Understanding & Measuring Compression Ratio : Static, Dynamic, Effective, Two & Four Stroke
Vložit
- čas přidán 7. 06. 2024
- Static and dynamic (or corrected and uncorrected) as well as effective (boost) compression ratios are explained for both two-stroke and four-stroke engines. Then detailed information about measuring these ratios is provided. Complete with an index after the intro to make it easy to find what you're looking for and a quick reference at the very end.
If you need help setting up a degree wheel, check this video :
• Setting Up A Degree Wh...
✅Tip Jar (Did this video help you?)✅
paypal.me/49ccscoot
#CompressionRatio #CompressionExplained #DynamicCompressionRatio
Hope it helps! Thanks for watching!
*******************************
Intro Music
The Brothers Records - Blow Thing (Attribution Free)
CZcams Audio Library
Sound When "vs" Appears
Left Hook sound by Mike Koenig (Attribution 3.0 License)
soundbible.com/991-Left-Hook.html - Auta a dopravní prostředky
Came for automotive content, stayed for the quality interesting presentation.
Thank you!
I'm just a dumb pro race mechanic but to me that was the best presentation on the subject Ive ever seen and I'm sure people will appreciate your effort to present. well done mate,
cheers Johno
Glad to see you back. I hope to see more.
Great video and explanation, but I'll have to save it so that I can watch it a few times to "completely" understand it.
Thank you for sharing your knowledge!,
-Thomas
Port Orchard, Washington
Good to have you back man
Sir you truly are an inspiration thank you
This video are so fully loaded. Thanks man!
You deserve far more subscribers than you have. I’d love to see more 4 stroke content! I’m working on my 4 stroke engine building skills currently!
Thank you sir... i learned something frm you... i will do it to my experimental 130 cc drag bike ... i really thankful to learned frm your idea
College level info easy to understand. Fantastic!
Lol this is kindergarten level easy to understand
@@lifelesskids if this is kindergarten then my iq is WAY less than I thought it was
*VERY NICELY DONE*!!!
wow! im so satisfyed by whatching this!
you know, i have spend many days by searching russian seagment of internet and youtube to find some piece of information about DCR. But there were only hints.
Here in Russia many firms and bloggers who work with engines use only SCR. And they treat the camshafts separately from the compression ratio! Like "we've got engine with 10:1 scr. So if we want turbo it we need to make 7:1 scr or lower. Otherwise there will be apocalypse".
Thanks a lot for disclosuring this simply definition.
Great explanation
That is an amazing amount of data in one short video. I get the feeling that scooter engines were not the first entrance that you worked on.
Incredible video
Very useful sir..tq for the knowledge...👍👍👍
nice one sir now i know how to compute compression ratio
best ive seen to explain how the hell i work out my machined pistons cos i cant buy them .world class video
Awesome info you should be doing documentary my brother!!
Great stuff!
Видео просто супер! Спасибо огромное!
Thanks man!
Very good
asli ilmu matematika fisika ... pakai e error ~ koreksi efective
great video!!!
Thanks!
Nice info
Sum good info m8.
Frikkin top channel this
Great information, very good !
Thank you!
I am writing this after lots of experiments I have done on my Honda scv 100. 4 stroke 102cc. I posted before as well, but this time I would really really really like ur experience to help me out. It's not that I am disappointed with my scooter. It's just it won't start as easily as my other scv 100 when cold. So far I have checked spark which is blue in colour, replaced and adjusted spark plus as per specification, rebuilt carb , replaced float needle and vacuum petcock , replaced carb intake gasket, and checked for air leaks . Still the problem remains. And I'll explain again the exact symptoms. These show up on leaving the scooter for 3-4 days. Overnight they don't show up. They only show up when I have left it untiden for 2-3 days atleast and it's cold. (10 degree Celsius). So when I use kick start it my other scv starts in one go no matter what . But this one's is a bit odd. The very first kick each time gives a very faint cough as if smthg did burn in combustion chamber. But it dies. After that the next 7-8 kicks are just completely dead. No action at all. Not even a attempt by the engine to start. And then finally when it's done with tantrums it starts, but that too very weirdly. It starts as if picking up from very slow rpm , u can hear it, and then it increases to the normal rich condition cold start rpm. But u can feel the initial bare minimum rpm and transition to high rpm . The other scv 100 of mine starts on cold start with same rpm at 0 seconds. It's doesn't build on rpm from low to high like this one. So what's the problem? Any advice ? Anything at all? Please. I hope I have been able to paint a clear picture. The scooter runs fine when warmed up. And starts fine when warm. Full throttle at cold start doesn't work always . Any advice?is it stator? Ig coil? Pick up ? CDI is fine I checked. Or maybe some weird vaccuum leak?
The 150 that I had did that it's entire life... till I tuned it. A friend owned it 10 years before me. It always did what you describe. It was a real pain to start and then it would idle low and I couldn't give it gas till it warmed up or it would die. Once it got warmed up, it ran fine. I messed around with the air cleaner and spent the time to dial the carb in and that went away. I honestly don't know specifically what did it, because I changed the main, pilot, and needle setting and I wasn't really trying to change that. If you haven't done it already, then I would suggest trying to dial in the carb. It's a good thing to do anyway. Another thought is valve clearance. If 1 starts great, maybe check the valve lash and replicate that on this one or just go by a service manual.
Cant thank you enough.
Well this helped me... I'm kinda new to 2 stroke engines... Plus this will help me with a school project
Great video
Keep it movin. ....
I have recently picked up a 2009 aprilia SR50 ditech Piaggio and I am installing a 70cc kit. Since it is fuel injected my knowledge about squish, deck height, piston protrusion are wasted as I’m told these act differently then carbureted two strokes. I raced 250 gp motorcycle for quite some time but this is a different little beast with FI and air pumps. Any experience with these?
So what the ideal corrected compression ratio for 2 stroke..have u ran in dyno n play with the dcr to see the feedback.tq for the video
Last comment, I promise-- Dude, MASSIVE props to you, I mean I am banging my head learning this stuff and honestly it's looking like chainsaw-engines are perhaps THE easiest engine-layout ON EARTH, am having trouble thinking of anything simpler....I mean even the older chainsaws at least had reed valve intakes, for whatever reason that is not even the case anymore (intake is achieved through the suction/vacuum of the bottom end, during the compression stroke, the moment the piston-skirt goes above the intake-floor the "intake influx" has begun.....so we port exhaust roofs upward, and intake floors downward, as "at home/dremel porting".....and I just found that some McGuyver'ing lets an at-home porter like myself actually do cylinder bases & squish bands *at home w/o CNC*!!! So yeah now I'm able to dial-in compression (oem is 13.1:1), thinking of retarding timing several degrees and running nearer to 15:1, thanks so much for this video I hate even saying how simple it's gonna be for me, relatively speaking, to get these volumetric measurements you have to fight so hard for, heck the combustion chamber//cylinder are 1 piece in this application :P )
Thanks again for such a well-presented piece of content, A+++ right here!!
I'm always glad to hear that I've helped someone. Good luck with your project. Can't say that I know much about saws, but I may have to look up the more modern designs. It's going to be sad to see the market go electric. Upping voltage and playing with electronics just doesn't do the same thing for me as getting into an engine... and of course the sound of a 2T makes life better.
Use the constant Bore x Bore x stroke x .7854 Same result, just fewer steps
Can you messure when you Install head
Very helpfull info.. chart or formula for compression ~ {bore diameter} Stroke cc ÷ {bore diameter} Clearance Deck Height TDC cc ... need Intake calculation please.. For efficient and effective compression..
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?
so helpful..but i got little bit confuse abt the depth of piston from the deck to calculate the crown volume...the depth measurement from the deck where we can get sir?
You have to measure it. If you are calculating the volume based on measurement of fluid, you use the depth in the bore when the fluid was added. Then that difference of calculated volume vs measured will lead you to the crown displacement/volume.
What do you think the compression ratio will be on a qmb139 with a 100cc kit (50mm) with a head machined for a 47mm(80cc kit) will be? It shouldn't be too high right?? Should I use two jug gaskets??? I'm going to use playdough to check the clearance, I'm sure there would be issues if the 39mm bore (stock head) was used, there may be clearance issues, but the compression ratio will be a bit higher, I did unshroud the valves, so that will drop the compression a slightly, I'm running the a9 cam with the 50mm kit, I'm hoping it will at least double the HP, from 3.2 HP, with the exhaust, the head porting, and unshrouding, the seats were crazy deep, that would never fly in a car engine cylinder head , it seems the factory would do just a bit more machine work, i
I also port matched everything! It was a crazy amount of core shift!! Vgreat video!! I also have a 20mm carb and jet kit, do you think 6-7 HP is possible? Or at least 5hp? The compression should be slightly higher,
There are multiple head designs, piston crown styles, and deck heights from various properties so it's anyone's guess. I would guess you would end up in a safe range with many common combos. It can get really high when people try to use a stock head on a 50mm kit. IIRC I calculated something like 15:1 with one of my old kits if I were to use a stock 39mm bore head without any other mods.
Hi, first off thank you for this detailed video.
I was searching the comments to see if there was an answer to my question but i didn't find it...
My question is, should we use a gas octane according to corrected or uncorrected compression ratio?
Either way, they're just going to be different specs. Most people seem to talk about uncorrected.
good day sir.. can i ask for measurement in pds copy.
I have heard a good running drag car engine is running around a 9:1-9.5:1 compression, dynamic (not the static compression) being the cam bleeds off cylinder pressure, while the calculated compression is about 14:1, I had a engine with 12:1 it was all I could do to get it to run on 93 octane, it could been closer to 12.5:1, but the cam did bleed some pressure, but it was at least 12.7:1, it's been years but I think it was about 215-220 psi average cranking compression, psi, the timing was retarded, I ran cold plugs and a cold thermostat and large jets, running it rich helped the most to get it to run on pump gas, I wish I had aluminum heads! Or dishes Pistons, it would probably ran much better! Allowing more timing advance, it sounded awesome, but was the peakyest engine I ever built, it had a very narrow power band, about 3600-4850/5000, it made great power there, but about dead everywhere else, the heads had small runners, and small Chambers, I was young and dumb, I wanted high compression, and a rough idle, 'big cam' I should went bigger, it would blead compression making it run better, it was recomended for 10.5-11.5:1 if I had more overlap, also the single plane intake was just dumb, even with the 3.42 gears, it was 2.73:1, if it had about 3k stall and more overlap, or just less compression, a 63-64 cc chamber would been plenty, (about 10:1) but I was running 58cc heads that had been cut a bit, I'm guessing they were about 52-54cc. I wouldn't cut them much more and trust them , maybe .020",more ( maybe) I think they were cut about . 050" -.060", I stay below 10:1 with iron heads, and 11.5-11.7 with aluminum heads, although I do have a 3.75" stroke , 4.040" bore engine, with 62-63cc aluminum heads, with flat top Pistons that are . 001-.002" proud, I was hoping for zero deck, but it was already decked, and setup for zero deck, abd my components were just a wee bit longer, I'd rather the Pistons be a couple thou below deck, but the MLS gasket is a bit thicker than I'd normally use, at about .045" I roughly figure about 11:1, I wish it was 10:1, so I could feel safe running about 10 psi boost, but with 385cid, and 11:1, it should do fine without! I may swap the heads for 68cc or 76cc versions, with nearly . 600" lift and 244° at . 050" but I'm going to swap cams, great video,
hi sir
your content is very interesting
can I borrow your video snippets for my content
Hola hermano creo que puedes ayudarme en hacer una jog artistica 101cc de competicion para mi pais que secore campeonato de bajo cilindraje para que unos cuantos trucos me vendrian vien al desarollo de la scooter
My anti-knock prototype let's me advance the ignition timing to the maximum factory setting without any knock.
What's the highest compression ratio that you would recommend for A port injected engine?
Spark knock is not A problem, so I just want to stay below the compression ignition threshold of pump gas.
If you're trying to push to the limits, you're going to have to work at it. There's no 1 figure that will work for all engines. Maybe you could aim for a figure on the high side (say something like 12:1) with a thin head gasket and then do some calculations to find out if available thicker gasket options could significantly lower compression if needed. Or the opposite approach of aiming low with a thick gasket and then using thinner gaskets to increase. Some applications probably won't have enough of a range for that though.
@@49ccscoot Thanks for your input!
I think I will start with some easier modifications and build my way up. If the engine can handle them all, then I will add some cams and then go from there.
I did create A short video of A test run, using my prototype. Pause on the distributor part if you wish?
Hey man, do you have any 49cc Scoot decals?
Just the stuff in the merch links below the vid or you can go directly to 49ccscoot.creator-spring.com/
Original CR on my scooter has 12.0 Compression ratio .. piston is 60mm. Honda pcx 160. i will upgrade piston to 62mm.. Shall i go higher on Compression ratio? ore stick with 12.0? 12.0 is very high already? Thanks :)
TBH I don't know much about the PCX engines. Your best bet would be to look for someone that works with them a lot and see what they find works best. Maybe there's a facebook group or reddit or something?
👍
Can you use a cooler spark plug to lower compression just a little?
Spark plug heat range does not change compression ratio.
I have a gy6139qmb with a 80cc bbk and I only ask do I have to run 91 octane at 2000 ft. In altitude or can I get away with 87 octane ? . You are the best on U-Tube and next payday I am going to send you a donation . Thanks.much...
Not all kits are created equal, so... maybe. With a stock head, I would expect it to need more than regular. It may not though. If it has an aftermarket head with a larger combustion chamber, then it's probably OK on regular. If you try regular, listen for spark knock and make sure you don't see peppering on the spark plug. Peppering is basically what it sounds like. It may look like someone sprinkled pepper on the plug if there has been detonation. It's not always present though, so it's not sure fire to say the plug looks OK so it's fine.
Wonder if you can help, brand new head and piston (taiwanese(welp))
Ran for several minutes and died never to run again, there's minute gaps at some places around the rings inside the cylinder, would this be enough to cause this in your opinion? Thanks in advance :)
And a nice little grey sludge poop at the bottom of barrel near crank :O
@@KentRoads So you're saying it looks like the rings or cylinder have wear spots that cause small gaps and you have grey sludge? If you see scuffing of the piston/bore as well, then maybe clearance was incorrect and the sludge is metal from the piston/bore scraping. If it was ran under load, then it could have seized. Could have been something defective from the start that you didn't notice or ring end gap was not checked or set too tight. A compression test would tell you if it's still sealing, but if it's as I'm picturing your description then I think the rings at least should not be reuse anyway and possibly the piston or cylinder.
It's almost like a hairs breadth of black(shadow) where the ring would intersect with the barrel and create a seal :/ I've tried both rings and it seems to be the same... The gap is so small I can even get light to shine through it as I don't have a lamp small enough as to not blind me at the same time :) thanks again!
@@KentRoads If there's actually a gap between the ring and wall, then the piston should be easy to move. Otherwise, it may just be the way it looks to your eye and not really a gap. If you can, I'd at least do a compression test and a thorough inspection to see if I could find the source of the sludge.
If I remember correctly I didn't set end gap so they've probably butted fml, no damaged to ports though from what I can tell D:
Well personally i look for compression ratio which is save for ron 90. Bc it is the fuel i can find anywhere here for reliability
For corrected comp.ratio-- On chainsaws, the intake is NOT open at BDC, chainsaw cylinders' intakes draw air UNDER teh piston-skirt's bottom, when the piston is going up its compression-stroke. The intake port is 100% closed by the piston at bdc. This doesn't change corrected compression-ratio, does it? Because corrected ratio only cares about the chamber down to exhaust-roof, right?
Thanks a ton!!
Corrected ratio would concern whatever the first point of escape for compression is basically. Generally that is the exhaust port opening.
BTW...where's the "chart" on "good #'s" for corrected-compression? IE, something that "lines them up" to un-corrected? I guess I mean that I can easily figure out all the #'s here, and I get the new corrected-compression for my saw (which is substantially lower than static compression ratio), but I don't know what this #'s telling me! Don't know if I should be happy/sad at the #, or want it up/down, yknow? For instance if 15:1 is pushing it for static, what is pushing-it for Corrected?
Thanks!
Sorry for such a late reply, but it flagged your last comment as spam for some reason. You can't accurately align corrected to uncorrected numbers for conversion. I tend to go with 7-8:1 corrected on my street scoots. 7:1 has been on the mild end of it. You could certainly push beyond those numbers, but these were for scoots that would be heavy on the throttle for long periods of time.
So what you're trying to say is: two strokes are petrol powered whistles?
Mntp👍
While it is commonly used, IMO calling Trapped CR the Dynamic CR is misleading.
Trapped CR is as static as Swept CR, Trapped CR can only be changed by some mechanical means like power valve not by any "dynamics" arising such as engine speed or the like.
Also be aware the raising the CR in a 4 stroke will produce the gains right across the RPM range however that does not translate to 2 stroke that will only benefit from higher CR at higher RPM
Question here, I was playing with a compression tester the other day and my honda is a 9:1 motor but tested 185psi…
If I do the math (184/14.7) it gives me a ratio of 12.7:1
Do you know why my math is wrong? If anything I would assume it would be lower than 9x14.7
Thanks!
Rough rule of thumb is about 16-21x static compression ratio is where cranking compression is likely to be. You're in that ballpark.
@@49ccscoot interesting, I was kinda curious about the math behind that
So what happens if I have a really tight squish band say 0.5mm - 0.6mm but I've deepend my combustion chamber pocket to reduce Compression ratio back to factory 7:1. Also using a spacer under my spark plug to make protrusion flush. Is this ideal? having a tight squish band, with low compression ratio. What happens if I reduce compression ratio BELOW factory spec of 7:1 but still have that tight squish?
Ideal would be to set the squish AND the compression where you want it. Keeping the squish tight can help to reduce the likelihood of detonation and the combination should help you get a little better performance. I've never seen big changes from changing squish only, but compression can definitely change the output noticeably. Just make sure that you don't push the squish so tight that you end up with piston to head contact.
49ccScoot hey, thanks for getting back to me. This is where I currently am in my Minarelli vertical build. I’ve reduced squish band clearance to minimum specs listed in Two Stroke Tuning by A. Graham Bell, I’ve also deepened the combustion chamber pocket and calculated my compression at about 7.5:1. No base gasket... if I add a thin base gasket 0.2mm it will increase my squish clearance and reduce my compression to 7.1:1. (Also slight change to port timing) Are there any issues if I add a base gasket that is 0.5mm which will reduce my compression ratio to below 7:1? Also slight port timing change, also wider squish band... my main concern or question is... what happens when I lower my compression ratio below the suggested 7:1 ratio? Just wondering if you’ve experienced this?
@@JoeStMars If you lower it too much, you will start losing power. The numbers without a base gasket sound the best, but there is more to it. Look at the position of your port floors relative to the piston at BDC. Ideally, you want the floors level with the edge of the piston crown at BDC. Since you are able to modify the head, you can probably get all 3 of those things very close to where you want them. Sometimes it's a compromise.
49ccScoot thanks again for getting back to me. It’s going to be a compromise for sure, and a learning experience. The piston does not clear the exhaust port floor at the moment. I may have lowered compression too much during my combustion chamber deepening procedures. I will try it as is no base gasket, piston slightly above exhaust port floor, 7.5:1 compression. Plan B is the .2mm gasket, 7:1 compression still not flush with exhaust port floor... but slightly closer. Plan C is to re start with a different head.
Thanks for the advice and feedback. You’ve been very helpful! Keep up the videos, they help me a lot!
So Do you think putting 95 octange gas in a 125cc scooter would make any noticeable power difference ? Also how are your injuries will you again ? It's amazing that motors are only %20 efficient the other %80 Is wasted as heat.
If all you do is add high octane fuel, no. It won't make it any more powerful. If you make changes to the engine or timing to go along with high octane fuel, then you can find power. You may be able to get a fuel with a higher BTU rating and see some difference. IMO race fuel is for race tracks though. It's just too impractical for most of us on the street unless distances are limited or we carry our own fuel supply around.
Injuries are much better. Thanks for asking. I'm getting around OK now, but I think the knee is gonna bother me for quite a while. I've been riding again, so I'm happy. :)
Why is effective compression ratio square rooted tho?
Hey, I Got a Suzuki katana 50cc from 1997 and i want to change the belt on her, but I do not know what to do for her to walk more, they say that when she is small she walks more, you know what I could put in?
Sorry, but I'm not understanding "walk more".
@@49ccscoot I mean go more faster, cuz my moto is a 50cc and only goes at 45kmh... I think is the belt
@@dimitrifonseca1507 OK. The first thing that I would do is to check the belt width. It may just be that your original belt is worn thin and a new belt would help you regain speed. Check a service manual for specifications.
@@49ccscoot Hmm ok thx man i will try :)
@@49ccscoot instead of "width" do you mean thickness? Width is how wide the belt is thickness that has been wore may cause what you're talking about. Am I right?
Oh and thank you for the video, I did appreciate it.
Hey I think you got an error with units at 11:00 . You did mmxmmxmm=mm^3, but you put the results in cc or cm^3
Edit: nvm you divided by 1000
Thank you so much!! That graph of thermal-efficiency, man my engine (92cc chainsaw) has OEM-spec of 13.1:1, so it was awesome seeing that *that* is basically nearing the 65% mark (and 70% is all you could ever achieve, it seems), IE I'm already near the "point of diminishing returns" at OEM-spec....hhhhmmm I was thinking "I'm going to up the compression as much as I can, as much as I think the engine's crank/bottom end can handle, within reason IE no knock", and planning to retard timing a lil bit if necessary, but now wondering WTH to do because the unit's OEM specs are all so damn close to what you'd "wanna do for performance" (it is a pretty renowned 'power platform' the ms660)
I did just make a cylinder for one with a tapered squish band and a chamber like 70% of original size, and realized I can no longer use "squish measurement" to get an idea of anything because I've changed the chamber's dynamics/volume so much, am going to have to do a volume measurement (hence being on these videos, thanks for making this it is incredibly helpful!!!)
What exactly is compression height ?
Compression height is the distance from the centerline of the wrist pin bore to the edge of the piston crown. It does not include and dome, dish or other features of the crown.
The easiest way for most of us to measure it fairly accurately is to put the pin in the piston, leaving some sticking out. Measure from the top of the pin to the edge of the crown. Measure from the bottom of the pin to the edge of the crown. Add those two numbers. Divide by 2 and you have your compression height.
If you have a couple of different pistons on hand for the same engine, you can kind of connect them with one wrist pin halfway in each one and look at the compression heights side by side.
Hello 7-8:1 For how many octane fuel ?
I use that for premium pump gas, which is 91-93 (R+M)/2 here. You may even be OK with lower octane. Ignition timing has to be considered too.
100 cc is common here in the Philippines
I was following along with the math explained at the effective compression ratio part and I don't understand how or where you got the approximate CR of 11.2:1...
I got 13.89 aka 13.9:1
Help me understand if you could.
P.S. Math is NOT one of my strong points. Lol Just hear to learn.🇺🇸🏁
Try following along with the step by step that I showed below the formula. Where do your numbers start to differ? 6:45
whats your educational background btw
mathematician/ physics/ engineering?
High school dropout? lol
@@49ccscoot Wow never would have guessed,
very impressive sir!
@@49ccscoot same here! Made me smarter than I would have been had I stayed in 11th grade to learn what they wanted me to learn.
Now I see why the Mazda 2.5 skyactiv power band is so wide and the torque comes on so low with its 14:1 compression 89bore 100 stroke
Thank u for sharing this knowledge. Flat earth crew
I don't really object to the term compression ratio. It's a good communication, in that we all picture the same thing: bdc vs tdc volume. We need that volume ratio to examine other dynamics. But underline the word 'compression': that implies work is being done, which... until the intake valve closes is not much more than ring friction and fluid being worked across the bearings by rotation. So basically, no significant work happens with an open system, and that means... the cam determines compression ratio of your bore/stroke combo - that's it.
and what would be the ideal value
There's no single ideal value. It will vary by setup. A boosted engine would not function well with the same compression as a naturally aspirated engine for example. Characteristics of one naturally aspirated engine may allow it to function better with higher compression than another. Fuel used, how it's driven or what it's for... so many variables.
what would be the best rate for a naturally aspirated 2 stroke engine
@@leotechmotos I usually go for 7-8:1 corrected compression ratio for street stuff, but it will again vary by setup and you can push it higher if it's more race oriented.
@@49ccscoot thanks for sharing your knowledge
@@49ccscoot 🙏👏👏
most ppl i kno think that high octane is a bettr, and nevr try to use a lowr octane fuel to c how it affects engine perf..
It depends on the engine. If the engine doesn't require higher octane fuel, the additional octane isn't useful. I have tried to reduce timing and use lower octane fuel on cars and scooters in the past, but performance was improved for me with more ignition advance and higher octane fuel each time.
I know someone that runs their lawnmowers on high octane because they think it's better gas. My mower is around 800cc to make 25HP. I can leave gas in it over the winter and come back and it will start right up. It's the least picky thing for fuel quality and it's running fine after 20 years of cutting grass 2hr/wk during the season with only routine maintenance to the engine.
What’s up!
Howdy! :D
90GTVert Holy crap man this was one of the most well done videos I have seen! Like seriously I’m gonna show this to my friends so I don’t have to explain anything to them!
@@MRTuning704 Thanks!
You specialize in 2-stroke cars
Lol cowboys in the house
please translate in BAhasa mr..
thanks
what you said about normal combustion vs denotation is just wrong
they are the same thing, ignition of the fuel/air...the only difference is the timing
detonation is when the fule/air is ignited earlier than a spark would ignite it
the damage happens when its early enough that the piston has not reached TDC so forces are pushing piston against the normal direction
but to call one burning and the other an explosion is a complete misrepresentation of what is happening
You're confusing detonation with pre-ignition. You said "detonation is when the fule/air is ignited earlier than a spark would ignite it". By definition, that is pre-ignition; as it happens before the spark-initiated ignition event.
When you look into this more, there are many scenarios for improper or unwanted events. It's tough to thoroughly define every instance with singular terms. There is a reason that detonation is called detonation and not conflagration though.
You don't need to trust me on this. I've read all of this over the years in books by Bell, Vizard, Jennings, Bettes and others as well as watching lectures on the physics of internal combustion. I'm not claiming to be an expert on all topics, but what I have said is out there from many sources and from many better informed than either one of us.
This is the only math i want🥲