silverTRD

iTrader: (36)

looks like a great driving road lookatme, lots of fun im sure.

i understand what you are saying about the softer spring rates for comfort and performance, but have you ever timed yourself to prove it? i know it would be a pain to switch back to 11/11 rates just for a test. plus you prefer how the car is setup and feels with the softer rates, just curious i guess.

BLUE TII

iTrader: (9)

Ah, highways. I just put the cruise control at 65mph.

I set the cruise control at 55mph for this one.


That corner at 46-48 seconds is the only one that gets your heart rate up the 1st time you take on cruise control at 55mph (hidden apex and no accelerator/brake weight transfer adjustments 'cause cruise control).

I prefer the tight twisty roads that are 3rd and 4th gear instead of 4th and 5th gear with a combined impact speed over 150mph if someone is in your lane around a corner.

lOOkatme

iTrader: (19)

I don't need to time myself. The softer rates springs allow me to run the car wide open throttle in almost all high speed corners. The 11/11 I could not do this as the car felt unstable. The straight away above 110+ mph the car would bounce in some weird way on the straight and destabilize the car. The 8/6 set up doesn't have a lick of this. I remember 4 areas I really tested the set up on.


at 3:23 to 4:25 & 4:38 to 4:46 on that up hill (that is a 7% grade), that uphill the 8/6 combo decimates the 11/11. I mean I can hold open the throttle the entire way up that hill and the car sticks. The 11/11 is all over the place at anything over 100mph. I back off on that uphill and don't do 140MPH+ (top of 4th) but the car with 8/6 drives VERY well and is planted. the 11/11 would dance everywhere and would literally scare the crap out of you.

at 5:40 to 5:43 there is bump mid corner on that turn, the 11/11 set up would skip the front tire over it and skid, the 8/6 I would notice a bump but wouldn't skid, I took it a few times with both set ups and I was extremely fast on the 8/6 set up, the 11/11 I couldn't push as hard as I was sliding over that bump. I couldn't tell you exact differences in MPH, but the difference is very large.

I followed a guy with ohlins DFV 11/11 on this very road and we do have footage but I don't have it. I was playing with him behind him as he was sliding all around. he had a corner where his rear end kicked out and I was at a brisk cruise for me.

I don't know if 8/6 is the fastest.....I do know for this road it is faster than 11/11, perhaps an 8/8 or 8/7 is faster or 9/8 or 9/7 or something in between the two spring rates.

One section where the 8/6 felt a little funky at times was between 1:04 and 1:10. those S turns can sometimes be tough because you want the car to settle faster when the speeds are high, so this makes me think if you run a 8/7 or 8/8 or perhaps a 7/8 or 8/9 set up that the car might feel better in those transitions as the rear needs more rate to settle the rear faster. everywhere else I didn't feel the need for more rear rate.

I used to own a Honda prelude, I did a lot of tuning to that car and I had some Tein suspension on it with a 1.5" lowering or something (coilover, corner weighted, etc). I tried the initial 8/4 KG set up that came with the car, HATED it so much. I upped the rear rate to a 6KG spring and had an adjustable progressive rear sway bar and stiffened it up with the stock front sway bar. The car was amazing after that, got rid of all understeer and felt GREAT.

I tried different front and rear sway bars on that car and different rate springs, etc. The best was the above set up. The rx7 seems to like the 7-9KG front spring rate and rear 7-9KG just for my type of driving.

The slow corner (10mph hard turns) the soft springs rates aren't great. The 11/11 set up would be better IMO. but for the majority of my type of driving the softer rate springs are better.

if I were to pull the ideal spring rate to try, 8/7 or 8/8. If I can find an 8KG 7" long spring I might try it for the hell of it and see how it effects everything.

LargeOrangeFont

iTrader: (7)

Don't ask for any empirical data here

For the street his setup is probably better. For the track the car would be rolling all over itself, especially with sticky tires.

Lookatme - if you want to try other springs, take a look at PAC. They are very light, high travel springs. Plus they post ALL springs dimensions on their website. They have a 7 inch 450 lb (8k) spring, and any other rate you'd want in a 7 inch spring.

ZDan

I'll point out again that you're not only comparing spring rates, you are comparing very different roll stiffness distributions.

Even spring rates (like 11/11, or 8/8, or 6/6) gives rear wheel rates that are 28% stiffer vs. front.
8/6 spring rates gives front rates 4% stiffer vs. rear.

That's a substantial difference (32%) in front/rear stiffness bias!

Um, literally? I usually clench up in such situations
Of course a more legitimate comparison would be between 11/11 and 7/7. Or between something like 12/9 vs. 8/6.

But in any case, there is no doubt that what works in general for performance driving *on the street* is not what's going to work best *at the track* for a few reasons.

One of them being that at the track you get to drive the same piece of road every minute or two for extended periods of time so you get very familiar with the whole track and learn how to place the car with inch precision and how to deal with any bumps/undulations/etc.

On the street, even on your favorite road, you just won't get that kind of practice, you won't be able to consistently place the car as precisely or have anything like as consistent entry and exit speeds.

For you, and perhaps for any reasonably talented driver who is leaving some in reserve and isn't able to PRACTICE critical corners dozens of times over the course of an afternoon or a day.

Ultimately what is "faster" is going to be highly dependent on a lot of factors, not least of which is who's driving! And on what tires, and under what conditions...

I don't think anyone here would disagree.

Again I'll point out that you are not simply comparing stiffer vs. softer. The 11/11 setup is 32% more rear-stiffness biased vs. your 8/6 setup!

I do agree that for the street, on more street-oriented tires, I would rather be on spring rates in the 8/6 range than the 13/11 I have on my car. But at the track...

8/8 would be interesting to try. Personally, especially for the street, I would bet that having front springs stiffer than rears, giving more even front/rear wheel rates, is going to be better overall on the street and at the track.
But this is highly dependent on driver preference! Not to mention alignment settings, limited slip, etc. etc...

lOOkatme

iTrader: (19)

I think it would be fun to try out all these rates, not fun buying all the different spring rates and the installation of all of them. The rear is pretty easy to change out and fast, the fronts suck a lot more.

ArmenMAxx

iTrader: (21)

Interestingly, as a DFV (flag-r) owner with 12k/12k swift springs, I feel a need for stiffer rates when on track especially in the higher speed zones. Also, the car is squatting/dipping/leaning a fair amount considering im on street tires. This is with my compression up about 17 clicks and rebound almost full stiff. On the streets and LA canyons I drop down the compression and rebound quite a bit and it feels very compliant with absolutely no jarring or bounciness.

lOOkatme

iTrader: (19)

How are you measuring that you need stiffer rates?

I ran 12/12 and 11/11 and I can tell you that these rates are extremely stiff. The car didn't lean much or have all that much movement.

I am running RE-11 285/30/18 tires on 18x11.5" wheels and I have a TON of grip, probably as much as a 255 running R-comps on a 10" wheel.

I am not hitting the bump stops anywhere that I am aware of on 25" front and 25.5" to top of wheel arches. I am running 24.8" tall tires which are smaller and give me a little more room than a 25.3" tall 265/35/18 I used to run on 18x10" wheels.

I have warmed these tires up and taken some extremely fast corners at 60 to 120mph and the softer rate springs are much more forgiving, they are much faster as the car doesn't wander at high speeds and it feels planted, instead of floaty. I also can literally push it to the ragged edge of drifting the car around corners with the back end coming out some.

The stiffer springs were less forgiving and were much slower as the car just couldn't grip at high speeds. It wanted to skip across the pavement instead of hook. Remember I have stretched 285 tires on wide wheels, not much of a energy damping mechanism but also why I have so much control with my tires.

I can understand how people think the car has too much lean or movement, doing fast transitions back and fourth I could see how this is not wanted. I think people aren't used to driving at high rates of speed and they want a rock solid fast reacting suspension because they are scared. I have found that body roll and lean are actually a good thing. I like running softer rate springs and high damping to control the movement (it's stiff but compliant). With high spring rates you control movement through spring rate and lose the compliance.

It's like catching an egg, you want to slow its movement down slowly not to break it, the same applies to your tires, you want the most force pushing them back to the ground, and you want to slowly transfer weight onto the tires, not one big transfer.

I noticed that people also like putting sway bars on, this just makes the car harder to drive at the limit and reduces grip. Putting both of these on makes the car a lot tougher to control at high speeds, it makes it an illusion that the car is faster because it slides all around at a lot lower speeds. I did think the balance of the 11/11 was alright and when I pushed the car hard it was sliding around, but I noticed that I was doing so a much slower speeds, the high transitioning might work better for autoX, but the high speed stuff the softer more forgiving rates have been great.

So How are people measuring that X is indeed faster than Y?

Also, it would be very tough for a person who drives stiff springs all the time to be comfortable and fast driving softer rate springs, there is a learning curve. so if you swap to a stiff to soft spring and find the softer rate springs are slower, they might not in fact be slower but the driver needs to learn how to drive on the softer rate springs first and eventually breaks the stiffer rate springs times.

I also understand that a softer rate spring might not be wanted in wheel to wheel racing, as you need the faster response. I understand that. I also see a lot of people in this thread pointing to cars with aero on them, mine has zero aero help. I am sure this also adds to the dynamic to run different rate springs.

on a side note, I am a mid 600lbs deadlifter. There are people always asking how they can improve their lifts? I watch them and they usually have poor form, after that it is strength and form refinement. I would say most people hit a brick wall between 405 and 495lbs for having poor form, they usually injur themselves. I show people the form and what is needed, most deals with moving the shins more upright, hips farther back and the chest needs to lead upward. All of them are not as strong as their incorrect lifting as they are using new muscles, and they need to develop it over the next year to get really good gains and learn the new technique. Most revert back to their old technique because the new technique takes time to learn and develop in order to lift over 500lbs deadlift.

I have a feeling that some of this could be happening here with running such high rates.

What is causing most of you to hit your bump stops?

LargeOrangeFont

iTrader: (7)

So NOW you want to actually measure things and get empirical data Look?

I would say ArmenMaxx has quite a bit more experience on a controlled environment (a track) pushing his car consistently harder than you could do on the street. Plus the guy can wheel the car pretty well.

And no, your 285s do not have more grip than a 255 r comp that is up to temp.

BLUE TII

iTrader: (9)

^^ basically what he said, but with a bunch of words.

I am not hitting the bump stops anywhere that I am aware of on 25" front and 25.5" to top of wheel arches. I am running 24.8" tall tires which are smaller and give me a little more room than a 25.3" tall 265/35/18 I used to run on 18x10" wheels.

I have warmed these tires up and taken some extremely fast corners at 60 to 120mph and the softer rate springs are much more forgiving, they are much faster as the car doesn't wander at high speeds and it feels planted, instead of floaty. I also can literally push it to the ragged edge of drifting the car around corners with the back end coming out some.

I'm not saying you should drive harder by any means- I have already told you how slow I drive on the street.

But... you have your car set up for comfort driving on the street and you drive up to the limits of your comfort, not up to the limits of the grip and equipment as you do racing.

All you have to do to see this is download an app for your phone to measure sustained G(th)s or measure the radius of the turns you are taking and compare them to a chart that will show you the max speeds you can take that turn at a given G.

You will find you are (rightly) driving much slower than the car can. A stock FD can pull 1G average on stock tires. Your FD could easily pull 1.2g average cornering.

How are you measuring that you need stiffer rates?

I ran 12/12 and 11/11 and I can tell you that these rates are extremely stiff. The car didn't lean much or have all that much movement.

I am running RE-11 285/30/18 tires on 18x11.5" wheels and I have a TON of grip, probably as much as a 255 running R-comps on a 10" wheel.

I am not hitting the bump stops anywhere that I am aware of on 25" front and 25.5" to top of wheel arches. I am running 24.8" tall tires which are smaller and give me a little more room than a 25.3" tall 265/35/18 I used to run on 18x10" wheels.

Because race car.

Racers can't drive up to the limit of their comfort and win (in most racing), someone else will drive up to the limit of their equipment and beat them.

They are on the bumpstops cornering with the car leaned way over is why they need stiffer springs racing.

Once they are on the bumpstops, any bumps the loaded wheels hit have to deal with the crazy high spring rates of the bumpstops and as you say, it is much easier to deal with slowly increasing inputs instead of a sudden input to the chassis from high spring rate.


----------
As far as wheels/tires.

Current wide max performance street tires on a wide wheel really can have as much peak grip as the old streetable DOT-R in sizes most people run on the FD- except not in all situations.

Wheel tire mass and lower tire weight loading make the wider wheel/tire worse over bumps and skating over debris/water.

However, I don't think any fitment of street tires can yet match a stock fitment of the fastest DOT-Rs (like Hoosier A7s)... which is what a racer will be talking about (because why race on a slower DOT-R?).

lOOkatme

iTrader: (19)

just take a listen, obviously one persons opinion and matches my experience.

BLUE TII

iTrader: (9)

I already agree with you that soft springs are better.

I am just saying a soft spring + bumpstop is a harder spring than a hard spring with travel to the bumpstop.

Look at how hard the racers that have to use stock springs geek out on bumpstops (the Miata racers he is talking about in stock class). Those cars corner on bumpstop springs and the stock springs with shocks custom valved to the aftermarket bumpstop spring rate.

Its a spring.

ZDan

Track =/= street usage!
Here's what trail-braking into a left-hander looks like on 13/11 springs on NT01 tires:

(Static ride heights 24.7" front, 25" rear.).
The car moves around quite a bit on 13/11. You shoulda seen it on 9/7 springs! 13/11 is a decent *compromise* for a street/track car, but it is still quite a bit on the soft side for a serious track car.

I don't think so...

On my car at NHMS South Oval, I went 2 seconds faster on NT01s vs. Dunlop Z1 *spec, a street tire with equivalent performance to the RE11. *Serious* track tires like Hoosier R7/A7 and BFG R1/R1S would be another 1.5 to 2 seconds quicker still.

A 285-width RE11 is *nowhere near* the equivalent of the top DOT R-comps in 255 (BFG R1/R1S) or 245 (Hoosier R7/A7). I would bet on 205 R7/A7 or R1/R1S over 285 RE-11 on a 2850 lb. FD at the track...

At 75-80%, without being able to place the car with inch precision, sure.
Um, maybe the car/driver system is faster, but the driver is the limiting factor here. Hopefully he has the good sense to leave a ton in reserve *on the street*, where conditions at a particular corner are not as well known as at the track, *and where there may be cars around being driven at much slower speeds, some coming in the opposite direction*.

No, the people who track these cars don't gravitate towards stiffer (vs 8/6) springs because "they are scared". They do so to go faster.

With stiffer springs, you can control the transfer better because the car's limits are expanded. If you need to transfer weight more slowly, you turn in slower, no prob. In a softer car when you need to turn in quicker, you simply can't. You're limited by the car's wallowing.

With lap times. That's how I know I was 2 seconds faster on NT01s vs. Dunlop Z1 StarSpec, and 1 second faster on 11/11 Ohlins DFV vs. 9/7 Tein SS (on the same Z1 starspec tires).

It is easier to find the limits on a slower/softer car vs. a stiffer/faster car. I am saying this in the context of our discussion, where 8/6 is "softer" and 11/11, 13/11 is "stiffer". I have pretty much since I started tracking always had a more track-oriented car and a softer street car. I find that tracking the softer street car, it's easier to find the limits and can actually make me lazy, such that when I get back in the stiffer and faster track car I realize I have to be a lot sharper and a lot quicker with my inputs and responses. But the reward is more speed, quicker lap times.

Start tracking your car and see where you wind up. Until then you have no basis for suggesting that 8/6 springs are faster than more track-oriented rates. Are they more appropriate for the street? Sure. Ultimately faster? No, demonstrably not.

j9fd3s

iTrader: (3)

we used lap times. the 2015 setup was, stock sway bars, 205/45/15 R7's on 15x9's. shocks are Ohlins DFV's. no aero. we're class limited to 134rwhp and 2380lbs.

to pick the spring rate we started at the spec miata rates and went up until the car got slower, then we went back down to the next highest rate. i mentioned the rates earlier in the thread, but i think its 9/7.

we're about half a second off the lap record at laguna in PTE. i think it was 1:46.3 and we're 1:46.8. we've got a few trophies too, actually its pretty neat, 14 months after being a DD it has, 3 national podium finishes, a regional championship and another regional podium, we did TTE and PTE

eage8

iTrader: (9)

Spec miata rates are 700/325 or 12.5k/5.8k aren't they?

eage8

iTrader: (9)

This thread is now the same exact conversation we were having a few months ago.

bottom line:
- you loose camber when you roll
- even good suspension like the FD doesn't reclaim the camber it looses when it rolls
- if you have enough camber in the car to account for loosing camber when rolling with soft springs (a lot) it's going to suck during brake dive and accel squat because the tires won't be flat at all... so it won't be fast.

I'm running 900/600# (16/11 kg) springs on my FC and it still rolls too much with hoosier A7s. (based on picture angle measuring and my front camber being maxed out and still not enough according to tire wear).

your springs work out to something like a 200# front wheel rate can't possibly be staying out of the bump stops if you're actually driving the car hard at all, especially over bumpy roads. Maybe the camber loss is so bad it's causing the cornering speed to drop low enough for your to feel comfortable

LargeOrangeFont

iTrader: (7)

I am running 700/400 springs on my FC. It is demonstrably faster on the track than when I was running 500/400, and that was faster than 8k/6k. All this is documented by quicker lap times.

I ran 700/500 for a bit and the rear bounced too much over rough sections of the track, so I dropped back to 400 in the rear. The 700 front springs also reduced brake dive a lot, and improved my braking performance.

As Eage8 noted, we are gaining speed by keeping the tire's contact patch planted as firmly to the track as possible by reducing (not eliminating) roll.

I am pretty happy with amount of roll I have at the moment.

BLUE TII

iTrader: (9)

eage8
Quote:
Originally Posted by j9fd3s View Post
to pick the spring rate we started at the spec miata rates and went up until the car got slower, then we went back down to the next highest rate. i mentioned the rates earlier in the thread, but i think its 9/7.

Spec miata rates are 700/325 or 12.5k/5.8k aren't they?

Don't forget the typical Miata set up has a rear compression stroke around 63mm at the shock.

13mm stroke on the spring alone and 50mm stroke on the spring plus bumpstop.


The bumpstop is a spring (especially on the Miata, but not so much as on an old Mini where the bumpstop was the only spring... and the damper as well).

ZDan

I get that working out to be just under 2 Hz front, 1.9 Hz rear, similar to an FD on 12.5/9.5 springs. Softer than I woulda expected an optimal track setup to be!

My car is just under 2 Hz front, just over 2 Hz rear. Seems a little soft at the track, but I have by no means optimized on spring rates...

lOOkatme

iTrader: (19)

My math for the miata, weight of 2100lbs 50/50, wheel weight and suspension of 55lbs per corner, gives a sprung mass of 214KG without a driver. I get a front frequency of 2.25hz and a rear of 2.19hz. will drop slightly with a driver in the car.

for the rx7 this would be like 17K front and 12.5K rear

j9fd3s

iTrader: (3)

lol, see what happens when i go off memory! you can look earlier in the thread, and i posted the rates from the car, its like 750/450

j9fd3s

iTrader: (3)

we're not running stock bumpstops. the Ohlins have their own top/bumpstop is really short. we didn't do anything fancy here either, we just lowered it until it got skittish, and then raised it. we then cut a piece of metal to measure the ride height, and just check it periodically.

ninesixtwo

iTrader: (9)

Just to throw some fuel on this fire... When I was having my Aragostas rebuilt, the owner of the company recommended either 14k/14k or 14k/12k for a low/medium speed track with R comp tire and 16k/18k or 18k/18k for high speed track. When I initially said I wanted 12k/12k he said it was too soft for any track use with sticky tire. For street use, 10k/8k is standard.

A shot of my "extremely stiff" 14k/12k springs not rolling during some low speed trailbraking:

j9fd3s

iTrader: (3)

see my math error, or just brain fart. our test was pretty simple, rear of the car really didn't like anything over, i'll say 450, so we have it at 450.

we didn't really ponder why the rates that worked worked, we just moved on and started tuning other stuff.

after the nats i drove the car at the miata pride parade, and its quite soft, it rolls a lot. we would have liked to run sway bars, but we needed the points for PTE/TTE.

lOOkatme

iTrader: (19)

When looking at some of the track pics, those surfaces look glass smooth compared to the street. This is probably the largest difference, as driving on the track probably only requires a fraction of suspension travel needed. I tried the 11/11 on the street and the rear was definitely too stiff, you could probably get away with leaving the front alone, but back off the rear rate.

On surfaces that are glass and only need 1/4" of suspension travel, then yea, stiff springs will be just fine.