"Moton's on a budget"- JIC/Cross Coilovers.

[aus]

I know most people here get the KW's or move up to the Moton's. The Cross coils are priced similarly to the KW V3, but are a monotube desige and come with camber plates. They are single adjustable vs. double adjustable with the KW's and Moton's.

I had some JIC Majic/Cross coilover installed about 2 month ago. I've read on Porsche sites that the Cross coils are suppose to be "Moton's on a budget." This set was suppose to be the first set up made for the E9x M3's. I bought it from 08M3 who got Moton's instead and never installed them; he bought the Cross kit from Ron at Mod Bargains- who I've updated with the install issues since they are selling the kit. Apparently this kit was made in Japan since the US guys didn't know anything about it initially. The only reason I was willing to be the first to get this kit is because Cross' North American Headquarter's is somewhat local in Alhambra- about 30 mintues from my home... and it was a good thing they were local because the kit didn't fit out of the box.

The rear shock lower mounts were made for the 335 with adaptors for the M3, BUT the adaptors didn't fit so Bryan (the main installer/tech) had to machine different lower mounts. A small spacer was also needed for the rear shock to clear the rear axle boot.
The front sway bar links in the kit didn't fit either, but they found that the one's from the R56 Mini bolted right in. The big plus was, Bryan and Jon (head of Cross NA), were able to drive the car stock and they felt the springs that came with the set were too soft (10Kg fronts and 12Kg rears). The original buyer had requested stiffer springs than the 335 set-up but they recommended even stiffer springs up front after driving the stock set-up.

I ended up with 14kg/mm fronts springs and 12kg/mm rears. I think this works out to 780 lbs/in fronts and 670 lbs/in rears, which would seem very stiff compared to the Moton's, which are suppose to run around 350 lbs/in. I don't know if each company measures their spring rates a little differently?

I was generally pretty happy with the ride of the stock suspension. I rides better than the Sport suspension on the wife's 335, which is kinda rough and sloppy at times. Bryan, on the other hand, thought the stock suspension was "rough and had a lot of body roll."

I was a bit concerned about the ride quality given the recommended spring rates, but the ride with the coils is VERY close to stock for comfort, and in some ways the ride is better, since it seems to soaks up the mild to moderate bumps with less up/down body motion when compared to stock. You will notice it's a little stiffer if you hit a pretty bad bump/pot hole, but nothing jarring. I have 18" stock wheels for now so that helps with the ride, though the RAC wheels should be here soon. I have to remind myself I have coils on during daily driving; it's that livable despite the drop. There is now also very little body roll, and turn in is very precise- but that likely has something to do with the alignment too. My wife doesn't even notice a difference.

The car is lowered about 1" in front and 3/4" back. There is a lot of room to go up or down. The camber is set at -2 on both sides up front, with 0 toe front and back- which was a bit of a concern since some people were not able to zero the rear toe when lowered. The passenger side camber plate would not allow any less camber. I'd have to get a different plate if I wanted less camber; our target camber was -1.75. I'm going to try it out and see how the tire wear is since many here have said toe will affect tire wear more than camber. I also do 3-4 HPDE a year, so they would likely help even out tire wear. I was surprised to hear Bryan does the alignement by hand. He said all the race teams he's worked at did it this way.

They have no plans for a E9x M3 specific kit but could piece together this set-up if people wanted it, and I know Ron is selling this set-up and you can specify the spring rates. I think a major concern for Cross is that most cars have the EDC, and they don't have a fix for the malfunction light. They were very happy when I told them I don't have EDC. I haven't tried another coil over set-up, but am very impressed with this kit so far for daily driving and during the single track event I've gone to so far. My instructor also loved the way the car drove, though it was his first time in an E9x M3. I also have not had any noise issues thus far.









More pic's of their shop here: http://www.m3post.com/forums/showthread.php?t=334190


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[Bart@AUTOcouture]

love that color, seems to be rare

[MMMorish]

Originally Posted by TurboBmaNN

love that color, seems to be rare

Space grey is not rare at all. Well, in comparison to the amount of AW M3's, then maybe you're right. It is rare.

[aus]

Maybe he meant Sparkling Graphite, which is similar, but has a hint of purple in it. I like it a lot, but BMW stopped making the color.




And in case anyone missed this great explaination between mono-tube coils (Cross) vs. twin tube coils (KW) by "Cleveland"

http://www.m3forum.net/m3forum/showp...7&postcount=14

Originally Posted by Cleveland

Well...most of the modern high-end performance shocks & struts will utilize mono-tube construction for a number of reasons.

The two primary types of shocks and struts are mono-tube and twin-tube designs.

In order to explain which one I think is better, I need to describe the differences between the two build construction philosophy's first...


Mono-Tube shocks:

Instead of using two chambers, mono-tube shock absorbers only use a single tube. (and two pistons) One of the primary advantages to use this design, is that a mono-tube shock has basically twice the piston power as a twin-tube shock.

The first piston is located at the end of the piston rod. This first piston pushes against a section of oil, which is forced downward into the second piston. This floating piston is sandwiched between a section of viscose oil and a pocket of highly charged gas (at 200–360 psi). By separating the oil from the gas, mono-tube shocks greatly reduce the risk of oil foaming and fade. (which results in smoother more consistent performance)

The dual piston design of mono-tube shocks provides stiffer dampening characteristics, which is exactly what most BMW enthusiasts are looking for in their aftermarket suspension options. Mono-tube shocks are better suited to the type of driving most of us crave. The end user ends up with a sportier handling suspension package on the street, and as an added bonus...a tighter more precise handling setup for the occasional track day at the local road course.

Mono-tube shocks are also air cooled, so they do not retain heat the way twin-tubes shocks will. Mono-tube shocks are also more flexible, since they can be mounted upside down for extra weight support.

One downside however, is that most mono-tube shocks are difficult to mount in place of many twin-tube shocks on certain cars. (because of the added length and range of movement) I should also add that mono-tube shocks are slightly more vulnerable to external damage, because there is no outer buffer.

A typical high performance mono-tube gas shock (or strut) consists of a rod that slides in and out of a pressurized sealed tube. The rod has a piston riveted to one end which prevents it from being forced out of the tube when it's pressurized.

The force of the gas strut is provided by the gas pressure acting on the cross sectional area of the rod. The higher the gas pressure...the higher the force of the strut. The piston has a metering orifice (valve) which allows the gas to pass from one side of the piston to the other. (by altering the size of this orifice the rate of extension can be varied)

The oil inside the gas strut produces the damping characteristics throughout the stroke. (if the shock strut is in the correct orientation) As the rod extends from a compressed position, the oil zone will dampen the movement as it reaches its full extension. (giving a smooth controlled stop) The damping characteristics can be changed by using different viscosity oil in the tube, and volume of oil in the tube.

Because a mono-tube shock doesn’t require a “tube-within-a-tube” for a given outside diameter, a mono-tube shock will have a larger inner bore. That allows the engineer to use a larger internal piston than a twin-tube shock design. This offers the advantage of designing a shock that can extract the maximum possible damping from the smallest diameter package. (which is important on heavier cars)

Mono-tube designed shocks also allow the heat in the oil to transfer directly to the outer surface of the shock body. That design allows the oil to be in direct contact with cooling airflow (as it passes over the shock body), so it can dissipate heat more efficiently than a twin-tube design.

The sum total of all these engineering advantages, is that the mono-tube design reduces heat-induced fade better than than the twin-tube designs.

Mono-tube designs allow the shock to maintain full damping characteristics as temperatures rise with hard use.


Twin-tube shocks:

Twin-tube shocks will typically deliver a comfortable, stable ride with very good dampening capabilities. In fact, twin-tubes are probably the most commonly used shocks in the automotive industry. (original equipment and aftermarket) Twin-tube shocks are the ideal shocks for most of the cars on the road today IMO. In normal street driving situations...they feel smooth yet still reduce body roll. They do allow the car to sway a little more during hard cornering, and during hard stops in 'spirited' driving conditions.

Twin-tube shock technology has been around for about 100 years, so this design concept has certainly stood the test of time. As its name implies, twin-tube shocks have 2 chambers: an inner and an outer tube.

The inner tube is where most of the work takes place. Here, the piston moves up and down through the main supply of oil. The outer chamber holds an extra supply of oil and a low pressure nitrogen gas charge. (at approx. 100–150 psi) The nitrogen gas provides the backstop against the flow of oil for heavy shock dampening.

Unfortunately, as the oil inside the shock heats up heats up (during heavy sustained use)...it can mix with the nitrogen gas.

That's the major downside to twin-tube shocks.

They tend to overheat quicker than mono-tube shocks (under the same loads)

That tendency to overheat, leads to internal foaming...which leads to fading...which leads to very inconsistent (and very poor) damping performance. (in extreme driving conditions)

That is why nearly all high-performance shock absorber kits use mono-tube shock designs.


In regards to the shock absorber technology that is used today...

The internal construction of a modern shock (or strut) is a very simple design...but it is also a very delicate process. It works great when everything goes according to plan...but when it doesn't, the performance can deteriorate rather quickly.

It's important to understand that mono-tube designed shocks will tend to work better on some cars, while twin-tube designs are better suited on others.

It's all about the application, and what you intend to use the car for down the road.

All the energy created by the chassis/springs/tires/wheels/brakes has to go somewhere...and it ends up morphing into heat. (inside the shock)

Unfortunately, when the shocks internal damping oil temps starts to rise, its viscosity starts to thin out. (so it absorbs less energy) If the oil gets too hot, it can start to bubble like a pot of boiling water on the stove.

That is what causes "shock fade".

In addition to just providing good suspension damping, a good shock must also be properly engineered to dissipate heat as efficiently as possible. (for consistent performance)

This is what separates the men from the boys IMO.

From personal experience, the very best shock manufacturers seem to find a way to keep shock fade and foaming in check. The most effective way to do this, seems to be the ability to maintain a consistent internal pressure within the tube even as the temps start to rise. Most of those solutions are proprietary, and are not available to the general public.

There are effective ways to prevent the heat from compromising the performance of an internal shock absorber. (even though it's basically a sealed hydraulic system)

For example:

Have you ever wondered why your radiator coolant doesn't boil over (and evaporate) even under extreme overheating conditions?

Now before someone chimes in with "the anti-freeze/coolant", I'm talking about the high boiling point of your engine coolant even without the 50/50 mix of water/anti-freeze. Contrary to popular belief, it's NOT the 50/50 coolant/water mix that saves your engine from overheating when it gets really hot. (it does helps a little, but it's only a small contributing factor) In fact, your 50/50 water/anti-freeze mix only increases the boiling point of your coolant system by roughly 10 degrees Fahrenheit. (not kidding, that's it)

That's not a lot of additional protection to keeping your coolant system from boiling over on a hot summer day now is it?

No, the real answer is not the water/coolant mix, but rather the PRESSURE the coolant system is forced to maintain as it operates.

Because your coolant system is pressurized, the atmospheric pressure greatly increases a fluid's boiling point. Just as the boiling temperature of water is higher in a pressure cooker, the boiling temperature of coolant is higher if you pressurize the system. Most cars have a coolant pressure limit of 14 to 15 psi, which raises the boiling point another 45 degrees Fahrenheit, so the coolant system can withstand higher temperatures. (without boiling)

Shock absorbers work the same way...

Several shock & strut manufacturers use a similar engineering philosophy to reduce shock fade in their designs.

In my opinion, there is no comparison. Mono-tube designs > Twin-tube designs.

[aus]

Originally Posted by TrackRat

Looks real nice. Good thing you weren't expecting them to be a simple bolt-on.

I know what you mean, but now that I've been the first, I'm sure **********s can piece together the right set-up, and Bryan at Cross definitely know's what's needed.

[Ron@Modbargains]

Originally Posted by aus

I know what you mean, but now that I've been the first, I'm sure **********s can piece together the right set-up, and Bryan at Cross definitely know's what's needed.

Great review, Keep us all updated as you do more track events and what feedback you have with it. One thing I've always liked about the cross is that they can set up the spring rates for relatively inexpensive, as the kit is inexpensive itself for a mono tube designed system.

To other guys if you need help in getting a kit similar please just contact me. Aus- great job again

[aus]

I just went back yesterday for some more negative camber in back, and they plan on making a kit for the car in a few months.

Everything will be produced in the USA. It seems CROSS in Japan has not been supplying the US guys with parts on a regular basis and so they're going to start making them here.

[M3Alpine]

nice drop. car is clean !!