Review: HKS Hipermax IV SP for 370Z

fantaZ

What type of front spoiler lip does OP have on his nismo? I want it for my car.

ShinyaPGH

I have the Carbonsignal CS lipkit that includes the front lip, side skirts, rear diffusers & spats, and the wing add-on.

__________________
2013 NISMO. Motordyne Longtube Headers/Catback exhausts, Carbon Signal CS lip kit etc.

Spooler

Hmm, So my Aragosta's have a 10 in. 12kg/mm spring on the front. My rears are 7 in 10kg/mm. I am using Swift springs. How does this calculate? Do I need more info? I do not have the stroke info handy.

MaysEffect

The info is listed on the swift spring link. Look for the length (need to select the right spring i.d) and then it shows the specification for each spring rate in mm & inch.

It shows the maximum and usable stroke of the spring, the maximum is when the spring is over 95% full compression, useable is between 25-75% compression.

Based off your information though, it doesn't match the balance of the oem design. It does however match or exceed the oem GVWR capacity. I think Aragosta tried to match the oem specification with a shorter spring. Is the rear spring a linear of progressive spring? On their site it shows 2 different types.

No thread jacking here......

Jhill

This thread is getting pretty interesting and I always thought it odd how much stiffer front to rear the aftermarket change vs the oem rates for most of the aftermarket. Also I know the increase in rear rate doesn't have as much effect as the front in terms of overall stiffness increase so Im curious with the motion ratio calculated in how much stiffer % the front vs the rear is going from the oem 7.5/8.1 setup to something like my 12/11 and also the hks 14/16 (I think that's what he said it had). Be curious if the powertrix is like a 40%/25% which would re confirm my balance I feel now and is the hks something like a 50%/50% keeping the balance also wonder where something like the fortune end up in stock form as they spec an 11/8 setup and dont think going stiffer in the rear is good as it doesn't let the car articulate (when I spoke to them in the past) which I thought that balance would be really understeer biased. As it is I'm glad I went with the swift upgrade for the 12/11 setup vs the 12/10 setup stock for powertrix. I don't really want to increase or decrease my rates as I like the ride now but wonder if I can make the % difference up in bar setting.

MaysEffect

The numbers in themselves have a lot attached to it. The first being the maximum stroke length in relation to the total capacity. This is what needs to be matched first before anything else. In most cases these different rated springs don't share the same length or the dampers don't share the same extension length. The HKS is not that extreme when you consider its free length is short compared to some other springs and the fact it uses a secondary spring to take up the remainder of droop. I think a properly matched tender spring would make the droop sensation feel even better, but this could add another 300+ dollars in cost. In most cases that can be the difference of someone going with a different brand.

Jhill

I'm not sure I follow you in this. The stroke will always be a ratio of droop vs travel. Now thinking about this vs other things like the offroad world I can see why they would require a helper/tender spring with very stiff springs. For example if you had a 5inch stroke shock (which appears to be the norm for the z) and you have say 30% sag with a 11k spring and zero preload (I choose 30% as that's a norm for my world). Now let's say with that 11k spring and zero preload you still feel too much roll and not enough support. Well with air suspension you can do some tweaks like reducing air volume (making it pregressve), firming the low speed damping to gain support at cost of sensitivity or boosting gas charge in damper to increase ramp up and more support. If doing it by spring rate as common in a car now you gain support at cost of traction. Given same example is 30% sag with 11k spring and zero preload what do you think your sag / - travel will be at 16k rates? Obviously less and there goes your traction over humps and inside tire lift which is where the helper / tender spring comes in to gain - / droop travel back.

Spooler

Linear springs. I am using SPL midlinks.

littlejuanito

OP, Any follow up reviews on these coilovers??? How are the holding up so far?

ShinyaPGH

it hasn't seen any other track days unfortunately. But more I drive on them, more I fall in love with. A track coil overs, that are impressively comfortable on the streets. As some of the guys were mentioning, the dampers are quite good and the car doesn't feel too stiff, even though they are such high spring rates.

__________________
2013 NISMO. Motordyne Longtube Headers/Catback exhausts, Carbon Signal CS lip kit etc.

ShinyaPGH

Any specifics questions you would like me to ask to HKS? I have access to the engineers in Japan who should be able to answer any technical questions for us.

__________________
2013 NISMO. Motordyne Longtube Headers/Catback exhausts, Carbon Signal CS lip kit etc.

littlejuanito

I've read that the Hipermax GT were cornered balanced for other car applications but would like to know if these are corner balanced for the 370z. Supposedly the HKS are pretty much ready to go outta the box, without the need to adjust height.

__________________
Fast Intentions Non-Resonated Carbon Fiber CBE | Berk Non-Resonated HFC | Powertrix Coilovers | RJM Clutch Pedal | LatheWerks Shift Knob | Stillen Sway Bars, |SPL Parts | Enkei RS05RR | Fujimura Diffuser | Ecutek Tuned by Seb | 308whp

ShinyaPGH

Isn't that nearly impossible? Difference in driver's weight can upset the corner balance. 150lbs driver versus a 250lbs driver can make quite a bit of difference. The right and the left coilovers did not come set up in different heights, so I doubt that they are corner balanced.

If you're talking about Front/Rear weight distribution, out of the box, the coils were set up with 689mm front, 690mm rear. But again, since the driver is no located in the dead center of the car, driver weight can change the front/rear distribution also.
FYI, I'm running F:669mm R:657mm, so I would've shifted the weight toward the rear with my current set up from the out-of-box setup.

__________________
2013 NISMO. Motordyne Longtube Headers/Catback exhausts, Carbon Signal CS lip kit etc.

littlejuanito

Are the HKS Hipermax IV GT coilovers corner balanced out of the box? | HuffPost

__________________
Fast Intentions Non-Resonated Carbon Fiber CBE | Berk Non-Resonated HFC | Powertrix Coilovers | RJM Clutch Pedal | LatheWerks Shift Knob | Stillen Sway Bars, |SPL Parts | Enkei RS05RR | Fujimura Diffuser | Ecutek Tuned by Seb | 308whp

MaysEffect

This example doesn't take into consideration driver weight or asb endlink alignment. Either factor can change the cross weight by 2-5% easily.

But for an out of the box cross weight of around 50% this is a decent range but not untypical, certainly if its a true coilover kit and preload is preset. This is much harder to do with a divorced spring in the rear unless the perch was preset evenly.