Magic HP #

[200MPHClub]

Typo....my bad, too many things on the brain, not the least of which is trying to earn a paycheck

 

[Blazer406]

Blazer406. I'm sorry if the tone of my writing appears harsh or critical towards you. That is the furthest from my intention. I am only trying to inform. That's all. Period. Again. I'm sorry if you've taken any offense to my writing.

None taken....

I was trying to point out... that mine was pure speculation ... and intuition.... which is subject to being wrong.... and that you were much more experienced on this..... your car and timeslips speak for themselves.... I hang around here to learn as much as I can... and help when I can... that is all..... again... no offense taken.

 

[Blazer406]

Also... My original intent was to make a comparison between port velocities on a N/A vs a turbo'd engine.

Relatively speaking... the velocities I would think are much more crucial in a N/A engine..... they may have some effect in a turbo'd engine.... I just felt it wouldn't be as major of a role as a n/a engine......

I hope you didn't take any offense to my wording..... sorry if you did...I had no intention either.

 

[Alky V6]

The dynamic increase in intake port pressure from pressure pulse wave tuning, at the point of the intake valve closing, can be as much as 4.4 psi at peak torque and even higher as rpm and intake port velocity increases. This is an example taken from my stage I engine.

 

[Alky V6]

Think about this. A naturally aspirated engine. You have a column of air and fuel moving through a passage at a given speed. That column of air and fuel has a weight value. That mass of traveling air and fuel has momentum and hence an energy value.

Now look at a turbocharged engine. Take that same column of air and fuel from the previous example. Compress it. The weight of that column of air and fuel has now increased in weight. More air, more fuel in a given space. That heavier mass of traveling air and fuel has momentum and hence an energy value. Is that energy value higher or lower than the naturally aspirated example? Do you want a grain of sand ramming down your intake port or a boulder? Yes. Ram effect does have a significant role in a turbocharged engine. And it's best to make sure the engine is properly configured to take advantage of it.

 

[Blown&Injected]

WOW, most interesting. It initially, on first thought, seems like there is simply a pressure tank - the intake track, and then a valve opens and that pressure simply flows. The increased density of the boosted air, hummmm, very interesting.

But, how does one tune for such an event as the pulse of the air charge in the intake without building an engine - or at least the top part of it - out of KL93? It seems like one would need a clear engine being fed with a smoke tracer so that the movement can be seen. And then to do something about it would require a way to mess with the valves (like have a dozen cams ready to swap) and length of the intake. Or so it seems.

 

[Alky V6]

The same pressure pulse wave tuning principles that have been used and revised on n/a engines since the 60s if not earlier, are the same used on a turbocharged engine.

The science of resonant wave tuning is way to in depth for me to try to explain here. Just keep in mind that every aspect of the engine plays a role in maximizing the effect. There is plenty of information available on the subject in books, on the internet, simulation software, etc. If you're looking to build the killer, record breaking motor, you'd better include pressure pulse wave tuning in the formula, because you can bet your competition will, is, or has.

 

[Alky V6]

I know this might be hard for some to envision, but imagine holding a slinky. Remember those? Hold it up in the air all bunched together in a tight package. Point one end towards the floor and release it, holding onto the other end. The free end falls to the floor and as it strikes the floor you then observe a wave action travel back and forth through the spring. As the wave is traveling to and fro, you can actually feel a back and forth force through your hand that is holding onto the one end. You have just witnessed a resonant wave. The column of air that is in your intake runner and head port acts like an amazingly fast moving slinky. The intake or exhaust valve is the floor.

Keep in mind that resonance is also occuring in the exhaust system. Mufflers and... Resonators?

Large intake plenums tend to cushion much of the pulsing that occurs inside the plenum, thereby allowing the intake runners to act more like an independant runner (IR), or individual stack intake system.

Another quite advanced type of resonant pulse tuning is the Helmholtz intake principle. It has its advantages and disadvantages though.

 

[Blown&Injected]

It still seems like, as is so common with so many other engineering feats, it will come down to using the science to get it close, but still observe and trial and error and correction with in this case, something like a clear engine with a smoke tracer to understand all the actions and their effects on the pulse of air. Or maybe tiny cameras - but they might mess with the air flow???

 

[Alky V6]

That's the beauty of resonance wave tuning. The principle has been around for years (centuries). A common application is classical musical instruments. Big organ pipes use resonance tuning. Engineers have formulas for determining the resonance properties for different materials in different designs. The proper resonance tuning of a 4 cycle engine can be very closely approximated using engine simulation software that has been around for years, if not decades now. I use a program that is also used by Kenny D., Mike of TA Performance and many other well known people and organizations. I commonly hear reports that this software has allowed people to get within 5 HP of what the software predicted. Applied science is a wonderful thing. If you don't trust an engine sim, then the formulas to manually determine, for instance, intake runner diameter, length, taper for a particular engine combination are out there. Understand that engine sims are just a collection of all these different formulas put together into a nice neat, user friendly package so you don't have to do all the tedious math yourself. Thank goodness for that because I wouldn't really want to do all the math manually.

 

[Alky V6]

If you want to see resonance wave tuning in action, go to You Tube. Find my channel(home page). My user name is DonW21G. On that page go to my favorites and go to the last page of the favorites. One of the last videos on that page is of a F1 engine being run on a dyno. The video is aimed at the intake runner inlets. You'll notice a fog develop at the entrance of the runner. The fog is caused by the fuel and air being upset by the resonance waves in the runner. This creates a chaos condition that is very effective at mixing and atomizing the fuel as you can see.

Another interesting note. Many people suggest that when you are manually calculating the needed intake runner length for your paricular engine combination, the answer to the calculation should include one inch beyond the actual physical length of the runner. That takes into account that the resonance wave action actually extends beyond the physical intake entrance. You can see this in the video.

 

[Blown&Injected]

1" beyond the actual calculated length? That's what I'm talking about when I said clear engine with smoke tracer. There are so many variables.

Gonna have to get to a real internet connection before messing with you tube but I will be looking into it - thanks.

 

[Alky V6]

1" beyond the actual calculated length? That's what I'm talking about when I said clear engine with smoke tracer. There are so many variables.

Gonna have to get to a real internet connection before messing with you tube but I will be looking into it - thanks.

If resonance wave tuning was easy, everyone would be doing it. Other than the professional ranks, I can count on one hand the number of people that may somewhat be taking advantage of this type of finite tuning within the Buick community.