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NA Engine With No Damper?

General engine tech -- Drag Racing to Circle Track

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tenxal
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Re: NA Engine With No Damper?

Post by tenxal »

RDY4WAR wrote: Sat Sep 26, 2020 2:39 pmSo in your experience, would an ATI Super Damper aluminum shell 6.75" (4.5 lbs) be worth a few hp compared to a stock 12 lb 7.5" damper in a drag car?
In testing on my engine (SBC), the aluminum ATI unit was a couple of ticks better than another aftermarket SFI 11.5 lb. balancer. It also smoothed out the torque curve and carried the torque out higher.
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Re: NA Engine With No Damper?

Post by maxracesoftware »

tenxal wrote: Sun Sep 27, 2020 7:20 am
maxracesoftware wrote: Fri Sep 25, 2020 5:35 pmlong ago, when NHRA first came out with Damper specs + requirements, Solid Aluminum Hub/Dampers became popular mostly because they were cheap alternative to beat new Rules, can't really call it a Damper : i ran a very small diameter red anodized Moroso Solid Aluminum Hub/Damper on my 3.250" Stroke C/ED 316cid Engine, trick John Lingenfelter C/ED steel pan ,5.67 rear gears , crossed 10000+ RPM every pass
still have the Pan + the Solid Aluminum Hub ... and a much larger heavier ATI Balancer was worth more HP on this engine in Dyno tests

Craig's Record setting A/ND and B/ND engines use just a solid Hub
reason : no way to run a real Damper because of all the front-driven drives Magneto,etc
Craig wants to run a ATI Damper , but can't fit it in
Several months ago, I was given one of the old Moroso red hubs to try on the dyno for my 327 Stocker engine. Two pals who use them on their 265 and 283 Super Stock engines see 3-4 hp increases every time they A-B-A test them on the same dyno. Main and rod bearings are generally good for 2-3 seasons and rpms are north of 8,500. I just couldn't make myself try it, though. :lol:

I occasionally crew on a pal's Comp car, so I know who "Craig" is. :wink: Hard racer! =D>
tenxal , i did run that little red Moroso hub on my 305cid 3.000" stroke C/ED engine with good success
i hit my counterweights with hammer after running that engine on Dyno + Dragstrip runs for about 1 year worth
and that crank still rings very good .

but try those same Hub -vs- real Damper test on larger Stroke engines like just a BBC 632cid
see how much more HP a real Damper will give you :)
plus it won't crack you Crankshaft :)

the larger the Stroke , the more critical the Damper is !
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tenxal
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Re: NA Engine With No Damper?

Post by tenxal »

maxracesoftware wrote: Mon Sep 28, 2020 2:43 pm but try those same Hub -vs- real Damper test on larger Stroke engines like just a BBC 632cid see how much more HP a real Damper will give you :) plus it won't crack you Crankshaft :)

the larger the Stroke , the more critical the Damper is !
Agreed! :)
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Re: NA Engine With No Damper?

Post by Schurkey »

Image


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Re: NA Engine With No Damper?

Post by maxracesoftware »

Schurkey wrote: Mon Sep 28, 2020 10:55 pm Image


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looks like GM / Chevrolet knew cast-crank might crack or have problems if it had no real Harmonic Damper 8)
and that the 283cid with a Steel Crank would live without a real Harmonic Damper

distance from Crank CenterLine -to- outer edge of Counterweights is also determining factor
for Harmonic Damper , as well, as Crank Stroke increases .

Note :
plain cast-cranks have a dull thud or very slight ring when counterweights are hit sharply with a steel hammer

nodular cast-iron cranks will ring , but lower tone , and not very long

real steel cranks will ring like a Bell or Tuning Fork

the "Trick" is always strike counterweights with steel Hammer when crank is new
and record sound or try to remember sound
then on rebuilds .. test the sound again !

i have a 296cid 2.900" stroke out of Comp Engine that use to ring for a very long time
now it rings about half that time
but i'm still going to use it in a little Dyno test mule, so if it fails or blows up ,
i really did not loose too much , i've been having all these engine parts in my shop for a very long time not doing nothing

 
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Re: NA Engine With No Damper?

Post by RDY4WAR »

This has turned into a great, informative thread. Thanks for sharing everything. I want to dig into this subject even more now.

When I swapped out the 4L60 for a TH350, I went from the stock 52 lb 12" lockup converter to a 29 lb 9" converter. The engine revs up so much faster after that. It made a huge difference.
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Re: NA Engine With No Damper?

Post by frnkeore »

That brings up a great question. Will a torque converter dampen harmonics also, in addition to a crank dampener on the front of a engine?
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Re: NA Engine With No Damper?

Post by tenxal »

maxracesoftware wrote: Tue Sep 29, 2020 12:29 am...distance from crank center line -to- outer edge of counterweights is also determining factor for Harmonic Damper, as well.....
Oooohhhh yeah! :!:
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Re: NA Engine With No Damper?

Post by maxracesoftware »

frnkeore wrote: Tue Sep 29, 2020 1:53 pm That brings up a great question. Will a torque converter dampen harmonics also, in addition to a crank dampener on the front of a engine?
that's a good question
probably contact ATI ... as that Company sells both Dampers and Converters , their Engineers can give you correct answer !

Post details when you find out .

All i know from experience is using Converters with both Internal and External Balanced engines does not seem to cause any problems .

Ballooning of a Torque Converter , can cause problems + wipeout a Crank Thrust bearing :(
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Re: NA Engine With No Damper?

Post by lefty o »

i cant imagine the torque converter can do too much, as its bolted to the flex plate, and hanging on the input shaft of the trans. it might do something if it was only bolted to the flex plate, but being captive on both sides really makes it fairly restricted in its direction of movement.
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Re: NA Engine With No Damper?

Post by David Vizard »

BlitzA64 wrote: Fri Sep 25, 2020 2:12 pm
Iirc vizard did tests on this topic, and no damper lost power. Actually going to bigger damper increased power.
Yet many people jump through hoops to shave crankshaft weight on some performance engines. Do to application, not necessarily by choice I have run many engines without dampers and saw no bad results in bearing wear on them. I digress, 1 inline 4 had one funky main bearing, I opened up the clearance on that one bearing and all looked new on the next refresh. Not sure if it is worth anything on the track but accelerating the damper weight should cost something measurable or not.
All the harmonics from the crank go straight to the cam and screw up whatever assets a well designed cam profile has.

I have many hours testing dampers with the torsional crank vibration equipment so all of this comes from personal experience.
JC at at ATI has spent many hours testing and building cutom dampers for outright race motors. A call to him will verify what I am saying here - you will be slower without a damper!!!
David Vizard Small Group Performance Seminars - held about every 2 months. My shop or yours. Contact for seminar deails - davidvizardseminar@gmail.com for details.
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Re: NA Engine With No Damper?

Post by BlitzA64 »

All the harmonics from the crank go straight to the cam and screw up whatever assets a well designed cam profile has.

I have many hours testing dampers with the torsional crank vibration equipment so all of this comes from personal experience.
JC at at ATI has spent many hours testing and building cutom dampers for outright race motors. A call to him will verify what I am saying here - you will be slower without a damper!!!
Perhaps this should be clarified with "You will make less power with a damper"? Adding weight in certain applications could be detrimental to speed. At this point I would ask why in the Wide World of Sports haven't Sprint Car engine packages changed their package to be able to run a damper? This I do not get if it would be a benefit to win their feature. I am not questioning the testing here just puzzled as to why someone hasn't come out and shook the World with a different sprint engine lay out. My situation has been due to engine compartment constraints, using a cam drive dry sump pump like a sprint car leaves no room for a normal size damper. I have looked often for smaller sizes that may fit to no avail.
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Re: NA Engine With No Damper?

Post by Ken_Parkman »

This of course is a tremendously good question. After seeing first hand the tremendous destructive capability of uncontrolled vibration - how come Sprint cars are OK without a damper?
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Re: NA Engine With No Damper?

Post by RDY4WAR »

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.
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Re: NA Engine With No Damper?

Post by BlitzA64 »

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>
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