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Everything posted by KONI Lee

  1. Digressive valving is not exactly "new thing" for companies who have been making performance dampers for a long time (KONI has been doing it for at least 50-60+ years) but it might be newer to companies whose products were more replacement grade and not really within the performance realm. It could be that their piston and valving component design might not have allowed the ability to really contour the damping curves very much but have moved in that direction. Many shock companies may not have been around that long or possibly just their marketing companies have simply latched onto "digressive" as a buzzword that they are using heavily now. Some consumer marketing messages may make a big deal about mono-tube or twin-tube design suggesting that one is always better than the other but it is simply not true. There are good and bad examples of both and different cars can have very different needs so it is more important that the damper function is tailored to the vehicle and it usage. Digressive and linear are general terms used to describe shapes of plotted dyno curves (however shocks on cars on roads never operate like dyno graphs look) but there are so many variables in car and damper design that you really can't just hang onto or use it as a "this is good" or "this is not good" gateway. Don't make your purchase on the use or lack of the word "digressive". You did not mention any specific shock brands but it is probably better that way anyway. As to your coil-over questions, it really depends on your usage and expectations of the car. To be a coil-over, it really only means that the spring is mounted on the strut of shock and all 3 of the early Z-cars do that already. Modern usage suggests that you are also wanting to make the lower spring perch height adjustable so you can customize your ride heights, corner weight the car if you want to, and have the flexibility to interchange spring rates is pretty easily. Beyond that, it is pretty wide open as to what your desired outcome will be and thus the path you should follow. With a coil-over, you can select a relatively soft spring rate for a compliant suspension and smooth ride, bump them up quite a bit for firmer ride and sporty control or run really big spring rates for a handling performance only/ don't care about ride quality set-up for mostly track use. It really boils down to what your uses and expectations for the car are. I would let that be the deciding point of whether you choose these Z-car specific Sport dampers or the much more aggressive RACE dampers that are clearly intended for Racing performance track duty with no comfort, no warranty, etc. in mind. Before these new Sports were introduced, there were few options for the car but now they offer more opportunities. Having looked at the damping specs of them all, the RACE units are much, much more aggressive on rebound and compression damping and not specifically fitted as a drop-in for the Z-car strut housings so some level of machining and fabrication may be needed depending upon your intended outcome. The Sport units are made to be a nice performance upgrade for the Z-car but still have a quite reasonable ride quality (so long as you don't overspring the car which will make it harsh), a standard lifetime KONI warranty against defects, be a drop-in solution to fit your housings, etc.. It all depends upon what you want, e.g. "Whats for dinner?" What do you want? Home cooked or eat out? Steak or chicken, Mexican or Italian, etc. Pick what you want to satisfy your interests as there is no specific one right answer for everyone.
  2. As with pretty much all KONI dampers, these are digressive valvings on the Z cars. This means that as they initially begin to move, they build damping forces at a pretty steep rate to give very low piston speed, subtle body motion control but the rate of climb continues at a decreasing or digressing rate at target piston speeds across their working piston speed range so that they do not get too firm and causing handling, tire grip, and ride comfort issues once the suspension and body get into significant motion. A progressive damping curve would normally be a bad thing as it would have very little damping force and control in subtle suspension motions but it would rapidly increase the rate of climb becoming overdamped and harsh over big motions and bumps. A progressive damping curve on a car would be an extreme rarity and I can't say that I have ever seen such in my nearly 25 years in the business. Some cars and specific suspension designs (typically not struts) prefer a more linear damping curve meaning that that the rate of climb is relatively even across the piston speed range and typically have pretty limited initial low speed damping forces. Some relatively linear damping examples are a number of BMW rear shocks that are mounted well behind the axle and trailing arm with an overdriving or more than 1:1 motion ratio. Progressive rates can very often be a very good thing for performance car springs but would be a bad thing for performance car damping. Progressive springs and digressive damper valvings can be very well matched, especially when adjustable.
  3. Those white plastic rings are called "bump plates" and they are intended as an extra layer of protection for the piston rod seals for when the car compresses fast enough for the bump rubber to make contact with the end of the damper body. The bump plates have two different designs, one a closed ring with a somewhat waffle shape and the other are flat and C shaped with a gap in one side. Because bump rubbers are round, fast moving, and soft to compress, it is defintiely possible for a bump rubber impact to the top of the strut to drive a puff of compressed air and possibly some road grit into and past the seal lip and into the damper. The waffle or C shape gives a path for this to just blow out to the side and help protect the seal that much more. Because KONI dampers are expected to last a very long time, some extra seal protection can be helpful for longevity. After tightening the gland nut, the first step of reassembly is to just drop the bump plate ove rthe piston rod then reinstall your bump rubber, dust cover, etc. The Miata forum thread calls the bump plates "packers" which is a relatively common name from the Oval Track Racing world where you might stack several of them to make bump rubber contact happen sooner for a number of possible reasons but you also risk handling and tire grip issues as well. The comment about them being related to an old, multi-piece style of piston rod seal is something that the poster has made up themselves. Yes, in the early to mid '80s there was a change in the seal design (I talked about ti earlier in this thread) but bump plates having some involvement with that is just someone interjecting their own assumptions. I have explained the bump plate installation and usage many times over 23 years but never heard that one before.
  4. Hello All, sorry for the late response. I was away from the internet and emails for most of three day Easter holiday with family so I am just getting caught up to a flurry of activity here. Issues of the last few days: Oil in the strut housing around the insert is always a good idea but it does not really matter what type oil it is. The benefits are twofold, although one is real world and the other a bit more theoretical. As mentioned in posts above, some type of oil between the raw steel inside of the strut tube and the outside of the insert can reduce or eliminate the chance of rust forming between the two and making it very difficult to remove the strut insert from the housing many years down the road if any service or replacement is ever needed. Any kind of spare oil will do just fine so leftover used engine oil, any gear or motor oil left at the bottom of an open bottle, etc. will do just fine. Anything to fill the void so that water or moist air cannot accumulate and start to rust the internal surfaces. I do not recommend anti-freeze as it is water based and will very likely start to rust and make insert removal much more difficult. The more theoretical benefit is potentially improved from inside to outside heat transfer but honestly unless you are trying to race off-road with extreme sustained piston speeds and heat generation, there is no need for cooling the insert for its own function. When we had the KONI Challenge road racing series, we found that there was more wheel well heat generated from the brakes and hubs that might spread into the strut than there was heat inside the strut that needed to dissipate out. Regarding the fitment concern on Nils’ front struts, I think there may be an internal lip or edge that it is catching on and not letting it drop all the way to the bottom. These inserts are exact dimensional matches to the earliest KONI 86 series red strut inserts that were offered from the beginning. I checked old ‘70s KONI catalogs that simply state “1970-1974”so there was no exclusion for super early production strut housings or a later start-up date. I think Nils’ situation is an anomaly and exception and not the rule so they can get a deeper look on a case by case basis. If someone does have an issue, please let Joseph or KONI know.
  5. It is a good example of how these cars are regulary upgraded with more modern wheels, tires, springs, bushings, etc. that many people use today. Each of those steps takes some compliance out of the suspension's motion and sharpens the feedback up to the driver and passenger. These cars will normally use a slightly higher initial rebound damping adjustment setting than will a truly stock car with softer springs, taller sidewall tires, etc. might. The stock cars will normally be adjusted to at or near the full soft adjustment setting and the modified car will likely have a higher initial setting however it will rarely be even halfway into the full available adjustment range. This helps show that the new KONI Sport option meets its goal to cover a broad range of enthusiast Z-cars, whether fully stock, upgraded with modern parts but still needing a very streetable characteristic, or for even more aggressive cars for autocross. track days, etc.. If we had fixed damper valving with no damping adjustment to help work with a range of stock or upgraded performance parts, then there would be greater concern about needing multiple strut part numbers to cover the range of cars. Being adjustable lets the car owner match to his own upgrades, handling and ride preferences, local road conditions, weekend competition goals if any, and also compensate for long term wear.
  6. I don't have a Z-car damper readily at hand to check one but most KONIs have a roughly 2.0 to 2.25 turn adjustment range from the stop at full soft to the stop at full firm. Depending on any minor stack height difference of the internal valving components used in that application, there is some possible variation but rarely does it go less than 1.75 turns or more than 2.50 turns. Because all KONIs have greater than 1 full turn of adjustment, having external numbered markings like the Tokico would not work.
  7. Thanks for the review and feedback, Ian. For clarification on knowing where your KONI adjustment settings are, just use the physical hard stop at the full soft setting (clockwise until it stops) and then the number of full or partial turns counter clockwise up from that point. Example: Full soft, 1/4 turn from soft, 1 1/8 turn from soft, etc.. This is always repeatable and easily matched side to side, front to rear if desired. In general most people probably use 1/4 turn adjustment increments but you can do larger or smaller increments if you want. We have a highly respected and picky BMW tuner whose recommendations go to the 1/16th of a turn. If you can discern judge that small an incremental change in your car, more power to you but most people are probably more in the ¼ turn range. Unlike the Tokicos that had only 5 defined adjustment settings, the KONIs can be adjusted to many more settings across a larger overall adjustment range min. to max. with broader affect across the working piston speed range.
  8. The new Z-car KONI Sports are a perfect drop in, easy fit to the factory Z-car strut housings so there is no need for any modifications to make them fit. The KONI RACE inserts are not Z-car specific but are a generic fit-all insert valved specifically intended for racing usage with a range of dimensional options in a wide range of cars including Mustangs, Porsches, Nissans, Mazdas, etc.. There are a number of vehicles that really respond well to the RACE valving but the factory strut housings are very tight such that one might need to take extra efforts to increase the ID of the strut housing (hone or bore) or decrease the OD of the RACE inserts (sanding down paint, etc.). If the car is a dedicated racing car, the extra effort to fit the KONI RACE into a Z-car is worthwhile and has been proven with a number of championships. If the car is used for the normal and performance street driving, autocross, track days, etc. but not up to the level of racing with very high spring rates, the KONI Sports are the right answer. Also, the KONI Sports do carry the full normal KONI Warranty because they were made for street use on that specifica car whereas the KONI RACE carry no warranty because they were specifically designed for racing on a wide range of cars.
  9. With the adjustable KONIs, you are adjusting the rebound (the upward stroke) damping forces generated when oil flows through the piston (the "plate" you reference) valving. By turning the knob higher or lower, you are closing or opening piston rod orifices and increasing or decreasing spring preload holding valves closed against the piston blocking other piston orifices. This provides changes in damping force from the slightest piston motion through very high pistons speed and lets the KONI Engineers finely contour the damping curve for optimizing both control and comfort. The lower the adjustment setting is, the more open or less restrictive the damper valving is and the softer the damping force is. That means you have less motion control but that doesn't necessarily mean that you have a softer or more comfortable ride quality because sometimes insufficient control can provide an uncomfortable ride quality.
  10. The 80 psi gas charge that you saw in the damper does not equate to an 80 psi increase in the spring rate, it doesn't work that way. It does add some quite limited preload boosting effect in conjunction with the preloaded spring rate when the weight of the car is loaded onto it and the damper gets closer to full compression. In the past I have heard engineering generalizations that internal Low Pressure Gas charge effect might have some similarities to a 7-8 psi spring rate increase but even that is not exact because it doesn't really work that way between gas charge and spring rate. I definitely disagree that one should try to change your spring rate or installed length to compensate for internal gas charge, especially when there are so many ways throw off ride height measurements. The most common that we see is taking measurements before the car has had an opportunity to move enough to settle from being raised in a droop situation, or from tightening control arm and similar bushings when in droop then putting the car on the ground with some lifting effect og bushing wind up in it. There are certainly others but those alone can cause measurements to be unintentionally off by greater amounts than the gas charge itself alone. I do not have any records to see if the factory Z-car dampers were originally LPG or non-gas charged so we don't know if there gas any gas effect or not in the factory info. That doesn't really matter though. If the limited effect of the LPG charge is still bothering you so much and you feel that you absolutely must must must have a non-gas charged, one could pretty easily degas the dampers oneself. This is a trick that has been used for years (only in a T-T LPG, not M-T HPG!) in Stock/Street class autocrossing and can be beneficial mostly on slight weight, light sprung independent suspension cars that get some camber change with ride height change. I am not going to explain how one would degas them on a public forum for a host of reasons but it can be done with no ill effects. Technically this could put your warranty at risk but the damper's actual function or longevity will not be altered if done properly.
  11. KONI is not outsourcing any services. We handle our warranties internally (replacement with brand new dampers when possible) and we still build our own prototypes and our own internal damper work as needed. We no longer offer automotive damper rebuild/revalve services to consumers directly ourselves because far less than 0.1% of KONI dampers ever get serviced and there are three independent outside companies who have decades of experience at it. It's just like an independent auto mechanic shop servicing someone's car except that we first require significant training, tools and component parts for them to be authorized. When we offered it, complete dyno testing was usually about $30 each to cover the time required for testing and that was waived if the there proved to be an issue that required internal service work. Since your stated that your adjusters are stuck, I would see no use to dyno test them because we already know that some internal service would be needed to get them fully functional. If the adjusters are stuck because the damper bottomed internally (similar to bending engine valves by hitting piston tops if you break a timing belt in an "interference" engine), then the ends of the piston rods will be bent and the compression valve cartridges will be damaged. Replacing those parts would further raise service costs far above the price of brand new. Its all about the best balance of time and money to get to your desireed end result. Making a KONI warranty claim is something completely different and not connected to having your existing dampers serviced by one of the outside shops. If you meet the warranty criteria (which it sounds like you do since you bought them new and still have the car), then we can start a warranty claim by using that link posted above to get the shocks inspected to see if the issue is warrantable or not. Once inspected and the trouble root issue is identified, then we follow the best path for resolution from there.
  12. A. There is no longer a KONI North America Automotive damper service facility as it was integrated into our Railway shock service facility several years ago. There are 3 outside businesses that are authorized KONI Automotive rebuild facilities in the US and their info is listed in the right side column of this link that can do testing and service for you: http://www.koni-na.com/en-US/NorthAmerica/Locator/ but you will have to pay them for their work. The Datsun Z strut with the attached spindle (used sometimes on ‘70s cars like RX7, 2002, etc. but rarely used since) is neither common nor simple so most companies with shock dynos do not have proper fixtures for strut housings, much less ones with spindles attached. We have a special dyno fixture for inserts which must be compressed within an outer structural shell for testing but that is very uncommon outside a company like ours. B. If you bought them brand new and have a purchase receipt in your name, have a current vehicle proof of registration still in your name, and there is an identifiable internal manufacturing or materials defect in the damper that is causing the problem, then it certainly is a candidate for warranty replacement for as long as you own them. Because those dampers were discontinued 25+ years ago, that causes some complications but they can be addressed. The warranty does not transfer to a non-original KONI purchaser, if sold on the car to a new owner, does not cover non-defect damage caused by external means (bottoming damage inside from hitting something, incorrect installation or usage damage, etc.). In my 20+ years of experience, stuck adjusters are almost always of external cause and not internal defect cause. It could theoretically be stuck from a defect cause but that is extremely rare and also extremely unlikely to happen to all four of the dampers in a single car set. Your comment about having them tested and possibly serviced made no reference to defects or warranty so I commented based on that. If someone is going to pay for service to be performed, the labor and parts cost will almost always cost more than a brand new one if an off-the-shelf modern replacement is available and you do not need a customized unit for racing, special needs, etc. If the above warranty info fits your situation, then KONI North America will be happy to address it that way. Most people 30 years later likely don’t fit that so a modern updated version is often the cheaper, faster, and better route for the future.
  13. Looks like Week 3 (January) of 1987 production. Being the 8641 prefix, they are the externally rebound adjustable, twin tube low pressure gas version that were made for a few years in the 1980s. I believe that the 8641 versions were likely made primarily (and maybe solely) for the North American market and likely even built in a US factory in Virginia that operated from about 1982 through 1989 or so. If the adjusters are not turning (probably from jamming by hand or impact tool or internal bottoming most likely), then dyno testing them will be of no value and wasted money and time. Additionally, whomever tests them will need to have a dyno with fixtures to hold the Z-car's uncommon spindle attached strut housing. They could likely be rebuilt but it would actually be much cheaper, faster and have a full warranty if you were to simply purchase the brand new ones from Motorsport Auto. You would be much farther ahead to start with fresh ones than pay the labor and parts to fix the old ones which would still not be entirely new. It is definitely less expensive per unit to build new in a large production batch than rebuil;d them onesy-twosy paying for labor and parts.
  14. Actually this photo shows that you have one each of the early, older generation seals and guides (fronts) with integrated gland nut threading and the later design (rears) with the different guide, modern Viton seal and a separate gland nut. What is interesting to me is that the 1980 date code on the newer design means that they must have started that conversion earlier than I'd thought. Since there are no 40ish year employees left from those days before major computerization, there is little to no record keeping and archives showing exactly when things happened. I'm pretty sure that happened over a period of time.
  15. Any spring that you want to put on it, from any soft OE springs to any much higher rate aftermarklet performamcne lowering springs. As you increase spring rate, you need a little bit more rebound damping but it is a non-linear relationship so often doubling or higher the spring rate may only require a 20-30% rebound damping increase to control excess oscillation. Since these KONIs have a roughly 100% range of adjustment, they will work well with about any spring from stock to quite aggressive that you might use. You simply turn the knob adjustment a little higher to meet your ride and handling preferences for your car, roads, modifications, etc. There are many variables involved beyond comparing simply spring rate and damping rate so your being able to tune to your own preference and usage is the best answer. As I stated in the first post, most people will find their preferred adjustment spot in the lower half or less of the adjustment range for normal to aggressive street driving when new.
  16. The new MSA Sports are twin-tube low pressure nitrogen gas charged (8641 prefix with the 4 indicating low pressure gas charge) and the Classics are 86 (twin-tube hydraulic non-gas charged). Generally an increase in internal gas charge can have a pretty minor if any increase in static ride height and can vary from car design to car design, I think your 1 inch comment might be overestimated as most cars are more likely to see 1/4-1/2" difference with several variables involved. Any static height changes are going to be related to a mix of things including the amount of gas charge itself (from zero gas charge to low pressure gas charged (3-5 Bar usually) to a mono-tube high pressure gas charge (10-20 Bar usually) in addition to vehicle weight, spring rates, damper piston rod diameter (effect is more on a large rod diamete, less on a small rod diameter), suspension geometry, etc. How well and consistently you make your before and after measurements and do the installation may likely have a greater impact on a height change than actual internal gas pressure difference. KONI is one of the few companies who makes all three different shock designs (T-T non-gas, T-T LPG & M-T HPG). Very few people understand what internal nitrogen gas really does or doesn't do in a damper however the gerenal public's limited info perception (mostly old ads from mass market, commodity shock brands) is usually that gas charged is better than not gas charged so often we will include a small gas charge to satisfy that "Is it a gas shock?" question if we don't have the abulity to discuss it technically. In fact, we are working on a KONI video script now addressing the very common misconceptions of gas charging or not.
  17. The red KONI Classics that have been made in the last roughly 20ish years are the much younger siblings of the very old set that I discussed just above. Their part numbers will be 86 1811 and 86 1812 (for 240Z/260Z) and have the modern seals and low friction guides and pistons and 86 strut insert part number prefix that I discussed. These were out of production for many years but it was revived in the mid '90s when the car saw a popularity rise including Nissan's official revival/rebuild program on some early cars. They have stayed in low volume, limited availability since then. They are the internally adjustable (compress-to-adjust off the car) version so they are not as friendly to adjust for general tuning, going back and forth for street, autocross, & track day use, wear compensation, etc. Their valving is a bit softer (but certainly not a "soft" damper) than the new Sports that we have just developed with Motorsport Auto. These were of twin-tube hydraulic (non-gas charged) design so they won't self-extend if you compress them off the car but that has no relation to actual damper function on the car.
  18. You were told the correct era for those particular parts. The 82R prefix tells us they are early strut inserts used before KONI made many major part number and component updates in the 1982-1984-ish era. Early on, 82 could mean shock, full strut, or strut insert. After the changes, all strut inserts were called 86, full struts were called 87 and 50-55mm OD body shocks stayed as 82s. The alphabet letter was dropped at that time too. So the red Z-car inserts after the mid 1980s would have been called 86-1811 and 86 1812. There were many internal upgrades during this time period as I alluded to above. The only externally visible major difference is the piston rod guide and seal assembly where the chrome rod goes into the body. The old style like yours will have a couple concentric rings visible on the end of the insert and usually a couple tool slots in them that created pressure on the old seal system of stacked felt and rubber rings. The newer design used since the mid-80s is flatter and has fewer concentric rings and a longer lasting, better sealing Viton oil seal in addition to newer bronze guides with Teflon and other low friction coatings to reduce friction and wear long term. So your 82R-1811 705 would be from 1977 Week 05 or early February production. Your 82R 1812 007 would be from 1980 Week 07 or late February production. Both will have the older guide and seal system and may not last the longest now 40 years later and not have the low friction updates. The Special D was a product designation for all red painted KONIs, the main color KONI used until they diversified in the 1980s to include yellow paint (KONI Sport) and much later black (KONI Classic), bright orange (KONI STR.T), and gold (KONI FSD). The red is also now used on other truck and car product lines are well. I have no info on your spring pic because it has no KONI connection. They could be either OE or some aftermarket springs but they are not a KONI spring that I have heard reference to in my 20+ years here. KONI has dabbled off and on over the decades with selling damper & spring combo packages, more in the USA than in Europe. Hope that helps some.
  19. Yup, KONI has always been a Dutch company, founded in 1857 as a horse saddlery in the little town of Oud Beijerland, about an hour south of Amsterdam. The main factory/world HQ is still located in the same town about about a mile or so away from the original saddlery, which is now a museum. There is a 3 or 4 digit manufacturing date code stamped into those old KONIs right near the part number. If you are interested and want to get me that number, I can tell you how old they are. There were major technology updates (mostly friction reduction and longevity extending) to the pistons, seals and top guide bushings in the early to mid-'80s so yours could be from before or after then. It would almost certainly be possible to service your old ones however done individually the labor cost with parts would probably be higher than buying brand new ones that have all new parts, the full warranty, and features.
  20. Hello all, my name is Lee Grimes and I am the Automotive Product Manager for KONI Shocks. I have been working with Greg and Joseph to get these new Z-car parts to market and help answer some questions. He pointed me to this discussion to maybe give some clarity or assistance. I won't be able to stay as a regular contributor but I will be happy to check in for a little bit to help people understand the new parts. A bit over a year ago, Motorsport Auto came to KONI to see if we could revive and modernize our offering for the early 240Z, 260Z, 280Z and 280ZX. Needless to say we jumped at the chance to offer proper products for these important cars. Off and on through the years KONI has offered the tradtional red painted KONI Special strut inserts with internal (off the car) adjustment for 240Z through 280ZX. In the late '70s-and early '80s KONI also offered an externally adjustable version for these cars excluding the ZX but they were discontinued by the mid-'80s. Now was time for an update. With Motorsport Auto as an exclusive partner stepping up to take full production run volume, we developed and tested new externally rebound adjustable (knob adjustable on the car) yellow painted KONI Sport strut inserts for these cars and a externally adjustable rear shock for the ZX. We started with the external adjustables from the 1980s as the launching point and even used the same part numbers this time with the SPORT suffix in the part numbers. We then updated the internals a bit (it was no slouch to begin with back then though) to more modern seals and guide components and set the valving to work well with either factory stock springs (starting baseline adjustment at or near full soft) or performance lowering springs for perforamnce street, autocross, track day, etc. use (starting baseline adjustment about 1/2-3/4 turn up from full soft setting). Like all KONIs, the adjustment range is about 100% so they are twice as firm at the maximum setting than at the minimum setting. This is a very large range of adjustment so we suggest that you start in the lower end of the range, drive it for a bit to get a feeling for it, and then tune accordingly from there for your ride and handling preference. I think it will be very rare that people will use more than 1 turn (about 50% higher than full soft) for normal use when they are new. Because the adjustment range is so large, it allows you to compensate for wear over extended time, tune it high for an autocross or track day, and then quickly turn it back down for street use. Because the range is so large, it is possible to overdamp the car for your needs and actually make it more harsh and have less grip than needed so do not just turn it way up figuring that "more is always better". Although these could be used for a dedicated track and racing car, their needs and expectations are different and we do have other racing options (e.g. 8610 RACE and 8611 RACE) where street handling and ride quality, high mileage longevity, etc. are no longer important. These new Z-car Sports are targetted to take you from stock Z- car to just shy of all out racing. They carry KONI's limited lifetime warranty against defects and materials to the original purchaser as long as tht person owns the car registerd for street use. Regarding the discussion about bump rubbers, you can use a good condition OE type bump rubber for a Z-car, one of the black urethane ones that Motorsport Auto sells, or the KONI Racing Silastic bump tops made for use on a 22mm piston rod. KONI does not have a specific bump stop length suggestions as different ride heights and springs will determine what length you need. The imporant part is that you have some bump rubber installed to keep the strut or shock from bottoming out internally which can cause internal damage that will cause loss of function and will not be covered under warranty. The first production runs of the fronts and rears for the 240Z, 260Z, and 280Z are currently in-transit from KONI in The Netherlands due in mid-March. The 280ZX fronts are in-transit as well but the 280ZX rear shocks are awaiting final production due to to different compponent sourcing but will be here ASAP. Please be clear that these were specifically developed only for these Z-car applications and they are not crossovers from ome other vehicle. Because these parts are exclusive to Motorsport Auto and no other KONI dealer has access to them, we will not be listing these part numbers on our official KONI websites for North America www.koni-na.com or Europe www.koni.com. If you have any questions, pelase contact our Technical Staff at info@koni-na.com or 859-586-4100 Option 6 from M-F 8-5 Eastern time.