When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I don't have the chassis mounts and don't think it matters from a performance perspective, and my shocks are inverted with all the spring force working on the shock top rather than the base. While the shock does go through an arc change over the travel length the forces are still mostly vertical rather than horizontal. Even when I had steel tops I left those brackets off for weight reduction. The aluminum hat material is fairly thick and flexure would be minimal imo. The brackets matter more from a cabin noise/vibration perspective.
The adapters are plastic (Delrin, I think) and came with explicit instructions to use the NC aluminum hats and not the steel hats. As Team says, I don't like the loss of bump travel. I also don't like the loss of the extra chassis mounts at the top of the steel hats.
Figured as much. Just wanted to be sure there isn't another reason. These Ohlins are already limited in rear bump travel. Probably not a good idea to make it worse. Actually, that is the THE reason I am thinking about adding rear spring.
Any reason you can't just follow SB's instructions in modifying the steel hats and use the Delrin adapters with them?
The adapters are plastic (Delrin, I think) and came with explicit instructions to use the NC aluminum hats and not the steel hats. As Team says, I don't like the loss of bump travel. I also don't like the loss of the extra chassis mounts at the top of the steel hats.
Yup, I don't recommend moving to the shorter NC hats... you're just decreasing stroke for no reason.
These mounts will work with the steel RX8 hats... they just need a little flattening.
Also that is correct, Goodwin's delrin spacer thing doesn't have much of a seat/interface which is why I believe they require people to run the shorter NC top hat. We have a small recessed internal seat for the RX8 hat... it just takes a little patience to get it flat. Once you do you're good.
Figured as much. Just wanted to be sure there isn't another reason. These Ohlins are already limited in rear bump travel. Probably not a good idea to make it worse. Actually, that is the THE reason I am thinking about adding rear spring.
Any reason you can't just follow SB's instructions in modifying the steel hats and use the Delrin adapters with them?
I'm not sure the delrin can take that sort of concentrated load... the steel is rather thin. Our aluminum adapters work great and specifically have a recess for the steel interface, but you do need to get it flat so there are no high spots/stress concentrations. It's a quick process with a little patience
Sorry for the late update guys, we've had these for a few months now as well as our Screw-In-Spherical which replaces the rubber top mount in the rear RX8 top hat (reducing severe hysteresis caused by the rubber bushings).
Here's the screw in spherical link with more information
and the spring adapter link which converts from beehive to cylindrical springs (70mm). This allows us to supply custom spring rates (optional helper/assist springs) and valving for RX8 kits, similar to our FPSpec S2000 and FD kits.
Who will benefit from these? "Strictly for the hardcore?"Will they increase noise and vibration?
Nope, these decrease hysteresis... they're on the damper side not the shock body side (so in line with the damper itself) which does not cause NVH (on a quality damper at least).
Here's a bit more info for those that are interested in learning a bit more (repost from Miata.net):
"
NVH (noise, vibration, harshness) is actually better than stock. A shock has an upper and lower mounting location... the lower is typically rubber and is used to absorb high frequency vibrations. The upper mount is required to be able to allow to damper shaft to move/pivot as the suspension compresses, (otherwise you'd risk bending the shaft). Spherical bearings are expensive, so OEM's will often use rubber for the upper mount to cut costs (pennies on the dollar vs sphericals) however there are some downsides. Since the upper mount is on the shock SHAFT side, not the shock body side, you are adding a second damper/spring in series with your actual damper (piston and rod... the bit that moves in the shock oil past the shock body itself). For low spring rates, a squishy piece of rubber isn't much of an issue as the damper has a long linear travel due to the soft spring, and has plenty of time/distance to compress the rubber bushing to a stiff state before the piston begins to act. Move to a stiff spring however, and the linear distance the shock moves for a given compression event (bump) decreases... the shock must operate over smaller and smaller distances. This is where the rubber bushing becomes a problem - especially with high end suspension like the Ohlins, which has three different flow paths to decide on (low speed, high speed, or ultra high speed). These flow paths are chosen based on the linear acceleration rate of the damper shaft... low rate will take a high compression damping path, high accelerate rate (hitting a pothole) will trigger a bypass valve to significantly reduce compression damping (i.e. "go limp" to absorb the impact). With the rod rate being the deciding factor for the valves, a delay in linear movement caused by compression of the rubber bushing is detrimental to the dampers ability to optimally damp the suspension movement.
We've measured the rubber upper mount on our spring dyno to be equivalent to a 10kg spring (---inch lbs)... that's pretty soft and enough to interfere with transferring accurate suspension movement to the piston in real time. What you get (or induce rather) is something suspension companies try very hard to reduce - hysteresis. Hysteresis is a lag or delay in motion or force... think of it as gear lash for suspension. Basically, how long does it take the internal seals, hardware etc, to move into place enough for the piston to begin acting to create a damping force. Cheap suspension has high levels of hysteresis or slop, while higher end suspension has low levels of hysteresis (high accuracy/precision). Commonly people associate high spring rate suspension with a harsh ride quality, however that is only partially true as a high quality damper with low levels of hysteresis can control suspension over very small distances. Put those same stiff springs on a damper with large amounts of hysteresis, and what you end up with is a very harsh ride as the damper can not act fast enough or over small enough distances to provide adequate damping force... essentially un-damped and riding on the spring. But as a As the rubber bit compresses and decompresses independently of the piston movement). Essentially you've taken a fillet minion, and put ketchup on it. Highly accurate suspension that is able to precisely attenuate even the smallest movements is now blind / delayed to small movements and the resulting effect is rough and unusual ride quality and early compression characteristics.
The spherical upper mounts were removed simply as a cost saving measure, or they didn't have a decent solution. Don't believe us? Look at every other Ohlins kit, they come with spherical upper mount
The Ohlins are very good dampers, but can only be as good as the feedback they're getting. The damper seeing through a 10Kg rubber spring is not ideal.
Here are some pictures testing the rubber top mount on our spring dyno... roughly a 10kg/mm or 560 lb/in spring equivalent. To reiterate, it's this rubber-spring masking actual shaft acceleration for the piston both in compression and rebound... inducing hysteresis. Basically, with rubber in the top mount, the dampers are not behaving optimally.
I'm not sure the delrin can take that sort of concentrated load... the steel is rather thin. Our aluminum adapters work great and specifically have a recess for the steel interface, but you do need to get it flat so there are no high spots/stress concentrations. It's a quick process with a little patience
I guess I'll find out soon. I ordered your kit and have a set of 5K springs ready to go on. Jumping from 4 to 5K isn't much, but it will give me the 1.6 F/R ratio I seem to like, and hopefully enough rear travel to overcome my snap oversteer problem. Hopefully fine tuning is all that will be needed.
.
Last edited by Steve Dallas; 06-20-2017 at 03:17 PM.
I guess I'll find out soon. I ordered your kit and have a set of 5K springs ready to go on. Jumping from 4 to 5K isn't much, but it will give me the 1.6 F/R ratio I seem to like, and hopefully enough rear travel to overcome my snap oversteer problem. Hopefully fine tuning is all that will be needed.
.
Hold on a second, is this for Ohlins? If so you already have a 5k in the rear! Ohlins rates for the RX8 are 8kg/5kg , anyone telling you otherwise has no business helping with Ohlins setup. We've seen blatantly incorrect numbers floating all over the place online.
Give me the back story on what you're trying to do.
Hold on a second, is this for Ohlins? If so you already have a 5k in the rear! Ohlins rates for the RX8 are 8kg/5kg , anyone telling you otherwise has no business helping with Ohlins setup. We've seen blatantly incorrect numbers floating all over the place online.
Give me the back story on what you're trying to do.
The Ohlins DFV manual lists the fronts as 80N/mm and the rears as 40N/mm. Unless my math is wrong, that translates to 8.16K in the front and 4.08K in the rear.
Goodwing Racing lists them thusly:
Front: 80 N/mm(8kg/mm or 458 lbs/in.) Rear: 40 N/mm(4kg/mm or 229 Lbs/in.)
Great googledy moogledy. If I have been trying to tune this suspension with incorrect information for the better part of 2 years, I'm going to be really annoyed with... nobody in particular, I guess.
That little fragment of information changes everything about my suspension tuning approach. Had a great conversation with Heath from SakeBomb this afternoon. He answered a bunch of questions for me and gave me a few things to try. Awesome folks over there!
Here's a pic of one of my rear springs. Now that I know the 50C marking refers to 50N/mm, I can confirm that my rear springs are ~5K. Interesting that Ohlins customer service couldn't tell me that, when I asked the question over a year ago.
Last edited by Steve Dallas; 06-21-2017 at 06:26 PM.
Here's a pic of one of my rear springs. Now that I know the 50C marking refers to 50N/mm, I can confirm that my rear springs are ~5K. Interesting that Ohlins customer service couldn't tell me that, when I asked the question over a year ago.
I took this picture before you posted of the "stock" springs that came with my Ohlins.
I'm not sure the delrin can take that sort of concentrated load... the steel is rather thin. Our aluminum adapters work great and specifically have a recess for the steel interface, but you do need to get it flat so there are no high spots/stress concentrations. It's a quick process with a little patience
Which is why I was unhappy with the Delrin spacers. I don't have or have access to a stationary belt or disk sander, but I do have a good file and some (some) patience. I'll be spending quality time with the steel hats.
Originally Posted by SBGarage
The Ohlins are very good dampers, but can only be as good as the feedback they're getting. The damper seeing through a 10Kg rubber spring is not ideal.
Awesome, so ship them to me already! Please. Or at least tell me when you are going to ship them so I can plan ahead. I'd like to have them by next Wednesday so I can get them installed and corner-balanced before three solid days of track time!
I emailed Ohlins (again) about the rear spring discrepancy. This is the response I received:
Hey Steven,
The rear rates on the RX8 are the stiffer 50N/mm rates. The mounting instructions incorrectly list them as 40N/mm because they used the MAS MI30, (NC Miata) mounting instructions as the base for the RX8. Thanks!
-Jake
Based on the information in this thread, plus that response, I emailed Goodwin Racing about the rates published on their web site. This is the response I received:
Hey Steven;
Thanks for sending this information over, I'll update our product description.
Cheers, Sean
Progress!
Thanks again to Sake Bomb for bringing this up. Having the right inputs to the equations should make my life a hell of a lot easier going forward.
Are these ohlins still made in Sweden or now in Asia,
Ohlins have always been designed in Sweden, made in Japan. At least for the "consumer" grade parts - read non race car.
Little known fact, Yamaha Japan manufacturers the DFV's for Ohlins with Ohlins pattented Pistons and valves Most aftermarket "Japanese" suspension manufactures have long outsourced their production to Taiwan or Korea... Tein, and other big names which you'd assume were quality Japanese products are manufactureed abroad and are made as cheaply as possible. There's a reason Ohlins hardware is the top of their class in quality and refinemt... and they're more JDM than most Japanese companies.
This is why we picked Ohlins shock bodies to build our custom valved FPSpec Long-Stroke suspension around... we couldn't think of any more accurate and feature packed hardware to start with.
Ohlins have always been designed in Sweden, made in Japan. At least for the "consumer" grade parts - read non race car.
Little known fact, Yamaha Japan manufacturers the DFV's for Ohlins with Ohlins pattented Pistons and valves Most aftermarket "Japanese" suspension manufactures have long outsourced their production to Taiwan or Korea... Tein, and other big names which you'd assume were quality Japanese products are manufactureed abroad and are made as cheaply as possible. There's a reason Ohlins hardware is the top of their class in quality and refinemt... and they're more JDM than most Japanese companies.
This is why we picked Ohlins shock bodies to build our custom valved FPSpec Long-Stroke suspension around... we couldn't think of any more accurate and feature packed hardware to start with.
I tought tein and arogasta are made in Netherlands? Any how, cheers for info
06-18-2017, 10:19 AM
I didn't want to overshadow it. Plus, mine's just sitting on a bench. Not sexy.
Most aftermarket "Japanese" suspension manufactures have long outsourced their production to Taiwan or Korea... Tein, and other big names which you'd assume were quality Japanese products are manufactureed abroad and are made as cheaply as possible. There's a reason Ohlins hardware is the top of their class in quality and refinemt... and they're more JDM than most Japanese companies. 