BOOST pressure vs. MANIFOLD ABSOLUTE pressure vs. ATMOSPHERIC pressure - BOOST SCHOOL #4

[@d4a]

AEM SS MAP sensors: bit.ly/d4a-map-sensors AEM SS Pressure (Gauge) sensors: bit.ly/d4a-pressure-sensors AEM boost controllers: bit.ly/D4AtruboostX AEM ECU: bit.ly/D4Ainfinity5 AEM wideband AFR gauge: bit.ly/D4Axserieswb

[@jaysmooth8888]

Cool

[@m721ac]

Hello.do you have a video that is more diesel specific?would really appreciate it.woukd be nicr content for you too i would imagine.you are ver well versed and give crystal clear explanations yhat even a doorknob would understand.thank you for this and more power to your channel

[@hieronymus..bosch8532]

Reirregardless , brilliant video 😉

[@RobOnMotors]

@driving4answers do you have a video that covers the principle behind turbo flow Vs turbo pressure. I understand that bigger turbos flow more therefore make more power, however, they are able to flow more and decrease manifold pressure. How is it possible have less pressure but more flow. If the restrictions stay the same, i.e. the head and inlet. Then why doesn't that extra flow turn into extra pressure?

[@caig9868]

Still blows my mind that this amount and quality of information is being offered for free. Big respect!

[@danielamorim2909]

I can't explain how well this series is put together. I am learning so much for my Gen 2 3SGTE swap into my ST162 Celica. Keep up the videos!

[@eTiMaGo]

school's back in session, kids!

[@WanderingExistence]

2:48 Death Valley has 14.9 psi of pressure due to being a 280 ft below sea level

[@edbo10]

death valley boost balley confirmed

[@gor4988]

Not to mention some of the mine shafts we've dug out

[@fastinradfordable]

When my car had no turbo it ran really REALLY well in Death Valley. Now it has a variable turbo it runs REALLY well, all the time :)

[@bene5431]

​@@fastinradfordable Death Valley is also very hot, so while it might have high pressure the air isn't very dense (unless you drive at night)

[@MI-sw3iv]

Think I'm in love with this dude? Hope you know how articulate and concise your content is, it's veryy impressive! No teacher Ive ever seen can teach like you do with these videos !

[@shautohaus]

I honestly don't know how someone can explain something so complex, so clearly that I have zero questions at the end. Amazing.

[@firstielasty1162]

Light planes have an interesting variety of turbocharger wastegate controls systems. Some are as crude as a fixed wastegate that relies on the pilot watching the MAP gauge and controlling with throttle (yes, you can overboost them simply by firewalling it on takeoff), others are more sophisticated and actually regulate the manifold absolute pressure. They will maintain the set pressure throughout a climb until the wastegate is fully closed, at the "critical altitude" of the system, above which power drops with the altitude increase. Wastegates are usually hydraulically actuated by engine oil. The control systems modulate the oil pressure to the wastegate. I added a MAP gauge to my turbodiesel RV...the gauge is from a multi engine aircraft (actually a dc-3). One port I left open, so it indicates ambient pressure, the other indicates MAP. I have driven it over the Rockies several times, interesting to watch both ambient and max MAP drop. Thus, available power drops proportionately..car people think their turbo negates the effects of altitude. Wrong, unless your turbo control system is designed to do so! It is probably not.

[@ibrahimqureshi2420]

your are literally the best instructor ever i appreciate you to spend your hard work and time just to explain something to us I have by far learned so much from your videos thanks!

[@maxcactus7]

Happy D4A Sunday, engine heads!!

[@SUNUVAGUN]

There are places below sea level on land. The dead sea depression is negative 413 meters sea level.

[@GaurdianAzzar]

Glad I'm not the only person to think of this.

[@ochisettingz3383]

depends on which sea you are referencing it to.

[@johnlovett8341]

Love the channel and this boost series. There's an occasional statement that's off from an engineering or physics perspective ... but that's not what this channel is about. It's about understanding what's going on rather then always speaking precisely. Put on your motor head hat and this channel is 100% binge-worthy, learning experience. Go D4A!

[@barrymckockiner4887]

What did he get wrong? Just curious

[@FinlayDaG33k]

WW2 fighter planes used turbochargers and superchargers so they could fly at higher and higher altitudes (which allows them to store more potential kinetic energy so they can start with a nice speed advantage when swooping down)

[@kapitainekram]

Another way to pass a MAF limitations is to devide your intake in 2, putting the MAF on only one side. It will then remain precise as it will measure only half of the air entering. Then you'll have to adjust the ECU program to take this into account (basically multiply by 2 the values related to MAF). If you want to be more precise by measuring exactly what's coming in the 2 sides, you can also use 2 MAFs, one for each side. Each will be measuring half of the air. You'll have to use a device between the MAFs and the ECU to add the 2 MAFs values and then send the result to the ECU.

[@fastinradfordable]

Great until one cylinder has a problem and it is either not noticed or over compensated.

[@SJR_Media_Group]

There is one more thing that is important; Mean Effective CR (compression ratio) Versus Boost. This takes into consideration pumping losses, heat, and altitude. Engine might have a fairly high static CR and too much boost = obliterated engine. The actual dynamic CR will be less. I was reading a article on aftermarket boost used on a high performance NA engine. According to my 'math' the boosted CR was 17:1. But the actual CR was 11:1. I was pleasantly surprised because engine I was designing had very low static CR so I could add 5 bars of boost and not blow it up. Plus the actual CR can run on Pump Gas.

[@MrSquezzy]

i did run over 30 psi because of my faulty wastegate. tune was on 25 psi. hopefully it didnt blow up

[@SJR_Media_Group]

@@MrSquezzy Thanks for comment. Sometimes shared knowledge is better than dry data from the engineers.

[@TheMapleDaily]

I feel every day I watch at least one of your videos and learn so much in such a short amount of time, you really are efficient at teaching and staying on point!!!!! Much Love!

[@csanton3946]

im learning a lot and this is free, you should receive value adding citizen of the earth award

[@Folderq]

Genious simply material, it will help the generations. Thanks !

[@LandDrifter]

That's a great video! Thank you for sharing all this knowledge about engine tuning and physics principles. Just for record: 1 bar is around 14.5 psi, not that far from 14.7 but wanted to make it clear. Cheers!

[@jasonanderson2876]

New boost school!! Yes love this series👌🏼👍🏼

[@breathlessboarding2791]

One of the best teachers out there, keep up the good work!!

[@JoeBob79569]

This is fantastic. I've got an issue with my car, likely the MAP sensor, and I've been searching for hours online for one, only to finally realise that all the shops online call it a boost pressure sensor, but my workshop manual calls it a MAP sensor.. Which is obviously how I ended up on this page!

[@fastinradfordable]

Manifold air pressure Is boost pressure

[@JoeBob79569]

@@fastinradfordable Yea I know that now, but everybody calling it different names is kind of annoying when you don't know, and you're searching online for a MAP sensor but can't find the right one! But it turns out my MAP/boost sensor was fine after all, it was my EGR valve that wasn't closing properly, and it was throwing off the pressure readings..

[@kjnkjnkjhkjhjk8465]

Irregardless is with regard or with respect, high estimation of value. Regardless is without regard, respect, or low estimation of value. Ir equals not, so ir-regardless becomes not regardless, thus with regard. A person I worked for did me a solid by correcting me on this matter. Thanks Shelly. Great video series, I've learned a lot.

[@MI-sw3iv]

You're the best, no other channel or content on technical mechanics and cars compares !

[@mikegreen2229]

When you do a skydive, that’s when you discover the mass and friction of our atmosphere you take for granted standing on the ground. It’s like falling through a very lightweight ocean.

[@christianmeeks4430]

I know all of this already but I still greatly enjoy watching these videos and still learn little tidbits here and there. Great series.

[@agentsj1]

I'm a simple man. I see a D4A video, i click Like.

[@ricobelcourt3797]

Thank you so much, all the other videos made no sense and only gave me little pieces of advice and left me confused. Full understanding now thanks to you

[@divin3kag3242]

Dont ever stop what your doing i enjoy informational vids like this

[@aaa72317]

Damn, those AEM plugs are smooth AF :D Amazing videos, man. Quality is up the roof.

[@fastinradfordable]

That’s what she said

[@martinluther1913]

First of all I am thanking you 🙏 with my bottom of heart such an experience explaining all the stuff which is all related to automobiles and I am learning a lot of knowledge from your videos. Thank you so much my brother.

[@sking2173]

I never understood why manufacturers installed boost gauges in turbo cars instead of a manifold absolute pressure gauge, as used in piston aircraft. Simple, accurate, and easy to interpret ...

[@RX7GSLSEowner]

Thanks, I've been waiting for the next installment in this series! Thumbs up!

[@corbinyoung5320]

I love how detailed the description is great info great video thank you

[@dagridiron94]

Happy Sunday I love this channel!!!

[@tdogg2535]

I get so excited to watch your videos! Roll myself a joint, make a coffee, sit back and relax! so educational your content, PLEASE DONT EVER STOP!

[@fastinradfordable]

Damn straight T dogg

[@NightWrencher]

Your growth has been insane, keep it up

[@fastinradfordable]

That’s what she said

[@fastinradfordable]

I mean come on it’s too good

[@NightWrencher]

@@fastinradfordable thats what she said

[@Janni069]

I think this couldnt be explained any better than in this video. Thank u very much for the uploading of the vid

[@komoru]

Thank you for the great explanation and most of all, for not using cheesy background music!

[@fernandoanatomia]

I like your videos because they are educational and at the same time enjoyable to watch.

[@blkdna748]

Things are getting so interesting and little bit complex. D4A keep going.

[@danchoiordanov6740]

thanks for all series bro. apriciate it !

[@denisfontaine2938]

nice Renault R5 Turbo vive la France time 9:50 even if I know everything you explain you show me a different way and my knowledge is kinda sharper. Thanks great videos!!

[@mpower3144]

this is the best ever explanation i have seen, i was struggling with the sensors functions ,

[@876Shottas]

Learning alot on this channel, thank you

[@pgtmr2713]

You may not feel the pressure at altitude but you can feel the effects of hypoxia. I wonder if orientation of a sensor relative to the engine position helps, perpendicular to the engine tq and not over the top of the head.

[@80Loke]

This is just explained in perfection, very very good:)

[@scotthodges5214]

Learning a lot from this series. Thank you~

[@marc21256]

Isolation rooms are negative pressure because they aren't airtight. There are microscopic cracks. A negative pressure room will suck "clean" outside air in the cracks, and exhaust only decontaminated air via filtration. If the room were positive-pressure, with air being filtered and pumped in, as is most common with commercial HVAC, you'll push "dirty" air out the microscopic cracks. That's why in the movies, you'll see people in labs in puffy suits. The suit is positive pressure, to protect the person in the suit, and the room is negative pressure to protect the people outside the room. Pressure should always be higher where you are protecting and lower for the "dirty" area, to ensure proper protection. Taking this back to cars, a clean room for painting a car will be kept at positive pressure, so that dust and contaminates can't come in. The air is pressurised through the filter system to prevent impurities. The room needs to be cleaner than outside, so it's kept at a higher pressure.

[@zues2013]

Always learning so much from Your channel despite being a tech keep the vids coming!!

[@zakaryreilly]

This is exactly the kind of video I was looking for

[@terjejohnsen3651]

Good video as allways thanks alot.

[@MrMatty1974]

this is just so, so good.

[@MrWilliam.Stewart]

Ever tired giving a wave to a passing motorist who's let you overtake him on your superbike and you'll feel the weight of air. As it happens, aground 1.2 Kilograms per cubic meter. Ahh, altitude, necessity is the mother of all invention, thank you to the Aircraft industry for the exhaust turbine charger.

[@marcstlaurent3719]

Don’t forget about Death Valley , it’s 282 ft below sea level

[@Lilmiddwest]

Now make more sense great video

[@codymoncrief8478]

For naturally aspirated engines, the approximate math for elevation-hp exchange is: +300M equals -5hp. Turbo and supercharged engines are different and can be case specific.

[@Ijusthopeitsquick]

Wouldn't the "math" give the power loss as a percentage instead of a specific horsepower loss? A moped with 2 hp at sea level can't lose 5 hp at 5,000 feet...

[@twinforce_fusion6560]

Made me smarter, now makes sense that the boost Pr curve is very similar with the MAP curve. Now makes it easier when I read my data logs.

[@AAAA-vm2nk]

i am so unpatiently waiting for the full 100+ video playlist to be complete

[@d4a]

It will take a while 😊 but I'll do my best to make sure it's worth it.

[@lorenzodicosmo2708]

I have a question about oxygen density: does it change drastically due to the changes in humidity? And if it does, does the map sensor know it? And if not, does high power applications have any sort of humidity sensor?

[@bowez9]

MAP has major draw back of not taking into account of wear. Either compression loss with less vacuum produced which is interpreted as higher eninge load irregardless of actual load; or blocked air filter which result in the exact opposite. Where as MAF measures the MASS of no matter state of eninge. As for modifications its as simple of upgrading the MAF and calibrating the ECU. MAF and MAP can do the same job but the MAF isn't relying on a reference table for interpolation--which is affected by wear items--as MAP is.

[@MattFahnix]

Whoa! The hair is gone! Loving the series. Thanks so much!

[@phoenixarian8513]

this makes sense. Turbo engines suffer less performance loss when you drive it to highlands such as Tibet. The turbo will compensate for the lower atmosphere pressure so you still get the same pressure inside your engine. However in this case the boost threshold will increase since it isn't enough to spool the turbo at the same low rev. This seems not so important for people outside China? USA is mainly flat.

[@jakubtrzpis2595]

I'm waiting for the assembly of a 4A engine

[@MisterMr2.775]

Thank you D4A, you make very very good videos

[@7sins979]

so there are some gauges that are not baro compensated and will show absolute pressure on a "gauge" scale. gauge meaning 0 = normal atmospheric pressure or 14.7 psi. you can tell this if your gauge does not always show 0 day to day or when you change altitude. however most newer gauges are baro compensated.

[@laochek]

So happy always to hear your explanations making complex stuff look simple. Can i ask if diverter valves are necessary in turbo cars and whether compressor surge is real problem. Some say it does not affect longevity of turbo and a source if boost leak. Thank you for any advice

[@fastinradfordable]

It depends on what setup. In my experience having diverted valve(s) (some high models have dual diverter valves. ) Diverter valves are better than wastegates because when the wastegate opens the turbo shaft changes speed. Diverting air does not interrupt the turbine spinning.

[@Excepticus]

i really love these videos. problem is if i ever get a car i wouldnt know how to ever start modifying because i have no experience with doing mechanical things.

[@MrCheeto01]

Could one not experience higher atmospheric pressure by visiting Death Valley that is -282.2 feet below sea level?

[@d4a]

You're right! And it's still on the surface of the Earth

[@MikeyMotorsport]

Very good video man. Thank you!

[@menooaderohanian4129]

Like before . I cant find words to explaine how much your videos is awsome

[@scriptmike]

I'm from Detroit, the Silver Dome in Pontiac when is was there had a pressure higher than 14.7 PSI to hold the dome up.

[@802Garage]

Boss as always.

[@96blackjacket]

Technically Death Valley in Nevada is well below sea level it’s also a cool place because not only is it the hottest place on earth it has rocks that move on their own and there are places were the earths plates are folded on each other which effects gravity and you can stand diagonally without falling or watch rocks curve as they fall

[@scunnerdarkly4929]

Always great content, brilliant lo-fi presentation without unnecessary gloss, and above all, the enthusiastic delivery. How about a name to go with the face? Turbo Jesus came to mind before the haircut happened...

[@fastinradfordable]

D4a Is a good name no?

[@alexsm3882]

I'm new to all this so I always feel a bit stupid watching your videos 😂 but they're very well explained, they help me learn a lot.

[@shadowopsairman1583]

Anything over 29.92" Hg or 14.7PSI at 59°F/15°C standard day sea level is considered boosted over MAP. Boosting is needed to either sustain 29.92"Hg in Aviation or to provide more horsepower.

[@dreednlb]

2:40 Sea level? I'd argue the lowest point would be the Dead Sea. Its shores have an elevation of 420 meters (1,385 feet) below sea level.

[@thatweirdoboi7588]

he was still talking about air pressure, I think the pressure you would experience below sea level is water pressure

[@victordasilva547]

yeah because someone is gonna tune their car specifically for the shores of the dead sea💀💀

[@dreednlb]

At this point in the video he is not talking about tuning, and neither am I. He is talking about geography. "Where is air pressure the highest? It's of course highest at sea level because that's the lowest you can be while still being on the surface of planet earth"

[@dreednlb]

@@thatweirdoboi7588 I am talking about air pressure as well. The shoreline of the dead sea is still 1,385 feet below sea level.

[@andersdaun3950]

Thank u. Greetings from Sweden.

[@bobross6677]

Ill refer to this cause i dont have any work to keep this fresh in my head

[@dawricktyndale7550]

always enjoy the content.. real useful information keep it up nuff respect from jamaica

[@mrinalkarmakar4066]

Make in depth videos on car sensors and their functions

[@Ahmed.Hegazy]

hiesght atmospheric pressure would be in below-sea-level depressions ... great channel and good info ...

[@mcdonald2037]

Your a great teacher ... I'm subscribing

[@kewlbrz07]

While the atmosphere is least dense atop an earthly land structure, mount everest. Technically the beaches on the equator are higher than mount Everest. Relative to the center of the earth due to the oblong shape of the earth at the equator from centrifugal force. The Hawaii Islands are the tallest mountains on earth sans water.

[@d4a]

I think you misunderstood the article. Mount Chimborazo is the highest point when measured from Earth's center, but Mount Everest is still by far the highest point from the global mean sea level, it's right in the first paragraph of the article in the link....

[@warrendegonzague]

I love your videos, man.

[@arnoldodida]

always a pleasure

[@vertigoalopolus]

It is not at all necessary for your boost gauge to measure your turbo boost pressure at the turbo, in fact its much better and more accurate in terms of engine conditions to measure it in the intake manifold, exactly where your ECU is measuring it. I have no idea why you would ever want to measure boost pressure pre-throttle body. Also, what youre essentially saying and what you should probably be saying directly is that boost pressure drops as intake restriction is encountered by the airflow from the turbo. The best possible measurement would be inside the combustion chambers. This is usually impractical, so as soon as possible pre intake valves is ideal. The most practical location is in the intake manifold. If you have ITB's, tapping the ECU's MAP hose would work best.

[@TurboHappyCar]

Great stuff man! Dropping a comment just to help out the algorithm.

[@danielferraro59]

you are the best !!!

[@ChadilacE30]

Actually educational and interesting to watch. Liked and subbed!!!

[@slightlyinsaneraf]

School was never so fun kids

[@windhelmguard5295]

just correcting a few errors in the first segment: sea level is not the highest atmospheric pressure a human can experience, many places on earth have solid ground BELOW sea level, which experience even higher atmospheric pressure. the peak of mount everest is also not the lowest atmospheric pressure you can experience without leaving the earth, even propeller aircraft can reach altitudes higher than mount everest.

[@brianbrigg57]

My turbo diesel has both MAF and MAP sensors.

[@oshanechin5395]

Thank u

[@noahwhite7848]

A video explaining sensor resolution and how it affects tuning would be much appreciated 🙏🙏

[@Luke-cz9tm]

2:15 isnt volume inverse to air pressure though? Surely the highest point would have low air volume and therefore high pressure?

[@nenadm.3269]

Koja si ti legenda.

[@ds15891]

Great video but this got me thinking, my car comes with a turbo and i do occasionally take it to hills of around 5000ft elevation, how exactly does the car adjust the boost levels to cope up? 1-The car anyways has a bit of turbo lag in normal elevation levels so i assume by this point the turbo itself does not have much more scope for producing more boost so i guess low rpms still would have less power in turbo powered cars in mountains with less dense air. Correct me if i'am wrong. (Mine is diesel i guess which makes no difference) 2-Even in higher RPMs how does the ECU instruct the turbo (a mechanical part) to make more boost? I'am guessing it has something to do with controlling the wastegate, but do all turbo cars have electronically controlled wastegates? And for those that don't (if they don't), do they have no mechanism to make more boost in those cases and the engines make less power like their NA counterparts?

[@fastinradfordable]

Every car is different. Asking a question about your car. … Helps to say what car.

[@fastinradfordable]

My car had a mechanically controlled variable turbo that can be changed on the fly by adjusting a valve On the shifter. Jelly?

[@ds15891]

@@fastinradfordable Creta 1.6 CRDi

[@gueburah]

the highest peak from its base is everest, but the highest point on earth is the chimborazo volcano, surpassing everest by 1,811 meters.