COMPRESSION RATIO: HOW to CALCULATE, MODIFY and CHOOSE the BEST one - BOOST SCHOOL #10

Eu não consigo mensurar a lógica por trás da redução da compressão do motor para aumentar o boost.
Veja:
12:1 tem chance de knock
Se eu baixar pra 8:1 e colocar 14psi ( o dobro da atimosfera) isso eleva a quantidade de ar dentro do cilindro ao dobro , correto?
Seria o mesmo que elevar a compressão a 16:1 (8x2 ) pois dentro do cilindro agora tem o dobro de ar.
Como não ocorre knock nessa compressão?
Pra gerar o dobro de potência tem que haver o dobro de ar/combustível.
Um cilindro de 100cm³ teria que comportar 200cm³ para dobrar a potência. Compressão:
100 x 10 = 10:1
200 x 10 = 20:1 ???

I am looking run around 300-350hp at the wheel on my k24z3 honda accord euro. would you consider dropping the compression ratio from 11:1 to like 10:5 or leave it as is?

upgrading the pistons, rods, wrist pints, & valve-train will enable the engine to take added boost from a turbo/supercharger without blowing up or throwing a rod for the most part??
Can you do that to any engine you'd like?

Normal people modding their cars:
- I've added cold air, heathers, exhaust, remap etc.
D4A:
- I grinded my cylinders by hand to increase volume, and reduce compression. Now I can run more boost

You mean cold air is better

Hello bro. My engine has a compression ratio of 10.5:1. I'm going to install a turbo gt3582r. Tell me please. What octane of fuel will I need to use?

Today is my exam and I am seeing your videos and videos are very informative.
Thank you ❤

It would be better to call the smaller "cylinder volume", the "combustion chamber" volume, as it is normally called and is easier to differentiate from cylinder volume which is the bore × stroke..of course, in calculating compression ratio both must be added together ... 🤔

A forced induction engine is a two stage compression system with a possiblity to cool down after the first stage. That's why (not only why) the potential max torque is higher than in a one compression stage NA engine. Then in a FI setup the CR/boost ratio is a compromise between the FI load (high compression mode) and the NA partial load (low compression mode) performances (torque, efficiency, ...).
Also the presented numbers and even the logic are only true for the traditional mid 90 engines without vvt/vvl. Don't believe ? Check the CR of modern engines.

So my bike with 150cc and CR 12.5:1 is better fuel than lower CR and bigger displacement?

How about a video of timing advance? And variable valve timing too?

Could you please do a you video explaining various camshaft lobe separation angles and how and why it affects torque and horsepower?

Thank you fellow gearhead

CR=efficiency, commonly right but technically not, efficiency came from expansion ratio, yes, mostly it is has the same value as compression ratio, but mr atkinson denny that, and decide to design engine cycle with low compression ratio (work required) and high expantion ratio (heat converted to work), to get better efficiency. The draw back it is not powerful, because it is basically regular gasoline engine with 70% volumetric efficiency

in theory compression ratio is how you say but real compression ratio also need take a thing more and is the camshaft value if the piston is gone up and valves close to 30 grades bdc here start real compression

Dear Driving4Answers will you do a video where you talk about squish setting and measurements?thank you

That is the best video I have ever watched.

only 14:1 with GDI and EGR recylculation of smoke. and regulation of moments inject of high octane fuel. In MPI injectors system high ratio not work

Crazy how a concept that has eluded me for years was explained so easily in the span of about 16 minutes. Ive been wanting to get into this type of mods and you’ve helped me immensely, thank you.

Супер сте браво ❤

Craziest thing you ever saw? FoMoCo installed a flex fan backwards. Always had AC problems... I found it when I changed his Camshaft(s) in a parking lot. It's a different story when the front end is no longer attached to the back end... Fixed.

You are an intriguing young man. Is the Infinity system yours? I was planning to build my own, but watching you a while, I see you understand the industry and science. Should I consider this, or build my own? From a Subaru stand alone to a GM 6.5 TD controller (3 outputs) and 4L80E transmission.
One mentor made the 1st transistorized motorcycle ignition.
Another learned from Smokey Yunick, and was Black Flagged at Daytona in '68.
"289 can't make 427 SCJ performance." Wrong!! 167.86 lap, 210 back stretch. '67 Shelby GT 350. 289 was from his Ranchero. Teched and won. For a Single guy plus week end pit crew, he kicked butt.

One very small thing to add. On a modern Atkinson cycle the compression is from intake close to TDC.

Remember children, the higher over stock horse you squeeze means the lower the life expectancy of the engine. So slightly milder over stock wins, as well as other goodies that can prolong the life such as roller lifters and rockers. Have fun and change your oil on time, it will last longer. ❤

We already know going up 1 full point in static compression ratio equals about 4% in horsepower.. The question is what the percentage in torque? I'm strictly talking about a N/A motor.

what is the optimum compression ratio for hydrogen engines ? is it 14:1

this was so informative!! the way u break it down is amazing. ty so much

How about air fuel ratio?

So take myself for example
I have a 320i b48, 11.0.1 ratio
330i b48 10.0.1 ratio
135i b48 9.5.1 ratio.

Only difference with these cars is ratio engine part are the Same with forged crankshaft and piston RODS , cast pistons

So with bmw I believe and looking at the models, above, a lower compression = more power in this case correct?

Also I would want a piston with a deep top in order to reduce the ratio correct?

How do i calculate what fuel (octane) i need?

I love this man! (in a family friendly binary way, just saying:)

D4A how does compression affect rpm limits? does a higher compression allow for a wider rev range?

My compression ratio on my latest build was too high to run standard fuel, its now permanently on E85. Only way around it is to run weak actuators or decrease dynamic compression via aggressive cam shafts and bigger turbo rear housing.

me watching this video knowing that im about to take apart a brand new crate engine to put even more money into it 😅

I'm building a chainsaw and I took a taller piston and machined the outer part of the top down so that I had a ride that matches the combustion chamber except for a little notch for the spark plug so it doesn't hit so it is closing almost completely up but I haven't Finished it yet but I may have to run racing fuel mixture in it so it doesn't have pre-ignition problems

Laughs in 13.1-1CR in carburettor fed, big bore, analogue engine.

i will always take a more responsive engine over a laggy but more powerful one, im not going to the drag strip or doing rolls on the highway, the fuel efficiency benefits of a high compression engine is also a plus

There is no better explanation! Thanks a lot for sharing 👌🏻👌🏻👌🏻

Earned a sub 🎉

How much displamant dose a turbo need

Very sad video! Dynamic compression is the factor needed! Determined what FUEL WITH INCREASED COMPRESSION RATIO. JUST WONDERING HOW MANY PEOPLE HURT OR BLEW UP THEIR ENGINES AFTER WATCHING THIS? I HAVE V6 1900 HP BOOSTED STATIC 12.5 TO 1 DYNAMIC 9.38 TO 1 COMPRESSION
RACE GAS OR BOOZE ONLY . DO SOME HOME FIRST.

Mazda says high - 14.1:1 CRs in Sky-G engines which Toyota pays in gold to have in their hybrids, and 16.3:1 CR in Sky-X - which is basically a petrol engine that doesn't need spark plugs (it has them but doesn't use them in certain scenarios). No other car maker gets even close to 14.1:1 in production engines.

You also have to run higher octane gas to prevent knock.

This is literally the best breakdown I’ve come across to date. Will be rebuilding an engine for my first time solo soon here and increasing compression and air flow is already on the top of my list

Could you work out all the specs for a 182 ford falcon ba XR6

Peace. Have u done any high compression 2gr-fe?

Hi, I own a Mazda 3 2.0l atmo with a 14:1 compression ratio. I want to put a supercharger, should we pay attention to the air pressure in the intakes? Is there a limit to avoid blowing everything up? Thank you in advance. a subscriber of the 🇫🇷