[PROJECT3SI]

Wow, that's some research, so basically everything is top secret protected by intellectual property, I've read some articles from bilstein, kyb, monroe, etc. and they mention that low pressure nitrogen is introduced to the strut and most of them use liquid nitrogen, but the kyb guy says that 150psi, but low pressure liquid nitrogen makes sense now.

No. It is 150 PSI but introduced as liquid nitrogen. When it "warms" up back to room temperature it becomes a gas which increases the PSI.

 

[oldmaninsaline]

well, I have found a video where they guy strips down an ECS strut and runs the motor on a bench with the goal of rebuilding it.

The design is like a Koni with superior machining of the bypass ports for the motor. Really an amazing bit of engineering.

 

[UselessPickles]

well, I have found a video where they guy strips down an ECS strut and runs the motor on a bench with the goal of rebuilding it.

That video was created by one of the participants in this thread and posted on the first page

Refill ECS Struts - Thicker oil - Increased Dampening

I have about 3 sets of ECS Struts piled up most of which are blown/weak and they all are technically in my scrapyard pile to be tossed... I was talking to a good ol' hot rodder who was talking about how back in the day they would drain the oil out of their shocks, and refill with thicker oil...

www.3si.org

 

[oldmaninsaline]

That video was created by one of the participants in this thread and posted on the first page

Refill ECS Struts - Thicker oil - Increased Dampening

I have about 3 sets of ECS Struts piled up most of which are blown/weak and they all are technically in my scrapyard pile to be tossed... I was talking to a good ol' hot rodder who was talking about how back in the day they would drain the oil out of their shocks, and refill with thicker oil...

www.3si.org

Me = Duh!

 

[MWRVR4]

+1 for any group buy. I am a CNC Programmer/Associate Manufacturing Engineer and can handle the design and production of any the metallic hard parts. Has anyone consulted with an actual Strut Rebuilding pro/shop? I'm sure there are places in the US that can do what that Russian guy did lol.

 

[oldmaninsaline]

+1 for any group buy. I am a CNC Programmer/Associate Manufacturing Engineer and can handle the design and production of any the metallic hard parts. Has anyone consulted with an actual Strut Rebuilding pro/shop? I'm sure there are places in the US that can do what that Russian guy did lol.

I'm failing to see what the issue is with rebuilding them. Seems to me the seal is the big hangup and with 3D printers and CNC and the equipment that speed shops have, seems like it could be done. Count me in for the group buy at #2. Even if they're not bad, having a new set on hand would be sweet.

 

[Noobi]

It would be really interesting to see if, when making new ones, its possible to tweak them slightly (smaller holes for the fluid to pass through?) to make them a little bit stiffer when in sport mode.
That would present a really nice option for people currently buying coilovers. That would also really go hand in hand with those running lowering springs and the upgraded version of the ECS computer.

 

[PROJECT3SI]

I'm failing to see what the issue is with rebuilding them. Seems to me the seal is the big hangup and with 3D printers and CNC and the equipment that speed shops have, seems like it could be done. Count me in for the group buy at #2. Even if they're not bad, having a new set on hand would be sweet.

You don't have to do all that. Seals are bought. I provided some information above.
Like I said in my post, it would take someone to characterize the oil. That is the only step needed to rebuild these. I have already found all the relevant information to allow someone to rebuild them in addition to the tear-down video. Just need to know what Mitsubishi intended for the fluid characteristics of the oil. KYB will not release that information they are duty bound by their NDA.

You cannot build a new set. It would be too cost prohibitive. It is not just the mechanics, it involves electronics too. Good luck getting anyone to buy at w.e. the end cost would be. It wouldn't be worth anyone's time unless they were selling them at $3k-4k a set and there is people out there to buy at that cost. Maybe if you used cores you could do it.

To clarify this for everyone, struts can fail for a few reasons. Either the strut is leaking (bad seal or seepage due to excessive rust) or the oil has broken down due to excess wear on the strut. The oil heats up every time the strut oscillates, the oil eventually thins out to the point it starts leaking (too thin) or fails to have the same characteristics through the valves inside.

What I recommend is the following for anyone who wants to undertake this.

1- Find a healthy set of struts
2- Send entire set front and back pairs to specialized strut service. These are aftermarket groups primarily dealing with the racing community. Some aftermarket struts are servicable which allow you to tweak the characteristics of said strut. The specialized shop can characterize the strut's performance under a strut dynometer.
3- Take apart healthy strut(s) and send a sample(s) of fluid to oil lab for analysis. This will allow you to determine factory viscosity
4- Buy new seal and fluid
5- Rebuild
6- Before sealing measure out correct about of liquid nitrogen (use chemistry / physics to ensure 150psi upon expansion aka room temp)
7- Send out to lab to see if performance matches factory

(at this point you may be able to start offering a rebuild service)

8- Buy strut dyno and understand how to use it correctly
9- Buy cores to have as back inventory
10- Ask for cores
11- Rebuild
12- Verify with dyno

Some outside references:
Can You Upgrade Your Dampers by Replacing the Oil Inside? | Articles | Grassroots Motorsports
Fortune Auto Coilover Rebuild Service
Red Line Synthetic Oil. Suspension Fluids

 

[PROJECT3SI]

I quickly responded, but you get the point. You can adjust how the strut feels by playing with the formulation, but IMO Mitsubishi got the ECS struts perfectly. IF your strut doesn't feel right, maybe your oil inside is failing.

In my opinion unless you can get 50+ people to sign up for a group buy it isn't worth your time to offer this service. The best thing one can do is find a partner willing to offer the service at any time. A partner like 3SX. Do the research, prove it out, and sell the equipment and process to 3SX or one of the other reputable 3S shops that you know will be around for a while.

 

[PROJECT3SI]

Forgot to mention that if your strut dust shield has failed that can lead to failure of the shock seal as dirt, moister, and grime will enter affecting the sealing and operation of the shock.

 

[Noobi]

Would be great to see one of the regular 3000GT vendors take this on. Selling items which will be in constant demand (due to wear and no availability elsewhere) would also be a good way to grow and maintain your customer base. If 3sx doesn't go for it, maybe Chris @ Rvenge could do it?

 

[MWRVR4]

"You don't have to do all that. Seals are bought. I provided some information above."

What do you mean by "seals are bought"? Did you hear back from NOK?

I came across this company just now. They don't make anything specific for our cars but might be worth a shot. I like the remote damping control and air lift options.

Fortune Auto - Performance Suspension Systems

Coilover Suspension - Higher Performance by Design. Race-Proven Performance on the Street or the Track. Fortune Auto Bespoke Coilovers. #AdvanceFoward

fortune-auto.com

Anyone have any experience with them?

 

[13diamonds]

Has anyone got anywhere with this? What stops us from transferring the cartridge to a coil-over shock body similar in size?

 

[MWRVR4]

Joe @ 3000GT / GTO Restoration is working on this issue also. Here's the thread link on his new forum:

ECS Strut Service/Rebuild?

Is anyone aware of any person/company that has made any good progress toward servicing/rebuilding OEM ECS struts? The best I can find is this forum thread with some good technical info and a tear-down video that includes discussion of some of the hurdles that must be conquered to successfully...

forum.the3000gtplace.com

Also, check out his great videos here:

3000GT / GTO Restoration

www.youtube.com

 

[DaveU]

2- Send entire set front and back pairs to specialized strut service. These are aftermarket groups primarily dealing with the racing community. Some aftermarket struts are servicable which allow you to tweak the characteristics of said strut. The specialized shop can characterize the strut's performance under a strut dynometer.

Don't need to do that.. strut performance is specified in service manual. Granted it's only at one rate but it's a starting point, they don't appear to have speed sensitive valving so it should be fairly linear. Besides.. even if you could find a decent set of ECS shocks.. they're 20 years old.. performance won't be the same as when it left the factory anyway

Front:

Rear:

 

[PROJECT3SI]

Don't need to do that.. strut performance is specified in service manual. Granted it's only at one rate but it's a starting point, they don't appear to have speed sensitive valving so it should be fairly linear. Besides.. even if you could find a decent set of ECS shocks.. they're 20 years old.. performance won't be the same as when it left the factory anyway

Front: View attachment 288842

Rear:
View attachment 288840

Yeap precisely. I guess I'm just curious as I'd imagine they'd want anti foaming agents and such additives added to the oil. This is easy enough though. Trial and error with off the shelf shock fluid and testing against these specifications should do the trick. The information is out there. All it will take is someone to commit themselves. I can't at this time. Too many projects I am working on.

 

[KnockingStealth]

You don't have to do all that. Seals are bought. I provided some information above.
Like I said in my post, it would take someone to characterize the oil. That is the only step needed to rebuild these. I have already found all the relevant information to allow someone to rebuild them in addition to the tear-down video. Just need to know what Mitsubishi intended for the fluid characteristics of the oil. KYB will not release that information they are duty bound by their NDA.

You cannot build a new set. It would be too cost prohibitive. It is not just the mechanics, it involves electronics too. Good luck getting anyone to buy at w.e. the end cost would be. It wouldn't be worth anyone's time unless they were selling them at $3k-4k a set and there is people out there to buy at that cost. Maybe if you used cores you could do it.

To clarify this for everyone, struts can fail for a few reasons. Either the strut is leaking (bad seal or seepage due to excessive rust) or the oil has broken down due to excess wear on the strut. The oil heats up every time the strut oscillates, the oil eventually thins out to the point it starts leaking (too thin) or fails to have the same characteristics through the valves inside.

What I recommend is the following for anyone who wants to undertake this.

1- Find a healthy set of struts
2- Send entire set front and back pairs to specialized strut service. These are aftermarket groups primarily dealing with the racing community. Some aftermarket struts are servicable which allow you to tweak the characteristics of said strut. The specialized shop can characterize the strut's performance under a strut dynometer.
3- Take apart healthy strut(s) and send a sample(s) of fluid to oil lab for analysis. This will allow you to determine factory viscosity
4- Buy new seal and fluid
5- Rebuild
6- Before sealing measure out correct about of liquid nitrogen (use chemistry / physics to ensure 150psi upon expansion aka room temp)
7- Send out to lab to see if performance matches factory

(at this point you may be able to start offering a rebuild service)

8- Buy strut dyno and understand how to use it correctly
9- Buy cores to have as back inventory
10- Ask for cores
11- Rebuild
12- Verify with dyno

Some outside references:
Can You Upgrade Your Dampers by Replacing the Oil Inside? | Articles | Grassroots Motorsports
Fortune Auto Coilover Rebuild Service
Red Line Synthetic Oil. Suspension Fluids

This is a great process, but I am not sure anyone will want to take on all of the upfront costs. I recommend starting with 4,5,6 and then see if you fixed it by leaning on it and a working strut. If it seems comparable, start a group buy that covers the costs for 1-3 and 7-12. Also, since you are already going to take the bad strut apart, you might has well have that hydraulic fluid sampled as a starting point.

 

[Ray]

Subscribing to this very important and interesting thread

 

[KnockingStealth]

This video says the max pressure from the nitrogen is 2.5 - 8 lb/cm^2 or about 50 psi. time=6:19

. Also filling the chamber should not be that hard because it could be with liquid nitrogen at room Pressure. Once it warms up to room temperature after the shock is sealed up it will increase in pressure. There is probably a decent range between the pressure that would blow out or past the seals and enough pressure to keep air entrained in the hydraulic fluid.

 

[KnockingStealth]

Found this video that shows dual tube shocks being made. It discussed the filling of nitrogen in the reserve tube. I don't know if they used liquid nitrogen or just plain nitrogen. Also, I don't remember seeing a plugged hole on our shocks where it was welded shut.