In the mean time I purchased Hawk HPS brake pads and another set of camber bolts for the front struts so that both the top and bottom holes have camber bolts in them.

I also did some Suspension frequency calculations with the springs that Chris was suggesting and it was predicting above 2.5Hz.
Of course that is without considering sway bars.

 

Since the last time I posted lots of events have gone by.

I ended up trying without the sway bar and on the stock suspension with both camber bolts set to max negative camber and it is hilarious the oversteer you get haha.

I also found that my times were no faster. I also discovered since I didn't realign that it increased the wear rate by 1500% lol. I drove 300 miles like that and it ate up the tires like crazy.

Not sure how much toe out it caused by I am pretty sure it was close to .75" with close to 4.5degrees of negative camber!. (I discovered how much it was after I bought a annotated level that displays the angle in degrees.)

I did a few events where I changed it over to -4.5 at the event and back again for road use and with the sway bar attached my times were no faster. Having that much toe out hinders cornering lol.

Also with that much camber you have the F-1 kinda problem where if you aren't turning hard enough your contact patch is smaller which made some slaloms tricky. (In F-1 its if you go to slow, you don't have enough down force).

I also found driving it like that in the rain makes the car uncontrollable at speeds above 35mph lol.

Recently I have set it and left it at -3degrees and did my own alignment which wasn't that bad and now I have somewhere around 1/8" of toe out. It seems to handle fine in the rain now

I also recently have settled on tire pressures. I run 49 FL 43FR and 27-28psi in the rear tires.

I have found running lower tire pressures softens the sidewalls a bit and allows greater rear slip angle resulting in predictable oversteer opposed to snap oversteer. Chris is the one who suggested this to me. Did end of spinning out in the rain once.

I am now running times that put me up with our local CRZ driver who has coilovers already.

After a few more autocrosses, I ended up deciding to get the Koni coilovers from Redshift. I will be getting 350F440R spring rates.

I did do a bit of research from around the web (alot from Autocross to Win!) which has given me a developed plan for how to set the coilovers up. I plan to run as close to stock ride height as possible in the front since the lower arm is already level. This should avoid the problems X_25 was having with his setup.

In the rear, the stock suspension gives a 1" rake and I plan to lower the rear end to reduce the rake to 0. This is to improve the weight distribution although I don't have scales so I can't say what effect it will have. Although intially I may keep it as close to stock as possible. I will be interested to see how much the stiffer rear springs will help keep weight forward during acceleration and how reducing the rake will reduce front tire grip. The CRX has 58/42 weight distribution and I doubt 1" of rake adjustment will shift our 62/38 past that point.

The reduced ride height reduces the loading across the car by 40lbs which is only like .1degrees of lean, but I haven't calculated roll center positions precisely so lowering an inch in the front could have quite the effect.

As far as shocks I used the Autocross to Win calculator and came up with the ballpark setting of 100lbs (@3in/sec) front and 125lbs (@3in/sec) rear settings. This is based on a setting of 65% of critically damped.

So I asked Chris to take Dyno charts. It was an $100 extra well spent because sheesh the front shocks he had were all over the place. I will have to post pics, but with the worst combo he found one was full hard at the other's full soft!

The sets I am getting are a near perfect match with either side being within 5% of each other or so. I plan to set them when I install them and leave them as it appears that it is near impossible to tune them by "feel".

I hope to get it on for this weekend's autocross runs!

 

Sounds like you have a good plan! My ride is fixed after raising the car back up. I am only lowered ~3/4" now. The handling is great. I put in camber bolts in the lower holes and set them to max. (Works out to -1.8 on drivers side and -1.6 on the passenger side.). You could see the toe in changing while I was adjusting it! Took it to the shop for a quick alignment and it had 1° of toe in per side! (2 total) you could hear the tires scrubbing while driving.

I will have to try dissconecting the sway bar sometime. I will also report back as to how the billies do at autocross. I will be running the 19th of october since all my friends will be there and their cars all fall into STF, so I figure I will bring the Fit rather than the Miata that day.

As far as adjusting the Konis by feel, it is totaly doable. I did it on my Miata no problem, you just have to play with them a bit to learn what does what.

 

I forgot to mention that with the front bar disconnected it would rub the sway bar against the drive shafts because the suspension traveled soo much at least with the stock suspension. With twice the spring rate it may be fine and I may try it someday again now that I will have 3.5x stock spring rate but I am not convinced its faster.

 

I have actually been thinking of going with no front sway in the interest of traction. The sway bar adds a significant amount of roll stiffness, even with stiff springs, due to the relatively large diameter and ~1:1 motion ratio.

You would need to increase the front spring rate to compensate, on the order of 200Ib/in. So instead of 350/440 you would run 550/440. These are ball park figures. Would need to dig up the exact diameter of the anti roll bar or better yet measure the bar rate to be sure.

Should help a ton with traction and consequently with brake dive as well.

 

When i change the numbers in the Autocross to Win calculator so you have the same amount of roll stiffness for the front with just springs as with front bar and springs. It ended up being around 1150lb/in springs :P.

According to the parameters I'm using which aren't perfect, but should be close, >70% of the front roll stiffness in a 1G turn comes from the stock 23mm Bar with 350lb front springs. With stock springs it seems to be closer to 90%!

Chris recommended 440F and 500R or 550R. In that case closer to 65% comes from the bar. In fact he recommended a bigger front bar going from 23 to 25 which increases roll stiffness numbers by 25%, but its difficult to add for our cars. Feel so jealous of my sister's 07' civic that car it appears quite easy to change.

The biggest problem with disconnecting the front bar I can see is that you end up incurring a lot more suspension travel which in turn requires more static negative camber to compensate for the added positive camber and its not worth it to squeeze the floating sway bar between the lower arm and the driveshaft.

 

What do they say, how do you make a Macstrut car handle, don't let it roll?

Of course taking into account your tire's abilities.

lol

I suspected those crazy geometry changes without the bar. Very interesting observations and numbers you've posted. Thank you.

 

I don't think our sway bars are 23mm. Regular GE8 is 21mm while Fit RS is 23mm. 21mm to 23mm is an increase of 44% according to whiteline's table:

http://www.whiteline.com.au/docs/bulletins/BL-281.pdf

Also, what are you using for the sway bar length and lever arm? I have a Spoon sway that I have yet to install. I'll take some measurements tonight.

 

If you could measure it out of the car that would be great!
I haven't felt like crawling under the car to figure out the exact numbers and today its raining here.
These are the values for the front bar I am currently using

All in inches
Diameter: .83
Length: 40
Arm Length: 12
Arm Height: 5
Motion Ratio: .9

Changed Diameter to 21mm it. Its now more like 60% on the bar with coilovers and stock is more than 80%.

 

I got on my bum and took some slightly more accurate measurements.
Which increased the % of stiffness due to the bars quite a bit and play a bigger roll actually
Front
diameter:.837
length:42
arm length:12
arm height:2

Rear
diameter:.748
length:36
arm length:8
arm height:1

 

The proportions between roll bars and springs you are coming up with just don't seem right. Have you tried manually calculating the roll bar rate? I get about 113Ib/in. A good reference:

http://forums.nasioc.com/forums/showthread.php?t=1279944

Also here is good read on suspension theory without bars.

http://www.mr2oc.com/showthread.php?t=298272

It is for an MR2 but the theory is the same just reversed for FWD.

 

Thanks I'll look at those.

 

I figured out my mistake based on your link. You are right it is around 200lbs/in from the front bar.

I confused arm length and arm height! Which your example cleared up. Arm length is the overall length, but the arm height is the length that runs perpendicular to the bar.

That is pretty small compared to the contribution of the rear sway bar! That is perpendicular so it gives roughly 1000lbs of roll resistance but the front bar doesn't do a ton although it is comparable to the stock spring rates.

Going to the 25mm swift bar would add 50% roll stiffness to the front.

 

I still don't get your numbers, but I suspect is due to the variance in our measurements. Here are mine based on the bar out of the car:

Perpendicular Arm Length (A): 11.5"
Length Center Section (B): 25"
Arm Length (C): 14.5"
Bar Diameter (D): 0.83" or 21mm

Let me explain how I got the length of the center section B. I consider that to be the distance between where the two bushings mount to the subframe. If you think about it it makes sense because the twisting motion, along with some bending, will occur between these two bushings.

Outside of these two bushings you have bending in two axis. The bending due to the twisting motion of the sway bar and the bending due to the fact that the endlink mounting point and the subframe mount are not in the same plane. This is why you need both the total arm length and the perpendicular length.

If you plug in these numbers, assuming I didn't make any mistakes, I get (this is incorrect, see below):

k = 112 lb/in for 21mm sway bar and
k = 224 lb/in for 25mm

Haven't done the rear. I'll need to raise the vehicle and take some measurements.

To reiterate, I think you only need to raise the front spring rate by roughly 100 pounds to achieve the same roll stiffness as the stock front bar. If you want equivalent roll stiffness as the 25mm bar, tack on another 100 pounds or so.

EDIT: After reading the thread more, I realized that in roll the calculation above doubles because the bar twist is twice that of the individual wheel travel as the sway bar acts on both ends. Thus the final rates IN ROLL are:

k = 224 lb/in
k = 448 lb/in

So if we start with spring rates of 350F/440R you would need to jump to 575F/440R to replace the stock bar and 800F/440R for the upgraded bar. 575 still sounds somewhat reasonable for a pig heavy front end with good valving but 800 is probably pushing it.

 

From what I can tell the stock bar and aftermarket ones are the same shape. I am just not doing a good job measuring the front :P.

Thanks for measuring the bar out of the car! That is going to be the more accurate measurements.

You had a very good starting guess!

I know Chris at redshift has run 700R in the rear and he says the rear would be good to 800R springs, but the dampers have a motion ratio >1. anything above 700F would be pushing the konis to their limits.

So the swift sway bar provides stiffness beyond the capability of springs alone.

Actually measuring the effect of the rear is interesting. I just measured the bar, but the whole rear suspension is a giant sway bar

 

That was a good guess, lol.

You could always increase the spring rate by 200 pounds and use the stock roll bar. That would give you the roll resistance of the lower rate with spoon roll bar but with a few benefits:

1. Way easier to swap springs than roll bar
2. You can finely tune the balance using springs
3. Car should be more consistent over different surfaces because a larger proportion of the roll stiffness comes from the springs which are independent
4. Probably more traction due to the independent nature thus you can get on the power earlier

Did you read that thread on the MR2 forums I linked? Most of the info is on pages 1,2 and 3. It's a very good read and makes it very easy. The only thing we are missing is the roll stiffness of that damn rear beam. I'll work on that

 

I got to point 3 on page 1 because I was only concerned about figuring out the sway bars last night. Tonight I will go back with a more open mind. Although since I will be installing coilovers it will be tomorrow and after autocrossing lol this will be my 13th this season

 

Wow some read that was. The coilovers are gonna come tomorrow :P so I had time tonight to look it over.

Based on that article in the long run I should be running 440F/750R with the bars I have to acheive ideal wheel rates which is what Chris ran I am pretty sure or close to it. The bias for the fit is the rear is 175% of the front spring rates (The MK1MR2 was 150%).He mentioned 700lb springs rear. Maybe someday I will run 2 sets lol but that sounds annoying and 750R gives a natural frequency of 2.9 lol, but the 440F is doable for sure.

Also it explained that lowering the car should not be a huge deal as long as the roll center doesn't go negative and in our case that the rear roll center is ~1" higher than the front. The car naturally has a 1" rake between jack points so that should be kept it sounds like. So I may end up lowering a bit, but I need to check the stock height geometry before I lower the car. 1" drop may be ideal depending on the stock geometry which appears flat.

 

Got the suspension on the car after many hours of laboring scratching my fingers a couple times accidently dropping a washer into the trunk interior and having to redo the rear end twice due to the lack of directions, but it definitely is more on it driving on the street. Hugs the road nicely, definitely noticeable difference but its not a rough kind of harsh. Probably will tweak the dampers eventually but learn what its like to drive with is more important. I have a 1" drop roughly. That's the max height of the rear dampers. Definitely leans less lol

I also now understand how silly the trunk strut bar you can buy is as it does not effect the springs and thus does not stiffen the rear end much if at all lol

 

This weekend was the first go with the new suspension in an autocross situation. I'll be posting run videos on my channel soon.
The suspension does a fantastic job of maintaining stability of the car and the roll is noticeably less lol. Though it seems with the change in geometry I have found that no camber has the wheels tucked into the wells and positive camber means they are sticking out of the wells. I found the car had a slightly understeer and the inside tire would lose traction in cornering. Also I ran with 3/16" Toe out measured at the tire and the car had much less turn in response than I would have liked. I had to crank the wheel farther than ideal to get it to turn. In spite of that the car ran times that we equivalent to pre-koni times with -3 degrees of camber and some toe in. So all in all not a bad day. I expected it to take a little time to get used to the new setup, but the car is not bothered by bumps so my calculated settings seem to live up to the expectation . It definitely is a setup that is only worth buying if you autocross or track the car because it can't be fully appreciated until used under those conditions.

When I got home I changed the camber to -.5 degrees from whatever positive angle it was before and that ended up changing the toe to 1/4" of toe in at the tires and I find the steering response with toe in is much better which results in much less steering output. Seems to me like the outside tire is more dominant for our cars when cornering at all. Its interesting that most books you read and people you talk to suggest toe out when it seems to hurt more than it helps.