New Product: Custom Harmonic Damper
05-13-2009, 09:17 PM
#1
Developer
Thread Starter
New Product: Custom Harmonic Damper
High-Performance Harmonic Damper for the Porsche® 928
Think about it. We make so many changes to the 928 engine in our love of HP and performance, yet we bolt up the same old, tired, harmonic damper to the front of the crank each time. Why do we expect no harm will come from this?
The stock 928 damper was good in its day, it is a dual-plane mass damper with a single elastomeric seam in it; but even if it was in perfect condition (and none of them at this age are) they are still miss-matched after we start raising the redline, changing the crank stroke, bore, or both, and changing the flyweight of the rods and pistons.
There are 928 racers who have reported multiple failures of the stock 928 damper in their race applications. Their damper failed in a catastrophic way (it came apart!) but there are countless more engines damaged silently by the wrong damper.
The harmonic damper is responsible for two things: to absorb the vibratory harmonics and to counter-react torsional oscillations of the crank. Let’s take each separately.
Vibratory Harmonics and How the Wrong Harmonic Damper Can Damage Your Engine:
The crankshaft receives multiple impacts from the rods each revolution, and at certain frequencies it will start to “hum” or resonate like a tuning fork. The right harmonic damper will absorb and nullify these vibrations. Left unchecked, these vibrations can both create and enlarge stress fractures in the crankshaft itself.
This is common enough that many engine builders believe that when they see excessive wear or failure of the #2 main bearing, the fault most likely lies in a miss-matched or broken harmonic balancer.
The wrong harmonic balancer can actually amplify the vibrations at certain rev points and make it worse than having no balancer at all!
Torsional Oscillations and How the Right Harmonic Damper Can Increase Your HP:
The other element we must consider are the torsional oscillations of the crankshaft. Because the load on the engine is attached at the far end of the crankshaft via the flywheel, the crankshaft actually winds up like a torsion spring in front of the flywheel, especially when the load is high and the throttle is on.
On the extreme opposite end of that crankshaft (where the effect of the crank twisting is the most severe) – this is where we drive our camshafts, and from them, our ignition distributors! There is enough twist in some cranks under load to retard our valve and ignition timing more than 10 degrees, with matching losses in HP and performance.
A harmonic damper of the right size and configuration for the engine will reduce and absorb this twist, adding accuracy to the timing and valve events and often adding between 10 and 30 HP to the typical V8.
If you bore the engine, change the weight of the pistons or rods, add a stroker crank, or change the redline of your motor, the old stock harmonic damper may not be able to keep up with your changes and rob you of either a lengthy service life or maximum HP.
The 928 Motorsports LLC Custom Harmonic Damper:
Our harmonic damper was designed as a collaborative effort between ATI engineers and 928 Motorsports. The finished product is a Super Damper that is configured precisely for your Porsche 928 engine and application.
Rather than a single elastomeric ring like the stock 928 balancer, our balancer has 8 separate synthetic rings that will be matched precisely to the harmonics of your engine by ATI engineers. Thus, these dampers are custom-tuned to your initial engine setup after you answer a few questions for us.
After that, the damper can be re-configured should you make even more changes to your engine.
The ATI Super Damper®, U.S. Patent #5,425,287, is the only damper designed exclusively for high RPM performance engines. The proven elastomeric design is actually two dampers in one: a 4" inner diameter and a 7" diameter damper contained in 2 shells that bolt to the crank hub. The inner and outer shells are available in steel and in aluminum to contain the steel inertia weight.
The inertia weight has 8 computer-machined grooves to retain the proper durometer o-rings (dyno tested for each application), and installed at ATI. O-ring life has been tested to over 3 million cycles in Nextel Cup competition (6500+ RPM, 500+ miles) and 10 years (188 - 11 round weekends) in drag racing. The unit is rebuildable to new specifications by installing new O-rings.
All units are SFI manufacturer certified and exceed SFI spec. 18-1.
For more information, pricing, or to order one, please follow this link:
http://www.928motorsports.com/parts/harmonic_damper.php
Thank you for your interest!
Custom-engineered for Modified Motors!
Think about it. We make so many changes to the 928 engine in our love of HP and performance, yet we bolt up the same old, tired, harmonic damper to the front of the crank each time. Why do we expect no harm will come from this?
The stock 928 damper was good in its day, it is a dual-plane mass damper with a single elastomeric seam in it; but even if it was in perfect condition (and none of them at this age are) they are still miss-matched after we start raising the redline, changing the crank stroke, bore, or both, and changing the flyweight of the rods and pistons.
There are 928 racers who have reported multiple failures of the stock 928 damper in their race applications. Their damper failed in a catastrophic way (it came apart!) but there are countless more engines damaged silently by the wrong damper.
The harmonic damper is responsible for two things: to absorb the vibratory harmonics and to counter-react torsional oscillations of the crank. Let’s take each separately.
Vibratory Harmonics and How the Wrong Harmonic Damper Can Damage Your Engine:
The crankshaft receives multiple impacts from the rods each revolution, and at certain frequencies it will start to “hum” or resonate like a tuning fork. The right harmonic damper will absorb and nullify these vibrations. Left unchecked, these vibrations can both create and enlarge stress fractures in the crankshaft itself.
This is common enough that many engine builders believe that when they see excessive wear or failure of the #2 main bearing, the fault most likely lies in a miss-matched or broken harmonic balancer.
The wrong harmonic balancer can actually amplify the vibrations at certain rev points and make it worse than having no balancer at all!
Torsional Oscillations and How the Right Harmonic Damper Can Increase Your HP:
The other element we must consider are the torsional oscillations of the crankshaft. Because the load on the engine is attached at the far end of the crankshaft via the flywheel, the crankshaft actually winds up like a torsion spring in front of the flywheel, especially when the load is high and the throttle is on.
On the extreme opposite end of that crankshaft (where the effect of the crank twisting is the most severe) – this is where we drive our camshafts, and from them, our ignition distributors! There is enough twist in some cranks under load to retard our valve and ignition timing more than 10 degrees, with matching losses in HP and performance.
A harmonic damper of the right size and configuration for the engine will reduce and absorb this twist, adding accuracy to the timing and valve events and often adding between 10 and 30 HP to the typical V8.
If you bore the engine, change the weight of the pistons or rods, add a stroker crank, or change the redline of your motor, the old stock harmonic damper may not be able to keep up with your changes and rob you of either a lengthy service life or maximum HP.
The 928 Motorsports LLC Custom Harmonic Damper:
Our harmonic damper was designed as a collaborative effort between ATI engineers and 928 Motorsports. The finished product is a Super Damper that is configured precisely for your Porsche 928 engine and application.
Rather than a single elastomeric ring like the stock 928 balancer, our balancer has 8 separate synthetic rings that will be matched precisely to the harmonics of your engine by ATI engineers. Thus, these dampers are custom-tuned to your initial engine setup after you answer a few questions for us.
After that, the damper can be re-configured should you make even more changes to your engine.
The ATI Super Damper®, U.S. Patent #5,425,287, is the only damper designed exclusively for high RPM performance engines. The proven elastomeric design is actually two dampers in one: a 4" inner diameter and a 7" diameter damper contained in 2 shells that bolt to the crank hub. The inner and outer shells are available in steel and in aluminum to contain the steel inertia weight.
The inertia weight has 8 computer-machined grooves to retain the proper durometer o-rings (dyno tested for each application), and installed at ATI. O-ring life has been tested to over 3 million cycles in Nextel Cup competition (6500+ RPM, 500+ miles) and 10 years (188 - 11 round weekends) in drag racing. The unit is rebuildable to new specifications by installing new O-rings.
All units are SFI manufacturer certified and exceed SFI spec. 18-1.
For more information, pricing, or to order one, please follow this link:
http://www.928motorsports.com/parts/harmonic_damper.php
Thank you for your interest!
Cool!
05-13-2009, 09:33 PM
#3
Rennlist Member
You know I'm just getting my car on the road for the season and then:
the fuel rails, very nice.
the damper, looks excellent.
I'll be placing my order around Nov for another set of winter projects.
the fuel rails, very nice.
the damper, looks excellent.
I'll be placing my order around Nov for another set of winter projects.
05-13-2009, 09:44 PM
#5
Rennlist Member
Never ever thought that Carl.............if I lived closer I'd pull the motor and have it built to spec. that suits.
Wonder what the logistics are between us?
Wonder what the logistics are between us?
05-13-2009, 10:16 PM
#6
Three Wheelin'
Join Date: Sep 2006
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Carl,
Sometimes it's hard to keep up with all the new stuff you come out with. Do you have a "New Items" link on the website? Then I could just check once a month and catch things I might have missed on the list.
Sometimes it's hard to keep up with all the new stuff you come out with. Do you have a "New Items" link on the website? Then I could just check once a month and catch things I might have missed on the list.
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05-13-2009, 10:55 PM
#8
Developer
Thread Starter
I do keep Gretchen pretty busy updating our catalogs.
She cusses at me about it from time to time... but you only see them after I have built them, tested them, and have them in stock ready-to-ship.
What you don't hear about is only those things that are not ready yet...
She cusses at me about it from time to time... but you only see them after I have built them, tested them, and have them in stock ready-to-ship.
What you don't hear about is only those things that are not ready yet...
05-13-2009, 11:13 PM
#10
Developer
Thread Starter
About the same - I am at home now and cannot remember what the weights were. I will look it up tomorrow if I remember. But keep in mind that the HP improvement comes from the better control of the torsional oscillations, not because its any lighter.
05-13-2009, 11:15 PM
#11
Developer
Thread Starter
Website is missing a "need"
The paragraph he's talking about:
Custom Damper Application for your Porsche 928
928 Motorsports LLC has done all the work for you! We already have the crankshaft snout profiles, and full dimensional specifications in a fixture at ATI. We have also designed-in elements to work with the unique Porsche 928 characteristics (like our firing order, for example).
All we need from you when we order your Custom Harmonic Damper is:
Bore: Stroke: Max RPM: HP:
…we will take care of the rest!
05-14-2009, 12:30 AM
#14
Rennlist Member
