Carl Fausett

Great Video on the subject:

mark kibort

Did you meet Andre Taratono at your last race? (driving a BMW) he is a long time racing bud. you were a litle faster but he was in a GTS1 or 2 bmw.
who's bmw are you going to race?

mark kibort

whats the spinning due to in the video. i heard that is natural, but what causes it?

Carl Fausett

Myles,

Specs as follows

Intake:
@ Installed height of 1.366" 113 lbs seat pressure
@0.412" 248 lbs - 928MS 32vR4 cams
@0.442" 262 lbs - 928MS 32VR3 cams
Bind: @0.516" lift

Exhaust:
@ installed height of 1.355" 116 lbs seat pressure
@0.398" 247 lbs - both cam grinds
Bind: @0.516" lift


PS: at 110 pounds of seat pressure we did have intake valve float at 6600 rpm with 18 pounds of boost. Changed the lobe profile a bit, went to 113 pounds of seat pressure, and had no valve float at 7300 rpm at the same manifold pressure. Just an FYI.

928Myles

Thanks Carl.
Will compare with the other options.

Myles

GregBBRD

Anybody, besides me, find it interesting that Porsche, Audi, Mercedes, Ferrari, Lamborghini, and a whole bunch of other companies aren't using beehive springs on their race engines?
Maybe these companies are not building real race engines, like Tuomo is speaking of?
How about Nascar engines....beehive springs in those engines? How about Formula One, where "engine development budgets" are virtually non-existant?
Regardless, it seems shocking that these companies (and race teams) who spend millions and millions of dollars on testing new technology, could be so far behind the curve on this.
Perhaps one advertising video doesn't actually tell the entire story?
Anybody here know why beehive springs were used in some applications, in the first place?

Somebody needs to do some more research......

.

ptuomov

Whether beehives are the best option or not depends on the amount of lift and spring load needed. If the beehives can be used for the lift and the load, they are the best option available today. The geometry with small retainer diameter is significantly superior to standard dual springs.

I think BMW for example uses single conical springs which are essentially beehives.

F1 uses pneumatic springs.

Carl Fausett

I can understand how the video from Crane might look - they sell valve springs. I just thought it was good strobe video to demonstrate the concept of valve flutter and the harmonic wave going through the spring. You can see the valve stays shut on the elliptical (beehive) spring and does not on the cylindrical spring...

PAC has a similar video on their website too. But, again, they make and sell springs. (Good ones!)

So if you doubt it because they are trying to sell something... please consider the link I posted to the Engine Labs article. They are not trying to sell anything!
http://api.viglink.com/api/click?for...ork-for-you%2F

There are many such articles on the internet about beehive springs with no retail connection.

Carl Fausett

As you should.

BTW: I will be posting numbers of another set we have put together for naturally aspirated cars - 100 pounds of seat pressure instead of the 115 pounds for the big supercharged motors. Might be a better fit for your application.

Here is the chart going up on to our website this week:

GregBBRD

That is a very cool video, thanks for sharing.

The waves that pass through the beehive spring are amazing to watch. The waves seem to be absorbed by the spring, instead of transferring to the valve itself.

Does this reduce the life expectancy of the spring?

mark kibort

anytime you have a sping-mass system you have harmonics.. the resonance frequency is at spots where the natural frequency equals the input frequency.

this test isnt reallly fair, because they didint show the Beehive spring at its natural frequency. maybe at 5200rpm or maybe it as some speed other than 6000. interesting that they didnt show the comparison at the same RPM. "apples to apples comparison", but at different RPM.... thats funny!

that movement is really crazy. almost like the cam is not round on the standard spring test. all that movement is resonance from the spring mass?

also , why the rotation of the valve. i know they are naturally supposed to rotate ,but i forgot why? keep the seats clean?

ptuomov

Go and look up the natural resonant frequencies of some beehive or conical springs. The frequency at which the whole spring resonates is much higher than that of cylindrical springs. The whole spring doesn't usually resonate at a powerful order at an rpm range that is relevant in a car engine. So much for an unfair test...

If you the lift and the spring load table of a beehive spring matches what your cam and valvetrain need, then it's usually superior to double or triple springs in many ways. The very high resonant frequency is one. The smaller retainer is another. The inherent stability due to the shape is another benefit, the valve guides wear less with beehives.

Just remember that the spring, as always, works best when it just matches what the cam profile needs at the redline rpm. More spring than necessary makes less power _and_ makes the engine less reliable.

mark kibort

natual frequency has to do with the mass and the spring rate. if it is the same, it will have a natural resonance of near the same frequency.

Im not discounting the test, just stating, ive seen a lot of tests where a critical element is changed and coined as being even worse for the challenger part, but in actuality its a huge advantage (i.e. operating at a frequency that is NOT a natural resonance point)

what you are saying below , makes sense though. not because of its shape, but because of its mass distribution (and then force distribution in the spring itself) .. that could be the key.... if so, why are not all valve springs made like this?

anyway, yes, there is a distinct possibility that it ISNT a fair test. Were the springs the same rate? maybe the behives were matched to the cam better.
are the behive a progressive spring rate?

Not an expert here, just curious. certainly you dont want there to be all that action on the valve. But, i dont think if you went to all engines at 5200rpm and looked at valve spring action , it would look like that, right? somehow the test was skewed.

look at this video of cylindrical springs at 7900rpm and then up to 9000. at the low speeds (sub 7k, its pefectly in control) this might mean the behive video is done with a mismachted spring and cam set up

ptuomov

The resolution to your puzzle is that the linear concept of a constant spring rate doesn't apply to the beehive spring. It's a progressive spring, or a spring in which the spring rate is not constant across lifts. Higher the valve lift, higher the springs rate locally. Each increment of the spring as you move up the wire resonates at a slightly different frequency. The net effect is that the whole spring doesn't really resonate at any rpm relevant to a car engine.

What's an interesting question though is whether the camshaft (negative) acceleration profile is such that it's an ideal match for the progressive spring rate off a beehive spring. Cams and springs must be thought of as a system.

mark kibort

i get that... and it seems that the behive might be a better damped spring-mass system. always draw backs to any concession (usually) maybe it has to have more force at the peak lift to make up for the lower spring rate at the ends which might increase cam wear. i dont know.

but, its not unusual for valve springs to be much more behaved at 5-6000rpm, as you can see in the video below.. which makes me think they did a mismatched spring and cam to make their point.