coilover question

[Jmatchley86]

looking to upgrade suspension soon and was wondering if anyone could explain the benefits of a true style setup vs an oem.

My plan is to replace everything with SPL so there is a cost difference between true and oem, but is there any other reason to switch to true style? Is there any benefit with sticking with an OEM setup?

I have my heart set on some fortune 510 coils if that makes any difference. But from what I have read using an OEM setup would allow (unless i'm wrong) for different options. Like purchasing penske shocks and using swift springs etc.

I'v searched the forums and the best answer I could find tech wise was "real race teams have true style" which is great but isn't exactly what i'm looking for haha.


Thanks in advance.

[Brendan]

If you plan on competing vs just doing random track days, read the rules as some sanctioning bodies will place you in a much higher class for changing suspension geometry, ie switching to a true style coil set up.

With a true style the rates in the rear will be much lower meaning that you cant swap springs from front to rear and you will need two "sets" so to speak.

True style will allow you to get rid of oem spring bucket saving a little bit of weight.

[Jmatchley86]

No competition in mind in the future that would limit this. I have an opportunity to purchase, for a steal of a price, everything i need to keep the suspension OEM style with SPL. It would save me a few hundred bucks overall vs going with a true style. But if there really isn't any benefit of one vs the other I may just go with the savings.

[Rusty]

Bucket style has higher spring rates then the true style.

[Jmatchley86]

Originally Posted by Rusty

Bucket style has higher spring rates then the true style.

But is there any advantage? Does moving the spring closer to the wheel allow for better "xyz" or is it a preference thing? If all things are equal, except the spring rates, I may as well save the coin for seat time.

[cv129]

Originally Posted by Jmatchley86

But is there any advantage? Does moving the spring closer to the wheel allow for better "xyz" or is it a preference thing? If all things are equal, except the spring rates, I may as well save the coin for seat time.

I think it’s in the ease of calculating spring rate change and tuning the shocks. That’s beneficial to someone that’s really fine tuning those two things (run a few laps, come into pit and tell crew chief blah blah blah, study telemetry, switch springs and change shocks settings, then go out run more laps again, rinse & repeat).

A simplified example...a car with perfect 50/50 front to rear and side to side weight distribution, true type all 4 corners. Driver says “spring too stiff”. Mechanic swaps all springs for same -1k all corners.

Now, same car but true type in front, divorced in the rear, now mechanic needs to calculate for a -1k in front, the equivalent for the rear may be -0.8k. Mechanic needs to calculate the “wheel rate” by taking into account of the spring being further away/inward from the hub.

For us, there isn’t any benefit on true coilover vs divorced. One isn’t gonna make a faster or slower driver, all else being equal.

[Jmatchley86]

Originally Posted by cv129

I think it’s in the ease of calculating spring rate change and tuning the shocks. That’s beneficial to someone that’s really fine tuning those two things (run a few laps, come into pit and tell crew chief blah blah blah, study telemetry, switch springs and change shocks settings, then go out run more laps again, rinse & repeat).

A simplified example...a car with perfect 50/50 front to rear and side to side weight distribution, true type all 4 corners. Driver says “spring too stiff”. Mechanic swaps all springs for same -1k all corners.

Now, same car but true type in front, divorced in the rear, now mechanic needs to calculate for a -1k in front, the equivalent for the rear may be -0.8k. Mechanic needs to calculate the “wheel rate” by taking into account of the spring being further away/inward from the hub.

For us, there isn’t any benefit on true coilover vs divorced. One isn’t gonna make a faster or slower driver, all else being equal.

One day i'll have a mechanic and crew... and a fast car lol... but for now this is exactly the info i'm looking for. Thanks!

[JARblue]

The biggest difference on the Z between true type and divorced suspension is probably the weight savings from getting rid of the spring bucket lol. The other consideration I see is the different products on the market for each style, which has already been mentioned.

[OptionZero]

For someone asking this question, zero benefit.

Just get the OEM types and be happy

The fortunes are good. Rebuildable, stateside service, warranty, swift spring upgrade, adjustment range.

Get some thrust washers before you install them.

[Spooler]

Save your money and get the SPL catalog for better alignment adjustment. Next would be a diff upgrade to a Wavetrac or OS Giken 1.5 way. The rest is seat time and tires.

[Volk Z]

I 2nd option zero. Oem style. I had M7 Japan. Also have used BC racing.

The only difference I would say is you have to reset pre load in rear on oem style when you adjust height but once locked all good. Otherwise true you can set preload and adjust without touching.

[AlWakRa]

The only two negative for oem style I could think of
1- Midlink is much more expensive than toe arm.
2- If you decide to go for a track only (very stiff) the rear spring will be too short, as far as I know.

As for true type, there is two concerns:
1- The strength of shocks towers, I cannot think of many beside cv who reinforced this area, I am running true type without reinforcement, but no reported failures.
2- Spring rates suggestions could be tricky, Fortune auto coilovers are very good quality, but their suggested spring rates for true type isn't that good.

[OptionZero]

i've never heard of the spring being too short on an OEM Type, for most cars 6 inch spring is fine

plus the SPL midlink has height adjustment

[2011 Nismo#91]

True types are preferred because most people in racing, books, guides, calculators, experience, are based on it.

Safety equipment will make you go fast too. Probably more than suspension would. A good seat, harness bar, harness, and Hans will make track days much easier on your body.

[AlWakRa]

Originally Posted by OptionZero

i've never heard of the spring being too short on an OEM Type, for most cars 6 inch spring is fine

plus the SPL midlink has height adjustment

As it has height adjustments, it made my second point invalid.