alvin l nunley
Site Supporter
it appears that people think you are quite funny, I don't know, not much at laughing at myself. I get this, you are a mean person. I call anybody who makes fun of somebody else, "mean".
Take a guess how much HP gain with illegal springs !!!
- Thread starter Mr angery
- Start date
sneaks12303
Member
Great results . My guess was based on stockers vs some cheater springs I ordered. I won't say from who , but visually they looked very stock . We had the same results up to 6300r's then my cheaters didn't keep up with yours . LOL , However , the point shows why U need to go to great lengths to get legal spring tensions right at the point of being illegal before the race . The BIG guess is how much tension will U lose during ...1.25hp when dealing with 12hp is 10% more. Who wouldn't KILL for those kinds of results in AKRA ..At 1.9hp your lapping the field.
Big Chris
Member
Interesting results.
I thought I'd add some info for the plate engine racers out there.
I thought I'd try to repeat what you tested with what I have on hand which was only new and used 10.8 lbs springs and some white stripe 26 lb spring.
Test criteria:
Go-Power water brake dyno, s beam load cell, Perf Trends Pro, pulls from high load to low load
purple plate clone
Engine allowed to cool between runs
gasoline
BSP3 cam
spring installed height is at .815"
ARC 6619 flywheel
ARC filter adapter
ARC blueprinted carb, rejetted for local conditions
JC3 big pipe w RLV silencer
BSP air filter
Notes:
Obviously the white stripes springs limited power in this engine. My guess is by excessive parasitic drag.
As expected, we see then that the newer 10.8lb springs performed better past the 6000 rpm mark when compared to the ones with 5 races on them. However, we also see some improvement with the 5 race old springs up to about 5800rpm. This is most apparent at 5200rpm.
So this goes back to controlling the lifter on the cam, perhaps the older springs allow the cam to throw the lifter off the lobe some extending the period of max lift or allowing the valve to open more than the cam lobe at rpm due to the valve train inertia overcoming the spring force. I.e. the lifter loses contact with the nose and backside of the cam lobe. Or perhaps the newer springs add just that much extra drag to be noticeable.
The profile of the HP curve with the older springs makes me think it's more than just drag, maybe some harmonic in the spring sets up.
All this seems to indicate that perhaps very frequent spring changes in the plate engines may not be that beneficial. Or perhaps, the stock weak springs may provide some benefit to a plate engine. More testing on my part is needed here.
Thoughts and opinions?
I thought I'd add some info for the plate engine racers out there.
I thought I'd try to repeat what you tested with what I have on hand which was only new and used 10.8 lbs springs and some white stripe 26 lb spring.
Test criteria:
Go-Power water brake dyno, s beam load cell, Perf Trends Pro, pulls from high load to low load
purple plate clone
Engine allowed to cool between runs
gasoline
BSP3 cam
spring installed height is at .815"
ARC 6619 flywheel
ARC filter adapter
ARC blueprinted carb, rejetted for local conditions
JC3 big pipe w RLV silencer
BSP air filter
Notes:
Obviously the white stripes springs limited power in this engine. My guess is by excessive parasitic drag.
As expected, we see then that the newer 10.8lb springs performed better past the 6000 rpm mark when compared to the ones with 5 races on them. However, we also see some improvement with the 5 race old springs up to about 5800rpm. This is most apparent at 5200rpm.
So this goes back to controlling the lifter on the cam, perhaps the older springs allow the cam to throw the lifter off the lobe some extending the period of max lift or allowing the valve to open more than the cam lobe at rpm due to the valve train inertia overcoming the spring force. I.e. the lifter loses contact with the nose and backside of the cam lobe. Or perhaps the newer springs add just that much extra drag to be noticeable.
The profile of the HP curve with the older springs makes me think it's more than just drag, maybe some harmonic in the spring sets up.
All this seems to indicate that perhaps very frequent spring changes in the plate engines may not be that beneficial. Or perhaps, the stock weak springs may provide some benefit to a plate engine. More testing on my part is needed here.
Thoughts and opinions?
Last edited:
youngengines
Member
^^ I agree.. I put a set of Honda 18lb springs on a stocker ( trying to figure out a problem).. It lost a decent amount of power in lower rpms.., I then put a legal set back on.. and the power came back.
The ramp angles of these "modern" lobe designs are getting pretty severe for a flat tappet design. I would have to think that the off seat acceleration of the valves is asking a lot of the level of springs that are used. Getting the thing to follow such a severe cliff on the drop side is also pretty tough without a roller and a seriously developed spring, valve weight, etc. the mere fact that they do as well as they do, is fairly amazing. I would guess that it boils down to two main issues. Hitting the harmonic resonance of the spring and lowering the friction / dead lift. Your results indicate that there is a "sweet spot" I would bet that is a point where the spring is able to keep up and the beat frequencies come to a crossing point or Delta. Springs are pretty tricky. When they are happy, they are predictable. When the are not, they make black magic. Just my opinion of a possible scenario that drove your results.
alvin l nunley
Site Supporter
That's really interesting stuff, thank you.
It says corrected horsepower. How is that accomplished? Is the barometric pressure, temperature and humidity automatically input?
It says corrected horsepower. How is that accomplished? Is the barometric pressure, temperature and humidity automatically input?
Big Chris
Member
astglenn,
As I sit and sip a cold one the wheel in my head turns. I'm thinking along the lines of you, some sort of harmonic develops. What is interesting is the shape of the curve of the older springs, it doesn't follow the nice smooth curve of the newer spring. That's what making me think about the harmonics. What that is, when it occurs, and is it possible to use it as an advantage? I don't know. Yet. This gets into some voodoo. Oh if I only had the resources to employ a high speed camera and watch this sort of thing in super slow-mo. That would be neat.
This particular engine is my dyno mule. What I do have is the ability to test different springs, and install heights, you can bet that's on the to-do list.
Do you think in this case a resonance can be affected by preload on the spring? or is it governed solely by the spring K? (knowing we are governed by rules which dictate the use of certain springs)
Here is another screen shot, all filtering removed.
Makes me think there is something going on at 3700ish rpm, 4700ish and 5400ish. Is there some interference between the harmonics in the spring, and valve train motion at a certain rpm.........hmm
Interesting video
https://www.youtube.com/watch?v=yfmb-tCo2yA
As I sit and sip a cold one the wheel in my head turns. I'm thinking along the lines of you, some sort of harmonic develops. What is interesting is the shape of the curve of the older springs, it doesn't follow the nice smooth curve of the newer spring. That's what making me think about the harmonics. What that is, when it occurs, and is it possible to use it as an advantage? I don't know. Yet. This gets into some voodoo. Oh if I only had the resources to employ a high speed camera and watch this sort of thing in super slow-mo. That would be neat.
This particular engine is my dyno mule. What I do have is the ability to test different springs, and install heights, you can bet that's on the to-do list.
Do you think in this case a resonance can be affected by preload on the spring? or is it governed solely by the spring K? (knowing we are governed by rules which dictate the use of certain springs)
Here is another screen shot, all filtering removed.
Makes me think there is something going on at 3700ish rpm, 4700ish and 5400ish. Is there some interference between the harmonics in the spring, and valve train motion at a certain rpm.........hmm
Interesting video
https://www.youtube.com/watch?v=yfmb-tCo2yA
That looks exactly like what a beat frequency oscillation does. I have worked with them before. Believe it or not it is a science of acoustics. And yes, you are dead on the right road. You don't have to film it however. There ways to "Listen" to it with a transducer. It ends up being recognized as an acceleration and frequency. When it goes bad, it makes a very visible "Audible" trace. This is why F 1 cars use pneumatic valve springs....The metallurgy, even the best in the world, at any cost, can't handle it. Sorry. Forgot to answer the question. I am not sure about if you can pre-load your way around the BFO. Your reasoning is great however and I think its possible. The hassle is that there are a couple of really demanding things going on. One is the high angle of attack of the ramp itself. The other is its a 4 dollar spring! I would love to see you take the best example of the stock spring and start shimming it and see what gives. Cool test. Tune those springs and see maybe?
There is need to call me names!
So take a look at some video of a valve spring running at 3,000 Crank RPM and above. There are some really interesting shots done under high speed video and strobe synchronization. Even allowing for the cam running at 1/2 crank speed, the things happening to that spring tell the story once it has been seen. The idea of a compression and recovery get blurred out real quick. What is really going on is one big oscillation. Damping is really tricky and is really not all about spring pressure. It is about tuning the natural resonance of the spring against input ROM (Motor Frequency) The Bee Hive valve spring was designed to provide that damping without stacking a bunch of differential frequency springs (Dual Springs) coaxially. I had some time spent with Dave Crower. He is the guy that really figured out this valve gear issue for the sweaty masses. Spring frequency damping is tough. The metallurgy is based in a stiff (High Modulus) material that is annealed to accept a nasty task. Its almost preordained that vibration and acoustics are going to be a big issue. Aluminum would not produce a high frequency reaction. Unfortunately, it also wont close a valve. It very much about getting a spring to behave well. Those peaks and subsequent recovery points, then repeat at the next RPM event are really good information. The fact that you recognized it for what it very likely is, is pure gold. Run it to ground man. EDIT IN- THEN TELL NOBODY!
Strobe Shots......Well worth watching
7000 RPM https://youtu.be/i_NpzU4pGjc
Float and oscillation at differing RPM's https://youtu.be/_REQ1PUM0rY
The valve gear and springs in the videos is top flight stuff. Correcting for the (sorry have to say it) JUNK than we are working with, it becomes a relevant issue. Basic stability is just not there, which amplifies everything.
The art of the game is how you guys match lobes and springs to recognize the least sustained points of instability. I wonder if less = more in terms of ramp angle? Early cylinder filling vs containment. VE is a subjective issue. When you figure it out (perhaps many have already) you hold a substantial legal performance gain.
Strobe Shots......Well worth watching
7000 RPM https://youtu.be/i_NpzU4pGjc
Float and oscillation at differing RPM's https://youtu.be/_REQ1PUM0rY
The valve gear and springs in the videos is top flight stuff. Correcting for the (sorry have to say it) JUNK than we are working with, it becomes a relevant issue. Basic stability is just not there, which amplifies everything.
The art of the game is how you guys match lobes and springs to recognize the least sustained points of instability. I wonder if less = more in terms of ramp angle? Early cylinder filling vs containment. VE is a subjective issue. When you figure it out (perhaps many have already) you hold a substantial legal performance gain.
Last edited:
Goinbroke2
New member
Good to see others are seeing what I meant by harmonic's. I was dealing with dual springs with a dampner, all three doing there own thing and touching/bouncing/etc. Want to go a step farther?.....check the difference between cold springs and hot springs! Running a spin fixture with cold oil running through it then heat the oil to 200f and watch the difference. The bigger the spring the more it seems to effect it, as in bigger springs are more stable when cold/change more with heat than a smaller dia spring all else equal. Also, using a temp gun on a spring it's interesting how they build their own heat slowly but when testing dual springs or even a single with dampner, the temp rises quite quickly.
Build a plexiglass valvecover and point a temp gun at it..interesting stuff.
Beehive springs are a really smart invention based on the theory that although the same dia of spring, the coil dia is ever increasing which leads to natuaral harmonic's cancellation. Several coils of the same dia set up a "ripple" effect where the harmonics causes a surge in the spring (from the retainer down to the head) and each coil of the same dia transfers and adds it's own shock to it.(EDIT: this goes back and forth obviously starting from the retainer but bouncing off the head and rippling back to the retainer, then on and on...) The beehive though, the shock is transferred to a larger dia coil which absorbs the shock, damping it. Put beehive springs on upside down and you'll see bizarre things including the coils breaking a the smallest coil first.
Good talk, good to see guys testing and sharing with others.
Build a plexiglass valvecover and point a temp gun at it..interesting stuff.
Beehive springs are a really smart invention based on the theory that although the same dia of spring, the coil dia is ever increasing which leads to natuaral harmonic's cancellation. Several coils of the same dia set up a "ripple" effect where the harmonics causes a surge in the spring (from the retainer down to the head) and each coil of the same dia transfers and adds it's own shock to it.(EDIT: this goes back and forth obviously starting from the retainer but bouncing off the head and rippling back to the retainer, then on and on...) The beehive though, the shock is transferred to a larger dia coil which absorbs the shock, damping it. Put beehive springs on upside down and you'll see bizarre things including the coils breaking a the smallest coil first.
Good talk, good to see guys testing and sharing with others.
Last edited:
Ted Hamilton
Helmet Painter / Racer
I wonder if anyone's partially de-tempering springs with a torch to get a variable rate through sag...
Also, if the spring tester just measures K by deriving F for a certain delta X, how do you account for a spring with stiff middle and soft end/s? I'd think you'd need a proper spring dyno with a baseline curve and % tolerances for spring testing...
Also, if the spring tester just measures K by deriving F for a certain delta X, how do you account for a spring with stiff middle and soft end/s? I'd think you'd need a proper spring dyno with a baseline curve and % tolerances for spring testing...
Good question. I wonder if normal wear relaxes the spring enough. The engine being the spring Dyno at this point is a pretty long chain of affected items, but it does ultimately work for the first test you bring up. So, does an old fatigued spring loose the stumble points along the RPM curve and ultimately just float at its yield RPM like everyones expectations are for the most part? I bet Eskenderian knows this stuff. It seems to me that a best in legal class of spring will need to be figured out and subsequently tested against available lobes. The data that Big Chris and Mr. Angry bring forward is interesting. I remember trying to force the idea of "controlled" valve float into my brain. It is a pretty hard concept to accept. Tolerating variable overlap and lousy valve events because the valves managed to miss a piston and shut somewhere around the right time, most of the time, does not equal "control" does anyone make a class legal 10.8 spring that is a high order component ?
First good conversation on spring oscillating and how its controlled with duals and behieve styles etc etc. Definitely more to controlling a valve then just spring pressure. I have delt with it on some work projects (direct fuel injection in particular) can measure poppet moment to .0005 so I have a bit of background as well but surly no expert.
When people ask about springs and oscillation I always bring up something that almost every person has experienced . Turning your tank on/ On the grill and having the regulator freak and start singing to you 1 time out of 100
With that said I don’t believe BC unfiltered graph looks like that because of spring oscillation issues. .15 HP max blips in his graph starting at 2600 would not take me down a spring oscillation path of investigation. Your unfiltered dealing with electronics for gods sake
When people ask about springs and oscillation I always bring up something that almost every person has experienced . Turning your tank on/ On the grill and having the regulator freak and start singing to you 1 time out of 100
With that said I don’t believe BC unfiltered graph looks like that because of spring oscillation issues. .15 HP max blips in his graph starting at 2600 would not take me down a spring oscillation path of investigation. Your unfiltered dealing with electronics for gods sake
It is not exclusively the amplitude of the line that gives me pause, it's the frequency at which it occurs and the event duration. It appears to be self correcting as motor shaft RPM changes. From my uneducated guesstimate, that is something tied to a beat frequency and resonance that are acting upon one another. If it was a fuel/air issue or ignition issue, it would be really odd for the repetitions to produce such identical percentages. At least I would believe that to be the case. It really looks like a reduction, self correction, then repeat at the next critical intersection. I am no expert on that data software, but it looks like a fairly clean log file. I would assume that a low sample rate or some fuzz would tend to smooth the data line? I could be out in space here. My own injection software makes me crazy enough. Crower Stagger Stacks, Batch Fired. Oh what fun it is. The word sequential is in my future! I am here to learn like everyone else. I do find this subject intriguing.
Big Chris
Member
Mr Angry is probably right, it's just "glitchy" data.
Hey Al. Got an excel challenge for you, I am requesting your math skills.
What is the relationship between 3700rpm, 4700rpm and 5400rpm? Think B notes, think interference waves, think harmonics, think log scales. Remeber we are dealing with camshaft speeds, so these values get cut in half.
Spring details: wire diameter of .071”, a minimum ID of .625” and a
maximum ID of .660” and a maximum free length of 1.250”
What sort of relationship can be drawn between the above mentioned rpm values.
Hey Al. Got an excel challenge for you, I am requesting your math skills.
What is the relationship between 3700rpm, 4700rpm and 5400rpm? Think B notes, think interference waves, think harmonics, think log scales. Remeber we are dealing with camshaft speeds, so these values get cut in half.
Spring details: wire diameter of .071”, a minimum ID of .625” and a
maximum ID of .660” and a maximum free length of 1.250”
What sort of relationship can be drawn between the above mentioned rpm values.