tend to stumble or have a "flat spot" just off idle. Yes, you can tune that out, but if those orifices are still there, you still won't get ideal performance without changing parts. This is also why those mustangs you mentioned used a system of switching between manifold vacuum and ported vacuum. Chrysler used a similar idea in their thermoquad carbs where they connected ported vacuum and manifold vacuum together inside the carburetor with a very small orifice between the two... essentially using both to operate the vacuum advance. "It is also not compatible with higher compression combinations using larger cams..." That's an interesting point. The only difference between ported vacuum and manifold vacuum is at idle where man vac will be full vacuum and ported vac will be near 0. Just off idle, the ported vacuum port is uncovered and at that point it will always be exactly the same as manifold vacuum. If you don't believe me, get two vacuum gauges, hook one to man, the other to port, with long enough hoses to be able to read them from the driver's seat, then drive the car and see what they do. Under load (which wasn't demonstrated in this video) they equalize at off-idle and drop off at the exact same rate while opening the throttle. So, considering that big cams with lots of overlap naturally run low manifold vacuum at idle, how could running manifold vacuum be any different than just running ported vacuum with the base timing increased? Sure, manifold vacuum may be the best choice in high performance applications where drivability isn't much of a concern, but for cruisers and daily drivers, you'll find that using ported vacuum with a proper corresponding tune will provide better drivability performance. In conclusion, I'm not saying that you should NEVER use manifold vacuum, and I'm not saying that you should ALWAYS use ported vacuum. I'm saying that it depends on what engine you have, what parts you have, and how you're going to be driving the car. Using blanket statements like "never" and "always" is a dead giveaway that a person probably isn't as much of an "expert" as they think they are.

Thanks!

Thank you! I hope so too!

Very interesting. This makes a lot of sense.

Thank you!

This is something I didn't consider. I'm going to have to research this.

​@@thejunkyardnecromancerSir, i commend you, and offer congratulation of your mind being open. And your willingness to do your homework cannot be left out!

Sorry but that is wrong. my Nova, 327, idles just fine at 28 degrees with the manifold vacuum. Also cranks much better than when i didn't no better and was running ported.

@@reevesautomotivefarm9614 so you have vacuum when your cranking

Good luck!

Vacuum advance is for part throttle situations only.

100%

Thanks!

I completely agree! And I'm working on testing it. Hopefully I will have the video out in the spring!

The power valve operates off vacuum too. It does nothing for sudden throttle openings. Many carbs have no power valve. That's the job of the accelerator pump.

@@carmudgeon7478 Ah yeah you’re right I got the two mixed up there!

@@carmudgeon7478 Carbs that don't have power valves do use a similar system to richen the mixture under heavy throttle. They use metering rods that are operated by a vacuum piston. ALL carburetors have one of those two enrichment systems AND accelerator pumps... except maybe some tractors, lawn mowers and such that are meant to run at a set, steady throttle... but accelerator pumps do no take the place of power valves in carbs that don't use them.

You're right! I need to get a costume like that for these sort of videos. XD

@@thejunkyardnecromancer no doubt. Go the whole 9 yards

Indeed. Andy has a really cool truck. Thanks for the sub!