ZDan

OK, that's 13.4/8.0, I get 2.40 Hz front, 2.05 Hz rear (2380 lb. car, 50 lb per side up front 45 lb. per side rear unsprung).

Equivalent to 18.5/10.7 on a 2850 lb. FD (55 lb front/50 lb. rear unsprung).

ZDan

I will mention this again: I run the heavily-loaded right-side tires over the 2.5" curbing on the right exiting the North Chicane (racing line makes it a single left-hand turn) at New Hampshire Motor Speedway while applying full throttle in 3rd gear without upsetting the car at all, on 11/11 and then on 13/11 springs. Most of the tracks I go to have their bumps, curbing, undulations you have to contend with, not many tracks will be pristine and smooth all the way around the racing line.

Anyway, speaking of suspension travel, with stiffer rates you will have more in reserve for bumps encountered while cornering because you aren't using up as much of it with lean.

You tried 11/11 and found that it was too stiff for you, for your usage (street). That doesn't mean it's universally true for everyone...

I do agree that for the street, 11/11 is on the stiff side for most people, and the even spring rates gives significant rear stiffness bias as well. IMO 11/9 or 11/8 would be a better street setup in general vs. 11/11. I also agree that softer rates like your 8/6 (still way stiffer than OEM) make a lot of sense and will be more enjoyable and handle great on the street.

j9fd3s

iTrader: (3)

track not smooth
the FC won, btw. nicest FC i've seen in a LONG time. the orange miata is a 40K build, the last off broke something major

LargeOrangeFont

iTrader: (7)

Willow Springs is not smooth either.

lOOkatme

iTrader: (19)

Here is just a little clip I took a while ago from an uphill drive they closed off for the day. those roads a good representative of what I drive on and the speeds are probably close to that since most of the smaller canyon roads are not busy at all.



Funny part is, when I went on the cruise up in 2014, we hit 150-160mph in some spots. We were going faster than these guys going "fast". The first car is supposed to be a pace car.

Video from the footage of the cruise. you see my black FD in there a bit.

ArmenMAxx

iTrader: (21)

Although I dont use very techy gear for measurements, I do use a pretty accurate 10hz GPS devices/apps to record my specific speeds at specific points on road courses. I also do go off my butt/feel and lap times to evaluate my suspension. Even with 12k/12k and 275/35/18 Zii tires, I am still waiting for the chassis to respond to my inputs.. especially at higher speeds. That waiting is time off the clock and my MPH on corner exits were lower with softer springs. Also, yes the lean can be disconcerting at 130mph, but I still bring the car to its ultimate edge of grip and exploit it.. I usually find this point by passing it on purpose which = understeer (boring) or a slide (fun). One of the most talented drivers I've met told me the best way to learn about your car (or a new car your racing) is to go out there are make it understeer. I liked his philosophy.

There was no doubt that the car was more stable and faster when I went from 10/8 to 12/10 and eventually 12/12 on the pettit track pro coilovers and I chopped down lap times with each move. I was bottoming out on 10/8 often especially on bumpy canyon roads. With the ohlins at 12/12 the damping was miles better so the car felt more flat, because it was leaning at a slower rate. This made it much more stable at high speeds however the car is still breaching ideal "wheel alignment"by leaning too much at some point. No doubt that softer springs work better on street roads. I am just sharing my .02 from my own road course experience. Later down the road when I up to 14k/14k I will post back and share the results.

Edit: Here is a old picture with 12k/10k springs and RS3 tires.

ninesixtwo

iTrader: (9)

What's everyone running for seat/harness?

LargeOrangeFont

iTrader: (7)

Kirkey series 47 Road Race seat for the driver, and a Kirkey Pro Street Drag seat for the passenger. Gforce 5 point harnesses for both seats.

I have an Autopower roll bar in the car to tie the harnesses to.

Kirkey seats are very easy to fit in FCs and FDs. They also come in multiple widths and are pretty light.

lOOkatme

iTrader: (19)

Thanks for your feedback. What size tires and wheels are you running?

Andy

BLUE TII

iTrader: (9)

ninesixtwo

What's everyone running for seat/harness?

Bride Vios III Japan seats/LowMax rails and Takata (Schroth) Drift III DOT harnesses/Sparco FIA eye-bolts/RotaryExtreme harness bar.

It is a great question, I couldn't hold a corner in the stock seats nearly as well.

Was reading an accident physics study and was disheartened to read they found the average driver can only tolerate 0.3Gs before they panic and crash because of poor inputs and their driving line is 8% tighter than the center-line turn radius instead of a larger radius like a "racing line".

So, remember that is whom we share the road with.

ArmenMAxx

iTrader: (21)

Wheels are 9.5inch front and 10inch rear with 265/35/18 and 275/35/18 tires respectively. Not the most ideal wheel sizes but im working with what I have at the moment.

valley

iTrader: (1)

So... what's different about Ohlin's that makes them so great? I've read their materials and many reviews but it always seems like people are going from basic shock/spring combos or shitty coilovers to them and the apparent improvement is simply from quality control and a not-stupid valving choice.

I am especially curious as (in particular) Fortune 510's are ~2k now, come with custom rates, and are dyno tested (and presumably consistent), while a custom set of Bilstein's will command ~1.5k+, and can be setup for nearly anything desired if you or someone you know/pay knows how to or gets lucky.

lOOkatme

iTrader: (19)

It's the valving that is better. If you look at their shock dyno the beginning of the velocity curve have a smooth not harsh damping, and slowly ramps higher over velocity and blows off at top. it does work well.

The linear valving is harsher at high velocities.

The bilstein is harsh in low movements because fluid cannot freely move.

On the compression side of things ohlins change compression and damping to match them up, which I agree with. you change low speed compression adding some more stiffness to the suspension while leaving mid to high speed movements alone. the damping matches the curve as well.

Fortune doesn't do this. They have a generic compression curve and only changes damping.

I am a big fan of ohlins damping and especially the damping in the lower (softer) damping settings. its softer damping for comfort and blows off at the top for better compliance. It also ramps into mid speed smoothly so its nice and compliant. you can adjust the damping to be much more aggressive, both ends of the spectrum.

fortune dampers are a little more harsh in terms of their damping, you want smooth transitions.

I purchased more Ohlins dfv on group buy for basically the same price as the fortune 510's.

LargeOrangeFont

iTrader: (7)

Geez I'm glad I got my Fortune 510s when I did. I have been pretty happy with mine, but they seem to be a more race oriented valving setup as noted by lookatme. I can see Ohlins being a bit better on the street. That is probably why lookatme likes the feel of them with softer springs. If I drastically dropped the spring rates on my Fortune 510s the car would feel overdamped on the street.

I have ran custom valved Bilsteins on other cars, but not on my RX7. The Fortune spring recommendation was not ideal when I worked with them, but I have dialed in the spring rates now.

As far as Bilsteins go, you can have Bilstein revalve them. They are fairly knowledgeable, and do a good job if you give them all the details of the car.

lOOkatme

iTrader: (19)

fatcatmotorsports reworks a bilstein shock with a ripple reducer, same as the ohlins DFV technology, to reduce the little ripples in the road, it allows the fluid to move freely back and fourth. I bet its expensive to have it redone this way.

LargeOrangeFont

iTrader: (7)

That is probably the skating around you feel with stiffer springs. The car is probably oversprung for the soft initial compression and rebound needed to soak up washboard sections in the road.

Dropping the spring rate lets the damper soak these up.

lOOkatme

iTrader: (19)

Yes, that is exactly what I was feeling. I had the shocks at the recommended 10/10 settings from Ohlins on the 11/11 spring rates. I was going pretty fast (100-120mph) testing the shocks out at different areas of the roads with different surfaces. The spots where I had trouble where the washboard areas where the car felt like someone grabbed the chassis of the car and shook it up and down in a very short distance and just kept shaking the car up and down, like a small distance pogo stick. When you turn the damping up the car wanted to skip over the bumps in corners where there was uneven or cracks in the road. I couldn't find a good medium with the 11/11 spring rate on the roads. I also ran the car over some roads where you go perpendicular across a main road and I put a little acceleration over it and the rear would want to jump over the depressions in the road from the weight of the cars (you know the road gets like a whoop section from cars always driving in one spot on the road). The 8/6 under full throttle was soft enough to maintain contact the entire time over this whoop section. It also knocked out all of the little whoops on the roads from washboard or whatever you want to call it. Another benefit when turning fast is the cracks and dips/bumps mid corner were soaked up, the 11's skipped over them. On the high speed sections the 11's skated around, it was very hard to control the car at high speeds, the 8/6 was completely stable and I could literally full throttle it WAY faster and the car was compliant and smooth and had tons of grip. The difference was not a little, it was like my car was completely new. I was scared driving one section at 90-100mph with the 11/11 and the car was all over the place. a mess. I put the 8/6 on and I was full throttle up to 140mph and the car was rock solid, felt like I could go even faster. That was how big a difference it was for me.

I am not sure if it was a damping mismatch or if the road and speed I was driving with those rates put it at a natural frequency or something like that. The car with the 11/11 felt better at low speeds in transition. Felt like you could really throw the car around, but the 8/6 had more overall grip, just the body would move around more. Once you get used to the body movement and learn how to drive the car with this movement it becomes more normal. the 8/6 is still stiff in terms of ride, but its not really stiff like the 11/11. Going over that same little whoop section where the 11/11 acted like a pogo stick, the 8/6 I went over and I didn't even notice there were bumps.

I am running 12/12 from full stiff on damping settings with the softer rate springs.

LargeOrangeFont

iTrader: (7)

You know part of that is because you have your tires stretched, right? I don't want to go through the debate again, but that is what you lose by stretching the tires. You have nothing to lean on at all because the sidewall is in tension. The car will want to snap away as it breaks traction, as opposed to a more progressive slide. A more square sidewall lets the car roll onto the tire a bit more.

Just saying.

But yes, if the car is bouncing around, you have too much spring.

ZDan

I found the Ohlins-recommended 10 clicks out to be way too little low-speed damping for my liking even on the street. I run 6-8 clicks on the street, 4-6 at the track.

lOOkatme

iTrader: (19)

the car rides more rough with a stretched tire, but I found the opposite for breakaway characteristics. the car behaves more predictably with stretched tires than it did with square.

BLUE TII

iTrader: (9)

lOOkatme

But yes, if the car is bouncing around, you have too much spring.
the car rides more rough with a stretched tire, but I found the opposite for breakaway characteristics. the car behaves more predictably with stretched tires than it did with square.

That is what I and my friends that raced my FD found as well. Slight stretch on a tire that liked slip angle made the car transition in and out of higher slip angles seamlessly.

One friend told me it was disconcerting because he could not tell when the car was sliding or not. I asked him what does it matter?

I did notice when I ran my FCs 16s with 50 series sidewall R-S3 on the FD with Ohlins the ride did feel much smoother, but it felt under damped over small bumps. I would have thought it would be over damped on rebound since the wheel/tire was 16lbs lighter then the 18s I had adjusted the damping for.

Took me a second to realize it was because you cannot damp tire sidewall flex and R-S3 have a very soft sidewall even at 45psi.

lOOkatme

iTrader: (19)

I agree. the slight stretch increases grip levels and acts more like a go kart. it slides a little when losing grip and regains easily. The other guy runs an AD08 295/30/18 on 10.5" wide wheel. The tire tread overhangs. His car has snap oversteer. The slop in the tires is not easy to drive and makes the car smushy from the tires. the steering is also more mush and not a direct super high grip that seamlessly can go in and out of grip. there is no grip grip grip let go phase, its grip grip grip slide regrip grip slide grip grip.

I also feel that the car tracks straighter under braking as well. Its a different feel going from a 10" wide wheel to an 11.5" wide wheel. it is one of my favorite mods on the car.

LargeOrangeFont

iTrader: (7)

I should clarify slightly what I meant. Going through a washboard corner section of road with stretched tires could be more unstable and could result in less consistency. That is what I noticed when pushing my car on the street. Dropping spring rates would help that. The caveat is that there is so much inconsistency on a street anyway, it is hard to nail down. On a track I agree that a more stretched tire would likely be more consistent.

Keep in mind I am speaking from an FC standpoint, and they like a bit less tire stretch than an FD from all I have seen.

To Blue TII's and lookatme's point, you set the car up for the tires you are running.

BLUE TII

iTrader: (9)

LargeOrangeFont

I should clarify slightly what I meant. Going through a washboard corner section of road with stretched tires could be more unstable and could result in less consistency.

Agree, even very good suspension can use a little help still from the tire sidewall. We are not yet at the point in suspension design where we can run non-pneumatic tires, but we sure are getting closer.

LargeOrangeFont

iTrader: (7)

Yea. Car setup is still all about the best compromise.