Ohlins DFV Coilover Kit - Page 12 - S2KI Honda S2000 Forums

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Ohlins DFV Coilover Kit

Old 01-31-2014, 06:52 AM
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Working with Patrick to reserve a set for March delivery...
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Old 06-10-2014, 06:16 PM
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The shocks are in my garage and now am waiting for "Group 2" to install them on the 19th of June. Do you have any advise looking back on your experience?
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Old 06-27-2014, 12:56 PM
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Drove home from the install at Group 2 and am now looking at confirming the "stock" 10 click settings. Great feedback form the Group 2 guys on the shocks and the 05 S2000 (they are "mostly" BMW/Audi not so much Honda guys).
Now set at 12 clicks from full stiff...
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Old 07-11-2014, 02:45 PM
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Gernby, if you're still following this thread, do you have any follow-up thoughts regarding the rear spring rates/piston-position/pre-load situation on these shocks? It's *shocking* (pardon the pun) that Ohlins would ship these with a setup that places the rear already on the bumpstops when the car is at static height. My calculations back yours up in that regard. Static load already exceeds the travel of the shock before engaging the bump stop.

I crunched some numbers and to get the rear pistons to sit in the middle of the stroke with minimal pre-load, you're looking at 13K-14K rear springs. It just so happens that those rear spring rates also achieve ideal ride frequency stagger front-to-rear when paired with the stock 10K fronts (roughly 10% higher in the rear, the way it should be). I'm wondering if Ohlins designed the shock bodies and pistons with those springs rates in mind from the start, but artificially castrated the setup with 8K rear springs so that the product could be strapped onto a stock car with an amateur driver without additional setup changes and not be too tail-happy.
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Old 07-14-2014, 10:58 AM
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Originally Posted by thomsbrain View Post
Gernby, if you're still following this thread, do you have any follow-up thoughts regarding the rear spring rates/piston-position/pre-load situation on these shocks? It's *shocking* (pardon the pun) that Ohlins would ship these with a setup that places the rear already on the bumpstops when the car is at static height. My calculations back yours up in that regard. Static load already exceeds the travel of the shock before engaging the bump stop.

I crunched some numbers and to get the rear pistons to sit in the middle of the stroke with minimal pre-load, you're looking at 13K-14K rear springs. It just so happens that those rear spring rates also achieve ideal ride frequency stagger front-to-rear when paired with the stock 10K fronts (roughly 10% higher in the rear, the way it should be). I'm wondering if Ohlins designed the shock bodies and pistons with those springs rates in mind from the start, but artificially castrated the setup with 8K rear springs so that the product could be strapped onto a stock car with an amateur driver without additional setup changes and not be too tail-happy.
I haven't touched my setup at all since I created this thread, and still believe they are awesome. I think the car would be a spin monster if the rear springs were stiffer than the front. On second thought, I did make a change to my setup that made an improvement, and that was to replace my OEM rear sway bar with a Miata front bar.
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Old 07-14-2014, 11:06 AM
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Originally Posted by Gernby View Post
I haven't touched my setup at all since I created this thread, and still believe they are awesome. I think the car would be a spin monster if the rear springs were stiffer than the front. On second thought, I did make a change to my setup that made an improvement, and that was to replace my OEM rear sway bar with a Miata front bar.
Good to know you're still happy with them.
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Old 07-15-2014, 10:06 PM
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may i know the model year of the Miata and what is the diameter of the front bar?
thx
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Old 07-16-2014, 06:44 AM
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I don't remember which Miata it was, but it's a much smaller diameter than the stock rear S2000 bar.
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Old 09-01-2014, 03:10 PM
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I recently installed a set of the Ohlins DFV R&T coilovers on my 07 S. I was certainly influenced by Gernby's experience and recommendation. His rave reviews (and many others) and the drop to sub-$2500 MSRP made these the easy choice for a street-only S2000 upgrade. Obviously, Gernby and others have great experiences with these on the track as well, but I was ready to ditch the OEM shocks to improve handling and ride on casual street and spirited back road drives.

I wanted to get them from Patrick at Urge, but PSI was able to get them more quickly (just luck of the draw, I'm sure). I encourage anyone looking for these to call PSI (Performace Shock, Inc) and ask for their best price.

I'll get to my setup details later. First, my review: OUTSTANDING! The difference vs. OEM is not subtle. It's a revelation. The handling characteristics of the car are profoundly improved. The MY 07 S has the softest rear OEM spring rate of all of the MY's. So, the difference might be less dramatic on other MY's, but I can't imagine that any of the OEM setups are as good as this.

My car has an ‘08 front sway bar which is about 20% stiffer than the 07 bar. I'm running OEM-sized Michelin Pilot Super Sports. The car is lightly modded - Berk header and HFC, T1R dual exhaust (didn’t see Gernby’s until he stopped making them, dam*it), intake insulator, and tuned by Evans Tuning with Hondata Flashpro. I only mention this because the hp and torque in the mid-range is WAY better than stock, which opens up the fun factor and rear end control quite a bit. I’ve also reduced weight from OEM by about 120lb.

The best way to describe the difference is to start by describing how it handled before Ohlins. "Spirited" corner entry would start with understeer which was corrected by putting some throttle in. Then, you ride the balance between oversteer and understeer. Fun for sure, but also a bit of a guessing game that would raise the pucker factor if you found yourself in an unexpected decreasing radius curve. While that was all very entertaining, it really made the car feel like it was short on rubber. I was actually investigating larger wheel options when I dug deeper into Gernby's post and realized that I might need to improve the suspension first.

With the DFV's, understeer is GONE. At least at (admittedly, slightly irresponsible) street speeds. Oversteer is still available, but you have to reach a little deeper to get to it. The result is big grip and a wider "band" to play within through the curves. Gernby used the term “planted” and that’s a great description. On some of my nearby favorite back roads, I could glide through at speeds that were a dance of throttle and steering inputs before. The extra grip is the surprising thing - what I would expect from wider, stickier tires, not just better coil-overs. On a few choice decreasing radius curves, I could pick between reducing the throttle and having it tuck right in, or adding throttle and aiming it in with the rear swinging out. The rear end also seems to slide more predictably. Before Ohlins, lifting the throttle led to severe understeer. The broader options for what you can do were surprising.

The composure in transitions is also an unexpected improvement. For example, before Ohlins, the car would bob and weave a bit if you had to lift the throttle while oversteering and turning the wheel back into the turn to set your line. You'd have a moment of understeer and snappish, pogo-like, suspension travel. Now, that same transition is nearly seamless. That's partly because you can stay on the throttle more, but even when you don't the car is just more composed as it leaves oversteer. The fore-aft pitching of the OEM suspension is absent (street driving, not track-level braking) which I'm sure has a lot to do with the transitional composure.

Icing on the cake – if you back off the damping around town, the ride is far better than OEM. You can still tell it’s more stiffly sprung than OEM, but the harsh jolts that the OEM suspension let through are smoothed off. The Dual Flow Valve technology is not just hype. It really gives a relatively compliant ride that allows the stiffer springs to do their job on the twisty bits without beating you up if your local streets are pure crap like those in Cincinnati.

I tested several damping settings while out on back roads and each click provides a noticeable change. Anyone could find their "Goldilocks" setting fairly easily, I think.

So, my recommendation is whole-hearted. If you're thinking about getting some sub-$3000 coil-overs (just a smidge over $2000, actually), these are the real deal. All of the rave reviews you've read from others, I echo.

Also, in the past, I installed some Buddy Club N+ Spec dampers. I tried them for a couple of months and went back to stock - too hard for typical quality streets (in southern Ontario at the time) and generally not discernably better handling.


Now about my settings. I found Gernby's write-up to be very, very useful. A few notes:

One, he doesn't explain why you don't want to set up the preload on the bench. You can set up the damper length, which you will use, along with your targeted preload, to achieve the ride height you want. However, you want to wait on the preload so that you can install the damper without screwing up that damper length when you're trying to line up the upper and lower mounting bolts.

Two, I know there are a bunch of people that calculated a MR of 0.7 for the front. Gernby is using the inverse of this, 1.4 (1.43 to be exact, but he used 1.4). When I looked at the drawings that were being used in other posts for calculating the front MR, I saw that they were forming the triangle, used to calculate the angle of the shock, by terminating the top of the triangle at the upper shock mount point. This is incorrect. The hypotenuse of the triangle passes through that point, but must extend upward until it intersects the line perpendicular to the lower control arm mounting points (I'm simplifying. Look at the drawing and you'll know what I mean). Anyhow, I calculated that the MR is 0.685, which give the inverse of 1.46. This may not seem like much, but it exactly accounts for the 1/2" lower ride height than Gernby was expecting. (That's based on 700lb per corner which he used for his calculations). Admittedly, I did my front MR measurements on the drawing on my laptop screen after a few beers, but since it matched what Gernby encountered, I decided to use the front MR = 0.685 and it worked perfectly for me when I did my set up.

Three, everything that Gernby said about preloading the suspension before tightening up the bolts is crucial. His method worked perfectly for me (tripod method).

Fourth, you should use the sprung weight for each corner instead of the total weight for your calculations. If you have accurate unsprung weights, please share them. I used someone else’s approximation, found in another post, of 316lb total unsprung weight. I’m sure it’s off a little, but close enough. So, I calculated the ideal corner weight = (total car weight + my weight - 316lb)/4 = 661lb. But you have to remember that the compression force experienced by the spring is related to the corner weight by the motion ratio.

My target was a 10mm drop, on average. I say on average because there were differences between the corners. Here were my OEM ride heights (measured from fender to top of center hole (not center of hole):

LF: 319.1 RF: 315.9
LR: 327.0 RR: 325.4

I used these preloads:
Front: 2.5mm (Ohlins’ reco + 0.5mm - just right for middle of damper travel at rest, but less weight than OEM helped keep me away from max damper length to get 10mm drop)

Rear: 21mm of preload (0.83in). I calculated 1.06” as desired preload, but wanted to hit 10mm drop without hitting max short damper length. I tried to stay away from max short or long damper lengths so that ride height adjustments could be made during corner-balancing without changing the preload.

My final damper lengths after several tweaks:
LF: 543 RF: 545 (Max damper length is 551)
LR: 405 RR: 405 (Min damper length is 405)

So, I didn’t succeed at keeping off the min length in the back. I don’t know if there is less weight in back than my ideal calculation (likely), or the MR for the rear is incorrectly calculated. I couldn’t verify it myself. I’m pretending more accuracy on those numbers than I’m really capable of. It’s not easy to get accurate measurements in place and I’m not taking them back out to measure them. However, it’s close enough until I can take it and get it corner-balanced.

My final ride heights right now are:
LF: 310 RF: 310
LR: 315 RR: 315

I found that the Ohlins reco of 10 clicks out from full hard on damping was fine for around town, but on the back roads, I found 7 clicks out on the front and 9 on the rear was pretty good. With more time, I’m sure I’d fine-tune that. It was a sauna in northern Kentucky this weekend, so I dehydrated before I could test many combinations.

One other note: I measured the Ohlins vs. OEM and had a total of 14lb weight savings. Not bad.

Gernby made a comment about how these dampers returned him to the street-driving joy of that made him want race rubber all of the time. I totally agree. I could not be happier with the choice.

In order of my favorite mods:
1. Flashpro (with Evans tuning)
2. Ohlins DFV
3. T1R Dual EM exhaust (because the sound is absolutely pornographic)
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Old 10-30-2014, 12:33 PM
  #120  
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Great write-ups!

Does anyone know if the box (with both packages) will fit in the trunk of our cars?
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