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Thanks for the info fella's. I guess I'm a little concerned about how going so stiff in the rear is going to affect the balance of the car with a big rear sway. Right now with stock springs, big hotchkis rsb, and some toe out the car feels well balanced with a slight propensity for oversteer. I fear going really stiff on the rear spring rate, added front end grip from more negative camber and the big rear bar will result in a very loose, oversteering car that I won't be able to properly rein in even with alignment changes. With big rear bar I'm thinking perhaps 350f/350r and 0 rear toe would be a good starting point.... Any opinions?

Which brings me to another question, what is better? Lots of rear spring rate with small rear bar, or less rear spring rate with big rear bar?
 

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Are you on the softer setting with the Hotchkis? If that's the case I would say look into the Tripoint Race bar, even on stiffest it isn't as stiff as the hotchkis, but it if you do end up with stiffer rear springs it gives you more adjustablity.

I'm not going to jump into saying which would be better, but one thing to also consider about going to stiffer springs is unlike just a stiffer sway vs soft springs, you also have to think about how that stiffer spring will react 100% of the time, vs a sway bar which is only during turns. Think power on, braking, etc. how will the stiffer rear spring affect all of that.
 

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The way I see it though... for Autocrossing, I would go with a softer setup, as you guys have FAR less smooth surfaces than tracks do, to me that is more than enough to think having a tire in contact is far more important than.. the tire being off the ground because you hit a small bump and there's no traction left.

If I were to put an opinion on it, that's how I would look at it.

& to reverse from that.. if you're planning on going to stickier tires or even slicks, I would say stiff springs would be the way to go.
 

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Awesome to see GC jumping in the MZ3 market!

...anxiously awaiting pics of the rear spring perch arrangement.
 

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I would say it's more important to have powerful damping over the stiff springs. Like Nuse said, autocross lots tend to have their share of unsettling bumps, decent damping will allow the car to glide right over without unsettling the car.
 

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They initially recommended an "aggressive" spring rate for me (525f/650r) but after reading ClemsonMZ3's thread and data I called them and dropped to 400f/525r. You can select whatever rates you want when you order. Front and rear springs are both the 2.5"/6" size, good for future mixing and matching.
Scott, is there a part # on your rear springs? I'm looking at the 2.5" diameter/6" length springs in the Eibach catalog (click on link below and drop to page 15) and they are not showing 525 in that diameter/length.

http://performance-suspension.eibach.com/sites/devperformance-suspension.eibach.com/files/catalogs/ERS-18_applications.pdf
 

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Wish someone just sold a shock that came without it for our cars (like the Miata design)
Difference is that our cars have struts in the front, miatas still have shocks. A strut = shock that is an 'arm' of the suspension. Miatas are double wishbone so if you took the shock/spring out it'd still be nearly wholly attached to the car. If you took out the strut/spring combo the lower arm would allow for the knuckle to fall.

So with the GC kit does it use an off the shelf shock and come with a lower mount you thread it into?
 

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So with the GC kit does it use an off the shelf shock and come with a lower mount you thread it into?
Here's how it works, the upper and lower mounting points are the same as stock. You use whatever OTS strut you want to (ie Koni, Bilstein, OEM, ect) hack off the spring perch and put a threaded sleeve with a collar onto the strut body. What you have then is essentially a coil-over with adjustable pre-load making height adjustment possible.

This isn't a Mazda3 below, but you'll get the idea.

 

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Discussion Starter #29
Scott, is there a part # on your rear springs? I'm looking at the 2.5" diameter/6" length springs in the Eibach catalog (click on link below and drop to page 15) and they are not showing 525 in that diameter/length.
On the invoice it shows as......GC 150.64.92

????
 

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On the invoice it shows as......GC 150.64.92

????
If you can, check the Eibach springs and tell me what you got there. There should be a part # on each spring that will tell us overall length, inside diameter, and also the spring rate. A 6" length spring, with a 2.5" ID, and 525 lb/in spring rate should have a part # of 0600.250.0525. However, I'm not showing it exists. I'm curious as to which springs you actually have.

Here's an example of the part # in the pic below. It tells us these springs below are 7" length, 2.5" diameter, and 450 lb/in.


 

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Discussion Starter #31
Springs

Yep, the other springs are listed as 0600.250.0400. Will look a little later today after breakfast. My guess is that the 525's are not Eibach, but GC.

I have to move the car to get to the springs, will do so as I check out my hoses later today...........

I found some coolant "seepage" on my thermostat housing. Hoping it's just the small heater hose leaking downward, or so it would appear. Game plan for today is to do just the radiator hoses and heater hose since I have the long drive to the event tomorrow.

If it's the thermostat housing, that might take me some more time?? Do those ever suddenly crack?
Easy to do, or does that darn pulley have to be moved?
 

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If it's the thermostat housing, that might take me some more time?? Do those ever suddenly crack?[/I] Easy to do, or does that darn pulley have to be moved?[/COLOR]
I replaced the thermostat last year on mine and didn't have to remove the pulley, belt ect. I went in and accessed everything from below mostly if I recall correctly. The hardest part of the job was removing the oem hose clamps. If you don't own a set of flat band hose clamp pliers they will put up a real fight and you'll mangle them in the removal process (like I did). Do yourself a favor and replace them with standard worm gear clamps.
 

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Discussion Starter #33
GC Springs

I replaced the thermostat last year on mine and didn't have to remove the pulley, belt ect. I went in and accessed everything from below mostly if I recall correctly. The hardest part of the job was removing the oem hose clamps. If you don't own a set of flat band hose clamp pliers they will put up a real fight and you'll mangle them in the removal process (like I did). Do yourself a favor and replace them with standard worm gear clamps.
Good advice, thanks. Will seek those special pliers. Have learned that having the right tool is worth it's cost many times over.

The 525 pound springs do say Eibach; part #309278 from right on the spring. They also have that other GC number on them too.

Maybe made special for GC?
 

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Good advice, thanks. Will seek those special pliers. Have learned that having the right tool is worth it's cost many times over.
Yeah, I would invest in some band clamp pliers. I'll probably do the same in the future once I need to replace the radiator hoses.

The 525 pound springs do say Eibach; part #309278 from right on the spring. They also have that other GC number on them too.

Maybe made special for GC?
Interesting, yeah perhaps Ground Control gets custom spring rates from Eibach that aren't listed in their motorsports catalog.......
 

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I am very curious to see how this rear set up is going to work. What prevents the spring from simply falling out when you jack the car up? Seems like most of us are planning to run a pretty high spring rate and I know I don't want the rear ride height to be really high, which, as far as I can picture, it's going to be.

If the spring is held in place by the shock (preventing the lca from going any lower) when the car is in the air, the spring is already slightly in compression and it won't compress that much under the weight of the car since the it's a high spring rate. This results in a high rear ride height. Lower the spring seat in the rear to lower the car, and the spring will completely unload when the car is raised.

If I am wrong with this, could someone please explain it? I've been thinking and researching about this for a while and I'm thinking if I get my rear yellows revalved to also have them shorten the shock rods so the car can hold springs in.

And then maybe it won't be as big a deal as I'm thinking it will.
 

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Perhaps zip ties could be used to hold the rear springs in place if necessary? Scott, have you installed the G/C kit yet? I'll be ordering my kit soon and getting this Winter project underway.
 

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Discussion Starter #37
Slight Delay.....

Not quite yet. Just installed my Magnaflow Exhaust system, and want to try that out for an event or three to gauge/measure what effect that alone has on times. (Note: The Magnaflow install directions have a major error - ask me!).

I know this will sound a little like whining to some of you guys, but it's a little chilly lately here in Arizona, with the nighttime lows dipping all the way into the 40's!!! At age 68 I'm not as anxious to go crawling around on cold concrete for a few hours as I used to be........:wink::wink::wink:. Might wait until a little later in the Spring.:rolledeyes:

Regarding the question, I'm just not sure.....yet. Might want to just call GC and ask them how to handle that issue. It may be that they just settle where they need to.

Perhaps zip ties could be used to hold the rear springs in place if necessary? Scott, have you installed the G/C kit yet? I'll be ordering my kit soon and getting this Winter project underway.
 

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I'll be ordering mine soon as well. I haven't started any winter upgrades yet either.

I did get some winter tires for my stockers though, first snow use expected tomorrow :D
 

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Any photos of the rear setup yet? Did you have any issue with using the Gen 2 stuff on the back of our older cars?
 

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Discussion Starter #40
Not quite installed yet here; just one event on the new MF exhaust. That helped..... a little.

Might install the GC Kit this weekend, or in three weekends, depending on schedule and weather. Anyone else get one and get it in yet? Feel free to add comments and experiences.
 
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