Intalled: SWIFT Springs / 15mm spacers / Z1 Star Specs

[STItoEVOX]

holy crap that drop looks perfect. My search for which spring provides the perfect drop is over. Where'd you get em?

[reggiesd]

nice..perfect height i'm looking for. where'd you buy the springs?

[jona31]

STItoEvoX / reggiesd: thanks for the compliments. I am based in Hong Kong and they were ordered directly from SWIFT in Japan through my local tuning shop. If you are in the US, I believe a number of EvoM vendors have them available at pretty good prices. Run a search on "SWIFT springs" in this sub-forum and a few names should come up.

J

[Alexander]

wow the combination of the spacers and the slight lowering really made a huge difference.

[Stop&TurnFreak]

So, in conclusion, do you think the car is better or worse than before? I agree, the look is perfect, but I am hesitant to change the springs, if there is no improvement in performance.

STF

[XOoET64oOX]

That's a nice drop for the GSR-Premium. I wonder if their regular GSR springs are the same, had the SpecR for the 9. Looking to go SWIFT again this time around.

[jona31]

Had more opportunity to get seat time with the new setup over the weekend on a variety of roads and driving conditions.

I can expand and clarify on my initial findings per my original post with the following additional observations:

RIDE QUALITY: at slow to medium speeds, especially over uneven concrete roads or if there are small ruts, expansion joints, etc. the extra ride stiffness is more pronounced. At higher speeds, the ride actually feels slightly softer than stock which I believe relates to my next point about body control.

BODY CONTROL: I tested the car through a sequence of flowing medium - high speed (top 3rd gear to mid 4th gear) corners. This route happens to be on the side of a mountain and while most of the surface is smooth asphalt, there are a lot of undulations, on/off camber surfaces and minor bumps to upset the balance of the car.

There is no doubt in mind that body control is compromised with the current setup at high lateral load conditions. If you throw in a mid corner bump, the sensation is such that you would probably want to try and increase a bit of rebound on the shocks (if this were an option) to ‘tie’ the car down better. Simply stated, the car feels a tad too soft and body control slightly imprecise.

I am noticing MORE body roll as well in these conditions. Someone on EvoXforums talked about roll center issues, and this could well be the reason behind sensations I am describing about body control. Since I cannot offer a clearer explanation, I hope ‘rtremaine’ from that forum does not mind that I copy and paste his excellent points here:

“Lowering the car, either by springs or coilovers alters the roll center of the automobile. The stock setup offers a good compromise between a fairly low roll center while maintaining a ride height that will clear most common features of the road (parking lots berms, speed bumps, etc). Most springs/coilovers that are primarily for purpose of lowering the car unfortunately put the roll center somewhere near or below the surface of the pavement which actually will hurt handling by inducing more body roll, this effect is usually not readily noticed at most speeds because the increased rate of the springs masks the problem. However at racing speeds the inner tires will become unloaded more easily due to the lower roll center and the increased spring rate. An easy eyeball test is are the outer lower ball joint pivot positioned higher than the inner lower control arm pivots when the vehicle is at rest? If they are, you will now have roll center issues. Another problem that arises is the issue of bump steer. This is the tendency of the wheel to turn as it travels through it's up/down motion because it is being 'pulled' by the tie rod. The stock relationship between the height of the steering rack and the centerline of the front hub/steering arm is designed to minimize this effect. When the car is lowered by means of shorter springs or strut assemblies the bump steer geometry is altered and your car will have a tendency to wander when traveling over irregular surfaces or when cornering forces compress the suspension. Whiteline makes a kit to cure both of these issues when lowering the vehicle however I'm not sure if it fits the X. That said, the bulk of lowered cars, Evo X's or whatever handle poorly compared to the original stock setup.”

RIDE HEIGHT: very pleased with this. The ride height is exactly what I’m looking for.

Z1 STAR SPEC TIRES: very happy with these also. In the dry, grip is far superior to the SP Sport 600s and inspires much more confidence.

CONCLUDING THOUGHTS: Once again it goes to show how brilliant the “MR” Bilstein / Eibach package is for street conditions. It never crossed my mind that it would be possible to improve on this package with a set of springs (and for that matter, most ‘over the counter’ coilovers) but instead I was curious to see how close the stock handling / ride characteristics can be maintained with SWIFT’s offering. I would also be extremely surprised if other springs which lower the car even further (such as Eibach’s pro kit) do not amplify these problems.

It is difficult to quantify what the effects I mentioned above might translate in terms of lap time because there are simply too many other variables involved but from a driver confidence point of view, it is not an ideal situation if you are often driving on the limit or trying to extract the maximum out of your car. Conversely, if you mostly drive your X at sane speeds on roads (like me), the huge improvement in aesthetics may be enough for most to forgive the slight compromise in body control.

Best,
J

[pomod333]

what is the spacer supposed to do???

[kirkklau]

jona31,

so what you are saying is that stock form is better off than dropping the X with springs or coilover?

i am planning to drop my car but do not know if i want to do it with springs or coilover? or should i not do it at all?


thanks

kl

[ZK]

The car definitely looks like it should come from the factory. The slight drop and the wheel spacers make the car look a lot better while still looking not modified. Good set up!

Do you think the Swift spring would work better with the GSR's KYB shocks? Those are what they are originally designed to work with. Perhaps it may work better because of the KYB's stiffer valving.

[wilson1]

Originally Posted by zk

the car definitely looks like it should come from the factory. The slight drop and the wheel spacers make the car look a lot better while still looking not modified. Good set up!

+1

[jona31]

Originally Posted by kirkklau

jona31,

so what you are saying is that stock form is better off than dropping the X with springs or coilover?

i am planning to drop my car but do not know if i want to do it with springs or coilover? or should i not do it at all?


thanks

kl

What I'm trying to say is that you need to be aware there is going to be a trade off. It all depends on what your priorities and objectives are. If you are predominantly driving your car on the street and you are very happy with how your car currently feels and handles (like I was), in my opinion it will be difficult to maintain the same ride quality / body control with a lowered setup. Whilst I am no suspension expert, I have been lucky (or unlucky) enough to have tried and tested numerous aftermarket suspension systems on street and track and this particular experience does not really come as much of a surprise.

At the end of the day, if you don't mind sacrificing some of the above in order to achieve a lowered look, go for it...

[jona31]

Originally Posted by ZK

The car definitely looks like it should come from the factory. The slight drop and the wheel spacers make the car look a lot better while still looking not modified. Good set up!

Do you think the Swift spring would work better with the GSR's KYB shocks? Those are what they are originally designed to work with. Perhaps it may work better because of the KYB's stiffer valving.

Thanks, that is exactly the look I wanted to achieve: stock to the untrained eye and much better to those in the know...

It is possible that these springs would work a bit better with the GSR shocks. However, if I were to take a guess, I would imagine that the valving of the GSR shocks would not be quite firm enough to mitigate the body control issues I mentioned at high load conditions though. Otherwise, the low speed dampening would probably be overly stiff.

J

[LVSBB6]

According to Swift:

4M020 Evo X springs will work for both GSR and MR. Through our testing, the progressive spring rates will fully maximize the performance for both the GSR and MR dampers. The drop height are also identical for the two application.

Source: http://www.swiftsprings.com/news.html

[ZK]

Originally Posted by jona31

Thanks, that is exactly the look I wanted to achieve: stock to the untrained eye and much better to those in the know...

It is possible that these springs would work a bit better with the GSR shocks. However, if I were to take a guess, I would imagine that the valving of the GSR shocks would not be quite firm enough to mitigate the body control issues I mentioned at high load conditions though. Otherwise, the low speed dampening would probably be overly stiff.

J

In my experience, the high speed dampening with the stock GSR suspension is very lacking and feels floaty with no road feel at all on track. Fast transitions are an issue and too much body roll. Do you think the Swift springs will help with that?

From what it sounds like, you are saying it would actually make it worse?