Backward thought process.

edit: additionally... it's disappointing that you still haven't had this clarified by BC.

 

Looks like you're right.
Here's a BC set up on a G37.

Threaded on both shock and perch adjusters.
However, you can see that springs are much wider to seat properly in the perch.

 

Running a true coilover in the rear you need a 4k or 5k spring , if you want to run the 8k rear, i suggest getting the proper matching front spring 16k, I do have a set of them you can try out.

With a 16k front and 8k rear you will need helper springs ( messed up earlier , and put tender)

2 things can be done with the adjustable body shock when running the spring in the OEM location. You can set the down travel at a point you know the spring has tension at full droop or you can set the uptravel to maximize the amount of suspension travel you have.

 

if you are maxed out at the lower cup/mount, then you can use the spring seat to get lower at the cost of compression travel. looks like there's plenty of adjustment left with the spring seat with your current springs, so getting shorter springs with the same spring rate will just be a waste of money. if anything get rear springs with the appropriate spring rates.

 

Ok finally got ahold of Sam at BC. Looks like with their true style this is as low as I can go, and yes the springs I have are the shorter ones already, not that that would make a difference. Sam has sent me out replacement rear struts/dampers, and they're 40mm shorter, which means I will be able to close the 1 1/4 gap between my rear fender. He assured me that this will have no effect on performance. Not sure why these aren't the standards for them but o-well.

terrasmak we should get together once I get this setup done and compare between this setup 10/8 k and with your 16k on my fronts, I would appreciate this! Just out of curiosity are you the guy I met at one of the AMU supports sections on base? I believe you had a silver z on RPF's?

 

Originally Posted by TeegsMR
Lastly when the the spring is moved from the OEM position to the true style position my 8k spring will actually act like a 4k OEM positioned spring!

Apparently my memory is crap, thought I had read this some where.... if someone can explain this please do so as I would like to know?

 

apparently they were "super busy" has to call them multiple times.....

 

Do more searching. they offer a lower spring perch adapter to adapt the 62mm spring.

 

It is called motion ratio, OEM location .649 and as a true coilover is .97 , what that means is take your spring rate 480 pounds (8k) as a true coilover 97% of the spring rate is the wheel rate , or 65% of the spring rate becomes wheel rate in OEM location.

Motion ratio is the fancy term for leverage.

 

Thanks for the info and clarification! Hey I asked a question a few post back.

 

Probably me , silver Z on base running NT03 or RPF1s , and trust me , 16k front springs are way to much for the street, and way to much spring for a BC coilover.

 

Well from what I understand I can purchase swift springs in various rates and put them on...now the question is how to determine if the shocks/dampers are dampened correctly for these springs...hmmm wishing now I would have just paid a bit more for something I would not have to keep throwing parts at.

 

You can support up to a 12K up front, and since BC is clueless, you can probably support up to a 5k rear in the true coilover position.

 

I run a ~16k on the front of my car...it's not a street car, though.

 

560/448 setup with oem rear spring location

Same setup, but mathed out to show how much spring actually makes it to the wheel to perform work 265/189 (wheel rate)

Now move the same 448lbs rear spring out to the rear damper that sits almost directly above the hub and you end up with following front and rear wheel rate 265/422

^ it would take a 1002lbs spring in the oem rear location to leverage the same 422lbs at the wheel. Oh yeah, someone doesn't know what they are doing.

Curious, who sold the setup to you?

A 4kg spring on the rear dampers would mean a 265/211 setup

 

After the cost of the BC coilovers and swift springs you could have purchased a set of KW V2s and been done and happy. Did BC charge you for the replacement dapmers (I'm assuming so)? Hope everything works out for you though. This is why I still haven't purchased a suspension setup (lots of reading and learning).

 

What dampers are you running with 16k springs?

 

I believe he is running Motons, if I was running R comps I would probably run 16k too.

I probably need to go up slightly in rate with the RS3's and full aero .

 

Not trying to get too far OT, just attempting to gain knowledge. So with a true coilover set up in the rear, a 4k or 5k spring is recommended. Then would a 10k front/5k rear or 9k front/4k rear set up be heading in the right direction for a street driven car that sees some track use?

 

10K front and 4k rear would be it. Better yet , 8k rear in OEM position would be best. Only reason I have true coil over rear is SPL spring bucket was back ordered for 4 months when I needed it. Even better is look into some quality coilovers starting at a KW V2