- If you want reliability from any aftermarket performance engine, a quality damper
is one of those essential components that's so often overlooked.
One of the questions we quite often get asked is if I've already internally balanced
all of my engine components then why do I need an aftermarket damper?
So we're here with JC from ATI Performance Products to find out why we do need
these dampers.
So JC, that question we quite often get asked, what would you say to that?
- Internally balanced versus externally balanced, that's fine, it really has nothing
to do with the damper, the damper is going to be internal/external balanced
with your rotating assembly and almost everything nowadays is internally balanced.
So when that's finished, great, and that's for your bob weight and your piston and your
assembly going up and down however you still have your crankshaft and you still have
your counterweights, you still have pistons being pulled, pistons being pushed,
pistons sucking or have boost behind 'em, so you inherently have a torsional twist
in the crankshaft.
Torsional twist is a twist without a bend.
If you have too much torsional twist, you get a bending moment, that's where you hurt oil
pump gears, you fail alternators, you have clutches coming loose and eventually you
fail a crank, bearings is another thing that goes first.
The damper's job is to counteract and dampen the torsional twist.
So just like a shock absorber, it rebounds the recoil of the spring, your damper is rebounding
the recoil of the crankshaft from when it's twisted to when it's trying to unwind.
- Alright so let's just go back and unpack a little bit of that there and try and break it
down so it's a little bit easier to digest.
So essentially what you're talking about there with the components being balanced,
so we've got a crankshaft, maybe the flywheel, the pressure plate et cetera, that's all been
professionally balanced so we know that that's all within spec, balanced all of the
set of the connecting rods, the pistons, if it's a V configuration engine, those go
into a bob weight that's added to the crankshaft journal when it is balanced
so even when all of that is perfectly balanced or as close as it can be to
perfect, even if we take into account just one aspect is when a cylinder fires,
that puts a force into the crankshaft and while the crankshaft is nice and rigid
when we've got it on the bench, really when we think about it, it actually becomes a
bit like a very stiff spring so that's that torsional movement that you're talking
about that goes into the crankshaft?
- Yeah correct so you have your main bearings which are inline, in a straight line,
then you have your counter weights which are off centre and to counteract your
rod that's bolted to that which is also off centre.
So they have leverage, twisting on the crank and when one's firing,
maybe with boost, it's really hammering the crank one way and then all of a sudden
another one is sucking in the other direction and another one fires.
So as those add up through the firing pulses and the firing order, that's where you get
your torsional twist in the crank.
So your engine balance, let's say you're balanced to 50%, some guys they run
NASCAR, they balance to 51, 52, 53% so that your engine has a little bit of
inertia to keep going over.
And that also affects the damper but not greatly.
It really comes down to crankshaft, how stiff the block is, how much your bob
weight is, what kind of RPM you're turning and ultimately the torsional twist is
going to be in any crank.
And a crank can withstand a lot of torsional twist for a short amount of time.
So as long as the damper's there to take care of the majority of the torsionals,
then your crankshaft lives longer, your timing belt, your camshaft, everything lives longer
and that's where your horsepower gain comes from as well 'cause your valve timing stays
where it should be.
- Alright so let's talk about what happens if we don't have a damper.
We see a lot of people in the aftermarket, they will replace a factory damper,
they won't go to an aftermarket damper like an ATI, instead it's common to use a
lightweight, solid alloy front pulley.
So you've got nothing there to absorb those torsional vibrations.
So what are we likely to see with no damper?
- So it's a cheap, easy way out.
You can under drive pretty simple and the motor probably does feel snappier
'cause you're taking four, five, six pounds off it, you can under drive it.
But you don't feel torsional vibrations, you'll feel vibration in the tyre
or driveshaft.
You can kind of feel it if the motor's really winding up, you'll feel the motor
fighting itself if you're really in tune, you're feeling for that and maybe in
a stiff racecar but nine times out of 10 you're never going to feel it.
Your first failure's usually an oil pump gear which then is catastrophic after that.
Your worst failure would be a timing chain breaking and taking out all your
valves and everything from the top end down.
Bolts coming loose, weird alternators breaking, flywheel or flex plate bolts coming loose.
They're all a sign of torsional vibrations.
When Ford came out with the Coyote, they were breaking a lot of the oil pump
gears, guys made stiffer oil pump gears.
Well it was really, your stock damper's made to work for stock horsepower,
stock driving habits and when you stretch those limits much wider, you need a
damper that can really cover all those limits so that's where it all kind of comes into play.
You need a damper, there's very few vehicles that come today without a damper.
Porsche is one of them and they're fine on the road.
As soon as they start doing any sort of road racing, they fail oil pumps.
- I think it's also important to mention there as well, just because you haven't
got a damper, doesn't mean you're instantly going to have a failure.
But the problem which we can't really see is as the RPM moves right through the rev
range, we will have certain rev ranges where there will be a resonant frequency
and the problem is if we sit at that particular RPM for an extended period
of time, that resonant frequency does a hell of a lot of damage in a very short period
of time so that's where we really get into more serious issues as opposed to engines
that are constantly moving through the rev range and moving through those
dangerous resonant RPM ranges quickly.
So let's get onto the ATI damper, can you tell us how the damper actually addresses
those torsional vibrations and how does it get rid of them?
- Sure so we're a rubber based damper, elastomer o rings.
There's eight in some of them, six in others, there's 10 in some depending on the
application and what we can fit.
We've got many different durometers from 40 through 90 durometer rubber, every 10 points.
- So that durometer, you're talking about the stiffness of the rubber?
- Stiffness yeah from very soft at 40 to almost like concrete at 90 depending on what
we're doing.
We have a damper that weighs 2.3 pounds all the way up to 48 pounds.
- Alright so just purely based on the number of potential options that I'm guessing you've
got given those different configurations you've talked about, how do you decide for a
given engine, what the ultimate setup is and how can you test and validate that?
- Yeah well we're lucky, we've been doing dampers for almost 30 years so we have
a lot of institutional knowledge.
We have our own torsional vibration testing equipment so when a new application
comes out, we can test it, we're in the process of installing a dyno in our shop
to run our own torsional test, have motors come to us.
But when we start with the OEM damper we can see the frequency the damper's
tuned to and that damper is tuned for a narrow RPM range so I know as long as
my damper will hit that, hit below it and above it, so we can really pick the
stock damper, I can see its weight, I can get an idea of what the crankshaft weighs
and what the bob weight is and what it's going to be doing.
Then more specifically if the customer's going to add 60 pounds of boost,
we need to put a lot bigger damper on than the stock damper versus a guy
that's running 300 horsepower with his Honda that's road racing, we know the
damper will cover him, he's going to maybe stay from 7000 to 8000 RPM
all the time.
We know we cover that right off the shelf so the institutional knowledge of
the years and then all the applications we're on from old 100 horsepower Triumph
motors to your latest, greatest Audi, Lamborghini motors, you name it,
Koenigsegg runs a damper as well.
- So once you've got one of these dampers for your engine, is this something that
needs to be balanced along with the crankshaft or do you purposefully make
sure it isn't balanced with the crankshaft?
- You purposefully leave it off, so the inertia weight inside is encapsulated with rubber,
it can't come out but it can move.
So when you're trying to balance it, it's going to throw you off a little bit
each time.
When you have an externally balanced engine and externally balanced damper, we shift
then unassembled, so you can have just the weight part of it and do your balancing.
And then put it together but you don't want to have the damper on the engine
when your engine builder or whoever's balancing the crankshaft.
- So if it was assembled and on the engine, from what you're saying there,
would you basically be getting a different imbalance every time you go and test it
because of that weight moving?
- Yeah so inertia weight's able to move a little bit and not be solid so you would just
be fighting yourself trying to, you'd pull your hair out.
- OK so in terms of these dampers, do you need to do any servicing work on them,
are they a fit and forget item or do they need to be rebuilt over time?
- So that's part of the beauty of our design, all the dampers are four to five individual
pieces, then we have the rings inside of 'em, the face decal bolts, SFI decal,
you can replace or rebuild any single part of that, let's say a rock hits it and bends your
outer shell, we can replace the outer shell for you, or if all the timing marks go away.
We have different rebuild applications for different engine applications,
different horsepowers.
As short as at each engine rebuild, as long as 10 years.
If you're putting it on a street car in a '69 Camaro, it's going to go a couple of
thousand miles a year and turn 5000 RPM, 10 years.
And you can make the damper new as where with others, you just need to throw
'em out or guess.
- So I guess this is where someone looking at a particular application could discuss with
you and you're going to be able to give them the information around the damper that's
going to suit their application and what sort of service schedule that damper's going
to need for how they're using it?
- Exactly, we have, on the different size dampers in the different applications,
we have a service, recommended service schedule printed on the damper.
Also in the directions, if you're going to spend all this money, at $30,000 engine,
and you're going to have it rebuilt at the end of a season, for another $75 you can
rebuild the damper and you know it's new.
- That's a no brainer really.
Now you just mentioned the SFI decal and this is another aspect that I just wanted
to touch on.
So it's not just the ability to withstand the torsional vibration or get rid of those
torsional vibrations that's important.
In some motorsport, you actually have to get rid of that factory damper so can you tell us
why that's the case?
- Yeah so most factory dampers are two pieces and the outside ring can come off and come
out of the car, we've seen it, we've seen it hurt people.
Seen it leave the track, bounce off and hurt engines.
So you can still have an SFI damper that is built like that, other companies make it
and they have snap rings to retain them.
Our inertia weight's totally encapsulated, you really have to do something catastrophic
to have ours come apart.
When we rebuild it we check it for cracks, we'll change all the bolts, we'll rebuild the
rubber and that way we'll re SFI it.
The SFI test for us is they spin the damper at 10000 RPM for an hour.
And then they make sure there's no cracks and they check the elongation and fatigue
strength of the metal, they do a metallurgy on it to make sure it's all within their specs.
Sometimes they have us send them one, sometimes they'll call Summit and order a
product off the shelf so nobody plays games with that.
It's safe.
- When you're competing at any level of motorsport it's nice to know that all of
your engine components including the damper are going to stay where they should be.
Now if anyone wants to find out more about your products or talk about a particular
application, how can they reach out?
- Yeah you can email tech@atiracing.com or sales@atiracing.com, all my sales guys are
tech guys, we don't pressure to sell, we just want you to get the right part,
whether it's ours or not.
And then of course atiracing.com, there's a white paper on there about dampers 101
in really layman's terms, that I wrote a number of years ago for that, talks about some
testing and tuning.
And then Facebook, ATI Performance Products.
- Perfect, look thanks for the chat there JC, appreciate your time.
- Yeah great questions, thank you.
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