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2 stage pistons...Do they work?

2 stage pistons...Do they work?

Old 11-20-2011, 07:01 PM
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Originally Posted by MantisWorx View Post
i will not guarantee they will fit because they are not designed to go upside down but they go on the shaft and in theory work. and please post some vids of your testing, i would love to see it!
I hope they fit and the bottom piston floats upside down, and maybe you will see some vids in the future!

-Matt
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Old 11-20-2011, 07:45 PM
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What is the a, b, c, d... in the graph? Looks to me like that may be a shim thickness.

So basically, that graph is nice if you want to know what the damping force is at a particular shaft speed with a particular shim, but it doesn't say that all shocks for all racing disciplines have to have a particular compression/rebound ratio.

Example.....I ran "90-10" shocks on the front of my 1:1 drag car, which had no extension resistance, and they were almost impossible to compress, they did the job they were supposed to, transfer weight rearward quickly and keep it there. I raced motocross wayyyyy back, and I remember my shock getting blown out, and jumping was freaking scary since it had no rebound damping and it wanted to pitch me over the bars.

Anyway, I'm going to dig my old RPM pistons out of the stash and play with them. In a vehicle. Maybe run them both ways. I'm running them easy bump, hard rebound mode in my comp crawler.
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Old 11-20-2011, 08:03 PM
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They are shim thickness and this graph is for onroad oval
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Old 11-20-2011, 08:16 PM
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Originally Posted by mattnin View Post
That graph is showing the amount of resistance from the dampers.

-Matt
I always will indulge in entertaining those who can't clearly see in their own argument that they are validating their opponents, thank you sir for such an occasion, it is priceless.
(Mind you there is never an extreme need to even be well versed in the content of the debate between opponents but simply to be able to understand the language as each party presents their argument which in this case it is very obvious that one party has a hard time in what he is reading in their own language which clearly explains the lack of comprehension)
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Old 11-20-2011, 10:34 PM
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I think a Mod needs to change the title of this thread to 2 stage pistons...They do work!!!
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Old 11-20-2011, 10:58 PM
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Part of the problem i think is Matt is thinking dirt oval in an offroad thread. Ovalheads can try some very strange things which can include slowing rebound on one shock thereby slowing the weight tranfer diagonally. If that is not what he is thinking about then I don't have a clue. The bad thing about doing this is when that hole gets blown out in 1-2 or 3-4, right where you want to run, the car gets so upset your not sure what it is going to do.
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Old 11-21-2011, 02:49 AM
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That is exactly what I am saying bentgear. However, slowing rebound just doesn't slow weight transfer diagonally, it slows side to side and front to back too.

I am not saying to damp rebound so much that the truck gets lower and lower with each bump either symmetricon. The reverse could be true too, if the truck is bump damped too much, it could get higher and higher with each bump.

Even Bilstein offroad race shocks are built with higher rebound damping forces than bump, 180/75 front 275/70 rear:

This is from the Bilstein Offroad Race Shocks website http://www.eshocks.com/bil_ORgd.asp?Manf=All

--------------------------------------------------------------------------------


Understanding Bilstein Valve Ratings

Damping forces of Bilstein valvings for Off-Road are measured in Newtons at a velocity of 0.52 meters/seconds (approximately 20 inches/second). The ratings shown correspond to those measurements; rebound force is the first number, followed by compression force (rebound / compression). Conventionally, the ratings are written as one tenth the damping force in Newtons.

EXAMPLE: Valve rating: 275 / 78
Rebound force is 2750 Newtons at 0.52 m/s

Compression force is 780 Newtons at 0.52 m/s

Higher numbers mean higher (firmer) damping forces. For example, 360/80 has more control (is firmer) that 275/78, while 170/60 has less control (is softer) than 275/78.
For valving recommendations please refer to the Valving Guide.

--------------------------------------------------------------------------------

Higher rebound numbers DOES NOT equate to a higher rebound rate. That number is the amount of force required to move the shock at the given rate (velocity) of 0.52m/s.
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Old 11-21-2011, 06:21 AM
  #818  
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Originally Posted by mattnin View Post
That is exactly what I am saying bentgear. However, slowing rebound just doesn't slow weight transfer diagonally, it slows side to side and front to back too.

I am not saying to damp rebound so much that the truck gets lower and lower with each bump either symmetricon. The reverse could be true too, if the truck is bump damped too much, it could get higher and higher with each bump.

Even Bilstein offroad race shocks are built with higher rebound damping forces than bump, 180/75 front 275/70 rear:

This is from the Bilstein Offroad Race Shocks website http://www.eshocks.com/bil_ORgd.asp?Manf=All

--------------------------------------------------------------------------------


Understanding Bilstein Valve Ratings

Damping forces of Bilstein valvings for Off-Road are measured in Newtons at a velocity of 0.52 meters/seconds (approximately 20 inches/second). The ratings shown correspond to those measurements; rebound force is the first number, followed by compression force (rebound / compression). Conventionally, the ratings are written as one tenth the damping force in Newtons.

EXAMPLE: Valve rating: 275 / 78
Rebound force is 2750 Newtons at 0.52 m/s

Compression force is 780 Newtons at 0.52 m/s

Higher numbers mean higher (firmer) damping forces. For example, 360/80 has more control (is firmer) that 275/78, while 170/60 has less control (is softer) than 275/78.
For valving recommendations please refer to the Valving Guide.

--------------------------------------------------------------------------------

Higher rebound numbers DOES NOT equate to a higher rebound rate. That number is the amount of force required to move the shock at the given rate (velocity) of 0.52m/s.
Ok...

I've stayed out of this because I am a nice guy but enough is enough!

You don't know anything about any of us nor our experience levels in racing or with suspensions yet you assume that because you are an engineer and found something in a book that you know better than everyone else!

You are dead wrong and confused!

Even worse you are filling up this thread with useless information and probably confusing any potential new customers for Marcus in the process!

Would you please just stop?

We are slowly becoming a small community on this thread, sharing information and helping each other to develop our vehicles. We've all been working hard with our dual stage pistons and we know what we're talking about.

I spent 2 months methodically tuning my SC10 before posting my setup sheet for the group at large. I did this not because the pistons were hard to setup but because i am very methodical and a perfectionist and didn't want to put bad information on this board for the rest of the group.

I did it to help, NOT to FEED my ego!

We're all knowledgeable and experienced.

Some of us are sponsored or past sponsored (me) drivers. I am in constant contact with some of the fastest racers in the world here in Southern California and I am on a first name basis with more than a few. Most of them believe what we do.
1) Dual stage shocks work.
2) Faster rebound is a good thing! Especially on bumpy outdoor tracks!

Many of them are secretly running them, too.

*In fact, the only sponsored guy I know that doesn't really believe in them is Frank Root. He'd be the first to tell you, though, he's tried them too.

I HAVE A SUGGESTION FOR YOU! TRY THEM! THEN POST! UNTIL YOU DO YOU ARE ONLY FILLING UP AN IMPORTANT THREAD WITH USELESS INFORMATION AND MAKING IT HARDER FOR THE REST OF US TO FIND THE INFORMATION WE NEED.

Thank you!
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Old 11-21-2011, 09:38 AM
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thank you sir! He is just digging a deeper hole, im done!

OSO has been in touch with me during his testing phases the entire time. i have helped him and he has helped me. I feel that he is VERY methodical (sp) in his testing and his results speak for it. he was a good driver and has now become a great driver, knocking on the doors of the sponsered guys! and i will turn to him when i need "west coast" testing done! while we are on the subject i want to personally thank everyone who has stuck with me through this, i started with an idea and it has now turned into a very good idea but i could not have done it without KNOWLEDGEABLE feedback from customers who understand how suspension works and can relate that information back to me. i myself am also an engineer as well as a machinist and have been my entire adult life (huge family owned machine shop since i was 12, i am 41). i own my own CNC mill and am responsible for every part that leaves my shop so when you recieve one of my "babies" it came through my hands! if something is wrong and i am approached with respect i will 100% make it right. if you approach me with BS and an attitude you can hang it up! since it is my show ultimately it is my decision on what I decide to do, you can bellyache all you want, start a hate thread and rest assured i will survive! i will not be bullied into getting what "you" want just because. those of you that know me personally can attest to the kind of person i am, i feel that i am a fair person and will help anyone that needs it, respect is the key. I am not the smartest person on the planet but i am pretty sharp! sorry for the rant just wanted to let some of you know what your dealing with!
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Old 11-21-2011, 09:54 AM
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If you are an engineer, please explain how a Bilstein Offroad Race shock works with 2750N @ 0.52m/s rebound and 780N @ 0.52m/s bump.

Do you understand how Bilstein got these numbers?

They use a scale which reads in newtons and extend the shock at 0.52m/s. This value becomes rebound. They use the same scale and compress the shock at 0.52m/s and this value becomes bump.

It is allright, I have ran into people who are deadset that the Moon has no gravity because there is no atmosphere, people who believe that if the Earth stopped spinning there would be no gravity,etc... Some people just don't understand physics.

-Matt
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Old 11-21-2011, 10:08 AM
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I think its time for a mod to block him from this thread and subsequently delete his posts as well. He seems like one of those people who just likes to debate and theorize rather than do real world testing.
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Old 11-21-2011, 10:37 AM
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You want me banned from this thread and my posts deleted because I post factual information? I have yet to hear from anyone explain how I should get faster rebound than bump with a Bilstein offroad race shock, or yet to hear someone explain how I am wrong with my description of a damping coefficient.

The only posts to the contrary are a 90/10 compression/rebound front drag race strut and tapered pistons which are meant to give more bump than rebound if installed a certain way, however the pistons can also be used reverse too.



I have contributed a lot of technical information to these forums over the years. Just google "mattnin brushless dyno" or go to the McPappy website, download the spreadsheet and see whose name is on it. Google "mattnin crossweight", etc...
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Old 11-21-2011, 10:38 AM
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Originally Posted by mattnin View Post
If you are an engineer, please explain how a Bilstein Offroad Race shock works with 2750N @ 0.52m/s rebound and 780N @ 0.52m/s bump.

Do you understand how Bilstein got these numbers?

They use a scale which reads in newtons and extend the shock at 0.52m/s. This value becomes rebound. They use the same scale and compress the shock at 0.52m/s and this value becomes bump.

It is allright, I have ran into people who are deadset that the Moon has no gravity because there is no atmosphere, people who believe that if the Earth stopped spinning there would be no gravity,etc... Some people just don't understand physics.

-Matt
OK MAN YOU FREAKING WIN!! ALL 30,000 VIEWERS AND 400 PISTON OWNERS ALL ARE WRONG! I AM STUPID, RETARDED DONT KNOW HOW TO RUN A MACHINE AND YOU ARE GOD!! IF YOU ARE SO FREAKING SMART THAN WHY ARE YOU THE ONLY ONE BELIEVING YOUR OWN BULLSHIT??? SEEMS TO ME THAT YOU ARE THE ONE THAT DOESNT UNDERSTAND PHYSICS I DONT GIVE A RATS ASS WHAT BILSTEIN SAYS, THE WEIGHT RATIO IS NOT THE SAME WITH RC AND 1:1. SO PLEASE STOP POLLUTING MY THREAD. SINCE YOU HAVE STARTED YOUR CRAP I HAVE RECIEVED 20+ pm'S FROM PEOPLE THAT ARE CLOWNING THE CRAP OUT OF YOU BUT THEY HAVE ENOUGH RESPECT TO KEEP IT FROM THIS THREAD. SO PLEASE JUST STOP, I AM ASKING YOU NICELY PLEASE STOP.....
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Old 11-21-2011, 12:25 PM
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Originally Posted by mattnin View Post
If you are an engineer, please explain how a Bilstein Offroad Race shock works with 2750N @ 0.52m/s rebound and 780N @ 0.52m/s bump.

Do you understand how Bilstein got these numbers?

They use a scale which reads in newtons and extend the shock at 0.52m/s. This value becomes rebound. They use the same scale and compress the shock at 0.52m/s and this value becomes bump.

It is allright, I have ran into people who are deadset that the Moon has no gravity because there is no atmosphere, people who believe that if the Earth stopped spinning there would be no gravity,etc... Some people just don't understand physics.

-Matt
Are you accounting ffor the internal gas pressure on that Bilstien shock?

I raced Dirt Late models for years, and ran some Bilstiens, as well as alot of other double adjustable, gas pressure shocks.

The internal gas pressure on them is probaly set in the 120 to 160 psi range. So that would have a large influence on the dyno results, in rebound. Especially on full stroke, aka displacement.

Also, we ran alot heavier rebound on the right side (oval) to counter the inate characterisitics of a spring. A compressed spring has 1.5 times the rate in rebound. So if you have a 300lb spring on the RF, fully compressed, you need more rebound dampening to control it. Plus we wanted to keep the RF, held down against the track.

Now with RC cars, i can see why you would want to run less rebound. As long as you can keep the roll rate under control. FWD bite i would think the light rebound is very good, hence drag racing 90/10's.

I will be installing some, very interested to see how the work in RL, sometimes shock dyno's do not translate well to race track, been there done that.

Just my opinions, Krom.
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Old 11-21-2011, 12:46 PM
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Matt, unless you've actually plunked down the cash to give these pistons a test then I suggest you hold your remarks to yourself. The pistons work in our trucks and work very well at that. You can not begin to criticize a product when you yourself don't have that product in your hands with actual testing time involved in it. You're basing all your theories on hypothetical information and not actual in hand testing. Those of us who have them, love them and see a great deal of performance gain in them, our lap times are getting slower, they're improving, why, because the handling of our trucks are improved due to better suspension. If you're going to critique anyone's product, then please take the time to invest in the product and properly test them. If you've got nothing positive to say or valuable feedback without owning a set, then zip it, you're only polluting this thread with false propaganda and causing potential customers to look the other way. We run them, we like them, our times are improved, what's your excuse?
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