ZPS Build Thread

Time to get nerdy again. I thought of a easy way to describe why the front ride height is effecting the geometry of the front suspension. So the LCA is 14" long and right now the inboard mounts are 1" lower than the outboard. That means at ride height it is at a 4 degree angle.

So to look at things simply without getting into too much accuracy with the M2 weighing 2250lbs and 60% is in the front which means 1350 on the front. Now when cornering lets say that 75% of the weight is on the outside tire, it is probably more than this, but this is just for sake of the explanation. That means what while cornering there is 1012lbs on the tire. With the tire making 1G of cornering that means that there is a side load of 1012lbs horizontally on the LCA. Now not even including the roll the car will see which will make the inboard mount of the LCA even lower, if you do the math with the LCA being angled at 4 degrees that is 72lbs off force which is going through the control arm which is pulling that side of the chassis down.

With the bilsteins being ~275lbs/in springs that means that that outer corner is going to lower 0.26" more than just the roll alone because of the geometry of the suspension. That is why those roll center kits help to reduce roll. It makes the angle of the arm better to prevent this extra lowering. On the inside of the car the effect is the opposite because the force on the LCA is going the other way. So the inside of the car will be pulled up.

Hopefully the picture helps as well.
susp geom.JPG

Oh and yes I am a suspension nerd and an engineer. This is all pretty simple stuff to me. Just trying to explain it to everyone.
 
As a former B13 Sentra owner I can say that I have looked into to this extensively. Over lowering can really hurt the M2s performance. Custom control arms and a bump steer kit was the solution ( a rather expensive one ) for the B13. I might go that route with my Mazda in the distant future, once it's relegated to track slut status. I'm not an engineer and math makes me dizzy but I force myself to learn this s***.

Here is some more nerd-porn.
http://www.motoiq.com/MagazineArtic...in-the-geometry-part-one-the-roll-center.aspx
 
yea I tell most of my friends that just because you have the parts doesn't mean that it is going to work. Setting it up correctly is really where the key is. I like the challenge for the 2 for me since it isn't going to be just a go fast car so it adds more of a challenge to it since there is more compromise to work around.

I try to avoid talking about roll center since it is just a geometrical oversimplification of what is going on and has a lot of scenarios where it is not accurate. Forces is where it is at.
 
So are you going to raise the car up a bit or fab a roll center adjustment kit to get a more parallel (to the ground) control arm?

This is one reason I never liked lowering the subaru's too much, way too easy to invert those control arms. Though roll-center kits are easy to find now for them.

I'd like to know at what point (how much lower than stock ride height) the LCA becomes parallel to the ground on the 2.
 
I am just going to raise the car since I already have issues with scraping the front bumper from time to time. Also raising the front will help with shock travel on the front shocks as well so it is all good things. Well it won't look as good so it isn't all good things.

From the measurements I have right now the front needs to be raised 1" to get the arms parallel so that would mean a fender measurement of 24" and the jacking point on the pinch weld would be 6.25" high to get the arms parallel.

I should be able to do the changes to the rear this friday, but the front will have to wait until next week since I will check the alignment. I will be filling my engine mount this holiday weekend as well. I really look forward to that.
 
So here is an update of things. I took the rear apart and cut the rear bump stops. Here are some pictures of how they go together and how long they are. I ended up cutting of 1.5". This length was good because you still have the rib in the bump stop to mount the shock boot to it. I drove the car a little and it seemed to ride better, but I had 2 different wheels on the car so I can't really well. I have my team dynamics on one side and my Stock Miata wheels on it as well. More on that tomorrow.

rear cut.jpg
rear.jpg

I also filled my engine mount and put it in tonight. I will have a picture of it tomorrow, but it definitely is better. I will have more detail on that tomorrow as well.
 
ok so now time for more information. I filled the dog bone mount with 3M window weld.

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Basically I used window weld because it is the hardest urethane you can get at a local parts store. 55-60 if I remember correctly. I like it. When you start the car you notice a slight shake as it starts. Other than that there is a very slight vibration at idle, but you really have to pay attention to notice it. My GF did not notice anything. While driving though it is a lot better. Basically feels like the clutch grabs better since the engine isn't moving around a bunch. I haven't been able to get my camera under the car yet to take another video though to see how much the movement has changed.

I also like how the car rides with the rear bump stops cut. Much better. I also had an idea for making my car even better for DD. I am thinking on putting my 14" Miata wheels back on it with the Falken 912's. I really like those tires and they are super cheap. The ride will also be better for DD since they have so much sidewall. The M2 wheels will be for just autocrossing, or mountain runs. Here are some pictures of the Miata wheels on the car. They are very dirty.

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I also put my team dynamics wheels on the car with the wheel spacers to see how they fit. They looked good and they did fit, but with a wide 205 they would poke. Don't think they would rub, but they would poke out. I didn't notice any rubbing while I drove it around.

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Oh and here is a better than a cell phone pic of the car as it sits now.

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Sad that I need to raise the front because it looks good, but I am 100% function over form.
 
Oh and here is a picture of the Mazda gang. If you look really close you can see the intercooler on the Miata. I also plastidipped the hood since the clear was pealing really bad. I like it. Don't really care though since it is the track car.

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I'm thinking of getting the next gen MX-5, I had one back in 1992-1997 and it was the best lil car I ever had ;)
 
yea, between the nest MX-5 and the new Mazda 3 it is going to be a hard sell to keep the 2 in the long term.
 
I need a DD, I used to drive my MX-5 all year around, snow, rain.... But my real life needs is a hatchback as DD and a fun toy as a second car.

I can't wait to see the new MX-5, I don't know why it's not out yet :( They better drop the price, it's too expensive at the present price for what the car is. A Scion FR-S or Subaru BRZ would be a better choice if the price is still high for the next MX-5
 
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Funny how big the 2 looks next to the miata, you'd never know they weigh about the same and the 2 is actually a hair shorter in length. BTW I love that garage setup. I recently went from a very nice and roomy 3+ car garage (extra tall, extra deep) to a normal 2 car garage. I've had to get somewhat innovative with space management to be able to keep enough room for both cars plus all the other stuff. Plus now its really hard to leave unfinished projects in the garage and still have room to move around.
 
The current gen MX-5 club Ed cost almost $40,000can, a Speed3 cost about $34,000can... the Miata shouldn't cost more than a Speed3, only is it would be a 300hp Miata I would pony up the cash for that price.

I could see 31,000$Can for a fully loaded Miata and the base should be at 20,000$can.

If they did that to the price they would sell a lot more MX-5's :)
 
yea we just bought the house 2 months ago. Really nice having the space for 4 cars since right now we have 3 and it will be 4 in a few years. The detached garage was empty for a number of months before we moved in so it is just full of spiders. I have been vacuuming them up trying to get it so the floor will stay clean before I then epoxy it. Then I can add the insulation and drywall and it is going to be a really nice garage. Oh it has a workshop room in the back as well. It has lots of potential. I just need to kill all of the spiders and be able to have the time to spend on it.

In reply to Scoobs, it does seam that the Miata is expensive, but remember you are buying a 2 seat convertable, where the MS3 is basically a hopped up hatch which is normally $7KUS cheaper. Same thing with the BRZ, yes the prices are similar, but the Miata is a convertible. There is going to be some added cost there.
 
Originally I wanted to do some nice flooring (the replaceable floor tiles) before i moved in the house I'm currently in...but in the grand scheme of things its just a garage floor. It's going to get dirty, stuff will spill on it, and there will be spiders. Personally, the end result (a nice garage floor) would not be worth the time and money put into it.

I say just put up the insulation (lots) and drywall, and if the floor is already concrete just leave it and enjoy. I leave some spiders (daddy long legs) in the garage since I feel like they help keep down the population of other more annoying bugs.
 
Well the thing is with all for the car work I do, the brake cleaner, brake fluid, and toluene and other stuff will break down the concrete. I have seen it at the shop I help out. I am not doing anything fancy, just a basic grey floor. All of that fancy stuff might look nice, but it is a pain to try to find stuff that you drop. I just want to put the epoxy on it to prevent the concrete breaking down.

For the spiders there is more than you think. The place was empty for 4 months before we got it and the previous owner used it to raise show chickens. He had a tarp over the floor so the floor is clean, but the smell and dander of the chickens made spiders like it a lot. If I don't go in there for 3 days I end up walking in through a bunch of webs. I already vacuumed the walls and that helped a lot, but I need to do up in the rafters. I ordered an extension for my vacuum so I can get up there. Yes I have bombed it 3 times so far. Most of the bombs don't really work well for spiders. I could do the floor, but every time I go in there there are more dead bugs on the floor and I don't want bugs stuck in my epoxy. I also have been waiting to spray in it and out for bugs, but it has been raining for the last 10 days here. I don't mind daddy long legs. That is not what I have in there.

Right outside I did kill a black widow which was about an inch and a half across.

I am not in a rush because most of the car work I need to do will wait until the fall/winter. I am just enjoying the 2 and the Miata during the summer.
 
yea we just bought the house 2 months ago. Really nice having the space for 4 cars since right now we have 3 and it will be 4 in a few years. The detached garage was empty for a number of months before we moved in so it is just full of spiders. I have been vacuuming them up trying to get it so the floor will stay clean before I then epoxy it. Then I can add the insulation and drywall and it is going to be a really nice garage. Oh it has a workshop room in the back as well. It has lots of potential. I just need to kill all of the spiders and be able to have the time to spend on it.

In reply to Scoobs, it does seam that the Miata is expensive, but remember you are buying a 2 seat convertable, where the MS3 is basically a hopped up hatch which is normally $7KUS cheaper. Same thing with the BRZ, yes the prices are similar, but the Miata is a convertible. There is going to be some added cost there.

Even as a roadster as it is I find the price a bit high, it should under cut or match the BRZ/FR-S. A lot of peeps are going gaga for the new Toyo-Baru's and these are sells don't go to Mazda. I would prob pony up for a Miata over a BRZ/FR-S, at least to be different since every one is jumping the gun ;)
 
Well things have been slightly slower for me since it has been raining for the last 3 weeks. I did get a chance to change the front ride height higher and corner weigh the car/align. I could only raise the front, I think, half an inch because that was all the adjustment that was in the Bilsteins. Also surprisingly without me in the car the front weight was only off 15 lbs from side to side and the rear was only off 7lbs. Pretty even really from side to side.

corner weight.jpg

I also had a chance this weekend to take the car up through the mountains. It was wet and raining, but the car still felt good. I would rotate around if I needed it to and you could make it understeer, but it would only really happen if you were just bring stupid with it. So overall I am pretty happy with it. It also rides a lot nicer as well now that there is travel without using the bump stops.

On July 27th there is an autocross at ZMax dragway I want to go to. Depends on the weather, but hopefully it will be nice.
 
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