24 replies to this topic

[EightySix200sx]

S12 Weld-on Coilover Conversion - Adjustable Suspension for the S12.
Written by Justin Carter

The following is a write-up of the coilover setup we have come up with here in SoCal. Engineered and tested by us of the Low.XII.Position crew, it is a for sure way to lower your S12 without converting to the S13 suspension. It is what I am running in addition to Andrew (demonic_s12) and Sterling (sterlingps12). The only difference between between our S12s and what Sterling did was that he used S13 tubes in the front. It can also be verified by Colin (draconis) who road passenger in Andrew's car last year.

In the past many months there have been much interest and many emails inquiring as to our suspension setup so the following is the list of our suspension setup.
This setup allows one to retain the factory S12 tubes.

You will need a welder and a grinder as the front tubes must be sectioned 40mm shorter to accept a shorter SW20 shock. Also, once can use S13 camber plate and in doing so, inform Techno Toy Tuning that you will be running S13 camber plates with SW20 AGX socks and they will send you two small collars that will slip onto the camber plate to take up the slack. They are aware of the situation, so do not worry about their confusion. You will have to grind off the stock perch and weld the Ground Control perch in its place. Other than that, the necessary steps for the modifying the front suspension.

For the rear, the setup is easy and literally drop in straight out of the box. The Mustang Foxbody struts however will require some shimming. To do so, one will need four washers on each shock on the lower mounting bracket on both sides of the car to take up the slack.

Parts list -------------------------------------------


FRONT:
ROLL CENTER ADJUSTERS- http://technotoytuni...etail.php?p=815
S13 CAMBERPLATES- http://technotoytuni...etail.php?p=819
280ZX GC SLEEVES- http://technotoytuni...etail.php?p=802
MR2 SHOCKS- http://cgi.ebay.com/...=item255c19e4ab

REAR:
SPRING PERCH [MUST USE SS-85500-A] http://www.daymotors.../SPRING-SPACERS
SPRINGS [MUST USE 5"X8" SPRING] http://www.daymotors...NT-COIL-SPRINGS
FOXBODY SHOCKS- http://cgi.ebay.com/...=item4cf6ee146b

This is what to expect throughout the process

Edited by Draconis, 07 July 2011 - 06:03 PM.
Edited upon opener's request. Bearing Low.XII.Position's logo on their pictures and to clarify the text.

[caraudiofoolery]

you can use a shorter spring. but you might not want to drag gas tank lol

[james]

Great info

On that note though, it would help of you could include a few photos of the height this setup delivers.

[Draconis]

Post is cleaned up for ya Justin.

[and_rej]

So i'm about to do my rear suspension and this looks bloody brilliant!

My question is, can you use those rear spring perches on a live axle rear end??? I can't think of any reason not to, but thought I'd ask.

Also, can we get these bits sent to Australia pleaaaaaaaaaaaase???

[Draconis]

If you cannot order the parts yourself, I know several of us can arrange to have the parts shipped to you.

[and_rej]

daymotorsports doesn't mention shipping outside of the US so I may need to take you up on that.

The big question is what would stop me whacking a pair of those perches on my solid axle gazzu!?

EDIT: Also, what's keeping the perch at the desired height once in place? Like, what's stopping it from working it's way back down that thread?

Edited by and_rej, 08 July 2011 - 03:36 PM.

[EightySix200sx]

just lmk if you want me to ship these items to you i have no problems doing so sir just email me at LOWXIIPOSITION@YAHOO.COM

[and_rej]

Thank you very much! Just shot you an email. And in the few minutes since then I've found out they SHOULD work fine in a live axle S12: http://club-s12.org/...p?topic=7848.40

Now I just need to find a better spring rate. As I mentioned in the email, the lowest spring rate in the linked catalogue is 550lb/in = ~9.8kg/mm = permanent spinal injury :/

[and_rej]

PM and email sent.

I'm really keen to get these into my Gaz so look forward to hearing from you lads!

Cheers.

[Rome11six]

Ok dont really know allot about suspension but enuf to say this is awesome and its the way i wanna go but i dont know what spring rate to use.
its going to be a track drift car with some road driving, so i want it pretty stiff but not to hard.
so what would be a good spring rate for a hatch s12 with a rb25?

[bman]

Low.xii to the rescue of no rear end suspension. Looks the goods guys. What would a rear set cost Inc. Postage to aus if any one knows?

[and_rej]

Ok dont really know allot about suspension but enuf to say this is awesome and its the way i wanna go but i dont know what spring rate to use.
its going to be a track drift car with some road driving, so i want it pretty stiff but not to hard.
so what would be a good spring rate for a hatch s12 with a rb25?

So I run 8kg/mm (448lb/in) in the front of my hatch and that's with an SR20. I would describe it as too stiff for the street, but definitely tolerable. On smooth surfaces with high speed it's perfect so you'd be laughing at the track. If your priority is track use, and taking into account your heavier engine, I'd go with close to 8kg/mm. If you value comfort during your day to day commute then go with something softer, a bit closer to 6kg/mm (336lb/in). Bare in mind that swaybars have a big effect on body roll and a softer spring + stiffer sway bar combo would probably be better suited to a street driven car.

For the rear, the recommended companion for an 8kg/mm front is a 6kg/mm rear. So if you go the softer 6kg/mm front, I'd go for a 4kg/mm rear.

I used this guy for my conversions http://www.hraefn.ne...pring_rates.php

Note: Personal taste is a big factor here. I tolerate a stiff car, some people don't. My girlfriend barely notices, some girls might get the shits. Use common sense

[and_rej]

Low.xii to the rescue of no rear end suspension. Looks the goods guys. What would a rear set cost Inc. Postage to aus if any one knows?

I'm getting some rear bits shipped to Aus soon through Colin. We can bundle if you're interested?

[Rome11six]

So I run 8kg/mm (448lb/in) in the front of my hatch and that's with an SR20. I would describe it as too stiff for the street, but definitely tolerable. On smooth surfaces with high speed it's perfect so you'd be laughing at the track. If your priority is track use, and taking into account your heavier engine, I'd go with close to 8kg/mm. If you value comfort during your day to day commute then go with something softer, a bit closer to 6kg/mm (336lb/in). Bare in mind that swaybars have a big effect on body roll and a softer spring + stiffer sway bar combo would probably be better suited to a street driven car.

For the rear, the recommended companion for an 8kg/mm front is a 6kg/mm rear. So if you go the softer 6kg/mm front, I'd go for a 4kg/mm rear.

I used this guy for my conversions http://www.hraefn.ne...pring_rates.php

Note: Personal taste is a big factor here. I tolerate a stiff car, some people don't. My girlfriend barely notices, some girls might get the shits. Use common sense

Ok thanks, ya i just needed to get a idea about what to use im prob going to go with like a 9kg/mm front and i guess 7kg/mm rear!
I thought you would want stiffer in the rear than the front?

[and_rej]

That'll be pretty damn stiff I reckon.

Yeah generally I think you want a bit more roll in the front to make the car tend to oversteer, but you need to remember that the rear of the car weighs a lot less! So for a given amount of suspension travel, you don't need as stiff a spring. Most coilovers will come as a set with the rears 2kg/mm softer than the fronts, that's how I got that ratio. It's useful as a general guide I think.

[james]

From memory, stock springs are ~4kg

Good stiff daily would be 6kg

8kg for track

10kg if you don't like your spine.


For the rear, most people go 2kg lower rate

ie. 10/8 8/6 7/5 6/4

8/6 is the most popular I believe

[Rome11six]

k thanks for the info, i did research about spring rate and more about our cars and what to run im prob going to go with 8 in the front and 6 in the rear if i dont like it i can always go stiffer.

[mikey]

do i HAVE to use the 280 ground control kit or can i use a GC coil from a different car say an s13 or maybe a civic ?

[SFort]

Old thread, but anyway... Rome, did you ever go ahead with the 8/6kg set up? I've got 9 and 6kg springs laying around and still deciding which to throw in the front of the track S12.

FWIW I ran 9/6kg in my street driven S14, and even on the track it struggled to put the power down with only 160-170 at the wheels.
I changed to Nismo S-tune 5.5kg set up and much stiffer sway bars - sooo much flatter and easier to get the rear to squat on the road and track. But not quite as responsive to small inputs.