[orionredwing]

Overview:

After enrolling in a few HPDEs, I was ready to look for a track suspension upgrade w/o sacrificing daily drivability. My stock sport suspension was starting to go soft after ~45K miles. It happened so gradually, I only realized after comparing to loaner cars from dealer visits.

I’m investing in this expensive upgrade to improve my track experience, but street comfort is my #1 priority, as I’m not into the lowered look. Comfort vs performance; hard to balance because it’s always a compromise, right? So why spend all this money if I’m only going to set my dampening rate so soft, it’ll only be a bit better than stock sport?

That was when Harold @ HP Autowerks mentioned a custom Swift Springs conversion for KW. I already know KW is amongst the best in street comfort, so this was interesting news for me. Swift Springs (http://www.swiftsprings.com/advantage.html) is made from a material that not only increases available stroke, but is lighter and does not fatigue much w/ age. Sounds good, but how durable is this ‘H5S.TW’ material? Swift conducted a fatigue test that showed some aftermarket brands X, Y, Z will start to degrade (spring rate) after 200-300K compressions. In comparison, Swift springs were as good as ‘new’ after 1 million compressions. Looks good on paper, I’m sold!

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Driving Impressions:

My set arrived and it was beautiful. I was so excited and in a rush to get it installed, I took off to my mechanic w/o taking pics. I went w/ 336 lbs/in (6 kgf/mm) in the front, and 672 lbs/in (12 kgf/mm) in the rear, for best balance between daily drivability and performance (refer to spring rate sticky to compare). A track setup would be something like 450 front / 800 rear.

After it was installed, I was a little bit bummed by the look. However, I soon confirmed that my mechanic did know what he was doing, and this is the right setup for track:
http://www.e90post.com/forums/showthread.php?t=310100

So here I am w/ my first coilover set installed, and all eager to go. Equipped w/ a Wavetrac LSD (http://www.e90post.com/forums/showthread.php?t=292510), I immediately took my car onto a freeway on-ramp. Woo hoo! …. wait, uh ... how come my car is accelerating slower? Did I lose tire pressure? OH! The car was not jerking back, haha. We’ve been so programmed to associate that little jerk w/ strong acceleration Will take some time to adjust.

Wow the car is smooth! The stock KW V3 factory setting feels very much like stock! Even my girlfriend won't complain! When I went over bumps, the car was a little bit stiffer, but still within OEM expectations. No THUNK THUNK feeling from a stiff setup. Big thumbs up for KW's street comfort.

Ok, it's cool to have good street comfort, but c'mon, I bought this set for performance! Get on w/ the show, right?

I got home, waited for rush hour traffic to clear, and took my car out after snapping those ride height pictures in the thread above. Got to a circular, down-hill on ramp. Woo hoo, let's play! Dammit, there's a friggin Lexus SUV in front of me! ARGH! He's taking the corner pretty fast though, so one of those drivers that think SUVs are sporty.

The guy was still going too slow for me to really test my new setup. Oh what the heck. Shift into 3rd (hehe, I have too much torque for 2nd), take a quick peek into my mirrors, and VROOM! there I go!! Slight left steering adjustment placed me into the carpool lane. Smooth torque in 3rd gear and a gentle push of the gas pedal launched me past the 'sporty SUV'. Woo hoo! I'm past that sucker. Oh boy, I'm going fast.

Let's go faster.... (This is where you normally have flashes of driver being stupid and spinning out, but you gotta be there to understand how planted I felt.)

Steering wheel adjusted and locked to the right, look for the apex, look past to the exit. Uh, not losing traction. Not understeering. Wow, no body roll. Oh cool, let's add some gas and MESS up my traction. Woo hoo, car feels so solid! Crossed over into the inside lane for the ‘apex’, then let it unwind naturally back into the carpool lane for the exit as I finished the turn. No DSC lights...

Floored it.

Bye bye SUV.

Fun fun. (I would NEVER have dared trying this stupid stunt before. But somehow, you just gotta be there to understand the confidence inspired by this setup. The key word was I ‘squeezed’ the gas to shoot past the SUV, not a reckless, I floored it to shoot past the SUV.)

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In Summary:

I wrote another page of driving impressions in my excitement, describing how little body roll there was, how easy it was to correct from understeer, etc, but it got a bit long In the end, KW V3 w/ Swift Springs AND LSD was really amazing. I took it back to the shop and had the front adjusted up to 5 from firmest (7 was factory default). Rear was left at factory default, 9 clicks from firmest. The mechanic took it out for a spin and came back with a ‘wow, the car is not as firm as I’m normally used to w/ a 5, and I’ve installed tons of KWs’. I told him this set had the Swift Springs conversion, and he was really impressed.

Comfort w/o sacrificing performance. Maybe some of you won’t feel right unless you have a firm setup, but just like me getting over the ‘no jerk’ during acceleration, a stronger ‘jerk’ doesn’t mean a car has more power, and a ‘stiff’ ride doesn’t mean the car performs better.

Hope you enjoyed the review!

PS. Heading to Infineon for 2 days this weekend. Will post track impressions after I get back!

[stratplaya06]

Great review!

So just to clarify: you never rode on the v3's without the swift springs right?

My stock v3's are too damn harsh, and get really choppy over bumps, so I was thinking of doing the swift conversion. I have a set of ps2's and 19"'s about to go on in place of the stock 17" rft's, so if between that and the softening of the kw's I am still disappointed, the conversion will happen.

How is it over speed bumps/choppy pavement? What tires are you running? Tire pressures?

Thanks man

[mkPOTO]

great review

[orionredwing]

Yes, I never tried V3s without swift springs on e90/e92s. However, I've sat in 2-3 335i equipped V2s and the street comfort was excellent when the dampening rate was adjusted softer. So I'm surprised your ride is so harsh as V3 has more adjustability.

Maybe it's the performance vs comfort compromise I mentioned in my review.

I also read about the softening over time. Some users reported the car begins to sag w/ time cuz of spring fatigue / wear. You shouldn't have that problem w/ Swift Springs but only time/mileage will confirm.

My V3 experience was on a friend's 350Z. He adjusted for track and it was very nice. Definitely firm, but not harsh.

I am running 19" M6 Reps on Goodyear GS-D3s (33 front / 39 rear psi). With my dampening set to 5 front / 9 rear, it's not as comfortable as stock sport over bumps, but I wouldn't say it's harsh. Basically, I can't even use the word 'firm' to describe my ride as it's so not harsh...maybe 'firm but soft' vs 'firm but harsh' is a best way to compare. In comparison, I believe a 5 front / 9 rear setting W/O swift springs would be considered 'firm and somewhat harsh'. Remember I'm also running higher spring rates than the KW progressive springs that comes w/ the V1, V2, V3.

When I had it on 7 front / 9 rear, I think 'soft' would be a good description. Normally, that'd elicit an eeww, but even though the setup felt MORE comfortable (softer) than stock on flat road, it performs WAAY BETTER. Pretty hard to describe. When people think soft suspension, they think body roll....but this soft had no body roll except on the most extreme cornering, where it dipped slightly and recovered immediately (good rebound setting). That's why I re-set mine to 5 for Infineon this weekend to get rid of that slight dip to compensate for not going w/ track spring rates (450/800).

For daily drivability, I'll adjust back to 7 front for better than stock comfort. However, going over bumps is still a bit harsher than stock...but once again, that's more because I chose a higher spring rate of 336/672 (much higher than factory sport). I was really wow'd by the comfort on non-bumpy roads.

Originally Posted by stratplaya06

Great review!

So just to clarify: you never rode on the v3's without the swift springs right?

My stock v3's are too damn harsh, and get really choppy over bumps, so I was thinking of doing the swift conversion. I have a set of ps2's and 19"'s about to go on in place of the stock 17" rft's, so if between that and the softening of the kw's I am still disappointed, the conversion will happen.

How is it over speed bumps/choppy pavement? What tires are you running? Tire pressures?

Thanks man

[zsapphire7]

is this ur experience with just the stock sway bars?

[Gen_E92]

excellent review!

[stratplaya06]

Thanks for the reply man!

I am getting my m6 reps with ps2's this week, and will likely have the coilovers softened a little if needed. A more compliant ride is the key for me now, as I am really not tracking, but love a great planted feel.

[JaysBlueE92]

thanks for the review..can this be done with e92s? Where do you get the springs?

[orionredwing]

Yes, it's available for both e90/e92 (not sure for e93, you'll need to ask). Right now, only Harold sells this custom swift spring conversion for our cars. PM HP Autowerks here on e90post. I was very surprised there weren't more of you guys running this!

Take a look at the AST thread for a pic of what the swift springs look like. Notice how few coils there are, and all that useable stroke.

http://www.e90post.com/forums/showth...=252017&page=2

I searched and found Harold's pic of the KW's w/ Swift Springs. I really regret not taking a pic out of the box for myself. Was too excited haha

http://www.e90post.com/forums/showth...12#post5999812

Originally Posted by JaysBlueE92

thanks for the review..can this be done with e92s? Where do you get the springs?

Yups, still have the stock sway bars. I plan on upgrading both front and rear later. Right now, I need to focus more on learning the lines and my car. I feel it'd be a waste to get sways at this time since I'm still a track noob. Coilovers are worth it for me because the body roll is starting to rob me of confidence, and this new setup will only allow me to learn my lines better.

Heading up to Infineon tomorrow. Can't wait! More impressions after the HPDE this weekend.

Originally Posted by zsapphire7

is this ur experience with just the stock sway bars?

[zsapphire7]

Were your springs installed with thrust sheets when coverted to use swift springs?

[HP Autosport]

Originally Posted by zsapphire7

Were your springs installed with thrust sheets when coverted to use swift springs?

Yes, thrust sheets were installed on the conversion kits.

[HP Autosport]

Originally Posted by orionredwing

PS. Heading to Infineon for 2 days this weekend. Will post track impressions after I get back!

Nice review!

How did it go at Infineon?

[Park828]

i have v2 with volshlag camber plates.. is there a swift spring kit for my setup?

[HP Autosport]

Originally Posted by Park828

i have v2 with volshlag camber plates.. is there a swift spring kit for my setup?

Yes, PM me please.

[HP Autosport]

Since "Orionredwing" didn't post any photos. Here is what his kit would have looked like...

[orionredwing]

It's been a few months, so I thought I'd update this thread with my track impressions. I have attended 5 track days since my installation (2 @ Infineon, 3 @ Laguna Seca), so have had enough track time to post some proper impressions.

Please also refer to my thread here for some info (includes VIDEO!):
http://www.e90post.com/forums/showthread.php?t=347748

In general, the setup's (KW V3 w/ Swift Springs & Wavetrac LSD) greatest contribution to my track experience has been in the confidence it inspires; specifically, the lack of excessive body roll, and the elimination of that 'floaty' feeling.

For those who have been to Laguna Seca, downhill turn 9 into 10 is pretty fast. On stock sport suspension, going fast and then bringing it into the apex can be VERY unnerving, because of how floaty the car feels at speed. And if the traction control triggered while experiencing this floaty feeling...omg, I'll leave it to your imagination how scary that was to me. Floaty w/ little jerks as the traction control kicked in was NOT a good feeling to have when you're pulling a fast downhill turn at speed.

http://www.mazdaraceway.com/pages/Track_Map

After my suspension mods, that was no longer the case. Bringing the car into the apex felt so natural, and controlled. There was no body roll. No more floaty feeling. And if I broke traction to the point where traction control kicked in, it was very controlled. No scary abrupt jerks anymore. Just a comfortable, confidence inspiring turn. Wow, what a world of difference. Turn 9 into 10 is now one of my favorite segments!

Because of this, I can now take turn 2 much faster as well. Imagine me driving like a grandma down the screaming straight coming into turn 2 because of the stock sport suspension. Man, talk about braking super early and making sure you're not carrying excess speed into the turn! After the suspension mods, turn 2 is SO much fun now. For this turn, the video is definitely the best descriptive. Please check it out in the above thread.

QUESTION:

Understeer?

It's a known fact that our cars understeer by a lot. Adding the Wavetrac LSD had the biggest impact in addressing this. While I was running this setup, I did not feel understeer was a major concern, because the car was definitely greater than my driving ability.

So for those of you deciding on what suspension mods to do, unless you're an expert driver, I would say get the LSD first to greatly reduce understeer and not worry again about this until later.

I added this little blurp because I just did the M3 Front Conversion, which greatly helps with understeer. I will post my impressions later, so as not to take away from this update. I have not had enough seat time yet, and no track time with this new setup.

[HP Autosport]

Time for camber plates!