Advantage of Swift Springs

[Speed Junkie]

So does anyone know what the advantage of Swift Springs is over the standard springs that come by default Fortune Auto coilovers for example? I hear and read a lot of "they feel better but I don't know why." Which rings all of my placebo bells.

Both are linear rate springs. So unless the "conventional" spring was significantly flawed in such a way that its spring rate would vary throughout its compression (which seems like a serious manufacturing flaw) so much that the driver would feel it as some "negative" "less-than-ideal" sensation, I'd be skeptical.

The Swift site states the following:

"Top suspension tuners know that these 4 factors play an intricate role when considering the effectiveness of the suspension coil spring."

1. The most consistent spring rate throughout the stroke
2. The largest amount of stroke
3. The highest durability against loss of spring height
4. The lightest in weight


I think we can mostly ignore 2 and 3 since most 240 drivers have an issue with suspension stroke, not spring stroke. We can exclude 3 since we are assuming these are new springs. That leaves us with 1 and 4. They use a proprietary steel alloy "HS5.TW" for what that's worth.


So are there any experienced drivers here that have experience with these springs and could explain (the more technical the better) the benefits they saw?

[slow_sr20]

Not technical but I’ve run both springs on same car in close proximity to one another. I will always run swift. Much better ride quality on swift. Less “bounce” more forgiving.

Something to do with the quality of the steel, windings farther apart than “standard” springs makes the compression more linear. I’m no engineer but go with swift def worth the extra cash.

[e30gangsta]

They're also a lot more true to their spring rating. So if you're ordering a 6k spring you're getting a 6k spring, whereas the china ones that come with your coils could all be labeled 6k, but there are differences between each one.

[tacotacotaco]

Heres my 411 doing a lot of suspension work in Nissan Challenge and Corner3 Motorsports.

The stock springs that come on most coilovers basically are from one huge spring that they cut as it comes out. They then go and dyno the spring and if its in a certain % of like an 8k or 9k thats what it gets rated at and put in a bin and put on your coilover. So if you have cheap coils or something to be cost effective thats the spring you get. So between left and right you have a possible difference in rate between the two.

Consistency. Swift springs are very consistent. If you put a swift spring on the dyno the rate throughout compression is very consistent. Also if its an 8k or 9k etc you can trust and verify that it is actually an 8k or 9k

Swift also resists sagging so after a year of racing you arent pulling off a spring that is now an inch shorter or more from fatigue.

Material used on swift is very high grade hence the ability to resist fatigue sag and remain consistent

What this all means: You can actually improve the performance of an off the shelf damper by putting swift springs because you just removed one of the largest sub par part and now gain more consistency from spring alone. so instead of rolling around with springs on each corner that can all be slightly off marked rate all springing up and down slightly different from each other at different frequencies you now have 4 consistent performing springs around each corner.

http://www.corner3motorsports.com/product/swift-metric-coilover-springs-60mm-65mm-or-70mm-id/

[mad-ass]

Linear and progressive spring rates are what you are looking for.

[slider2828]

Check out this thread.

http://zilvia.net/f/showthread.php?t=317684

[tacotacotaco]

Linear and progressive spring rates are what you are looking for.

Linear springs= springs that maintain a constant rate throughout compression
Progressive springs=springs that have varying rates though its compression cycle

https://bimmertips.com/wp-content/uploads/2016/10/suspension-linear-vs-progressive_mid.jpg

[Speed Junkie]

So I looked at the swift spring test (https://www.northamericanmotoring.com/forums/suspension/157535-swift-springs-dynoed.html) thread you posted. It shows that between the springs tested (Eibach, H&R, Hipercoil, Cross among them), Swift springs deviated from the specified force value the least (no more than 5 lb/in of travel). So this seems to be the most plausible of the stated advantages that the layman driver might actually be able to feel.

The other obvious advantage are the fewer number of coils which increases the springs maximum stroke and reduces its weight. Assuming our imaginary layman driver doing his comparison just driving down the road and not "maxing out" his springs then I think we can also exclude this advantage as a factor. Spring weight is a significant factor but again, is the typical 240 driver that brags about his new springs after driving around town really feeling the different between a slightly lighter spring? I don't think so.

I also read through your thread. Specifically the back and forth between Def and NINJAS14. Nothing was really established and Def's stance falls on the side of my opening post.


EDIT:
Linear and progressive spring rates are what you are looking for.

No I'm not.

[slider2828]

That linearness makes a huge difference through on the stroke. True doesn't matter if you tested 1 coil, but you have 4 of them..... over 2800lbs.... That WOULD make a difference on feel....

Its a noticeable difference + unsprung weight.... worth the upgrade...

[S14DB]

Most of the spring rates on coil overs increase as they compress. Making the spring rate feel higher than rated. There are very few brands I would trust their spring rates to stay linear.

Swift springs are a common upgrade in Japan because of their linearity. There are many more brands made in the US or available in the US. Going to a more linear spring at the same rate will improve the handling.

Hypercoils, Eibach and Swift are the only ones that usually fit.

[mad-ass]

Since my very simple post didn't explain and you weren't happy with it, let me explain. I figured you did enough research to even be remotely be interested in this topic so I thought you'd understand with my previous post. Which still is very important on why I posted it.

The said no-name brand generic springs claim to be linear, but in fact they are not linear which give them the bouncy ride, and bouncy ride means loss of traction and grip. 95% of coilover struts in the current market comes with poorly made springs that are advertised linear springs, but in fact they act like progressive springs due to their material and manufacturing process. Poorly made springs will have irregular spring rates also, so your advertised 8k springs on driver side may act 7k and on passenger side may act like 9k, you can't tune this out even with corner balancing and sway bars! The "advertised/generic" linear spring will changes it's rates very drastically with every millimeter of compression, making them a progressive spring.

Generic springs being progressive isn't necessarily a bad thing either, progressive springs are meant to provide all around comfort and traction over all different types of terrain and weight. Think of motor cycle manufacture's rear springs for a second, they sell the motorcycle and their buyer/rider might weight 120lbs or 280lbs, and they have to make the motorcycle safe to ride for either riders and can't customize all of their motorcycles off the assembly line; solution is progressive spring. The rate of change in spring rate in good progressive springs will be very smooth and gradual upscale if plotted on a graph, and now take our generic coilover springs and put that on a graph, it'll almost look like a cliff on the charts due to it's range of compression.

Now that the obvious things are stated, look at how much the coilover struts compress compared to factory struts, I am willing to bet most factory strut will travel double the distance of what coilover struts will. Let's say factory strut travels 8 inches and coilover struts travel 4 inches, you are asking a lot of traction out of 4 inches of travel.(no pun intended) So you need every little help you can get because you are asking the strut to give you same amount of traction out of 4 inches that you used to get out of 8 inches, the short travel just cannot compare and it does not help if your spring decides to act like a pipe after just 2 inches of compression when you need 4 inches of compression.

Let's not forget that coilover struts are meant for very specific use and YOU have the ability to change the spring rate and damping rate at will for what you are going to be using it for. If you want truly comfortable yet capable coilover setup, use 4k springs front and rear in longest spring you can find to fit.

Swift springs are considered gold standard along with Eibach due to their materials used and manufacturing process ensuring their products act as they are promised.

TL:DR Swift and Eibach springs are what they say they are, no-name brand generic springs that come preinstalled on majority of coilovers are not what they say they are and way too stiff for S-chassis.

Also, now that I've told you the benefits of Swift/Eibach, what is your intention with this information? Are you actually going to buy said brands? We still need to talk about actual spring rates and how they should be calculated to be used on a car based on ride height, weight and desired suspension travel.

[TheRealSy90]

Sounds to me like he is trying to justify using the cheaper springs to himself.

[Speed Junkie]

Since my very simple post didn't explain and you weren't happy with it, let me explain. I figured you did enough research to even be remotely be interested in this topic so I thought you'd understand with my previous post. Which still is very important on why I posted it.

1) "Linear and progressive spring rates are what you are looking for" is completely irrelevant to my original post because:

2) Calling linear rate springs "progressive" as an attempt to describe spring rate delineation (undesirable) from the advertised spring rate is a misuse of the word in the context of this discussion. Especially when "progressive springs" are actually a thing. It seems like tacotacotaco also misunderstood your comment as he posted examples of actual linear rate springs and progressive springs.

In other words, I know exactly what progressive springs are but I'll give you the benefit of the doubt and assume you do as well. Despite your misuse of the word in the context of swift springs being used on coilovers for 240SXs which completely excludes the use of progressive springs.


The said no-name brand generic springs claim to be linear, but in fact they are not linear which give them the bouncy ride...

Big no. Spring rate delineation is not the primary cause of a "bouncy ride". The damper is the primary device that controls spring oscillations. A bouncy car, whether bouncy at lower frequencies (softer springs) or bouncy at higher frequencies (harder springs) is usually underdampened or poorly dampened (linear valving instead of digressive with sufficient rebound dampening).

Even a Swift spring will oscilate excessively if not properly dampened.


*attempts to explain what has already been discussed either in this thread or on linked threads.*

Did you read everything that was posted before you?


The "advertised/generic" linear spring will changes it's rates very drastically with every millimeter of compression, making them a progressive spring.

Again, this doesn't make them into progressive springs which deliberately increase spring rate with stroke. This makes them into bad springs.


Generic springs being progressive isn't necessarily a bad thing either, *continues to blur the line between actual progressive springs and bad springs.*

*Attempts to explain the benefits of suspension travel no better than someone who for the first time was taught the benefits of suspension travel.*

Again, did you actually read anything that was said before you commented? more usable travel out of the spring was already stated as a benefit. Not sure who youre trying to prove wrong on this. It's also safe to assume that the majority of the members here have cars lowered to the point that their main issues with travel is with tires hitting the frame of the car, not with the usable spring stroke. That includes myself. My car isn't even "that low" in 240/zilvia standards, AND I've set up my coilovers to hit the bump stops just short of the tire (wheels straight) contacting the frame as you should, but despite that I run out of wheel travel long before spring travel.

It's a practical limitation of my choice to have my car look half decent at a somewhat low height. Maybe if I wanted to raise it to scca autocross spec then I would have to worry about spring travel. But I'm not because I didnt get a 240 as an ideal autocross car.


Swift springs are considered gold standard along with Eibach due to their materials used and manufacturing process ensuring their products act as they are promised.

More catalog fun facts that have already been mentioned. I came here for technical information/conversation (that was my first mistake lol) and not sideline bleacher salesmen.


Also, now that I've told you the benefits of Swift/Eibach, what is your intention with this information? Are you actually going to buy said brands?

For the record, I have gen. 6 FA 500 coilovers. 8kg F and 6kg R. And again, you didn't tell me anything I didn't already know nor have you provided any actual personal driving experience.


Sounds to me like he is trying to justify using the cheaper springs to himself.

I had Ohlins PCVs in my old Miata and have driven a wide variety of cars and suspension combinations including ADAC spec E90 on race valved Ohlins DFVs, a Swift on off the shelf DFVs, and plenty of Japanese platforms on Japanese coilovers. So I'm hardly limited in what I've actually driven. So for someone to try to catalog bullet point convince me of why I need springs on my half decent coilovers (in the 240 world) will at least make me raise an eye brow.


We still need to talk about actual spring rates and how they should be calculated to be used on a car based on ride height, weight and desired suspension travel.

Lol I'm good. Thanks though.

[Bluejayde]

If you already know everything then why come here? Just to act "holier-than-thou"?

[tacotacotaco]

So what did we miss in this discussion that wasnt already discussed?

[mad-ass]

1) "Linear and progressive spring rates are what you are looking for" is completely irrelevant to my original post because:
Calling linear rate springs "progressive" as an attempt to describe spring rate delineation (undesirable) from the advertised spring rate is a misuse of the word in the context of this discussion. Especially when "progressive springs" are actually a thing. It seems like tacotacotaco also misunderstood your comment as he posted examples of actual linear rate springs and progressive springs.
In other words, I know exactly what progressive springs are but I'll give you the benefit of the doubt and assume you do as well. Despite your misuse of the word in the context of swift springs being used on coilovers for 240SXs which completely excludes the use of progressive springs.
Big no. Spring rate delineation is not the primary cause of a "bouncy ride". The damper is the primary device that controls spring oscillations. A bouncy car, whether bouncy at lower frequencies (softer springs) or bouncy at higher frequencies (harder springs) is usually underdampened or poorly dampened (linear valving instead of digressive with sufficient rebound dampening).
Even a Swift spring will oscilate excessively if not properly dampened.
Did you read everything that was posted before you?
Again, this doesn't make them into progressive springs which deliberately increase spring rate with stroke. This makes them into bad springs.
Again, did you actually read anything that was said before you commented? more usable travel out of the spring was already stated as a benefit. Not sure who youre trying to prove wrong on this. It's also safe to assume that the majority of the members here have cars lowered to the point that their main issues with travel is with tires hitting the frame of the car, not with the usable spring stroke. That includes myself. My car isn't even "that low" in 240/zilvia standards, AND I've set up my coilovers to hit the bump stops just short of the tire (wheels straight) contacting the frame as you should, but despite that I run out of wheel travel long before spring travel.
It's a practical limitation of my choice to have my car look half decent at a somewhat low height. Maybe if I wanted to raise it to scca autocross spec then I would have to worry about spring travel. But I'm not because I didnt get a 240 as an ideal autocross car.
More catalog fun facts that have already been mentioned. I came here for technical information/conversation (that was my first mistake lol) and not sideline bleacher salesmen.
For the record, I have gen. 6 FA 500 coilovers. 8kg F and 6kg R. And again, you didn't tell me anything I didn't already know nor have you provided any actual personal driving experience.
I had Ohlins PCVs in my old Miata and have driven a wide variety of cars and suspension combinations including ADAC spec E90 on race valved Ohlins DFVs, a Swift on off the shelf DFVs, and plenty of Japanese platforms on Japanese coilovers. So I'm hardly limited in what I've actually driven. So for someone to try to catalog bullet point convince me of why I need springs on my half decent coilovers (in the 240 world) will at least make me raise an eye brow.
Lol I'm good. Thanks though.

I didn't know your understanding level of suspension, you were able to hash through my attempt to explain it like you knew nothing. Now that I know how much you understand and how much experience you actually have, I don't understand why you even started this thread. If you already knew all the benefits of good name brand springs, why do you even want to know what other people think about the benefits will be? Aside from personal opinions, the fact is that Swift/Eibach springs will give you the most true specs out of the springs so you aren't chasing other suspension tuning issues when you are dialing the car in. Wouldn't it be painful if you are trying to dial out over steer but your springs are not spec'ed to what they say they are? If I told you Swift/Eibach springs are pieces of shit product and waste of money, you should have a rebuttal because you know they are supposed to be better with facts; just as if I were you tell you they are 1000% better than generic springs because it feels better on my spines, it's nothing more than my personal opinion and NOT a FACT and should be questioned.

tacotacotaco didn't misunderstand my first post, he just posted a explanation about what I posted first time to clarify the definitions of linear and progressive. The reason why I kept on calling generic springs progressive is because that is what they act like, I suppose I could have just called them bad springs like you did, but that doesn't explain why they are bad if I just simply called them bad springs. "Bad springs" we are all talking about are off spec linear springs and at that point they are no longer linear springs, if you advertise something to be linear and it acts like it's progressive, which one is it? he? she? they? them? If a compression type spring is not linear, it must be progressive.(strictly for vehicle use) This makes it full circle to my first post, bad spring is bad because they advertise to be linear but they are progressive or off spec.

You wanted technical information about springs, there are literally only two different types of springs for what we are talking about, how much more technical do you want to get into? I can tell you 8kg front and 6kg rear spring setup you have is too stiff, and I hate that industry standard springs specs for S-chassis is 8kg/6kg, that is literally to impress first time coilover purchaser that think stiff suspension is good suspension. (oops, personal opinion and not facts)

Catalog fun facts? They are FACTS and that's what matters when you want to talk technical information. And nice neg rep you gave me, just because we are having a debate over a topic we needed to establish a common ground on, doesn't mean you have to belittle everything I said. I am sure if we were actually talking in person this would have been a nice 10 min conversation tops and would have been cool topic to talk about. Who knows.

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"Both are linear rate springs. So unless the "conventional" spring was significantly flawed in such a way that its spring rate would vary throughout its compression (which seems like a serious manufacturing flaw) so much that the driver would feel it as some "negative" "less-than-ideal" sensation, I'd be skeptical."

^^YES! Exactly what I have been trying to say this whole time, you already had the answer. Not all generic springs are this way, and high chances of hit & misses; and that is exactly why Swift or Eibach springs will be beneficial over generic. True to spec and consistency is what is beneficial.

Average coilover owners will not know the difference to feel said sensation, because chances of them experiencing true linear spring is slim to none. How many people do you personally know that owns a S-chassis that has changed out their springs to Swift/Eibach because they wanted to see how their cars will drift differently?

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"So for someone to try to catalog bullet point convince me of why I need springs on my half decent coilovers (in the 240 world) will at least make me raise an eye brow. Lol I'm good. Thanks though."

You literally asked for inputs and what the benefits will be. Would it have been better if I said you'll get all the girls to lay with you with the sight of you in your car? We are not playing Capt. Obvious and General Information here, Major Asshole doesn't even care to comment anyways.

[TheRealSy90]

TLDR: OP is a nerd and made this thread as a sad attempt to flex.

[S14DB]

Come on guys, you're supposed to justify my decision to not buy swift springs...

[Speed Junkie]

*I didn't know your understanding level of suspension, so I assumed you didn't know anything.*

I'll summarize. I was looking to get someone's actual technically-educated driving experience which seems to be the most lacking factor here. From the beginning I made it clear that I was already aware of the main points that would affect the performance of the spring (slider2828 posted a great link). But everyone kept NPC defaulting to "I read somewhere they're amazing!" Lol, I know they're better, but are they really so much better considering the context of the situation (derp suspension geometry 240 with decent coilovers to begin with) much like Def pointed out in the link that slider2828 posted.

Honestly, I probably will eventually get the springs and I'll find out for myself if whatever improvement I feel will be worth $300+. Just not before I get far more important things like knuckles that will make the job of my current springs a lot easier. At least in the front. Speaking of which:

I can tell you 8kg front and 6kg rear spring setup you have is too stiff

Really? I actually didn't think so. Now of course, being that my car (and any 240 lowered any more than an inch) has such a large roll couple, it rolls way too much even with basic 215 Achilles ATSs. Once I get knuckles and raise the roll center I'll see how much it helps reduce roll on the same tires. From there I'll decide whether or not 8/6 will be sufficient. I want to do occasional track days (not the primary purpose of this car) so the car will have some decent tires on it so naturally it will roll more. I'll see.

I had 10/8 eibach springs on my old Miata and didn't think it was too stiff. And because of the dampening the ride was far better than the 240 now with 8/6 springs (less oscillation both at low speed and high speed travel). But to be fair, miatas have a lower wheel rate than 240s (at least at the front).


*I can't read*

Sucks for you.


Come on guys, you're supposed to justify my decision to not buy swift springs...

Sounds like a logically sound way to go about making these sorts of decisions.

[mad-ass]

Come on guys, you're supposed to justify my decision to not buy swift springs...

Actually, don't buy swift springs. I believe they are over priced at this point and I would rather recommend Eibach's over Swifts. The biggest difference between the two is price and customer support. Two biggest factors when it comes to product IMO.

But if you are looking into resale value, Do buy swift springs because it will sell within a week even used.

[S14DB]

Actually, don't buy swift springs. I believe they are over priced at this point and I would rather recommend Eibach's over Swifts. The biggest difference between the two is price and customer support. Two biggest factors when it comes to product IMO.

But if you are looking into resale value, Do buy swift springs because it will sell within a week even used.
OK, I'll keep my Taiwanese springs then!

[slider2828]

@speed junke. I can tell you by first hand experience over the shitty chinese springs vs. swifts they were definitely noticeable.

Removing any spring bind with needle or torsion bearings is also a noticeable feature if you are in a non-snowing state. Salt in the roads tend to destroy all suspension parts anyways.

[mad-ass]

I'll summarize. I was looking to get someone's actual technically-educated driving experience which seems to be the most lacking factor here. From the beginning I made it clear that I was already aware of the main points that would affect the performance of the spring (slider2828 posted a great link). But everyone kept NPC defaulting to "I read somewhere they're amazing!" Lol, I know they're better, but are they really so much better considering the context of the situation (derp suspension geometry 240 with decent coilovers to begin with) much like Def pointed out in the link that slider2828 posted.

Honestly, I probably will eventually get the springs and I'll find out for myself if whatever improvement I feel will be worth $300+. Just not before I get far more important things like knuckles that will make the job of my current springs a lot easier. At least in the front. Speaking of which:
Really? I actually didn't think so. Now of course, being that my car (and any 240 lowered any more than an inch) has such a large roll couple, it rolls way too much even with basic 215 Achilles ATSs. Once I get knuckles and raise the roll center I'll see how much it helps reduce roll on the same tires. From there I'll decide whether or not 8/6 will be sufficient. I want to do occasional track days (not the primary purpose of this car) so the car will have some decent tires on it so naturally it will roll more. I'll see.

I had 10/8 eibach springs on my old Miata and didn't think it was too stiff. And because of the dampening the ride was far better than the 240 now with 8/6 springs (less oscillation both at low speed and high speed travel). But to be fair, miatas have a lower wheel rate than 240s (at least at the front).

Cool, now we both understand each other let's converse on topic.

I keep on harping on the fact that generic springs can wildly very on their specs, and Fortune suspension company may have actually done a good job picking out their generic springs to sell to the masses that doesn't want to spend extra money on higher standard springs, and who knows, you might have decent springs in your current coilovers and you may not see big improvement with Swift/Eibach upgrade. Now this is where it gets a bit tricky on recommending you personally to buy Swift/Eibach, because you already own the coilovers and you may not see big difference if the springs you already have are actually decent and spec'd correctly.

You can adjust body roll(specifically inertia of body roll)with stiffer springs AND sway bars + lower center of gravity. So I hope that is not the only reason why you want to upgrade springs before you do sway bars(Do you have adjustable sway bars?).

You know better not to compare McPherson to double wish bone, they react completely different you know you it. But since it's brought up let's talk about that and why you didn't think 10kg/8kg was too stiff(mainly because it was on a double wishbone car, and to clear it up for someone stumbling on this thread years from now that doesn't know what wheel rate is). Double wishbone will accomplish same amount of wheel travel with less compression of strut/springs than McPherson will. Let's say 6 inches of wheel travel is requested, McPherson will need 4~5 inches of compression while double-wishbone will require 3 inches or less to do the same job.(The same reason why we find using a 24" breaker bar easier to turn a tight bolt compared to normal 8" ratchet.) Keeping that in mind let's go back to how off-spec generic springs can be and every millimeter of compression can change the spring rate on them, so even with a stiffer springs double wish-bone car will translate that very differently than of McPherson type. If higher-standards of springs are required to get any variable out of the way, then of course you should be buying Swift/Eibach.

Lame comparison but let's say you know your car will make extra 50whp with E85 tune, and no other changes to the engine, so you fill up your car with E85 that's close to your dyno tuner 50 miles away, you get your car tuned and BAM you are making 50whp extra with E85. You run out of E85 and fill up near your house and now it's only making extra 10whp. What changed? the E85 was not consistent. Just because it's sold saying it's one thing that doesn't mean it's what it is, one of biggest reason why people whom are serious about racing use 1 brand of race fuel, so that it is consistent(insert Swift/Eibach here) and if they are having engine issues they can over look at fuel.

If your end goal of this thread is to lessen your body roll, I would highly suggest you get into adjustable sway bars first before you even mess with anything on coilovers. Yes stiffer springs does help with body roll, but that also comes with harsh ride going over bumps and uneven surfaces. and you even mentioned your primary focus of this car is not track racing, yet if your heart still desire to try out the Swift/Eibach springs, I would recommend that you buy them USED if at all possible.

I'll quote my self, "We still need to talk about actual spring rates and how they should be calculated to be used on a car based on ride height, weight and desired suspension travel." Yet making another full circle of the spring topic and why I think it's important to talk about spring rates to better tune the car for what you want to improve. But how a car should handle is up to the driver and what the purpose of it is. Since we are working with S-chassis here it'll be easy to tell what one may do with such car.

But what do I know, I just roll with Tein S-Tech lowering springs with biggest adjustable sway bars available on my S14.

[Speed Junkie]

You can adjust body roll(specifically inertia of body roll)with stiffer springs AND sway bars + lower center of gravity. So I hope that is not the only reason why you want to upgrade springs before you do sway bars(Do you have adjustable sway bars?).

I have stock S13 sway bars up front and aftermarket rear bar (whiteline I think. It has been a while). I was going to use an s14 front bar but I think I read x months ago that the bolt pattern wasn't the same or something. Either way my issue with roll is entirely caused by the roll center being so far from the CoG (large roll couple/moment).


You know better not to compare McPherson to double wish bone

I know. That's why I mentioned exactly that on my previous post. And why I mentioned wheel rates. And by the way the wheel rate is a question of leverage, not dampening.


If your end goal of this thread is to lessen your body roll...

My end goal was to figure out whether swift springs were worth $300+ of improvement. the question of roll was completely secondary. In fact, my plan was to keep the same 8/6 spring rate depending on how much the car rolled with knuckles.


I would highly suggest you get into adjustable sway bars first before you even mess with anything on coilovers.

Like I said, I have aftermarket rears which drastically change the handling balance towards less understeer. the car is actually fairly mild and understeer slightly during steady state limit. So not sure if I want to get a larger front bar. The oem bars are pretty large anyways. So again, its a roll center thing before it is anything else.


Yes stiffer springs does help with body roll, but that also comes with harsh ride going over bumps and uneven surfaces. and you even mentioned your primary focus of this car is not track racing, yet if your heart still desire to try out the Swift/Eibach springs, I would recommend that you buy them USED if at all possible.

Just need to fix the roll center, then we will see where we stand.


I'll quote my self, "We still need to talk about actual spring rates and how they should be calculated to be used on a car based on ride height, weight and desired suspension travel." Yet making another full circle of the spring topic and why I think it's important to talk about spring rates to better tune the car for what you want to improve. But how a car should handle is up to the driver and what the purpose of it is. Since we are working with S-chassis here it'll be easy to tell what one may do with such car.
But what do I know, I just roll with Tein S-Tech lowering springs with biggest adjustable sway bars available on my S14.

The Silvias (I have an S13 with S14 SR and mid mount) have a 52/48 weight distribution. AND they have a far greater wheel rate at the front McPhersons than the rear multi link. So that 8 kg spring is already effectively applying more force than an equivalent 8 kg spring in the rear would. Except it's 6 in the rear lol. So that's a pretty rough ideal roll resistance distribution and tends to be pretty common for a variety of cars. the question remains, how much is having such a large roll couple at the front affecting the roll rate distribution.

I would almost guestimate that because of that, the front roll rate is actually lower than the rear 6kg spring. Again, in roll.


So yeah, before all else, the front knuckles need to be replaced.

[mad-ass]

S13 and S14's do have different sway bar and are not interchangeable, I can't remember exactly what is different off my head. What is your ride height at now? And considering how much you are interested in suspension geometry, I would say it's worth the money even if it's for an experiment, because at the end you will have better suspension, if not at least resale value of the springs will remain. someone is always willing to buy swift springs off you.

Update when you do get knuckles(I'm going to assume you are getting drop knuckles to level out the LCA angle while lowering CoG)


edit: which swift springs are you looking at buying anyways?
http://swiftsprings.wpengine.com/products/metric-coilover-springs/

[Speed Junkie]

The center of gravity isn’t changing. That’s just a function of the height of the car whch isn’t changing. But yeah I’m getting the knuckles to raise the roll center. The spring size I need is 65mm ID, 7” long. We will see whether I decide to stay with 8kg.

Not the best photo for ride height but this is it. I raised the front slightly so there’s about a finger’s gap between the top of the front tire and the fender to get rid of the rake.

https://i.imgur.com/EE8UoKK_d.jpg?maxwidth=640&shape=thumb&fidelity=medium

[TheRealSy90]

You've said dampening twice now on a suspension thread. Your opinion is now invalid.

[Speed Junkie]

You've said dampening twice now on a suspension thread. Your opinion is now invalid.

Oops. I must repent.

[slider2828]

S14 rear pickup points for suspension is different for suspension, so the rear sway bar is not interchangeable. The front track width are also different and also S14 utilize straight bolt through sway bar where as s13 is blade type.

Don't bother with S14 sway bars on s13, you will get suspension bind....

8/6 is sufficient for road going s13's with some stick rubbers. 10/8 if you running the track with wide tires like 265 or 275s with all suspension mods.

Don't bother much with knuckles and junk until you swap your s13 subframe for a s14 or s15 subframe. That will give you better traction than spending all the monies on knuckles.

[Speed Junkie]

S14 rear pickup points for suspension is different for suspension, so the rear sway bar is not interchangeable. The front track width are also different and also S14 utilize straight bolt through sway bar where as s13 is blade type.

Don't bother with S14 sway bars on s13, you will get suspension bind....

Yeah figured. I had read about them not fitting a long time ago but yeah.


8/6 is sufficient for road going s13's with some stick rubbers. 10/8 if you running the track with wide tires like 265 or 275s with all suspension mods.

Also figured. And yeah I don't even plan on running THAT wide lol.


Don't bother much with knuckles and junk until you swap your s13 subframe for a s14 or s15 subframe. That will give you better traction than spending all the monies on knuckles.

I already have a rear S14 subframe. I was mainly talking about front knuckles since the rear roll center isn't nearly as bad.

[slider2828]

Yeah figured. I had read about them not fitting a long time ago but yeah.




Also figured. And yeah I don't even plan on running THAT wide lol.




I already have a rear S14 subframe. I was mainly talking about front knuckles since the rear roll center isn't nearly as bad.


Yeah front roll centers suck on an S13.... I recently got driftworks knuckles.... They are the V1's but meh I am not doing any competition stuff... I think they have Time Attack or Track or Drift versions now where ackerman is different I think.

[Speed Junkie]

Yeah front roll centers suck on an S13.... I recently got driftworks knuckles.... They are the V1's but meh I am not doing any competition stuff... I think they have Time Attack or Track or Drift versions now where ackerman is different I think.

I plan on getting GKtech grip knuckles. How did your car feel after installing yours? Aside from rolling less.

[slider2828]

Quicker turn in, and a bit more stability under braking..... Braking used to feel like shit... now its average to sports cars nowdays....

[gills]

Any part that serves any dynamic function that needs to be rated and needs to be consistent that comes from the chinaspeed factory is at risk of being a complete lie.

Back when I was having "fun" messing around with OEM type springs since that's what I was limited to at the time in the racing I was competing in, I procured and measured several different OE type springs.

The worst offender of them all was this Megan Racing front S-chassis lowering spring. This is advertised as ~350 lbs/in which no other company even comes close to. The second I opened the package I knew immediately it was a lie just by looking at the spring wire diameter.



You can calculate the spring rate yourself:

Free length:
https://i.imgur.com/kN5qFYh.jpg

Compressed to a little more than what the static corner weight on the front of an S-chassis is:
https://i.imgur.com/se5jM06.jpg

And then a little more the spring is completely blocked and the force spikes:
https://i.imgur.com/QUGI80u.jpg