In my random internet meaderings I came across some circle track sites that sell threaded sleeves. Seems like rhis would be a cheapish way to get coilovers. Am I wrong in this? Has anyone done this?
In my random internet meaderings I came across some circle track sites that sell threaded sleeves. Seems like rhis would be a cheapish way to get coilovers. Am I wrong in this? Has anyone done this?
I know miata guys do with the factory bilstein shocks. Im watching to see what else comes up.
I did it on a VW GTI that I built for road racing. On the front the sleeves fit over the Bilstein HD shock body and rested on the remains of the spring perch. I had to cut the perch off and grind it down until there was just a ridge left, little more than the weld really. I slipped the sleeves on and had put 3 or 4 beads on silicone vertically on the shock body. After the silicone cured the sleeves stayed put for several years of racing. Mine were sized to use 2.5 inch springs.On the rear, the sleeve sat on a C-clip around the shock body. Again I used the silicone.
The whole thing was straight forward and worked well.
Fitzauto wrote: In my random internet meaderings I came across some circle track sites that sell threaded sleeves. Seems like rhis would be a cheapish way to get coilovers. Am I wrong in this? Has anyone done this?
Yup.
My Mazda2 front coilover build:
https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/2011-mazda2-not-so-srs-bzns-stf-build/100748/page1/
I did it primarily to get known good quality dampers up front. If you do this with crappy shocks there's really no point unless you want to mix and match test and tune pretty light rates. I'm running 550/450 lb springs, going to likely be upping them to 700/450 for daily driving then swap rears to 550+ for auto-x(takes all of 3 min to do in the rear).
With good dampers you can daily drive pretty high rates tolerably. I put 100mi every day on my setup. After some fiddling with rebound adjustments and removal of sway bars it finally rides actually REALLY well. Even with my Star Specs. With my winter tires or all seasons its downright comfy.
That's a cheap way to get adjustable height spring perches, a wide variety of spring rates and lengths and smaller diameter coil springs to fit more tire under the car.
You already have "coil-over" springs.
Realistically, you should spend money on the shocks with proper valving. Springs are less of a concern as long as they are a decent brand.
I'm sure Keith's book on Miata modifications should go into this in a little detail.
The downside of this type of setup vs a full-threaded coilover is that you can't adjust ride height without affecting shock travel...that and the possibility of the sleeves moving relative to the shock.
In reply to GameboyRMH:
I thought about that as well but the car is already on lowering springs with stock length struts.
In reply to GameboyRMH:
Huh? any type of adjustable spring perch will impact the amount of travel, just the nature of having the spring hold the car up.
The only way to change the height of the car with the shock/spring and keep the relative travel is to relocate one of the shock/strut mounting points.
My Celica was easy. eBay Honda Civic springs with those crap threaded sleeves and collars. Then kyb agx's from an mr2 and a camaro. Then mustang gt springs for my rear. Had to buy spring top hats from T3, but all in all everything cost me 350$. Cheap! And rails!
Stefan (Not Bruce) wrote: In reply to GameboyRMH: Huh? any type of adjustable spring perch will impact the amount of travel, just the nature of having the spring hold the car up.
Fully threaded coilovers means adjustable lower mounts 
Im thinking i may cut the spindle tube down and run some zhorter shocks to compensate for the low.
Koni coilovers are super common on old Z cars. That is absolutely what I would do.
http://forums.hybridz.org/topic/98897-step-by-step-coilover-conversion/
http://dirtys30.blogspot.com/2011/04/how-to-240z-ground-control-coilovers-w.html?m=1
IMO the height adjustability of "fully threaded" coilovers is not necessary. If you really want, cut 1/8 or 1/4in off the bump stop to compensate. You don't want preload on the springs(at least VERY LITTLE if anything) anyway so being able to preload the springs will just do goofy crap to the way it handles anyway.
Summit sells a wide variety of springs so you can choose the length, diameter and rates for around $40 a piece if I recall correctly.
In reply to GameboyRMH:
and that does nothing for the travel bud.
In reply to flatlander937:
The goal would to be about 2.5" lower than stock. Its right at 2" lower right now.
Do it all the time,remember to shorten bump stops accordingly.
Fitzauto wrote: In reply to flatlander937: The goal would to be about 2.5" lower than stock. Its right at 2" lower right now.
Then definitely poke around on Ratsun... Done MANY times. Going that low you definitely need some of the shorter available shock options and probably some higher rates. I run the 8610-1436(shortest single adjustable Koni offers) myself.
http://community.ratsun.net/topic/39512-strut-insert-and-rear-shock-guide/
Use GOOD dampers and high rates are not bad. I'm commuting on 550/450 which works out to a 2.5/2.9hz ride rates... Most will tell you to not go that high. No idea what the 280zx is like but search around some and copy some well-known setups to start.
Edit: more great links to look over:
(Read all over this site that you can. Click on the "Dynamics Calculator" link on this page in particular!!!) http://farnorthracing.com/autocross_secrets5.html
http://farnorthracing.com/autocross/konis.html
kevlarcorolla wrote: Do it all the time,remember to shorten bump stops accordingly.
YES!! This made a MASSIVE difference on my daily drive in the rear... I was hitting the bumps just on heavier bumps/whoops over a bridge I go over every day... I trimmed another 1/4in off and also raised ride height in back by another 1/4in(for 1/2in change total) and it went from pulling muscles in my neck straining to stay in the seat to relaxing without issue for the most part.
Tip: use zip ties on the shock shaft to visually see how close to the bumps you get on a given road/etc. You use a LOT more travel than you think even on seemingly smooth roads.
Also keep in mind when turning, the outside will compress a bit... So if you hit a bump while turning you're that much closer to hitting the bumps while cornering.
Tha ks for all the info guys. Keep it coming. I love learning about suspension stuff.
From my reading the hardest part appears to be the rear. Not sure what shock to use to make it shorter.
Stefan (Not Bruce) wrote: In reply to GameboyRMH: and that does nothing for the travel bud.
It lets you adjust ride height independently of shock travel (by moving the lower mount)...you could end up having the wheels hit the fenders, but that's a different problem 
In reply to GameboyRMH:
Im guessing there is now way to DIY that cheaply
In reply to GameboyRMH: and that does nothing for the travel bud.
Running out of compression travel on the damper is a very common problem on lowered cars, especially when you consider you have to leave room for a bumpstop ON the strut shaft on a lot of cars. Being able to adjust the damper itself farther down into the strut yoke helps address this problem, even if the damper itself is shorter overall.
At some point you run into a lack of travel for the actual tire up into the wheelwell, but on most cars you will have damper problems before you have body-rubbing problems, and that's by design.
Got one more question for now: are the eye things at the bottom of shocks all the same size or do they differ? Second: if the eye things are different size should I just make a strut tube with an eye on the bottom?
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