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NA Engine With No Damper?

General engine tech -- Drag Racing to Circle Track

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BlitzA64
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Re: NA Engine With No Damper?

Post by BlitzA64 »

Another question. If I am driving off of the snout and no room for the damper, if I made an adapter to bolt the damper to the flywheel end of the crank would it be the same benefit as a damper on the snout end where the cam timing is? It would seem to me to be not as effective?
Kevin Johnson
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Re: NA Engine With No Damper?

Post by Kevin Johnson »

Dual mass flywheels could be (and have been) devised to help reduce the torsional load on the crankshaft from the rear. Camshaft dampers also exist.

I think a rule would be introduced to stop an "arms escalation" that could reduce competition and participation. Maybe such rules already exist.
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Re: NA Engine With No Damper?

Post by Ken_Parkman »

The way I understand it is the dual mass flywheel is there to attenuate low frequency vibrations more related to torque pulses. It is a different function, and I do not believe this would have any control on torsional vibrations. You would think the damper should be on the opposite end of the crank compared to the largest rotational inertia. But it leads to a thought - what flywheel does a sprint car have? A lighter flywheel would move the mode frequency up, maybe that a makes a damper a little less critical?
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Re: NA Engine With No Damper?

Post by David Vizard »

frnkeore wrote: Fri Sep 25, 2020 2:59 pm I can't remember seeing a F1 engine with a dampener.
All the Cosworth DFV and DFL F1 engines ran with a Holset vicouse damper.
DV
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Re: NA Engine With No Damper?

Post by David Vizard »

lefty o wrote: Fri Sep 25, 2020 3:00 pm the right dampener will actually gain you power.
Absolutly right!!!
DV
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Re: NA Engine With No Damper?

Post by David Vizard »

maxracesoftware wrote: Fri Sep 25, 2020 3:25 pm
lefty o wrote: Fri Sep 25, 2020 3:00 pm the right dampener will actually gain you power.
i did a bunch of different Damper tests for Troy Coughlin's (Jegs) NHRA ProStocker in 1994
ATI , Rattler, Fluid Damper, etc.

and then i personally did a bunch on various engines i had in my Shop -vs- no Damper

you will always loose TQ and HP if you run without a Damper
ATI Damper always beat out the other Dampers i tested thru the years !

i put all that Data info into equation form in PipeMax v4.50
so you can instantly see how much TQ and HP a Damper or without a Damper can give you

Edit : i forgot about Innovators West Dampers ... these Dampers were neck-and-neck HP results as ATI Damper in Dyno tests on NHRA SuperStockers
Ditto. I tested the torsionals and the power of the Inovations West dampers and they score big time in my book.
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Re: Per DMFW

Post by Kevin Johnson »

Ken_Parkman wrote: Sat Oct 03, 2020 10:04 pm The way I understand it is the dual mass flywheel is there to attenuate low frequency vibrations more related to torque pulses. It is a different function, and I do not believe this would have any control on torsional vibrations. You would think the damper should be on the opposite end of the crank compared to the largest rotational inertia. ...

https://www.schaeffler.com/remotemedien ... DMFW_1.pdf

Yes, as with Fig 13.

I am trusting that a competent engineer with a focus on reducing high rpm torsional vibrations can adapt the DMFW. It just takes money.

The request was for torsional vibration control at the rear of the engine.
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Re: NA Engine With No Damper?

Post by David Vizard »

BlitzA64 wrote: Sat Oct 03, 2020 12:23 pm
I actually remembered today that I know a guy who works with David Gravel. He said the sprint cars could benefit from a damper, but with the cars being just 1250 lbs, every pound counts. The reduced weight of not running a damper is more beneficial than controlling harmonics.
This is what I was getting at. More power on the dyno doesn't always guarantee faster on the track. Sort of like a slow to recover port, it can show great dyno power and be a dog on the track. Like I have written I would like to run a damper on some things that it is not real practical to do so. I was told some years ago "there is no perfect engine combination, there always seems to be a compromise. It can be due to finances, parts available, weight, reliability, a myriad of other things". I would say pretty much all engines are a compromise, we do our best to make things as good as we can. =D>
Your car will go faster with a good damper.

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Re: NA Engine With No Damper?

Post by Ks Fats »

Ken,
Sprint cars are direct drive; push start, no flywheel. Crankshafts are run for "X" amount of laps and cycled out; that's why buying sprint car parts at an auction is a poor investment.
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Re: NA Engine With No Damper?

Post by Kevin Johnson »

David Vizard wrote: Sat Oct 03, 2020 10:36 pm ...

Your car will go faster with a good damper.

DV
I might be misinterpreting some of the queries but I think that they might be referring-to or comparable-to a higher sweep rate for an engine to a given desired power level due to lower mass versus the same engine being able to achieve an ultimately higher power level but with the added mass of a damper.
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Re: NA Engine With No Damper?

Post by David Vizard »

Kevin Johnson wrote: Sat Oct 03, 2020 10:44 pm
David Vizard wrote: Sat Oct 03, 2020 10:36 pm ...

Your car will go faster with a good damper.

DV
I might be misinterpreting some of the queries but I think that they might be referring-to or comparable-to a higher sweep rate for an engine to a given desired power level due to lower mass versus the same engine being able to achieve an ultimately higher power level but with the added mass of a damper.
Kevin,
My guys and I have tested on both the drag strip and road courses. Though heavier, the damper does show a small advantage. For road course a very consistent and precise driver is needed.

DV
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Re: NA Engine With No Damper?

Post by Kevin Johnson »

David Vizard wrote: Sat Oct 03, 2020 10:14 pm ...
All the Cosworth DFV and DFL F1 engines ran with a Holset vicouse damper.
DV
Was this in addition to the quill drives for the cams or is this another (or the proper) name for them?
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Re: NA Engine With No Damper?

Post by RDY4WAR »

Ken_Parkman wrote: Sat Oct 03, 2020 10:04 pm what flywheel does a sprint car have?
They don't have one. They just have an aluminum U-joint.
Ken_Parkman
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Re: NA Engine With No Damper?

Post by Ken_Parkman »

Thanks guys, I know nothing about sprint cars. But NO flywheel would for sure add some confusion about dampers. Would a normal one even work? Seems very logical you simply throw the crank away after so many cycles. You cannot argue with what works.
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Re: NA Engine With No Damper?

Post by Dan Timberlake »

I believe dual mass flywheels' typical function is to smooth out the power delivery "out the back" at low loads and heavy throttle especially with engines with few cylinders. Variations in instantaneous rpm. Not to tame the crank twisting events.

=============
The basic damper mounted on a crank snout is to control the amplitude (angle) of torsion, or twist between the front and rear (typically the flywheel) of the crank. When the power pulses are coming along at the "right" (wrong) timing or frequency the amplitude of twist builds up real quick. The "right" frequency, if you are looking to make the crank twist and untwist rapidly 0.5 degrees or more, is the resonant frequency.
265 AMC AND STUDEBAKER.jpg
.

The forthright Studebaker engineer SW Sparrow proclaimed Studebaker provided a curious double plate rubber bushed damper for its "contribution to smoothness."

Note GM states for the original 265 their concern was not crank durability on passenger car service, but instead what could be "felt" in the car at ~ 2700 rpm. ~ .6° double amplitude. +/- 0.3°.
The full +/- 1° windup at 5300 rpm and full throttle without damper would be stressing the crank about 4X higher (!) than if a damper was fitted.
It takes a major material upgrade to withstand a 4X stress increase.
And at 5300 rpm the 4th order events would accumulate a highly significant and damaging 1,000,000 stress cycles in about 45 minutes. Not out of the question for a track car.
Would a hydraulic lifter 265 even rev over 5000 rpm?

Order X engine rpm = excitation frequency.
Note all the 265 high amplitude peaks without damper are at ~ 21,000 cpm excitation frequency or 350 Hz. This is the torsional "resonant frequency.

Changes in journal Diameter, journal "overlap", component weight and to some degree crank material would change that 350 Hz value.

==========.

1920s automotive and US Navy tech discussion of dampers, crankshaft torsional vibration, heavy hubs on crank snouts and more.
One of the Duesenberg boys in attendance.
.
duesenberg total .gif
.
.

==============.

5:45 here. Not torsional resonance. More like lateral or rolling or pitching resonance. Blade rpm is pretty low (450 rpm 7.5 revs/second) max), and it takes less than 10 seconds from the onset of resonance for the vibration amplitude to build to the destruction of the machine. It sounds like the pilot even kills the engine pretty quick as soon as bad things start to happen, but the rotor rpm don't drop off.
https://www.youtube.com/watch?v=Sa-nhqHmTm4
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