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Old 10-12-2007, 01:27 PM   #1
Aaron
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HOW TO: Coilover Installation - KJ/BA

Installing JIC Height and Damping Adjustable Coilovers
The pics link to larger versions
More pics can be seen at http://photos.ausmicro.net/JIC_coilovers


Installing strut type suspension is pretty straight forward when you don't need to break the struts down into their basic components. It doesn't take much time for someone with some mechanical knowledge and it certainly doesn't take much in the way of tools.

Here's a write-up of how I swapped the Monroe Sensatrac/Whiteline Super Low combination for a set of JIC Coilovers.

The JIC Coilovers
I sourced these through our friendly Rupewrecht, we didn't know much about them as their Yahoo Auction was very simple and could only make assumptions on condition and setup however they looked good in the pics and the price was very convincing.

If you pick Auctions well Rupewrecht can land these from about the AUD700 for a set, which is very favourable compared with buying off-the-shelf replacement parts here. It is a lottery though on condition, but the JICs can be rebuilt by a number of places in Australia for up to $150 a corner for full damping adjustment. Even if you end up having to rebuild them you're still likely to spend less cash than buying a new set of D2 or G4 coilovers.

JICs come in two basic varieties and two different "ages". That is Height Only and Height + Damping adjustment. The ages are basically Black or Purple Springs with the purples being newer and most commonly having helper springs.

It turned out that my set were early model (Black springs, no helpers) with Height and Damping adjustment which was a bonus for their price.

Once they ended up in my garage I had to hunt up a "C Spanner" for adjustment. Motorcycle shops will sell universal types that work well, however Peddars will do one to suit the Peddars branded coilovers for about AUD10. It works on the JICs and with percussive adjustment (beating with hammer) it works even better with JICs.

Using my newly adjusted C-Spanner I wound the perches down as low as possible so that the springs were free and I could cycle/pump the shocks. The first few strokes were done slowly to encourage the oil through the internal valves and lubricate the innards correctly.

Once a few cycles had been done and I could feel the resistance to the motion I started to cycle them more quickly before trying out each of the 4 damping settings.

Firmer = AntiClockwise
Softer = Clockwise


Each shock felt good and I was relieved, if you can't get even pressure and feel the changes the damping adjustment to hand movement it's likely they will need a rebuild.


Sundry Items
If your car uses any aftermarket alignment products like Camber pins you'll want to work out if these should be used with coilovers. On the Lynx there were camber pins in the front, a castor kit and at the rear just camber pins.

I ordered through Mazda Genuine bolts and nuts to replace the Camber Pins. These were about AUD46 for a pair of bolts and nuts. Expensive, but they are overnight freighted and 100% perfect size and strength for the job. If you source bolts elsewhere they MUST have a diameter that is a good fit in the knuckle otherwise they could slip causing some severe problems.

At the rear I've elected to keep the camber bolts as these are more accesible than the strut tops making life "easier". Mazda lists a pair of rear bolts for about AUD55 per pair with nuts.


The Workspace and Car Prep
Most workshops quote about 30 minutes per corner to change struts. In the home garage without airtools and hoists you will take longer, Factoring about an hour to 90 minutes per corner if all goes well.

No other prep is needed except it's nicer to work on a clean car with well washed down suspension. I didn't do that and regret it.

You will need an assortment of Metric tools including spanners and sockets.
I used:
17mm Spanner
17mm Socket
14mm Spanner
14mm Socket
Flat Screwdriver
13mm Socket (Camber Bolts)
15mm Socket (Camber Bolt Nut)

Ratchet (obviously)
Long breaker bar
150mm extension
"Deep" versions of above sockets for convenience.

The car will need to be a decent height off the ground, so I lifted it and had it on Stands - as I only have one pair of stands I did front then rear.

NOTE: For years I have been using the cars stock jack to lift a side of the car, pop a stand under then go around to the other side and lift and insert stand. I have always felt this method works "OK" and is still safe. Until I was doing this on the rear of the car and the Jack collapsed. The car basically pivoted off the jack as the jack base couldn't handle the sideways load. The jack is ruined (about AUD30 to replace with a new one) but luckily no damage was done to the car or a person.

Do yourself a favour and buy a decent jack if you're going to be working on the car. They're not that expensive and are much quicker to use and ultimately safer.

As is always said NEVER work on a car that is only supported by the Jack.

Into Action: Wheels off and Out with the old
The first step is the "crack" the wheel nuts prior to jacking the car onto stands.



Once the wheels are off you'll get a view much like this. I then removed the clips holding the ABS wheel sensors and the Brake hydraulic line in place. This gives a little more access around the two through bolts. Before tackling the through bolts I did "crack" and slightly loosen off the top mounting bolts in the engine bay.



Next I tackled the through bolts, aiming to "crack" the nut and loosen it off a few turns. Once the nut was loose I tapped it with a hammer to move the through bolt slightly. They are a close fit and I found they needed the tap to break any light corrosion between the bolt and knuckle. Once I knew both bolts were able to move I supported the lower ball joint (preventing the suspension are from dropping once the strut is unbolted) and removed the nuts from the strut top.

With the strut now free from the top of the tower the through bolts can be slid out with on hand while the strut assembly is supported with the other.

Once all the bolts are out it's a bit of a wrestle to get the strut assembly out of the space.




Ohhh So Shiny:
Getting the JICs into position is fairly easy. First work out which is left and right (the brake line bracket goes to the front of the car). If your car has ABS like Stinky it's about now that you realise the JICs don't have a way of attaching the brackets supporting the sensor wire. Hot Tip: Cable ties fix everything!



I lifted the struts up into position and had an assistant guide the mounts into place and loosely put the nuts on so that I had the ability to "wiggle" the strut around but didn't have to support the weight.

The tricky part now comes as you have to lift the knuckle up into the foot of the coilover and get a through bolt into the mount. There's a bit of wieght and nowhere real good to hang on so it can take a few moments to get the right grip and line it all up. If you're fighting with weight use a jack under the ball joint to lift the knuckle up into position.

I did up the nuts finger tight before cable tie'ing the ABS sensor wire in place and tightening up the top mount.




You can see in the pics above the shiney new bolts compared to the original stock ones.

Repeat and Repeat and Repeat
The fronts are the same and the rears more of the same so I won't describe the process once more. Except for a few pics and explanations.



You need to remove a lot of interior trim to get to the rear tops. Unlike the 17mm nuts on the front strut tops the rears use 14mm. On a Lynx there's just enough room to spanner off the third nut with the big rubber + plastic domes over the strut tops. These can be unscrewed and pulle dout of position by hand.

I don't have pics, but the rear anti-roll bar links can be hard to get back in position. I popped them back in place with the car on stands but only did the nuts up with the car back on it's wheels.

It's a Wrap!




Here's some pics of the finished ride height. For comparison previous the top of the tyre was at the edge of the guards. Obviously I have these set very high, with the goal being to make the car more practical as a daily driver and also to pass a rego inspection. Previously the can didn't even fit under the sills.

(Continued Next Post)
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Old 10-12-2007, 01:28 PM   #2
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Stiffy!

Lastly some pics to give you an idea about the stiffness of the body shell on the Lynx. With a single stand under the passenger side of the rear (and the jack point) both rear wheels are held clear off the ground. No tricks, no magic.

I've been able to lift both front & rears on one side of a car before but this is the first time I've seen a single rear stand like this.

To lower the car we ended up having to pop something under the wheel to support it otherwise it got too unstable.



Thanks go to Bear for the assistance on the day and Rupewrecht for sourcing the struts.

And as a note 8:30am is a great time to start working on the car on aSunday morning

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Old 10-12-2007, 03:21 PM   #3
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Good write up Aaron!

LOL @ the rear wheels... My car when jacking up the front, actually lifts the rears up 1st as there is zero movement in the rear coilovers.

I never had the problem with lifting the ball mount tho. I just extended the coilover to the required length and inserted the knuckles into the strut foot.

And I didn't have ABS lines to worry about. Altho the D2 kits come with a bracket to hold the line in place. So I had 2 spare not used.

And my top bolts front n rear were the same? Not 17mm and 14mm???

Ryan

Last edited by project.r.racing; 10-12-2007 at 04:52 PM.
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Old 10-12-2007, 04:20 PM   #4
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mad aaron nice work.... although i feel bad in saying this and i hope that you already knew ....but coil overs are illegal in ACT. unless engineered! but i guess with the GTX transplant you would need engineering anyway?....

looks way better

keep it up
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Old 12-12-2007, 09:54 AM   #5
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First Impressions:
With the car aligned back to a stockish sort of setup it's immediately apparent that the Coilovers have transformed the handling. The car still has a tendancy to understeer but there's a lot more "snap oversteer" and with enough lateral load it's possible to get oversteer mid corner under power. I'm not looking forward to the first quick drive in the wet becuase it will be a very loose car to drive with that much roll stiffness.

I am yet to start tweaking pre-load on the springs and other things which will affect the ride/handling balance.

At the moment it's too stiff, but the 4 positions on the dampers do make a differnce, enough to balance out things a bit. However it's still too stiff. Tein Australia tends to set up their gear here with at most 5kg springs on the front and these are 7kg. I'll probably clone the rates they use on the Mazda3 or 3 door Civics down the track.

The other thing is that at low speeds coilovers are noisy, they transmit all the noise directly into the cabin thanks to not having any form of rubber mounting isolation. Plus there's a but of spring clash with the pre-load I'm running at the front.

As for legality, depending on the interpretation of the rules these are very easy to engineer "legal", they have dump stops, keep the spring trapped and will do so even at the lowest legal ride height.

Helper springs will keep the spring retained under all conditions which means it's even more likely to be legal. (however the engineer should only assess setups from Legal height up).

As Stinky already had non-stock suspension it's possible the nuts were changed way back when.

The ABS Brackets will have to be sorted out. I think I already have a solution just have to knocke one up and test it out.

A.
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Old 12-12-2007, 03:57 PM   #6
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Despite all the -ve's, would you ever go back to a conventional coil and shock setup? Do you feel that the coilovers are going to be too stiff for every day driving, or will you be able to 'set it up' so that its not going to be too stiff?

Do you still have a stock rear swaybar or have you and aftermarket heavy duty one? If when you drive in the wet and you find the rear wants to snap out really easiely from either rapid acceleration or deceleration, maybe you'll need to play around with the swaybar a little? i found on mine that as soon as i put a beefy rear swaybar on (even with stock suspension) it still wants to kick the rear out.
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Old 13-12-2007, 06:54 AM   #7
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Despite all the -ve's, would you ever go back to a conventional coil and shock setup? Do you feel that the coilovers are going to be too stiff for every day driving, or will you be able to 'set it up' so that its not going to be too stiff?
I don't think there's many negatives with a well chosen strut/spring combo. And likewise there's no real advantage to going coilovers if you're going to put them into the car and then let them at stay the same height and damping settings (and spring choices).

I wouldn't go back to the strut/spring combo on this car, but I certainly would not automatically buy coilovers for every car I wanted to modify.

The Coilovers I have are a victim of the Japanese trend to run modified cars mega stiff for a more "race car" feel. And on a smooth track or road I can understand why becuase it really is quite close to the track car feel, although overall grip is compromised.

The best example is Tein who now re-spec most of their kits in Australia with the main change dropping the spring rates dramatically. On some setups they run about half the spring rate they do on the JDM version of the kit on the same car.

Unlike 90% of people who buy coilovers I will be changing the springs down the track, at the end of the day Springs are available off-the shelf in the 64mm ID from a number of suppliers. I do feel that buy using the rear 5kg springs in the front and buying a lighter pair for the rear I can get back a lot of the comfort level for minimum cost.

I think the biggest problem with suspension is that it's a decision you can only really afford to make once because each change effectively throws away components. I do think that the Mazdaspeed/KYB struts combined with Mazdaspeed/Eibach springs would be one of the better combos, and the Monroe Sensatrac/Whiteline combo being one of the worst. Years ago when I had a good relationship with Whiteline I talked about using Monroes with my car and was strongly advised against it, I ended up with Konis and they wound springs to suit the Konis and my own height criteria. In simple terms Monroes are to replace stock struts and work with stock springs and yet on Stinky they were made to work with a ~50+mm drop...




Quote:
Originally Posted by newman View Post
Do you still have a stock rear swaybar or have you and aftermarket heavy duty one? If when you drive in the wet and you find the rear wants to snap out really easiely from either rapid acceleration or deceleration, maybe you'll need to play around with the swaybar a little? i found on mine that as soon as i put a beefy rear swaybar on (even with stock suspension) it still wants to kick the rear out.
Stinky has a Whiteline Blade bar at the rear. It's currently on the stiffest (short arm) setting and I will experiment a bit.

I haven't driven the current combo in the wet back with the old setup there was a tendancy to tail-out under brakes entering roundabouts etc wet or dry. The Lynx having different weight and COG to the BG/KF and BA/KJ "norm" thanks to the body design seems a little more stable thanks to a bit less pendulum effect at the rear.

On the last car I went down the suspension path with seriously (and tracked the car) I had about 4 rear bars made up: 18mm (up from 16mm), 20mm, 22mm and 25mm. The 18mm made the best street package with stockish suspension. I ended up running the 20mm rear bar all the time becuase it worked best with the Koni/Spring combo on the car and the 25mm was based on the most extreme available in the USA - it was a killer (as in backwards into the trees) on the street, and was really designed it seems for circuit racing.

The blade on Stinky should let me find that compromise, but in all honesty at the moment it feels like the springs are too stiff to really let the 'bar make a difference.

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Old 13-12-2007, 07:17 AM   #8
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The Coilovers I have are a victim of the Japanese trend to run modified cars mega stiff for a more "race car" feel. And on a smooth track or road I can understand why becuase it really is quite close to the track car feel, although overall grip is compromised.
That's our problem in OZ - the road a rough and ****!!!

Quote:
Originally Posted by Aaron View Post
Unlike 90% of people who buy coilovers I will be changing the springs down the track, at the end of the day Springs are available off-the shelf in the 64mm ID from a number of suppliers. I do feel that buy using the rear 5kg springs in the front and buying a lighter pair for the rear I can get back a lot of the comfort level for minimum cost.
Newies cost between $40-$80.

Quote:
Originally Posted by Aaron View Post
I haven't driven the current combo in the wet back with the old setup there was a tendancy to tail-out under brakes entering roundabouts etc wet or dry. The Lynx having different weight and COG to the BG/KF and BA/KJ "norm" thanks to the body design seems a little more stable thanks to a bit less pendulum effect at the rear.
Being a bit over-dramatic, normal driving won't seen any of those things happen. My BA has to be doing 80kph before the rear is affected by lift-off oversteer. But I do have some wide tyres there also.

Quote:
Originally Posted by Aaron View Post
The blade on Stinky should let me find that compromise, but in all honesty at the moment it feels like the springs are too stiff to really let the 'bar make a difference.
Yes I noticed the same thing, I wasn't impressed by my 20mm sway bar as I installed coilvers 1st and they did 90% on the bars job.

Ryan
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Old 17-12-2007, 10:17 AM   #9
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Being a bit over-dramatic, normal driving won't seen any of those things happen.
Ryan
Aaron's normal driving is.... well.... um..... spirited driving to say the least.


I am not defending his driving, nor do any of us here at AGT condone illegal/unsafe driving practises


But, well, Aaron needs good suspension
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Old 17-12-2007, 12:32 PM   #10
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Being a bit over-dramatic, normal driving won't seen any of those things happen. My BA has to be doing 80kph before the rear is affected by lift-off oversteer. But I do have some wide tyres there also.
In my KE you can be doing as little as 30-40kph before lift-off-oversteer happens. It's truely a handful, and this is why I want a responsive turbo package to control the RWS effect with throttle input. The KE can be made to turn like a RWD, and is about 3X easier to FF drift than my nuetral>understeer handling Astina was.

Aaron: I like your idea of using the rear 5kg springs on the front. Ideally I would like to have 4/3kg (F/R) spring rates. But if you go 5/3kg, you might find a nice setup.

Gav.
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Old 17-12-2007, 01:29 PM   #11
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Aaron: I like your idea of using the rear 5kg springs on the front. Ideally I would like to have 4/3kg (F/R) spring rates. But if you go 5/3kg, you might find a nice setup.
For BAs I think this would be the better spring rate for Australian roads. I have thought about doing this. But stayed a little firmer for the track, but sucks sometimes on the road. With the mazda original open diff, I though having the firmer springs was better for traction on the left power wheel. Now with a LSD fitted, maybe I can go to lower spring settings.

Ryan

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Old 17-12-2007, 01:41 PM   #12
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I have about 3.2/2.4kg on the Astina with the Tokicos, and it is quite firm even with 14s on atm. The Laser is insanely firm in comparison, and that's with 14s still. The biggest problem I had with the Astina was I would get the tyres skipping on some rough roads when I had the 16s and 17s on. This was only a problem on Samford Valley, Mt Glorious, and Springbrook though... The Laser is teeth shattering on these roads, so I'm not too fond of the Dobinsons for this reason. Damn, makes me wish I had the soft squishy King springs still...

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Old 17-12-2007, 02:05 PM   #13
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The 5kg to the front is a quick (well mostly quick) and easy way to try out the softer spring theory.

I could for example say buy a pair of 3kg Springs and go 5/3 then if that's no good try a 3/5 combo to see how the front handles the 3's then pick a rear to suit. The way i see it the less springs bought the better!

I've determined there's something loose ont he left side of the car though - there's far more clunk and rattle that on the right side and it's something moving.

Will need to investigate.

The stiffer suspension does help with grip but it sure makes everything else work hard, engine mounts, tyre sideways, and even fuel slosh (below 1/4 tank) are all factors to weigh up at this 7/5 combo...

A.

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Old 17-12-2007, 04:34 PM   #14
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Yeah, I get the fuel slosh in the KE too, but the BJs seem very well baffled. I wonder if there is a way to inprove the baffeling in the fuel tank easily...?

I'm not keen on the sound of a 3/5kg combo on a FWD.

Gav.
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Old 18-12-2007, 02:06 AM   #15
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Yeah, I get the fuel slosh in the KE too, but the BJs seem very well baffled. I wonder if there is a way to inprove the baffeling in the fuel tank easily...?

I'm not keen on the sound of a 3/5kg combo on a FWD.

Gav.
swirl pot would be the "easiest" way of doing it... dropping the tank, having it opened, having new baffles installed etc would be grossly expensive (if it can be done at all)...

Basic swirl pots can be had for relatively cheap (although you'd need to buy another pump as well - intake lifts to the swirl pot, then high pressure from the swirl pot to the fuel rail)...

There are legal considerations - its technically illegal (and potentially dangerous) to mount one in the boot of your car because it is inside the passanger compartment.... undercar mounting would be the go, if there is room...
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Old 18-12-2007, 07:24 AM   #16
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Or just install a surge tank???
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Old 18-12-2007, 10:30 AM   #17
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Swirl Pot = Surge tank -> Well it's doing the same job I guess. There's a thing called a "Fuel Accumulator" used on the Chrysler Neons with the retunless fuel system that may be the fix for the problem as it was installed to resolve that exact problem on stock cars. I had one in a drawer for years but chucked it when I cleaned out my old office. I'll have to check if there's one fitted on the returnless Focus that a collegue is stripping for a Clubman he's building (I'm doing the engine management on it).

Chicaboo the 3/5kg combo woudl be only to assess the rate for the front only without buying more springs than needed. Although it may mean chucking the rear bar is an option

As it stands the 7/5kg combo on Stinky now feels quite even front/rear in terms of compliance and all that. To me that indicates the ratio between the front and rear rates matches the weight balance of the car reasonably well.

So the theory would roughly expand to:
Code:
Front:   Rear:
7          5
6          4.3
5          3.5
4          2.9
3          2.2
This is assuming a linear link between the rates and the weight balance...

A.
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