Shock Building

[Dirt_Buster]

I switched from bilsteins to another brand for a good reason. Piston flow and the seals they use. I like consistency as well as someone knowledgable. I'm very happy with my shock guy now. We understand wants and needs and get it every time.

[RCJ]

What are the advantages of a piston that flows more?

[turtle1hp]

Ok. I was in contact with Jim at Bilstein. I will just copy and paste the highlights of his answers to my questions...... ( Getting close to having the curriculum done, haven't set a date yet.The basic class is one hard 8 hour day. 3 hour classroom, 4 1/2 hours of hands on build and dyno, then a thirty minute classroom wrap-up. Later there will be additional advanced classes available, one balancing base valves then an additional class about building and tuning adjustable mechanisms. Attending the basic class at Bilstein will be a prerequisite for attending any of the advanced schools.Looking into the future I'd like to have the resources to conduct a hands on track class utilizing data acquisition to teach racers to properly analyze handling issues at the track, how to correctly identify and define handling issues, how to decide whether the issue is best addressed with a shock change or a different chassis element, or both, then go through the process of making the change(s) and data testing the new set-up for comparison.Cost: Not sure, but we are trying to make it affordable. We aren't going to look at the shock schools as a profit maker, just need to cover the cost of shutting down our shop for a day and tying up three full time employees.It's been over ten years since we held any of these schools and we charged$250 for a while (going back to 2000), then later $275. I'd guessing now it will be around $300 but it isn't my decision. Whatever the tuition, I promise you your money's worth. It will be a hard day for all of us, we try hard. Not sure of class size, I want to limit the basic class to a max of eight guys at a time, six would be better, but it is a matter of time vs money.Hope this helps, and please stay in touch, looking forward to having you in class.

[Dirt_Buster]

Just ask him how his Pistons flow vs a PENSKE/JRI/OHLINS and heck BSB. See what he says to that one. Hahaha

[turtle1hp]

Trust me. I will be inquiring about that. What you were saying makes sense. I have some Penske stuff and I can see a difference in the design. Smoother flow transitions. I am wondering if that is a reason for running higher gas pressures? To control foaming from the cavitation??

[MasterSbilt_Racer]

Trust me. I will be inquiring about that. What you were saying makes sense. I have some Penske stuff and I can see a difference in the design. Smoother flow transitions. I am wondering if that is a reason for running higher gas pressures? To control foaming from the cavitation??

I am not a shock guy, but I do know there is a mechanical reason, due to construction, that the bilstein requires more gas pressure. Something inside can move if the pressure is too low. That said, the ASN shocks perform well.

[RCJ]

On the l/r with a lot of compression I've seen the divider piston move.That was with low gas pressure(50lbs).I've never been inside other shocks, but you would think they all would do that to some degree.
With higher flow pistons don't you have to run more shim stack to get the same rate?What are the advantages or disadvantages?

[Dirt_Buster]

Trust me. I will be inquiring about that. What you were saying makes sense. I have some Penske stuff and I can see a difference in the design. Smoother flow transitions. I am wondering if that is a reason for running higher gas pressures? To control foaming from the cavitation??

Nailing all them nails on the head.

[zeroracing]

To answer Masters_built, they do require a decent gas pressure, many guys that rebuild them do not put the clip right under the rod guide back in them, makes rebuilding easier. That said at low or no gas pressure during compression that may move inward.

To respond to Dirt-Buster, I do think there are shocks out there many times better than Bilstien, however, that may be why one piston on my JRI cost more than the whole shock from Bilstien. For a low budget racer, or guy wanting to have fun Bilstiens are not a bad option, but yes I will agree there are many better options on the market overall.

[Renegade Cust Susp]

To answer Masters_built, they do require a decent gas pressure, many guys that rebuild them do not put the clip right under the rod guide back in them, makes rebuilding easier. That said at low or no gas pressure during compression that may move inward.

To respond to Dirt-Buster, I do think there are shocks out there many times better than Bilstien, however, that may be why one piston on my JRI cost more than the whole shock from Bilstien. For a low budget racer, or guy wanting to have fun Bilstiens are not a bad option, but yes I will agree there are many better options on the market overall.

Beat me to it

[Wizard 05]

Integra Shock (which is part of Port City Racing) in Coopersville Mi. Has a very nice shock school..It is either one or two days depending on what YOU want to learn. 1-800-472-2464

[turtle1hp]

To answer Masters_built, they do require a decent gas pressure, many guys that rebuild them do not put the clip right under the rod guide back in them, makes rebuilding easier. That said at low or no gas pressure during compression that may move inward. To respond to Dirt-Buster, I do think there are shocks out there many times better than Bilstien, however, that may be why one piston on my JRI cost more than the whole shock from Bilstien. For a low budget racer, or guy wanting to have fun Bilstiens are not a bad option, but yes I will agree there are many better options on the market overall.

Beat me to it

I was thinking the same thing. BUT.... The higher end shocks have high flow pistons for a reason. Are they really necessary for a typical dirt track shock? I have been more concerned with the 3" - 6" per second velocity range for tuning the chassis. What are the typical velocities seen on an average racing surface? I was "assuming" around 10" - 20" per second range when hitting bumps or the cushion. Has any anyone done some data acquisition tests on this? At what velocity does the high flow piston become an advantage?

[Renegade Cust Susp]

Shaft speeds

I was thinking the same thing. BUT.... The higher end shocks have high flow pistons for a reason. Are they really necessary for a typical dirt track shock? I have been more concerned with the 3" - 6" per second velocity range for tuning the chassis. What are the typical velocities seen on an average racing surface? I was "assuming" around 10" - 20" per second range when hitting bumps or the cushion. Has any anyone done some data acquisition tests on this? At what velocity does the high flow piston become an advantage?

Have actually discussed this first hand with a group that did some R&D with Fox and they numbers are much higher than you would expect, which is why I think the flow rate of the piston comes into effect. But I have my own opinions on what this changes and effects as far as being a builder and the resolution it allows. That being said, shocks are becoming more and more critical because the information on the rest of the car is so wide spread. It makes the sciences behind damper tuning much more specific.

[Racer96m]

Just ask him how his Pistons flow vs a PENSKE/JRI/OHLINS and heck BSB. See what he says to that one. Hahaha

I run Bilstein XVS. I build my own shocks. Noboby runs stock pistons in anything. Every corner of my car has a different piston in it. All the top guys have custom built shocks, no one I race with just puts a stock out of the box shock on and does any good no matter what brand shock.

Dave

[Dirt_Buster]

Fox piston is basically a bilstein one. They don't flow either and have to gas them up. Masking a problem if you ask me.