Moment center design

drifttec101 · Post by **drifttec101** » Wed Feb 03, 2010 5:18 pm

Yeah, I might just do that. I'll do a bit more research into spring rates to see what exactly I want (and what's available).

Maybe when people slam their car on the ground they are UNDERTHINKING it....hmmm

hansken_yo · Post by **hansken_yo** » Wed Feb 03, 2010 9:20 pm

Not the least bit, but then I paid to play.

Also, what makes you think that the original geometry is the "Best?" I certainly could not do the things I've done with just stiffer spring rates or stock geometry. No where even close.

Post by **racer12306** » Wed Feb 03, 2010 9:26 pm

So how about this...

Bust out your calculator (I'm assuming you know how to calculate all this stuff since you are mentioning it) and get to figuring all of this out. Then you will know exactly where you need to be.

I guess the fact that the second generation neon has been out for 10 years means absolutely nothing and there are people that have exceeded the limits of what anyone would think an econobox can do.

Trust me, you aren't the first to think about this stuff.

drifttec101 · Post by **drifttec101** » Wed Feb 03, 2010 10:27 pm

You need way more than a calculator... kinematics software would be great for bump steer and camber change curve. To find moment center I've used the solid modeling program SolidWorks before (not for a neon).

But once again I think you've missed my point. If you slam the car on the ground then you have to start considering geometry, otherwise strange things can happen with handling. If I stiffen my car without putting in on the group then I won't have to concern myself with that stuff therefore my life is a touch easier.

As a side note, I was just curious to see if anyone knows what the moment center is doing with Neons. It would be pretty hard to adjust it I'm guessing.

If you pay to play then go get yourself some coilovers and have professionals tweak you alignment... then have a blast. I'm not looking down at that approach at all, I think it's great. It's just not the route I'm going to go. A lower center of gravity is great, but I don't want to screw up the geometry. Stock geometry isn't the best I'm sure, but it will keep the tire flat on the road at stock ride height, which is great.

Post by **racer12306** » Wed Feb 03, 2010 10:29 pm

I do get your point.

There is a huge difference between a slight lowering with stiffer springs and slamming the car.

You seem to be putting them in the same category, however they are not.

drifttec101 · Post by **drifttec101** » Wed Feb 03, 2010 10:33 pm

I hear ya, it's true they aren't in the same category at all. It's just that the aftermarket caters to those looking for an aggressive drop. I'm just not that guy.

Post by **racer12306** » Wed Feb 03, 2010 10:35 pm

If you search around you will see that there are options if you don't want a massive drop.

I'm pretty sure H&R springs are one of those options.

stdlystdmufn · Post by **stdlystdmufn** » Wed Feb 03, 2010 10:38 pm

just get BCs and dial it in to where you want it

drifttec101 · Post by **drifttec101** » Wed Feb 03, 2010 10:38 pm

Yeah I think they offer a 1.5''. In case anyone is wondering http://www.performancedrivenllc.com/default.aspx those guys offer a 1.75'' drop of the 2gn's.

Post by **racer12306** » Wed Feb 03, 2010 10:38 pm

They are too expensive.

drifttec101 · Post by **drifttec101** » Wed Feb 03, 2010 10:44 pm

hansken_yo · Post by **hansken_yo** » Wed Feb 03, 2010 11:40 pm

drifttec101 wrote: But once again I think you've missed my point. If you slam the car on the ground then you have to start considering geometry, otherwise strange things can happen with handling. If I stiffen my car without putting in on the group then I won't have to concern myself with that stuff therefore my life is a touch easier.

The thing here is that we do get your point and have expressed options that cater to what you "want" - coilovers, but you don't want to spend the $$$ for that. This limits the other options available to you and will most likely affect one of your primary concerns regarding the stock geometry in some manner.

Just out of curiosity, what are these "strange things" that can happen with handling that concerns you with the geometry?

My only real issues are steep inclines and curbs

oh and semi truck tires

Some other things besides stiffer springs that you may want to consider first are a good set of sway bars and tower strut bars. That may tighten things up for you without having to change spring rates.

drifttec101 · Post by **drifttec101** » Thu Feb 04, 2010 9:38 am

Yeah sway bars would be nice too.

The strange things are as follows:

If the moment center falls below ground your car won't explode or anything, but it's generally not good practice. The stock Neon has a pronounced rack to it and most lowering springs level this out. My concern with the moment center is that by lowering the rear more than the front you would take the roll couple distribution out of stock parameters. If you were to do such a thing (IDK where stock is at, that's why I asked) you could really unbalance the car's setup. Lets say the moment center is closer to the center of gravity in the rear than the front... if you were to bring them even closer together you would really stiffen the back of the car. Combine that with a heavy rear bar and rear spring and you could have yourself a snap oversteer problem.

When you lower the car you'll toe it out because of normal bumpsteer so you can do two things. You could just realign the toe, but now because of less suspension travel you won't have all the bump steer you want (maybe). Or, you can adjust the steering rack location relative to the steering arm (that's the proper fix). Just adjusting the toe is fine though in my opinion.

Ackerman may come into play also. That would involve some measuring to see where you are at after lowering. You want ackerman if you drive in parking lots, you don't want ackerman if you race autocross in parking lots. The proper fix to excess ackerman adjusting the steering arm location.

Really I suppose just having an idea of the balance before and after is most important.

Camber needs to be flattened out at your new ride height so you don't kill your tires. But that depends on the tires you're running anyways.

Modern cars have a ton of caster from the factory. I'm guessing the Neon has around 10 degrees. I don't care for lots of caster personally, but it does make highway driving easier.

I almost forgot camber change curve. This becomes a problem when running wide low profile tires, as these tires are far more sensative to proper camber settings. If you lower the car with stiff springs you may reduce suspension tavel severly which reduces camber gain. So if you have these low profile tires you'll need to run a lot of static camber which may wear out your tires before you'd like them to be worn out. How to adjust it? Well you need to either make the control arm shorter or longer. You can move the ball joint but that involves cutting and welding... not a good idea really and will only yield limited results. The best way is to buy adjustable control arms. The aftermarket is limited in this department.

That's all I can think of at the moment. To sum it up... balance is key, and balance from person to person is different. So there's no right or wrong answer, but knowing what you have is important in my opinion. I'm sure somewhere I'm misinformed or I've forgotten something so let me know.

Mopar_Korean · Post by **Mopar_Korean** » Thu Feb 04, 2010 10:02 am

Personally I think you looking to much into it. The average neon enthusiast is not going to know what your talking about. Your talking about the neons suspension as if its some sort of priceless race car. I understand you want a good handling car and all but for driving on the street its not a viable option to get all crazy with it.

There are tried and true methods to making the neon handle better. Poly bushings, swaybars, coilover or lowering springs w/ quality struts, sticky tires.

If you want this kind of data from the neon you need to talk to race car engineers or read "Making it stick" by Mike Kojima. Its a series of SCC articles.

drifttec101 · Post by **drifttec101** » Thu Feb 04, 2010 10:07 am

Yeah I agree with you I just wanted to answer hansken_yo's quesiton. I wouldn't give two shits about most of that if/when I do lower my car. I won't have to mess with alignment so much if it's nearly at stock ride height, that's all.

hansken_yo · Post by **hansken_yo** » Thu Feb 04, 2010 11:16 am

* the Rake from front to back is 1.5" and lowering springs will level that out. That is where coilovers come in handy since you can still maintain the proper rake, get full strut travel and still lower you car (though you don't have to lower it).

* Ackerman is insignificant, what is significant here is that the tire outside tire maintains traction throughout a corner. This is where I think a little bit of negative camber helps out. Tests have been done on tire wear and negative camber with our cars and they have shown that anything less than -2* of camber the tire wear is negligible in comparison to the whole tire wear. My personal experience also shows me that this is pretty damn near the truth. By the time you start seeing the wear done by the negative camber the tire itself is pretty worn out and in need of replacement

* snap oversteer. The only way that I've heard of this happening with our cars has been from people running a looser front end and tight rear. They would accomplish this from removing the front sway bar and tightening up the rear. The gains they claim (people who are far more experienced drivers than myself) are that they are able to enter and exit corners faster with a car that has oversteer. So their setup is on the opposite side of Neutral than how I set mine up. Then again I also need my car to handle well on the street as well as the track.

* pretty much stock parameters on our cars are designed for econobox commuter boring driving with no real handling capability. You are right that balance is key and that it changes from driver to driver, but I think you are mistaken thinking that stock geometry is "balanced" and that you can not find a different balance through various setups. Even something as simple as changing spring rates will throw off how the geometry of the car works and its balance.

As for messing with alignments, any work done to suspension would more than likely require the car to be re-aligned and even slammed cars are able to get set to factory specifications with nothing more than camber bolts. The only real difference then is how much the suspension actually travels.

Regardless, if you really are as picky as you sound regarding the "geometry" of the vehicle and its balance then don't waste your money on anything other than coilovers and a good set of sway bars. You'll get stiffer spring rates, you'll be able to adjust dampening to compensate for the stiffer spring rates and you'll be able to set the car height and camber as you see fit. Anything else is just a waste of money for you.

drifttec101 · Post by **drifttec101** » Thu Feb 04, 2010 3:45 pm

My suspension spiel was just in generalities. I've never tuned a Neon suspension. Like I said before coilovers are great, but I only NEED to replace my front struts. I have no intention of getting coilovers for all 4 corners when all that needs to be replaced is front struts. That would be kind of silly.

Post by **racer12306** » Thu Feb 04, 2010 4:52 pm

Ok, then this entire thread is a moot point.

Go buy some KYBs or some Tokico struts and put your existing springs on it and call it a day.

If you want stiffer, you will have to lower. Accept it and move on.

drifttec101 · Post by **drifttec101** » Thu Feb 04, 2010 5:07 pm

Thanks for making my mind up moderator

Post by **racer12306** » Thu Feb 04, 2010 5:10 pm

It sounds like you had your mind made up before you even got here.

You shot down every idea posted here. There are tried and true ways that work every time. People have been racing 2GNs for a long time and I'm sure everything you are thinking of was sorted out about 9 years ago.

drifttec101 · Post by **drifttec101** » Thu Feb 04, 2010 5:14 pm

I didn't shoot down anything. There were some really good ideas such as the tuning group in Indy, and SRT springs. Coilovers were never an option for me, but some people really like them and suggested that.

hansken_yo · Post by **hansken_yo** » Thu Feb 04, 2010 8:27 pm

hansken_yo wrote:

Burn the car.

is it okay to quote myself?

fixitmattman · Post by **fixitmattman** » Sat Feb 06, 2010 1:44 pm

After being away for a few days and coming back I don't understand your angle nor what you're trying to acomplish here. At first I thought this was a simple question, who knows where the roll center is and what's the roll stiffness. A pretty far out question for these boards, but a question none the less. I think you're trying to overcomplicate something. Are you just trying to get a nice suspension setup or are you doing a full kinematic analysis here?

Post by **racer12306** » Sat Feb 06, 2010 2:23 pm

fixitmattman wrote:After being away for a few days and coming back I don't understand your angle nor what you're trying to acomplish here. At first I thought this was a simple question, who knows where the roll center is and what's the roll stiffness. A pretty far out question for these boards, but a question none the less. I think you're trying to overcomplicate something. Are you just trying to get a nice suspension setup or are you doing a full kinematic analysis here?

This.

fixitmattman · Post by **fixitmattman** » Sat Feb 06, 2010 4:26 pm

^^What the hell is This. supposed to mean? You forget a link or something?

Post by **racer12306** » Sat Feb 06, 2010 4:27 pm

Sorry, I'll fix it.

fixitmattman wrote:After being away for a few days and coming back I don't understand your angle nor what you're trying to acomplish here. At first I thought this was a simple question, who knows where the roll center is and what's the roll stiffness. A pretty far out question for these boards, but a question none the less. I think you're trying to overcomplicate something. Are you just trying to get a nice suspension setup or are you doing a full kinematic analysis here?

JeffM · Post by **JeffM** » Sat Feb 06, 2010 4:56 pm

Let me just say that this thread has been very informative; even if it ran around in circles.

MoxHair · Post by **MoxHair** » Sat Feb 06, 2010 7:01 pm

Coilovers + Sway Bars + Strut bars + rear tension struts + Professional Corner Balance = Better than all the garbage bullshit being talked about in this thread.

Why are we severely over complicating a discussion about a suspension on a Dodge Neon?

Let's reengineer the wheel while we at it.

fixitmattman · Post by **fixitmattman** » Sat Feb 06, 2010 7:35 pm

Just throwing a pile of suspension parts at a car doesn't necessarily mean it's going to handle as good as it should,

MoxHair · Post by **MoxHair** » Sat Feb 06, 2010 8:07 pm

You should never throw parts at a car.. You'll dent the exterior.

Cars with the above suspension that I listed plus having it professionally corner balanced will handle better than 99% of the cars on this site.

hansken_yo wrote:* snap oversteer. The only way that I've heard of this happening with our cars has been from people running a looser front end and tight rear. They would accomplish this from removing the front sway bar and tightening up the rear. The gains they claim (people who are far more experienced drivers than myself) are that they are able to enter and exit corners faster with a car that has oversteer. So their setup is on the opposite side of Neutral than how I set mine up. Then again I also need my car to handle well on the street as well as the track.

I love Snap Oversteer.