A while back I was searching high and low for an adjustable coilover setup for my XJR. I found that J-Complete used to make these, but have long been discontinued. The only available option now is the Mina or Arden lowering springs for the X308...I'm sure everyone knows that.

The suspension in my XJR was already sagging and the Mina springs only lower the car 1.2"...that's not very much. With the sagging stock springs, my car was already as low as the Mina springs. So what was the point? Well...the lowering springs are a little stiffer than the stock springs. And I do mean a LITTLE...probably nothing too significant. But that coupled with the fact that they are a linear spring gives way to the fact that they can be cut and NOT have an affected spring rate.

So I cut a coil off of the springs and lo and behold, the right height was about perfect. But with the reduced ride height, OF COURSE you will lose suspension travel. Even if you just use the lowering springs as they come, you are still going to lose that 1.2" of suspension travel. There really wasn't a whole lot of travel to begin with, and of course even less once I had the lowering springs in. Go ahead and check your sag now and see how much travel you have...jack the car up to where the wheel is off of the ground, measure from center of wheel to the fender arch. Now with the car fully on the ground, measure from the center of the wheel to the fender arch. This will give you your sag. The stock struts have about 5" of travel. After measuring your sag, you will notice you have maybe 1.5 or 2 inches of travel left. Couple that with your bump stop, you can see where the issues are going to lie when you put the lowering springs in.

OK, get past all the technical confusion...with my stock struts and the lowering springs installed, I cut down the bump stop to ONE part. It originally has 3 sections. Even with it cut down that short, I still only had between 1/2 and 3/4" of strut travel. This is HORRIBLE. Going over dips or bumps in the road, you will hit the bump stop. Makes for an *** clenching ride anticipating that front end jar.

And as you MAY know, there are no options for shorter struts by any manufacturer. Finding something comparable from a different vehicle is a bit difficult as well. Either your lower mount will be the same, but the compressed and extended length will be all wrong...or vice versa. I've run coilovers in the past. You have an adjustable strut body and spring...yadda yadda. My main focus here is the adjustable strut portion.

It took some research, but I found a lower mount with the same eyelet as the stock struts and then from there it was only a matter of finding a suitable extended and compressed length. Remember, the goal here is to have an overall shorter strut with nearly the same amount of strut travel. The other thing to make sure of is the strut needs to have an 10mm upper threaded portion and a 12.5mm shaft due to the way the upper mount collar is set up.

After much back and forth with BC Racing, I was able to get exactly what I needed and it works GREAT. Straight bolt up and on top of that, now I can control the dampening of the strut, as it is a 32 way adjustable dampening system. The only thing is the top threaded portion sticks out farther than the stock struts...not necessarily a bad thing, as it doesn't interfere with anything. After everything was adjusted, I now have roughly 3 inches of strut travel with a bump stop in place. This is A LOT better than the 1/2" that I initially had.

If anyone has been looking for a shorter strut or adjustable strut, it IS possible. It took a bit of research on my part, but it was worth it. Anyway, I suppose some pictures are in order.

 

Part numbers and/or build specs?

 

The strut cartridge itself is 230mm length with 130mm stroke. M10 threaded upper with a 12.5mm piston shaft.

The lower mount you need is the REAR mounts for Toyota Tercel. The eyelet diameter is 10mm. I forget the width of the eyelet, but it is the SAME as the X308 stock.

You will also need the lower locking ring to lock the lower mount so the strut cartridge doesnt come unthreaded.

Reuse your stock upper nut....and the damper adjuster knobs are OPTIONAL. I just to get them due to ease of use in adjusting the damper. However, you can use a long thin allen key to make the adjustments as well.

All of these are BC Racing parts. You can order D2, Ksport, etc. but you are going to be paying double what BC charges. And all of those brand coilovers are made in the same factory in Taiwan...just different colors and looks.

 

xjrjag, I think you may confuse people by repeatedly referring to the shock absorber as a "strut"


It's a coil over adjustable shock absorber (without the coil spring in your case).


Its not really a good idea to use one with a lower spherical bearing instead of a bushing in a road car as the dirt, water and grit can ruin the bearing in short order which leads to annoying suspension rattles.


You may be able to get away with using them If the car is not driven much in a dry climate, but they are just not suitable for prolonged use, even with rubber dust boots in a road car.


They do look nice though, as do most race car parts!


Wayne

 

Thanks for correcting the strut/shock portion. However, the lower mount is a bushing type. The pictures may not show it well, but the bottom part where it mounts is all aluminum, with the center having the metal eyelet encased in a clear urethane bushing.

 

Sorry xjrjag, it looks very much like a spherical bearing, must have been made to look like one.

 

How do they perform? Are they well matched to the XJR application and spring rate? Seems a Tercel would be very different to our cars in regards to weight and spring rates.
What are you doing with the rear?
Any pics of the lowered car?

 

Wayne, I think it is just the pictures. In person it does not look like that. I am sure because the urethane part is clear, is why it looks funky in the pictures.

Steve, the only piece that is from the Tercel is the lower mount. The part that is below the gold locking ring. The strut cartridge is exactly that...a threaded cartridge that threads into the lower mount. With the stock shock, you have the cartridge with a welded on lower eyelet mount. With the setup like this, instead of being welded, it is threaded on so you can lengthen or shorten the overall length.

The strut cartridge itself can be valved all the way up to a 32kg spring rate, which the XJ is NOWHERE close to that. Even with the lowering springs, the spring rate is 8kg or even less. Most coilover kits that you get come with a 12kg spring in the front, depending on the vehicle. This is a significant increase in stiffness over stock springs. The Mina or Arden springs really arent that much stiffer than stock. The cartridge I have is valved to 12kg, which if I were to have stiffer springs custom made for the front, I could run up to a 12kg with no issue.

As for the rear, I am still using the KYB Gas A Just shocks because I still have enough travel. The front is where I didnt have much suspension travel and why I upgraded the shocks this way.

 

Makes a compelling argument for me doing away with the CATS... decisions decisions...

 

I do not have the CATS system, so I cannot comment

 

Excuse ignorance, but I'm still a little confused.

You started by saying you don't have enough 'strut' travel. Are you talking about distance the wheel etc travels, or just the shock absorber travel?
You started with 5" of travel (unloaded), but with the weight of the car this dropped to 1.5-2" (of COMPRESSION travel). Then you talk about cutting the bump stops down to get more travel, but ended up with even less??

Now you've gone and replaced the shock absorbers, and magically have 3" of travel. Is this compression travel?
Has your ride height changed? You mentioned cutting the springs, which will make the car sit lower, but somehow you've gained all of this travel?
To get more travel, the wheel has to physically travel further. If the original shock absorber was the limiting factor then that would make sense, but then you wouldn't have needed to bother cutting down the bump stops.

Also, coil spring rate is directly related to the number of coils. If you have cut a coil off then you will have increased your spring rate.

 

The thought occurs to me that a simpler way to accomplish the goal of
adjusting the travel of the piston would be to cut and rethread the
piston rod of the existing stock shock absorber by the amount that the
suspension has been lowered.

Not as pretty as custom shocks, but cheaper and guaranteed fit.

 

I think you are reading too much into it. The only thing I am talking about here is travel in the shock absorber itself. The stroke you have is 5.87 inches from fully extended to fully compressed. When you install it on the vehicle and have it sitting on the ground, the springs and shocks compress. That 5.87 inches of stroke is now decreased by X inches...X being how many ever inches of sag is present. Probably about 2 inches of compression, maybe more. Let's just say 2 inches in this case. Your stroke is now 3.87 inches. This is TOTAL stroke of the SHOCK ITSELF. This is NOT what you physically have with the shock installed on the car. Look at the way your upper mount is. You have a "cap" in the wheel well where the bump stop sits. Above that, you have the shock tower and the mount and bushing. All of that takes up space in your available travel too. The amount of usable stroke that you really have is between that "cap" and the top portion of the strut body. Look in your wheel well with the car planted on the ground and see how little of the piston is visible. Your bump stop is probably taking up quite a bit of space as well...actually I know it is, because it is a couple inches thick.

The ride height isn't changing here...you are just gaining more usable stroke. The stock strut has 5.87 inches of total stroke. The new strut cartridge I have has a total stroke of 130mm (5.11 inches). The new strut cartridge has a total length of 230mm (9.05 inches). This DOES NOT include the lower mount/eyelet. The stock strut body has a total length of about 12.5 inches. Again, this DOES NOT include the lower mount/eyelet. Do you see where the gains in usable stoke are? You have almost the same total stroke, but the cartridge (AKA BODY) is shortened.

And the front springs are a linear spring. With linear springs, the spring rate is constant throughout compression. Cutting a coil off of a linear spring does not affect the spring rate. The rear springs are progressive springs. With progressive springs, the rate INCREASES through compression. Cutting progressive springs will most definitely affect the spring rate, IF you cut the progressive portion. Cutting DEAD COILS off of those springs will NOT affect your spring rate. Dead coils are spaced so close together that they are already touching before the car is fully on the ground.


Can't do that. The shock body itself needs to be shorter, not the piston. Cutting the piston will give you less suspension travel. The reason for the shorter shock body is so that you can preload the spring before the shock ever sees any compression. So imagine you take your stock springs off...you have your jack under the control arm. Now you install a shock that has a body that is 2 inches shorter...so that lower mount/eyelet is moved 2 inches HIGHER than where the stock shock was. You now have to jack the control arm up 2 inches in order for the holes to meet up and put the lower bolt through the bottom of the shock. This preloads the spring...when you put the car back on the ground, the spring is already preloaded by X amount, so it has to compress LESS once on the ground. The end result is the same...your spring is going to compress X amount whether you have the stock strut in or shortened struts.

 

Like to see what u have done, those adjusters look kind of old-fashioned and cool.

I see your line of thinking, but the only thing what baffles me is the bump stops.
Are they not there to prevent the wheel from getting any higher in the wheel-well, thus preventing contact?
I guess there is always some tolerance, but if I look at my front tire at full turn, there is not much space till the fender.
You might have the travel in your shock by now, but I wonder if it is needed and useful.

Eric

PS. After reading this, I will surely cut the springs on my Jag, would love to see that lady a bit lower then she is right now. Just too many other things on the list...

 

The bump stops are there so that you don't "bottom out" the shock. Bottoming out meaning riding with the shock at the end of its stroke...it will blow the strut. You don't want to ride on the bump stops either, because the ride will be harsh.

To put things into perspective, I am running a 20x10 wheel with a +20 offset all the way around. I am tucking almost the entire tire up front, and the entire tire in the rear. I have no issues rubbing whatsoever in the front. The only issue I had was not enough shock travel AKA stroke. Which is why I did this mod with the shortened shocks.

 

While some of the points you're making have merit, this is fundamentally wrong. The spring rate of a coil is directly related to how many coil you have. Cutting a coil removes one coil's worth of resistance to movement, which will increase your spring rate.

A linear spring means that the spring rate remains constant as the spring is compressed. A progressive spring means that the first inch of travel takes less force than the second inch of travel. The spring rate still depends on how many springs you have.

As for the shock, ideally under static load the piston would sit in the centre of the shock body, so that it has maximum travel up and down. When you lower the car and retain the factory shocks you move the piston out of it's ideal central position, so you have done a good thing by changing the body of the shock to match your new ride height, but the travel itself is still limited in the upward direction by the chassis (bump stop) and downward direction only by the length of the fully extended shock.
If you have a shorter overall shock you will get less downward wheel travel, but the entire purpose of this is to get better control of the upward travel, which you haven't affected in any way, especially geometrically.

By having adjustable dampers you can dial in a harder shock, and make it harder for the wheel to rise up and hit the bump stop, but the shock itself has nothing to do with how far the wheel travels to reach this point.

 

Great info, Ive been looking to do something very similar. Quick question if you notched the original spring perch slightly would you have the room to run a spring on the coilover?

 

Ive now seen 2 cars with bc coilovers on them but no info from bc themselves. Any one else out there done this?

 

I'm still looking for answers if there's a kit available. I'm currently trying to work with a manufacturer to develop a kit that converts to a coilover shock instead of the stock configuration

 

I cant find an off the shelf coilover kit for our cars anywhere. I am going the air route, and I had Iceboxx Customs in California make a set of brackets to mount the bags into the stock location.