Jeremy Wilkey
Owner, MX-Tech
- Jan 28, 2000
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A new piston Design
- Thread starter Jeremy Wilkey
- Start date
Totally Cool design
I REALLY need to quit staying up late. This is gonna be cool topic.
Everybody else is in trouble in my opinion. Would be hard to better this one.
Piston design is something we have often discussed dude. I have enjoyed that very much since it is my favorite topic. Like Jer, I believe in maximizing the role of this component. I do not beleive in minimizing it.(well known theory) We can go deep here.
Nice improvements, very nice.
I REALLY need to quit staying up late. This is gonna be cool topic.
Everybody else is in trouble in my opinion. Would be hard to better this one.
Piston design is something we have often discussed dude. I have enjoyed that very much since it is my favorite topic. Like Jer, I believe in maximizing the role of this component. I do not beleive in minimizing it.(well known theory) We can go deep here.
Nice improvements, very nice.
Jeremy Wilkey
Owner, MX-Tech
- Jan 28, 2000
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Thanks Shocknut.. But is it mine? Before we let the cat out of the bag, lets just say that its been a longtime comming..
Anyway kiwi yeah thats right.
Soo freinds what do you think the coffe chuging alnight working maniac was thinking when he came up with that? :p
Yeah good topic, but I was hoping for more to start with.. What do you think is better about this one? It's actually rather fimalar looking.. You know four ports with holes... (sorry)
Seriously dude, I know what your thinking.. Imporoved feed area, maybe improved responce on square edge bumps, but what else... I don't see any progressive bleed.. So maybe it's not that high tech..
J
Anyway kiwi yeah thats right.
Soo freinds what do you think the coffe chuging alnight working maniac was thinking when he came up with that? :p
Yeah good topic, but I was hoping for more to start with.. What do you think is better about this one? It's actually rather fimalar looking.. You know four ports with holes... (sorry)
Seriously dude, I know what your thinking.. Imporoved feed area, maybe improved responce on square edge bumps, but what else... I don't see any progressive bleed.. So maybe it's not that high tech..
J
KiwiBird
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- Jan 30, 2000
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So I'm observing that the pockets under the compression shims are deeper than I've seen and also (hard to tell from the pic) the pocket doesn't appear to have a square bottom like the rebound side.
The ports look more like intake ports on a head - are they cone shaped or the same diameter all the way? Straight or pointed towards the outside?
The ports look more like intake ports on a head - are they cone shaped or the same diameter all the way? Straight or pointed towards the outside?
Pete Payne
MX-Tech Suspension Agent
- Nov 3, 2000
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The pistons look great !!! It does look as if alot of R&D time went into these , not to mention time programming the tool paths for the CNC. I also like the seal head in the background with the wet bushing ( on the oil side ). Are these for the PDS WP shock?
marcusgunby
LIFETIME SPONSOR
- Jan 9, 2000
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Looks like 2002 SXS PDS pistons to me??
Jeremy Wilkey
Owner, MX-Tech
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Marcus, Pete, Kiwi,
Actually the Piston is a all most direct result of all the PDS testing..... What we learned we carried over.... Anyway what do you think the paths do? See anything else? Pete if you could see it every corner is perfectly radiused and filleted.. Lots of set-up time... As for the seal head thats a Fox and Martin LeMareaux was doing oil side bushings for years.. We started doing that a few years ago ourselves for the KYB and Showa units.. Surprised you did not know..
Regards,
Jer
Actually the Piston is a all most direct result of all the PDS testing..... What we learned we carried over.... Anyway what do you think the paths do? See anything else? Pete if you could see it every corner is perfectly radiused and filleted.. Lots of set-up time... As for the seal head thats a Fox and Martin LeMareaux was doing oil side bushings for years.. We started doing that a few years ago ourselves for the KYB and Showa units.. Surprised you did not know..
Regards,
Jer
Relative to direction of "flow", if you have a small area on inlet and large area on outlet(stock KYB shock piston for example) some will label that a restriction. But what really needs to be determined is if that "restriction" is indeed causing problems relative to the actual speeds the shock is seeing. Some say yes simply because the 2 volumes are not equivalent. I personally do not think stock components are restrictive to the point of being labeled junk.
So, you look at stock pistons without shims stacked on them and you see no problems really. But, when you look at them with shimstacks on them you see a entirely different deal when trying to follow oil path. In the stock stuff you don't have quite the issue you would in a small port design. It is critical that those smaller ports do not face any directional flow restriction issues. On that "feed" end of the port there would be no such thing as excess. A hole can only take so much velocity before it will begin to restrict itself. If small enough it CAN lock up. It is all relevent to application requirements.
So, my opinion is that your improvements are well worth whatever extra cost is involved. If you have no directional restriction, and ports are sized to requirements, then you have much improved your product. I thought before that the previous version was a good performer and I think now with these changes it is about as good as you can make it. Simply put, of what I know is available out there currently this is what I want in my shock.
Last year, I intentionally set up stock shock piston to provide even more restriction than how they come. Guess what? It was one of the best shocks I've ever ridden. How did I do it? I restricted the "feed" even more by using larger face shims than stock. Where stock compression face shim size was 40mm I tried a 42mm. This restricted flow to the rebound ports. And vice versa. So, that tells me that for what the shock is asked to meet the stock pistons are not restrictive at all as they come. It was pretty cool and kinda blew my mind. I was expecting some problems, and although we did have a small problem in chatter, the rest of the shock was so good it overshadowed that problem.
I strongly feel that this one area is very important part of your design. Of course there is more, but for now....
And yeah wiseguy, it's YOURS.
So, you look at stock pistons without shims stacked on them and you see no problems really. But, when you look at them with shimstacks on them you see a entirely different deal when trying to follow oil path. In the stock stuff you don't have quite the issue you would in a small port design. It is critical that those smaller ports do not face any directional flow restriction issues. On that "feed" end of the port there would be no such thing as excess. A hole can only take so much velocity before it will begin to restrict itself. If small enough it CAN lock up. It is all relevent to application requirements.
So, my opinion is that your improvements are well worth whatever extra cost is involved. If you have no directional restriction, and ports are sized to requirements, then you have much improved your product. I thought before that the previous version was a good performer and I think now with these changes it is about as good as you can make it. Simply put, of what I know is available out there currently this is what I want in my shock.
Last year, I intentionally set up stock shock piston to provide even more restriction than how they come. Guess what? It was one of the best shocks I've ever ridden. How did I do it? I restricted the "feed" even more by using larger face shims than stock. Where stock compression face shim size was 40mm I tried a 42mm. This restricted flow to the rebound ports. And vice versa. So, that tells me that for what the shock is asked to meet the stock pistons are not restrictive at all as they come. It was pretty cool and kinda blew my mind. I was expecting some problems, and although we did have a small problem in chatter, the rest of the shock was so good it overshadowed that problem.
I strongly feel that this one area is very important part of your design. Of course there is more, but for now....
And yeah wiseguy, it's YOURS.
Doc,
BUT, there is more to this. I was convinced that I had matched the performance of MX-Tech design pistons last year with stock components. NOW, go back and read what I wrote about the "small" problem I had in in chop. No matter what I did I could not valve that out. What Jer has done now should and will take care of that problem. I believe I was faced with a "feed" restriction problem there. He won't have that problem, and the plus's of a small port design(not forgetting there are other contributors) will rock!
I'm saying that between the restriction I created in the stock parts and compared to small port designs I was having the same problem. It was not a huge problem, but still, getting kicked a around a bit in braking bumps is something we need to get rid of if we can. Properly valved, I think Jer's design will do that. I want to make this plain... Unless I see something new someplace else soon, I personally think this shock piston is the best you will be able to get.
BUT, there is more to this. I was convinced that I had matched the performance of MX-Tech design pistons last year with stock components. NOW, go back and read what I wrote about the "small" problem I had in in chop. No matter what I did I could not valve that out. What Jer has done now should and will take care of that problem. I believe I was faced with a "feed" restriction problem there. He won't have that problem, and the plus's of a small port design(not forgetting there are other contributors) will rock!
I'm saying that between the restriction I created in the stock parts and compared to small port designs I was having the same problem. It was not a huge problem, but still, getting kicked a around a bit in braking bumps is something we need to get rid of if we can. Properly valved, I think Jer's design will do that. I want to make this plain... Unless I see something new someplace else soon, I personally think this shock piston is the best you will be able to get.
will pattison
Sponsoring Member
- Jul 24, 2000
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i see two round blobs that look sort of like raisins or oreo cookies leaning up against a metal thingy. so, what's the deal? you gone beyond double stuff or what? increased the viscosity of the rich, creamy filling? made them absorb milk a little better?
:eek:
maybe if they sell good you can spend some of the profits on a new camera! :p
wp.
:eek:
maybe if they sell good you can spend some of the profits on a new camera! :p
wp.
sounds like you're scared jers gunna take business from you er somthin', willard.Anyway, i've seen them, they're sweet-almost has a "tribal" design on the rebound side for better flow, and the compression side has shim "stilts" to more evenly bend the shim and prevent cavitation.-----i've seen a shim get crushed into the piston before
Jeremy Wilkey
Owner, MX-Tech
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- #15
Hey moto 242...
Did you smack your head too hard boarding last weekend or what? Keep talking like that bro and I'm gonna put your piston in backwards before your next supercross qualifer.. :p
Anyway care to contribute? You crazy pro "guy" with your tribal stuff... Next I guess we will here about Shocknuts pericings....
Regards,
Jer
Did you smack your head too hard boarding last weekend or what? Keep talking like that bro and I'm gonna put your piston in backwards before your next supercross qualifer.. :p
Anyway care to contribute? You crazy pro "guy" with your tribal stuff... Next I guess we will here about Shocknuts pericings....
Regards,
Jer
Jeremy Wilkey
Owner, MX-Tech
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- #17
Shocknut,
I was harassing M242 about his "tribal" commnet.. The piston does have pericings.. :p
Jer
I was harassing M242 about his "tribal" commnet.. The piston does have pericings.. :p
Jer
will pattison
Sponsoring Member
- Jul 24, 2000
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wish i could see em...
wp.
wp.
KiwiBird
LIFETIME SPONSOR
- Jan 30, 2000
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So I'm guessing the port shapes are to allow hi frequency response to be good like breaking or acceleration bumps?
Do the other designs get in a funk when asked to do that - reason I ask is that my Penske piston is ported in a manner similar to that and it was awesome on little high speed stuff.
Do the other designs get in a funk when asked to do that - reason I ask is that my Penske piston is ported in a manner similar to that and it was awesome on little high speed stuff.
motojunkie
Member
- Apr 25, 2001
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I think it's a fluid flow thing. IMHO I think he is trying to achieve more "laminar" flow. Laminar flow is fluid flow that is without turbulence. Turbulence is bad in this application, because it will cause low pressure regions around the piston. These low pressure regions will cause cavitation which can severely damage componetry as well as further degrade the flow characteristics. So since fluid velocity is important, the "porting" around the orifices allows for better flow characteristics by achieving more laminar flow.
Am I close?
Am I close?
marcusgunby
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- Jan 9, 2000
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I think theres more to piston designs than i have given credit for-just when i think i know a bit, someone posts something that almost sounds like another language.
Pete Payne
MX-Tech Suspension Agent
- Nov 3, 2000
- 933
- 38
Jer,
I knew a few companies like Elka made the similar design on the seal head.
RT also makes some , but I do not think there is a replacable bushing onthe RT model ???(Not sure). Is the purpose of all the perfectly radiused edges to cut down on cavitation ???
I knew a few companies like Elka made the similar design on the seal head.
RT also makes some , but I do not think there is a replacable bushing onthe RT model ???(Not sure). Is the purpose of all the perfectly radiused edges to cut down on cavitation ???
Jeremy Wilkey
Owner, MX-Tech
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- #23
Pete,
My buddy Martin, Runs Elka.. :)
Yes we actually found the problem in a very werid way... Difrent than Shocknuts method, but ours was not intentional as most discoveries arn't.
In the past I had actually manually made chanels, however through testing found that it made no diference. The major problem was that our valving had not devloped to the exstent that it has now.. Now when we run this type of set-up the diference is easier to spot... the intreging thing about suspension is that you never really figure anything out.. Only learn more.. Again and again what I thought I once knew I in fact only partially understood...
What do you guys feel the bridges are for?
Yes the corners do infact reduce shear and cavitaion.
Regards,
Jer
My buddy Martin, Runs Elka.. :)
Yes we actually found the problem in a very werid way... Difrent than Shocknuts method, but ours was not intentional as most discoveries arn't.
In the past I had actually manually made chanels, however through testing found that it made no diference. The major problem was that our valving had not devloped to the exstent that it has now.. Now when we run this type of set-up the diference is easier to spot... the intreging thing about suspension is that you never really figure anything out.. Only learn more.. Again and again what I thought I once knew I in fact only partially understood...
What do you guys feel the bridges are for?
Yes the corners do infact reduce shear and cavitaion.
Regards,
Jer
Last edited:
Jeremy Wilkey
Owner, MX-Tech
- Jan 28, 2000
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- Thread starter
- #24
O-yeah,
Sorry for the bad pick.. On my shop computer I can't see anything.. In the office..its pretty clear.. I'll have some professional grade pictures on the website tommrow...
Regards,
Jer
Sorry for the bad pick.. On my shop computer I can't see anything.. In the office..its pretty clear.. I'll have some professional grade pictures on the website tommrow...
Regards,
Jer
motojunkie
Member
- Apr 25, 2001
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I need to wait for the better pictures before I make an educated guess on that one. :)
Is it me, or does everyone love these type of threads?
