Ohlins Coilover Setup

[FSUZ33]

I took measurements of the loaded spring lengths before I started pulling them apart. That, compared to the unloaded spring lengths would get you a 'Sakebomb' preload measurement, however that may change based on spring rate...idk Also, I don't know IF millimeter precision is important. Generally, 5mm from tight is considered perfectly fine.

What's the thread pitch of the front upper top plate bolts? Guess I should replace those now. I assume that OEM plate should stay there.

 

[RSS]

1.25 is the thread pitch you want. I went with 35mm.

I remember you saying you measured everything out, I hope they get back to me quicker Then not on this. I want to finish up under the car with all but the end links. I will do those once stance is set and aligned. interior sometime next week.

 

[FSUZ33]

M6 or M8?...or M10? Not looking at them but they can't be M6.
I did ONLY ask for the pitch...my bad.

 

[RSS]

lol crap I can’t remember, too many numbers running through my head I want to say 10mm.

I do feel like a dumb _ss though. Apparently I totally missed any preset in my set up. I am running Apex wheels with different offsets so nothing is preset. Need to do all the set up ie: free length/preload myself based off tire wheel combo and desired preload. So back to the beginning, but at least the SPL parts are on. LOL

My son (whom I refused to ask for help and teaches this stuff) reply was simple and ruthless. “How are you fenders” Oh My how things reverse as your children age.

 

[FSUZ33]

Ohlins recommends 7mm of preload for the current US-spec R&T kit.

Rear is simple. Measure from perch to perch with the bottom perch hand tight. Then tighten the bottom perch to shorten the stack 7mm.

Front with air cups is harder as I’m assuming it’s difficult to measure the spring/stack with the bottom perch hand tight (little to no clearance inside the cup to measure accurately).

Two options in my head For the front.
- 1. Temporarily lock the bottom sleeve/mount, maybe a little tighter than hand tight. Set the lower perch to hand tight and measure the gap between the mount lock nut and lower perch. Tighten the lower perch until that gap is +7mm.
- 2. I haven’t confirmed this but it’s possible the thread pitch of the shock is 1mm, meaning one rotation of the perch moves it 1mm. If so, hand tight, then another 7 rotations. Even if the thread pitch thing is true It seems like #1 would be the better/easier solution.

 

[RSS]

Yes understood, however since I am not running a stock wheel, offset, tire set ups the free length needs to be set. I could use what they have for stock set up (where I was wrong in thought as all previous I have dealt with are non adjustable really) and adjust from there but starting at zero is just as easy. No spring, jack tire up and adjust bottom sleeve to desired setting on one side measure adjust other. Then set lower spring perch to desired ride height/corner weight on wheel. Well that’s the short version of it anyway.

 

[RSS]

Oh and don’t hold 10mm on those flange bolts as gospel. They might be an 8mm I am not home to check

 

[RSS]

FSUZ33 is your set up for grand touring or street and track? I was looking at the different set ups and notice 7K rears on yours, I am 14k, and I saw someone else at 13k rear.

 

[RSS]

Redid all the calculations in the rear and I am back into the same situation. I believe my spring length is to short, waiting to get a hold of SakeBomb.
This is mounted and set, I have 5mm I can lower th spring perch prior to the spring becoming uncaptured by the upper and lower perches. Pretty much as low as it can go. Yes I know spring is upside down

 

[FSUZ33]

Initially I spoke with Heath/Nick on the phone about what I wanted/expected from the car. We never discussed specific levels like that. Originally (divorced) it was going to be 14KG-F and 11KG-R (actual spring rates on the springs, not wheel rates). Swapped to True and it became the front stayed at 14KG and the rear changed to 7KG.

I don't know the specific numbers, but the rough calculation for wheel rate on the rear of a Z34/RZ34 is something like 0.5 to 0.6 for True over divorced (divorced being 1.0).
Example: We'll say the OEM divorced spring is 10KG. To switch to a True rear setup and maintain that same OEM firmness/feel ("wheel rate" technically), you'd want around a 5KG to 6KG spring rate.

Main focus right now is my health, and the Z has taken a back seat basically since I pulled the trigger on this FPSpec setup. It hurts that I can't actually dig in, focus and physically work on it right now, but it does seem odd that similar kits for similar-ish setups can have such different spring rates. This situation seems a little cumbersome, but I've gotta admit, my brain is a little in the weeds right now., so that could be me, my situation and my knowledge (or lack thereof), not Sakebomb.

 

[Suzuyabot]

FSUZ33 is your set up for grand touring or street and track? I was looking at the different set ups and notice 7K rears on yours, I am 14k, and I saw someone else at 13k rear.

For reference, I chose street/track for nismo z and the rates are 16F/13R. True rear setting

 

[OptionZero]

For reference, I chose street/track for nismo z and the rates are 16F/13R. True rear setting

that can’t be right
True to divorced conversion rate is 1:2
13kg on the rear with trues is extraordinarily high