JRZ RS1 from Bimmerworld

[STALKER]

Originally Posted by VictorH

Short-term update- Playing with the clicks
I've had the JRZ system for about a month now. No issues to date. I've recently been playing with the shock adjustment, but I'm still on the street. Most of my driving is in town, some limited freeway (less than 20 miles) a couple times per week.

So, no surprise when you turn up the adjustment, the shock gets stiffer. However, what's interesting is that at low speeds, i.e. 30 mph or less the car just feels stiffer everywhere. At speeds above 40 mph particularly on bigger bumps where you think, "I need to brace myself, I'm going to feel this in my teeth," the car just absorbs the impact like it's suddenly on a lower setting and just keeps moving along.

My findings so far - 4 clicks from full-soft- ride is like EDC set on "comfort," i.e. soft
6 clicks from soft, suspension is notably stiffer particularly at low speeds, but as noted above at higher speeds seems to be more compliant. Would rate this as slightly stiffer than EDC set on sport/stiff.

The other thing I just need to experience a bit more is I think the compliance over bumps varies depending on if it's something sticking up above the road surface as opposed to below, like a pothole. I need to go over a few more really good bumps but I'll just say it now and see if I can confirm later, but on the 6 click setting at 40mph and up, the compliance, i.e. the ability to absorb an irregularity is better for potholes or depressions as opposed to things sticking above the road surface.

Will experiment with stiffer and stiffer settings every week or so until I can't stand it just to see what it's like.

If you go back and read my reviews of the RS1 out on track, you will find I had a similar impression. At the Glen and at Mosport they do a fantastic job of controlling roll, while being able to fully absorb all the bumps, and never feeling nervous or just "stiff".

[M3SQRD]

Originally Posted by VictorH

The difference between soft and firm on EDC is, by my approximation, perhaps a 10-15% difference. Two clicks (+) on the JRZ feels to be about the same, perhaps a bit more stiffness. In terms of what I feel on the street some of this is due to the heavier springs. Yes, it's still reasonable and "street friendly" but to me it's at 6 clicks already stiffer than stock (the combination of heavier springs and shocks at 6 clicks).

A big issue is defining someone's "tolerance" to any suspension setup, especially an aftermarket, dual-purpose setup with stiffer than stock spring rates. There are a lot of people that think the stock suspension is too stiff and harsh...

Personally, I didn't like non-ZCP and ZCP EDC on the Comfort setting because the car felt underdamped/uncontrolled (i.e, bouncy). Also, I felt there was a much more significant change in damping between Comfort and Sport settings (I did like the adaptable damping ability on ZCP Sport vs non-ZCP Sport). Again, it comes down to "tolerance" - neither of us is right or wrong

I agree with STALKER's post - the RS1 damper does an excellent job at controlling roll and transitions without feeling "nervous" over bumps. I think with more time on the street, and track, you'll get used to the higher spring rates as well as the different damping characteristics/adjustability of the RS1

[HP Autowerks]

Originally Posted by STALKER

If you go back and read my reviews of the RS1 out on track, you will find I had a similar impression. At the Glen and at Mosport they do a fantastic job of controlling roll, while being able to fully absorb all the bumps, and never feeling nervous or just "stiff".

That is the wonder of these RS1's, it Dr. Jekyll & Mr. Hyde all in one, the ability to handling all the little bumps and big ones alike.

[1MOREMOD]

better all around set up than the ast 4250?

[M3SQRD]

Originally Posted by chriszeh

better all around set up than the ast 4250?

The RS1 is a SA damper with an internal canister (adjust N2 pressure). I have no personal experience with the AST 4250 (or even the 4200; also I do not know if they have an internal adjustable canister?) but the AST is a DA damper...Harold is in a much better position to compare the two dampers. However, I just switched from a Moton DA damper to the RS1 and I've been extremely impressed with the performance and range of adjustment of the RS1. Harold is correct - the RS1 damper does have a "Jekyll and Hyde" personality

[JamesClay]

Originally Posted by chriszeh

better all around set up than the ast 4250?

It is a very solid setup. We have labeled these JRZs an Ultra-Premium piece. There are a lot of good dampers out there (and some not so good) and without question a suspension is the best way to make your BMW fast on the track. Our Ultra-Premium lines (for us, JRZ and MCS) not only have excellent and I feel superior performance, but they do it elegantly - huge performance without all the rough edges usually associated with it. Usually with lesser (and typically less expensive, so there is that) setups, you can get some part of the whole improvement, but not all of it: will take enough spring, but feels like you are on a washboard, feels really good and minimal NVH but performance improvements are moderate, or simply just doesn't last because the quality isn't there.

I won't comment on better than 4250 because I obviously have an opinion, but I can say that I think the JRZ RS1 is an absolute top performer, can handle a lot of spring smoothly, and is a very quality, well-made piece that will be extremely durable and last for a long time - and you can rebuild it when it wears out.

[M3SQRD]

Originally Posted by JamesClay

It is a very solid setup. We have labeled these JRZs an Ultra-Premium piece. There are a lot of good dampers out there (and some not so good) and without question a suspension is the best way to make your BMW fast on the track. Our Ultra-Premium lines (for us, JRZ and MCS) not only have excellent and I feel superior performance, but they do it elegantly - huge performance without all the rough edges usually associated with it. Usually with lesser (and typically less expensive, so there is that) setups, you can get some part of the whole improvement, but not all of it: will take enough spring, but feels like you are on a washboard, feels really good and minimal NVH but performance improvements are moderate, or simply just doesn't last because the quality isn't there.

I won't comment on better than 4250 because I obviously have an opinion, but I can say that I think the JRZ RS1 is an absolute top performer, can handle a lot of spring smoothly, and is a very quality, well-made piece that will be extremely durable and last for a long time - and you can rebuild it when it wears out.

Excellent description James

[bigjae1976]

Originally Posted by chriszeh

better all around set up than the ast 4250?

I think something like a KW V3 or TCKline x2 adj setup is in the class of an AST 4250. I believe these JRZs are a step up in terms of performance...and a small step up in price as well.

[1MOREMOD]

okay thanks for the input. not getting coilovers just yet but just curious. thought that the ast was a step ahead of the kws. havent looked into pricing on the jrz but if they are in line with mcs then might be out of my price range anyways.

[M3SQRD]

Originally Posted by chriszeh

okay thanks for the input. not getting coilovers just yet but just curious. thought that the ast was a step ahead of the kws. havent looked into pricing on the jrz but if they are in line with mcs then might be out of my price range anyways.

Dampers start around ~$2650, and ~$3600-3800 for a complete setup (price varies depending on choice of camber plate, height adjusters, helper springs, thrust sheets, etc). Definitely worth it!

[1MOREMOD]

Originally Posted by M3SQRD

Dampers start around ~$2650, and ~$3600-3800 for a complete setup (price varies depending on choice of camber plate, height adjusters, helper springs, thrust sheets, etc). Definitely worth it!

damn good to know thats actually cheaper than the AST full set up. i just put in vorshlag camber plates this month so waiting a while to see how i like this set up. made a big difference already. im the guy trying to go fast on stock suspension, brakes and street tires.

[bigjae1976]

For suspensions...nothing worse than having buyers remorse thinking I should have gotten somethig a little better. I'd just wait a little longer and spring for something nice.

[1MOREMOD]

Originally Posted by bigjae1976

For suspensions...nothing worse than having buyers remorse thinking I should have gotten somethig a little better. I'd just wait a little longer and spring for something nice.

good thought. i want it to make a huge difference when i do it because i will be going to r-comps at the same time probably. Im ready now driving wise but enjoy my car as is for the time being so in no hurry to spend more cash. love the camber plates! if i was smart i would have thrown a set of springs in while i had it apart.

[HP Autowerks]

Originally Posted by M3SQRD

The RS1 is a SA damper with an internal canister (adjust N2 pressure). I have no personal experience with the AST 4250 (or even the 4200; also I do not know if they have an internal adjustable canister?) but the AST is a DA damper...Harold is in a much better position to compare the two dampers. However, I just switched from a Moton DA damper to the RS1 and I've been extremely impressed with the performance and range of adjustment of the RS1. Harold is correct - the RS1 damper does have a "Jekyll and Hyde" personality

4200's, like the RS1's use internal canister as well.

4250s when officially released will be right up there in performance with other top brands, but there may be some rough edges and time spent on set-up that James mentioned.

JRZ RS1's require much less setup to yield the performance you expect from dampers of this caliber.

Originally Posted by bigjae1976

I think something like a KW V3 or TCKline x2 adj setup is in the class of an AST 4250. I believe these JRZs are a step up in terms of performance...and a small step up in price as well.

Having personal experience with KW V-series(numerous Swift spring conversions try to improve them), TCKR DA's and AST's. KW V-series do not have nearly the performance of the TCK DA's because the use of progressive spring rates and the valving package on the TCKR's are much better and more precise. The AST 4250, when properly set-up, would be above the level of the both KW V-series and TCKR DA's.

[Alekshop]

Originally Posted by STALKER

Congrats. I'm sure you are going to love them.

Could you post your ride heights at each corner whenever you have time, I need to reset my ride heights. Thanks!!!!

set it to 26" with the driver and you should be pretty happy ... It gives enough travel

[FrenchBoy]

Originally Posted by bigjae1976

I think something like a KW V3 or TCKline x2 adj setup is in the class of an AST 4250. I believe these JRZs are a step up in terms of performance...and a small step up in price as well.

I am a bit confused. I was under the impression the AST 4200 were similar in spec to the JRZ RS, not the RS1. The AST 4200 and JRZ RS are double adjustable. The RS1 is single adjustable.

What are the main differences between the RS and RS1 in terms of on-track performance and off-track usability?

I am planning to upgrade at some point in the future so I am interested.

[dawgdog]

I am on to a different car now but ran the AST 4200 for 25 plus track days and was super impressed with them. Easy to set up and with a few clicks of rebound that took about a minute was comfortable on the street. I personally am skeptical that the RS1 offers a clear advantage to the AST.

[M3SQRD]

Originally Posted by HP Autowerks

4200's, like the RS1's use internal canister as well.

I must've missed the schrader valve on the 4200/4250 damper body and that's why I asked if the internal N2 pressure's adjustable on the AST damper - thanks.

[bigjae1976]

Originally Posted by HP Autowerks

Having personal experience with KW V-series(numerous Swift spring conversions try to improve them), TCKR DA's and AST's. KW V-series do not have nearly the performance of the TCK DA's because the use of progressive spring rates and the valving package on the TCKR's are much better and more precise. The AST 4250, when properly set-up, would be above the level of the both KW V-series and TCKR DA's.

What's KW's linear spring offering? Clubsports?

Originally Posted by FrenchBoy

I am a bit confused. I was under the impression the AST 4200 were similar in spec to the JRZ RS, not the RS1. The AST 4200 and JRZ RS are double adjustable. The RS1 is single adjustable.

What are the main differences between the RS and RS1 in terms of on-track performance and off-track usability?

I am planning to upgrade at some point in the future so I am interested.

When I was e46 coilover shopping JRZ was just about to release a single adjustable damper, not sure about the model name. In talking to Bimmerworld extensively, they were pretty clear on the differences from going with TCk and AST and that JRZ was stepping up.

In case anyone is wondering, the ASTs are nice...don't get me wrong...but it was explained to me that the TCK's had a better rear spring design and the dampers seem to hold up better. Plus you can talk to TC Kline himself when you call and ask retarded questions. (I think he waits until I hang up to laugh at me.) I've seen a couple of somewhat in depth articles on how TC Kline develops suspension systems and I like their approach.

[M3SQRD]

Originally Posted by bigjae1976

Plus you can talk to TC Kline himself when you call and ask retarded questions. (I think he waits until I hang up to laugh at me.)

[HP Autowerks]

Originally Posted by dawgdog

I am on to a different car now but ran the AST 4200 for 25 plus track days and was super impressed with them. Easy to set up and with a few clicks of rebound that took about a minute was comfortable on the street. I personally am skeptical that the RS1 offers a clear advantage to the AST.

There you have it, a happy AST 4200 customer!

When properly setup I have no doubt the 4200 series offer performance advantages over the RS1.

[HP Autowerks]

Originally Posted by bigjae1976

What's KW's linear spring offering? Clubsports?



When I was e46 coilover shopping JRZ was just about to release a single adjustable damper, not sure about the model name. In talking to Bimmerworld extensively, they were pretty clear on the differences from going with TCk and AST and that JRZ was stepping up.

In case anyone is wondering, the ASTs are nice...don't get me wrong...but it was explained to me that the TCK's had a better rear spring design and the dampers seem to hold up better. Plus you can talk to TC Kline himself when you call and ask retarded questions. (I think he waits until I hang up to laugh at me.) I've seen a couple of somewhat in depth articles on how TC Kline develops suspension systems and I like their approach.

Yes, to get linear spring rates you will have to step up the the Clubsport two-way, three-way or beyond. Even then the valving the the KW will not be as good as the TCKR DA's.

TC has been doing this for 20+ years, both in suspension development and racing. He offers suspension kits for M cars dating back to the E30 all the way to the late E9x. The spring design you are referring to might be the E36/E46 barrel style springs for increase stroke/travel, his E9x springs are constant ID linear rate.