AIR! ALL about AIR and how we get it TO FLOW into ENGINES

We're taking a flyer on this one but we couldn't resist talking about AIR! True to form, Technical Editor Kevin Cameron starts talking about us breathing and how gravity holds air on the earth ("Which is really good for us.") and we take it from there. Poppet valves, pressure waves, exhaust and intake tuning, and so much more. Ever heard of an Aspin valve? Rotary valve? Sleeve valve? You can say yes to all those if you just have a listen to this week's Cycle World podcast. Join us in the air!
Subscribe to Cycle World KZbin: kzbin.info?s...
Listen on Spotify: open.spotify.com/show/6CLI74x...
Read more from Cycle World: www.cycleworld.com/
Buy Cycle World Merch: teespring.com/stores/cycleworld

[@ozgurdeva4343]

You know what they say about people who ride don't need therapy, well I am on vacation at the heavenly mediterranean and your podcast increases my therapy coefficient two fold. In Turkey we shake hands with everyone to show that we hold no threat in our hands as an ancient custom arising from our imperial/warrior past, but again from that past rose the custom where we kiss the hands of our elders to show respect to their wisdom. Mr. Cameron is worthy of such respect not only for his wisdom but also for his humility and joy while conveying it to others. Please keep it up. We are thirsty for more.

[@kiwialfa2083]

Kevin Cameron's tech knowledge has always been awesome. I've read Kevin's writing since the 1980s and apart from the knowledge he has acquired through his hands-on work and inhabiting the same space as other top tuners, what is special is his ability to communicate that sometimes arcane knowledge in an incredibly accessible way, to those of us who risk desiccation by trying to read dry texts or a brain hemorrhage trying to decipher mathematical expressions. What is becoming more apparent as this wonderful pod-cast series develops is Kevin's sense of humor and personality. This really is icing on the cake. The disembodied voice inside my head when I read his words back as much younger man, are now being fleshed out into less imagined and more human form. The internet for all it's foibles, sometimes actually enhances life, and broadening the communication band-width of a great communicator is a life enhancement.

[@josephreisinger33]

Tanks for saying it better than I can.

[@donniebaker5984]

Who was the greatest motorcycle tuner of them all ??? Answer Hideo "Pops" Yoshimura

[@stan0matic]

I love these discussions. My fave thing on the worldwideweb. Thank you Messrs Cameron and Hoyer.

[@geraldgreen6278]

What a joy to learn physics without brain pain and some humor as the icing. Great stuff !

[@1969Escobar]

My father tune and race his engines in the 60s, he was a nerd for the flow, tuned my 2Ts in the 80s, i know he is listening to you guys and enjoying like me, thanks

[@SuperBigdanno]

I would love to see a discussion on 2 stroke fuel oil mixes in regards to horsepower and engine wear or any other effects ratios have. I realize there are not any new production road going 2 strokes but some of us still enjoy the old smokers and off road applications. Love these videos!

[@37leg]

Kevin was always one of my first articles to read when I got my issue of CW. Miss that, then these podcasts! Thank you for feeding my Kevin fix! My first shop class our instructor made a statement that all two strokes have a blower or supercharger on it. Me and a fellow two stroke rider looked at each other and raised our hands and said wait a minute, my yz125 doesn't have a supercharger on it? But wait it does the downward movement of the piston!

[@user-nl6st8eu5x]

I had built up an old GS1000 motor for a customer. later on, he installed a Muzzy 4-1 pipe with very short primaries. the customer thought I'd built him a very poor engine. it would barely run above idle, but might be persuaded to get to about 7000 rpm, then began to run decently. having seen similar things before, I pulled off the pipe (bike still strapped to dyno) and gained 30 hp through the midrange. the dyno saved my rep !

[@antd-jy9ds]

Just to clarify a typical point of confusion: Boost modifies air density, not velocity. VE is a process of how well the engine can move air into the cylinder. While boost can increase the density of said air, the engine's ability to move that air is a function of (primarily) the cylinder heads moving air quickly into the cylinder (velocity). That's part of the reason why we've seen smaller ports make better power across the rev range time and time again. It is also the reason why a given size port (sized correctly for rpm range and displacement) will be the right size for an engine at 1 bar absolute (atmospheric) and at 5 bar. Also, Kevin had me in tears at 25:17. As many others have said, his talent lies in his ability to explain complex subjects in a digestible manner.

[@Errol.C-nz]

And create in.. digestion.. some of his verbage is garbage

[@LTVoyager]

@@Errol.C-nzSuch as?

[@LTVoyager]

It isn’t that simple. Pressure matters as well as density. Sure, you can say that if the density is doubled then you get twice as much air into the cylinder with the same flow rate. However, you still have acceleration considerations at higher RPM as more dense air is harder to accelerate into the cylinder and higher pressure helps here. I think we need to acknowledge that boost adds both pressure and density and both are important in efficiently charging the cylinder.

[@antd-jy9ds]

@@LTVoyager My comment was meant to put emphasis on the importance of velocity. As you mentioned, air is heavy, I am simply trying to dispel what I have commonly heard that you need bigger ports for boost.

[@LTVoyager]

@@antd-jy9ds Yes, I understand and agree, just saying that both density and velocity matters and boost affects both. However, for heavily boosted engines, bigger valves can help a lot.

[@37leg]

Talking about sounds of engines, my favorite sounding enging I ever owned was a 2000 5th gen VFR800FI, had a D&D exhaust on it, idle once warm was very lopey (is that a word) and when it got on the pipe at if I can remember 9k or 10k made the most beautiful trumpet sound!

[@throwedoff1961]

Standoff is something I learned about as an air cooled VW owner. A lot of VW owners would ditch the stock oil batch air cleaners for the low profile paper element air cleaners. They then couldn't figure out why their Bugs wouldn't run right. It was because of the "standoff" (the fuel cloud) that would propagate above the mouth of the carburetor.

[@louisesamchapman6428]

Oh !....Oil BATH !...

[@bigcheese781]

Single variable change. System interaction adjustment (multiple variable change). Steady state tuning or dynamic analysis. Are all valid tools you should master in your toolbox as a calibrator/tuner, learn when to apply each one. They're just tools in your toolbox.

[@christophercurry7410]

I love your podcast content. Please keep it coming!

[@scottbarham8455]

Great to see Kevin 1

[@markward6076]

Mr Cameron your a genius. 😎👍

[@BallaCorra]

I really liked this podcast. Learned a lot. I was taught "change one thing at a time" for ALL problem solving, not just (motorcycle) engines. My only regret on this podcast is that you did not talk about rotary disk valves for 2-stokes (as used in the Kawasaki A1 and A7). In the mid '60s when my late father (Iain Gunn) was forced to switch (for racing) from his 4-stroke Ducati to a 2-stroke (the Ducati was no longer compeitive because the different race classes were based purely on displacement) he was sure that the rotary disk valve Kawasaki A1R would be better than the piston port (this was pre reed valve) Yamaha. But that turned out not to be the case. Why?

[@paulthompson4367]

Oh, engine sound podcast, yes please!!!

[@mountainmandale1587]

I love the technology behind the simple air pump that makes me smile.

[@darreldanger7464]

Excellent Chemistry

[@jerryandnancywertzbaugher7778]

I'd like to see a discussion of the 4-valve revolution, especially the part about low-end torque since most folks think high-end power. My '93 Isuzu Trooper 4 valve V-6 3.2 liter engine was revolutionary in being a "truck" engine that had (has) a really flat torque curve which pulls smoothly from right off idle. Amazing. I wondered back in '93 why they would put a "racing" dohc 4-valve engine in an SUV only to discover it has a flatter torque curve than anything I'd ever driven. My Two bikes, a 2019 Bonnevile T120 and a 2020 BMW F900 XR both are 4 valve engines but have comleately differant power characteristics. The BMW is faster on a track becuse of considerably more hp while the Triumph is faster in traffic because of considerably more and flatter torque.

[@DanMay2000]

Hey Kevin, when you are tuning an intake tract, do you like to add length before or after the slide/butterfly ? Some like the throttle response you get when you are closer to the intake valve, others like the extra length to swirl up the mixture better. Thoughts ?

[@bretloyd8097]

Wondering if Kevin is actoss fill porting in late 90s superbikes?

[@70sport37]

I noticed my ex. Valves on my k2 suzuki 1000 has a wide seat out closer to the margin of the valve face .

[@robertcrosser5946]

Does intake air exceed the speed of sound

[@billmanty3636]

I want a slide trombone exhaust pipe that can spread out the "boost" pulse over a wider rpm range

[@Pompomgrenade]

😂 Hell yeah adjust that tune 😜

[@markpavletich747]

Exup

[@Errol.C-nz]

Kevin.. EXPLAIN to the masses.. tuned exhaust pipes .. & pulse tuning.. negative pressure exists in the cylinder well before the piston begins it's down stroke.. Manx Norton has the record for highest volumetric efficiency over 100%

[@donniebaker5984]

. Harley-Davidson now has overlapping valve timing on their overhead cam models

[@philipdarnall787]

Please, please address nitrogen in tires! I get it for free at work but some say I’m an idiot to worry about the “extra” nitrogen.

[@LTVoyager]

If you get it for free, by all means use it. However, for street tires the benefits are minor. If you have to pay much for it, then it is seldom worth using.

[@dougrobinson8602]

Nitrogen is fine if you always have access to it. What makes me laugh is that most drivers will have to top off their tires at some point, and they will usually be doing it with air. Apart from that, when you mount a tire there is 14.7psi or one bar of air pressure in it. All you're doing, unless you have a means to suck that air out is to add nitrogen to that air. So all you're doing is using nitrogen enriched air no matter how you look at it. If you have access to free N2, then go for it. Even on airliner tires with 200psi of (mostly) nitrogen in them, we still have big pressure changes due to temperature. That's why we don't release pressure from hot tires.

[@cpuuk]

Come hither friendly inlet charge 🙂 Anyone know why modern engines lean the mixture at full throttle, when logically you expect it to give the richest mixture?

[@MrBCRC]

Because it's going so fast that the valves aren't open long enough to get the air in. The inertia he mentioned is too high and by the time the air gets up to the velocity the valves are starting to close.

[@rolandtamaccio3285]

Ths engine only makes power when the valves are closed . Not true , the engine also makes power on the intake stroke , in boosted applications ; however that statement might need a disclaimer . To be technically correct this is only true with turbosupercharging ,,, !

[@dereksmith5019]

Instead of burning air at 20% 02 , why not plumb an oxygen cylinder to the intake and try that ?

[@andygilliland]

💥

[@ericalger5003]

It's been done. Don Garlits has a dragster in his museum that has a large cylinder of pressurized oxygen that was plumbed into the intake. The NHRA took a look at it and said NO.

[@randytolle6706]

Nitromethane fuel contains it's own oxidizer which is another version of the oxygen tank you mentioned.

[@ericalger5003]

Roots style blowers don't turn for free. They are a parasitic drag so the idea was to instead have a free source of forced induction with the pressurized tank. Fair enough of a idea but I am sure the NHRA just saw it for what it was, a bomb.

[@joemueller-zt9hn]

makes sense in a lad but very difficult in the "real world" that's why nitrous oxide exists. and, is so widely used.

[@gordonborsboom7460]

Where are all the opposed piston engines with their high efficiencies. Did they realize too late that there will no longer be a market for them?

[@Pompomgrenade]

😂 Wait a minute. You mean to tell me I'm living at idle watching you on the telephone... Produce KZbin p*** Well I should be wound out at 11,000 RPMs burning at 13:00 to 1:00 and spitting out a little bit of blue smoke. Just enough to keep my plug Coco Brown 🤎 cool??