10-03-2018, 05:38 PM | #1 |
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JRZ RS PRO for M2 : A review
Hey guys, thanks to Expert@ApexRaceParts this year we had the opportunity to run JRZ'S RS PRO suspension on our race-winning F87.
I just wanted to take the time to briefly review my experience with this set up from a perspective of dedicated track use, backed by previous knowledge and experience with tracking BMW platforms, and also with the full technical support of a larger organization behind the effort, which was really helpful in extracting the best set up on this car. To paint a better picture this car also has : -Full race suspension including either spherical or hard poly bushings -Dinan Sway bars (to be swapped over the winter) -Ground Control height-jackers in the back and Ground Control Race front camber plates -The car is 3180 LBS with driver. -The car runs on Apex Race FL5 wheels (m2 specific rear fitment) with 285/30R18 Hoosier R7's (We've experimented with many different tires and sizes this year...more on that another time) At the beginning of the 2018 Race season after we began to work out the various cooling issues at the car we spent a test day at our local track, New Jersey Motorsports Park, trying various settings on the suspension. In my opinion, in order to optimize your suspension settings you must have a good point of reference. For me, this was my Crew chief Drew. We work together both over the radio on track, and by reviewing notes after a session to optimize the set up. He is intrumental in helping us make the best decision on which way to go with the changes, based on many factors on any given weekend... While there were many various trial and tribulations dialing in what I felt made (our) car have confident handling on track, we ultimately learned that these cars have such stiff chassis, especially with a full cage, that any changes to the suspension , even small ones, had big effect on handling . That being said my first piece of advice is to take that into consideration when starting to dial in your JRZ suspension (or any performance suspension) on your M2 . We ended up eventually landing on 1000LB front Springs and 1200LB rear. What we found with this car is that it experiences a lot of roll- probably due to both the weight of the car and the speeds its capable of, and that the roll center has been changed significantly by lowering it to "race height". Our splitter is only about 2" off the ground in the front, with a slight rake to the ride height. This , in combination with trying to balance out our aero provided for a car that has a slight push on entry, neutral corner behavior, and on power over-steer. This is how I prefer mine, everyone drives differently... Anyways, I will post up some corner balance #s and weights, as well as base settings , hopefully as a **POINT OF REFERENCE*** should you install JRZ RS Pro suspension on your car, and track it Installation of the suspension was very straightforward. Everything fit with better than factory fit, the directions are clear , and we had no trouble with hardware or mounting. I'd recommend at minimum when installing adjustable coil overs on your M2 to get adjustable end links for your sways, even if you intend to leave stock. This will allow you to dial in suspension corner weights easily because you won't be binding on the sway bar with small variances in ride height. We chose to mount our rear reservoirs in the back corner pockets of the trunk, which -on the left rear is ok, but on the factory car in the right- is the battery compartment. The braided hose that connects the actual shock to the reservoir is quite long, so it affords you significant range of placement(if not too much) depending on where you're trying to put it. In the front we routed accordingly up through the front fender liners into the engine bay, and affixed to the stock front strut bar on either side. In some instances you may have to disconnect the reservior from the hose to route it into the body (not necessary in the front) which will require de-pressurizing and then re-pressurizing after installation. This is an easy task with an appropriate shrader style shock valve tool, and a small bottle of N2. Speaking of pressures, we upped ours from 300psi to 350psi, which seemed to help take away some of the initial under-steer we were experiencing on the tighter tracks like T1 At summit point, and through the esses around Pittsburgh International Raceway. That being said during initial on track testing we found the following settings to be effective for the JRZ RS PRO on the M2 chassis: -4.5* Camber, front -2.8* Camber Rear (Fall Line shim stack* --0--- to 1/16" total toe out up front 1/8" total toe in , rear Front Bump is set at 11/15 Clicks Front Rebound is set at 14-15/22 Rear Bump is set at 13/15 clicks Rear Rebound is set at 13/22 While I can't promise you this will be 100% effective for a street-driven-track car, we have worked all year to dial in the suspension to my liking, which yields a pretty quick lap around the glen. : https://www.facebook.com/tyspeedauto...3440048126709/ Overall, I think its an excellent set up for this car- the dampers respond immediately to changes and have been holding up to crazy abuse all year long in full race conditions. What more could you want from a damper? I will take some opportunity over the weekend in the garage at Watkins Glen for our championship race to grab some pics of the suspension on the car, including our chosen mounting locations. IOU Oh and PS if you want to buy these for your car , Apex is running a group buy with some steep discounts : https://www.gangup.com/apex/jrz-rs-f...2-q3-2018.html Last edited by TYSP33D; 10-03-2018 at 05:46 PM.. |
10-06-2018, 09:06 AM | #3 |
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Great write-up and thanks for the tips. I'm looking into the RS TWO Touring for my car, so hopefully some of your info will be useful for my shop to do the setup!
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10-26-2018, 01:01 PM | #5 |
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Huge thank you for taking the time to share your experiences with your JRZ suspension and the trials and tribulations it took to get things set up just right. We are very excited to be able to offer these premium suspension kits to the community at an absolutely insane discount of up to 20% off through our Group Buy. We have been getting tons of questions about how to choose the perfect setup, and your feedback as a shop owner and as a successful driver is invaluable to other M2 enthusiasts.
To all, no matter your experience level, do not hesitate to reach out to us with any questions regarding these suspensions or other parts/modifications you're thinking about. In the meantime, here's an article we wrote to answer many of the questions we've been receiving about JRZ dampers: ”What makes JRZ so special, and which damper from their RS Line is best for me?” Since APEX first released these custom suspension packages built around JRZ RS dampers, these have been the two most prominent questions proposed to our Product Experts. This is usually followed up with, “what spring rates, rear shock mounts and other accessories should I choose”. As car enthusiasts we all share a passion for a specific marque, but often times that is where common ground ends. Even within our tight knit team of car enthusiasts here at APEX, it is clear that these cars are enjoyed in different ways, and we each have different goals, opinions, and expectations on how a car should or shouldn't be modified. This sentiment has stuck with APEX over the last 10+ years, and has been a driving force behind offering the community a wide array of wheel fitments that specifically met the diverse performance and budgetary needs of our customers. Forcing limited “cookie cutter” wheel fitments onto a diverse audience meant compromises would have to be made along the way, and that was quickly something that APEX navigated away from. In more recent years, this theme continues with our suspension solutions. APEX hand picked race proven suspension components from three industry leading manufactures to create fully customizable coilover packages, and with JRZ’s 60+ years of experience in development and production of Motorsport grade dampers, we knew the JRZ RS line would provide our customers with the right foundation for each configured kit. Back to the Basics Before we dive into the details and differences of JRZ RS dampers available to us, let's review some basic suspension principles at a high level. In order to make an informed purchase decision, it is important to have a general understanding of the different components that make up a coilover, as well as the job of supporting suspension components. This is best explained by Motorsport guru Jay O’connell featured in the SAFEisFAST series, and we’ve compiled cliff notes below. 1. Springs
2. Dampers (Shock absorbers)
3. Damper Adjustments
4. Bump Stops
5. Anti-roll Bar
Moving in the Right Direction - JRZ RS Dampers Quite often aftermarket suspensions targeted at car enthusiasts are not actually improving the handling capabilities of your vehicle. There’s never a shortage of “lower grade” dampers or coilover packages on the market disguised in enticing packaging with fancy marketing, so it is important to know the genetic makeup of what you are buying. When I ask customers to identify some of the key features they would like out of their new suspension, height adjustability is commonly the first answer. The ability to adjust vehicle ride height is desirable for a few reasons beyond getting rid of that unsightly wheel gap, however this is a standard feature of any coilover design and you owe it to yourself to set the bar much higher. Premium grade coilovers are designed around quality dampers built for a specific operating range of spring rates, and these two components are co-developed to ensure maximum control over the vehicle's movement while it negotiates uneven road/track surfaces. The end goal is to reduce drama transmitted to the chassis, prevent loss of tire traction / maximize grip, and to keep things consistent and predictable for the driver. This is not to be confused with suspension that is overly stiff - a common misconception amongst car enthusiasts. Needless to say, not all coilover packages are created equal. The JRZ RS-Line is hand built on the same production line as their ($8,000+) red motorsport-grade dampers. The build quality and attention to detail is second to none, and this is apparent from the moment you open the box and begin to handle the components. Every piece is anodized, leaving no uncoated corrosion-prone surfaces. Because the dampers are made by hand, each and every set is reviewed by a craftsman/craftswoman to ensure consistent quality, and personally signed off before making its way to you.
The Golden Question - To What Degree do you Want to Tune Your Suspension? Through conversing with a broad spectrum of customers, this is the major fork in the road. We can all agree that we would like our aftermarket dampers to significantly improve the handling characteristics of our vehicle, but to what degree are you willing and able to fine tune your dampers to optimize results given your vehicle setup, intended use, driving style etc.? Since dampers are the centerpiece to any high performing suspension package, it is important lay everything out on the table before making a decision. What are your long term goals for the car? Do you desire to compete in a form of class racing or time trials where the governing body imposes restrictions and guidelines? These are things to consider to ensure you are satisfied with your purchase in the long run. I want to be clear that all JRZ RS dampers are very capable, and with the right supporting suspension components and chassis alignment they will dramatically improve the drivers ability to control the vehicle. The question is, how involved do you want to be? As we move through the different RS dampers available, each increases your ability to fine tune the suspension in a more granular way. The ability to externally modify damping characteristics is a desirable feature, particularly for those in continuous pursuit of improving lap times or beating out the competition. These enthusiasts and racers alike will go through the effort of adjusting rebound, compression and even external reservoir nitrogen pressure to compensate for tire wear, variations in track surfaces leading to poor or inconsistent levels of grip, and even in some instances driver errors. RS ONE - Single Adjustable Dampers The RS ONE is a single adjustable damper with 21 precise clicks of adjustment, and valving capable of handling a broad range of spring rates. Through the twist of one knob, JRZ strikes a balance of adjusting both rebound and compression together. Moving between comfortable street use, aggressive track mode, or anything in between has never been easier. The RS ONE design minimizes complexity, while still providing a significant increase in performance. If you are not the type of enthusiast to explore different spring rates, alignment settings or other chassis setup features on a continuous basis, and prefer to get a capable suspension as close to “set it and forget it” as possible, the RS ONE dampers are the perfect solution. RS TWO - Double Adjustable Dampers The RS TWO is a double adjustable non-remote damper which offers independent compression and rebound adjustment. Having both compression and rebound adjustability independent from one another allows users to make more precise inputs to find the balance they are looking for. The RS TWO has 21 precise clicks of rebound adjustment controlled by a knob positioned at the top of the strut, and 14 precise clicks of compression controlled by a knob positioned at the bottom of the strut. Whether you are interested in getting slightly more involved in the suspension tuning process from the get go, or ensuring you have the option to get more granular with suspension adjustments as you become a more experienced driver, the RS TWO has you covered without the added complexity of external reservoirs. RS PRO - Double Adjustable Dampers The RS PRO is a double adjustable damper which incorporates championship winning external reservoirs for maximum control. Like the RS TWO, compression and rebound adjustments are made independently from one another, allowing enthusiasts to calibrate their suspension from compliant street mode to taking the checkered flag. The RS PRO has 21 precise clicks of rebound adjustment controlled by a knob positioned at the top of the strut, and 14 precise clicks of compression controlled by a knob located on the external reservoir. If you are a suspension geek, serious track junky or competitive racer, the RS PRO is an extremely effective weapon. These dampers and external reservoirs are aimed at enthusiasts who will take the time to explore and document a variety of spring rates, alignment settings and other chassis setup features all in the name of pushing their cars and their skills to the limits. The value added from the external reservoirs is listed in the "remote reservoir" section below. RS PRO 3 - Triple Adjustable Dampers The RS PRO 3 is JRZ’s flagship triple adjustable damper for the RS line, which incorporates championship winning external reservoirs for maximum control. The RS PRO 3 has 21 precise clicks of rebound adjustment controlled by a knob positioned at the top of the strut. It also has 14 precise clicks of high speed compression and 8 precise clicks of low speed compression, both controlled by knobs located on the external reservoir. Independently tuning high and low speed compression allows track junkies and competitive racers alike to get the absolute most out of their suspension. Double adjustable suspensions do not allow users to isolate and control high and low speed compression damping. Low speed compression controls the speed at which the suspension compresses while the car negotiates small bumps, and prevents wallowing. High speed compression controls the speed at which the the suspension compresses while the car negotiates quick or abrupt movements, like hopping berms or drastic changes in the road surface. Although more adjustments can add a level of complexity to the end user, it is important to note that you can set low speed compression to full stiff, and the damper will now behave the same as the RS PRO double adjustable suspension. As you develop the car over time and become more familiar with fine tuning the suspension, you can then make adjustments to the low speed compression to find the perfect balance for your specific track surface(s). The RS PRO 3 is the ticket for hard core track enthusiast and competitive racers looking for any and every available edge over the competition. The value added from the external reservoirs is listed below. Remote Reservoirs - Applicable to RS PRO & RS PRO 3 External reservoirs significantly increase performance capabilities by providing more fluid displacement and increased cooling capacity. Track enthusiasts and racers push their cars to the limits, and external reservoirs are one of the key ingredients to consistent damping performance from the starting line to the checkered flag. The nitrogen pressure within the external reservoir can also be adjusted between 150 - 350 PSI; a key feature for track and race enthusiasts looking to fine tune their suspension to the highest degree. Lines to each reservoir are long enough to comfortably mount them under the hood and trunk in a cool location that’s easily accessible. For a painless installation, all PRO kits come with front quick disconnect lines. Some enthusiasts within the BMW community have years of experience and seat time under their belt, and with good information available to them, they are able to digest it with relative ease and make good purchase decisions. For many others it can be information overload, and therefore we recommend having a one on one consultation with an APEX Product Specialist to further discuss personal goals, expectations and budget. We may not have all the answers, but working closely with JRZ, Ground Control and Hyperco allows our staff to deliver top notch customer support, pre and post purchase. Keep in mind, configuring a suspension package and installing it on your vehicle is only half the battle. To get the most out of your new purchase, you’ll want to know that experts are there to support your efforts along the way.
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10-26-2018, 07:01 PM | #6 |
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Our previous E36/E46 JRZ Group Buy was a success last month, and a production run for those lucky recipients is currently underway. Below you will find some dramatic shots of the raw strut bodies, staged to receive their protective coatings. It is said that mastering a craft has less to do with the end product, and more to do with the process. We completely agree as these are truly a work of art in raw form courtesy of our technical partners in the Netherlands.
- Ryan
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10-27-2018, 06:06 PM | #8 |
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10-24-2023, 05:22 PM | #11 |
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10-26-2023, 11:18 AM | #12 | |
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10-27-2023, 10:50 PM | #14 |
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This is great information, really appreciate it! Good luck with your season!
Your description of the car's behavior is exactly what I am seeing, my spring rate is a bit less - 800/1000, and I am only running -3.5 deg in the front, and a bit less canister pressure - I am using MCS 3W. I would love to know how you got the weight down so 'low'... I have done some basic stuff, rims, brakes, interior, and am pushing3400 unladen Thanks Ray Last edited by rbahr; 10-27-2023 at 10:56 PM.. |
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