JRZ RS1 Nitrogen Pressure?

[shirtpants_]

I just got a set of JRZ RS1's used from another member here, and I was wondering if anyone has adjusted the nitrogen pressure in their dampers.
I really don't have a clue as to what pressure range they should be in, especially on a primarily street car.
I've read anywhere between 150 and 300 PSI, but that's a pretty broad range.

I won't be installing them for at least 2 weeks(Have to get RSFB's in first) and I'd like to make sure everything is in good working order before I put them on.
If anyone has any insight into what pressures are acceptable, please share.

Thanks

[!!]

Due to cavitation in high pressure monotubes, 10bar is the minimum recommended. Above that allows for more leakage, and can be a tuning tool. If you are on the street, 150psi will ride much better. If you set them to 150psi, check them regularly, especially if you are tracking them. Cavitation can cause expensive damage quickly.

I have heard that they improved the new valving so you can run down to 8bar, but not sure I'd risk it without confirming what's inside during a rebuild.

[shirtpants_]

Originally Posted by !!

Due to cavitation in high pressure monotubes, 10bar is the minimum recommended. Above that allows for more leakage, and can be a tuning tool. If you are on the street, 150psi will ride much better. If you set them to 150psi, check them regularly, especially if you are tracking them. Cavitation can cause expensive damage quickly.

I have heard that they improved the new valving so you can run down to 8bar, but not sure I'd risk it without confirming what's inside during a rebuild.

Thanks for your input! I've since done some more digging around, and it's my understanding that from just measuring the pressure of the shocks, you can lose 25 or more PSI from the dampers. Since its such a small of air that's being measured, the amount that leaks out when measuring with the pressure gauge can lower the PSI inside the damper a significant amount. I will most likely have them filled to around 200 PSI, and leave it there.

[Richbot]

Originally Posted by shirtpants_

Thanks for your input! I've since done some more digging around, and it's my understanding that from just measuring the pressure of the shocks, you can lose 25 or more PSI from the dampers. Since its such a small of air that's being measured, the amount that leaks out when measuring with the pressure gauge can lower the PSI inside the damper a significant amount. I will most likely have them filled to around 200 PSI, and leave it there.

I have taken pressures, forgot I've taken them, come back and checked again the following day and been right at the target pressure I had forgotten I set them at. Then checked the following month or months later and same pressure. If it's leaking any significant amount between checks, shock's busted. If you're losing 25 psi just from checking, you're busted.

This may or may not translate to the JRZ's but MCS recommends 100psig or more for street use, and more if you need the extra "spring" rate or the dampers are being used hard, up to 300psig, though keep in mind this will affect ride height especially up front so be prepared to check toe if you're making significant changes for street vs. track. I usually ran about 105-110 in front and 150 rear on the street, and added some if on sticky tires, left alone if on street tires for motorsport activities

[shirtpants_]

Originally Posted by Richbot

I have taken pressures, forgot I've taken them, come back and checked again the following day and been right at the target pressure I had forgotten I set them at. Then checked the following month or months later and same pressure. If it's leaking any significant amount between checks, shock's busted. If you're losing 25 psi just from checking, you're busted.

This may or may not translate to the JRZ's but MCS recommends 100psig or more for street use, and more if you need the extra "spring" rate or the dampers are being used hard, up to 300psig, though keep in mind this will affect ride height especially up front so be prepared to check toe if you're making significant changes for street vs. track. I usually ran about 105-110 in front and 150 rear on the street, and added some if on sticky tires, left alone if on street tires for motorsport activities

Thanks for the advice, I have zero personal experience, the leaking pressure is just what I read on another forum from the other German manufacturer. Looks like Ill have to contact JRZ directly to be sure of what pressures to run on their dampers.

[!!]

JRZ, Moton, and MCS are all pretty much the same with MCS being the latest and most improved. Taking measurements should be minimal changes.

[Richbot]

the incest in the industry is shocking

[JustAnothaM4]

150psi in all 4 canisters for street and track. If you need "more spring" I believe 25psi is like adding 15 ft/lbs of spring.

[Move Over]

At what PSI does the nitrogen pressure start to lift the car?

[Cloud9blue]

Originally Posted by Move Over

At what PSI does the nitrogen pressure start to lift the car?

Even 10 psi will "lift" the car by a tiny tiny amount.

Given the small diameter of the shock and the weight of these cars, the effects of such will be barely noticeable unless you are running hundreds of PSI in each shocks.

[shirtpants_]

I should be getting the dampers filled up tomorrow at a race shop nearby.
Ill try and let you guys know what I learn is recommended for different applications, and what pressures I go with.

[Move Over]

Originally Posted by shirtpants_

I should be getting the dampers filled up tomorrow at a race shop nearby.
Ill try and let you guys know what I learn is recommended for different applications, and what pressures I go with.

I am winding up just ordering all my own stuff. You can have a good setup for around 300 bucks. I am planning to run 14 Bar in my Moton reservoirs. Interested to see what you like.

What are your spring rates?

[shirtpants_]

Originally Posted by Move Over

I am winding up just ordering all my own stuff. You can have a good setup for around 300 bucks. I am planning to run 14 Bar in my Moton reservoirs. Interested to see what you like.

What are your spring rates?

450# front, 800# rear. I should be installing everything this weekend, so weel see how it works out...

[shirtpants_]

Well, one front damper was at 150 psi, other was a 300. One rear was at 210, other was at 250.
I'm glad i got them checked. Set all 4 to just over 200 psi since that was kind of in the middle of where they all were already at.
Guy I was talking to said 150-250 is where most are at, and 300 is pretty high. He said front to rear are usually run pretty similar, but that an extra 25 or 50 psi can be used to artificially raise the spring rate if you're in a tight spot.

After seeing this, ill probably be buying the nitrogen damper fill kit from Bimmerworld in the near future. I think it's a good idea to check the pressures every so often, just to be safe.

[Move Over]

Originally Posted by shirtpants_

Well, one front damper was at 150 psi, other was a 300. One rear was at 210, other was at 250.
I'm glad i got them checked. Set all 4 to just over 200 psi since that was kind of in the middle of where they all were already at.
Guy I was talking to said 150-250 is where most are at, and 300 is pretty high. He said front to rear are usually run pretty similar, but that an extra 25 or 50 psi can be used to artificially raise the spring rate if you're in a tight spot.

After seeing this, ill probably be buying the nitrogen damper fill kit from Bimmerworld in the near future. I think it's a good idea to check the pressures every so often, just to be safe.

This is an awesome find, appears to be the same kit that Amazon sells for power tank although it looks like it's missing a part (the part says not included). I'm gonna call BW Monday. I'll let you know what I find out

[shirtpants_]

Finally got them put on this weekend. They feel stiffer than stock, but much less harsh. Haven't had time to play around with the adjustment too much, so weel see how it goes...

[JustAnothaM4]

Originally Posted by shirtpants_

Finally got them put on this weekend. They feel stiffer than stock, but much less harsh. Haven't had time to play around with the adjustment too much, so weel see how it goes...

What do you everything set to for street driving?

I would keep compression and rebound around 1 or 2 clicks and set the pressure to around 150-175psi in all canisters. It should feel very comfortable at those settings.

[shirtpants_]

Originally Posted by project e46m3

What do you everything set to for street driving?

I would keep compression and rebound around 1 or 2 clicks and set the pressure to around 150-175psi in all canisters. It should feel very comfortable at those settings.

I'm still messing with the settings, trying to get a feel for what the front stiffness feels like is a little difficult. Each click of adjustment does have a noticeable change in damping force though, which is great.

[Move Over]

Originally Posted by shirtpants_

I'm still messing with the settings, trying to get a feel for what the front stiffness feels like is a little difficult. Each click of adjustment does have a noticeable change in damping force though, which is great.

Are you planning to keep the same nitrogen pressure for street/track? It's going to be hard as hell keeping the car aligned if you're changing pressures between street and track.

[shirtpants_]

Originally Posted by Move Over

Are you planning to keep the same nitrogen pressure for street/track? It's going to be hard as hell keeping the car aligned if you're changing pressures between street and track.

No, same pressure for both. I've been within 8 clicks of full stiff and 6 of full soft, and there is an enormous difference. I think running within 2 clicks of full stiff for AutoX or track would be fine with the pressures I've got.

[Move Over]

Originally Posted by shirtpants_

No, same pressure for both. I've been within 8 clicks of full stiff and 6 of full soft, and there is an enormous difference. I think running within 2 clicks of full stiff for AutoX or track would be fine with the pressures I've got.

Ok, good to hear. I've read on some other forums they are running higher pressures for track and I don't really want to be messing with my pressures before a track day. Lol

[shirtpants_]

Went and got my dampers filled to 250 PSI the other day, I left the comp/rebound setting the same and I think I like this better.
My dampers settings are right in the middle of the adjustment range, and they are completely comfortable on the street.
I also found this nifty little piece of information (below picture)

Looks like I was right on the money as far as the recommended pressure goes.
I might try 300 psi next time I'm by the shop.