Nick's setup was the one that started this whole discussion and was the one we were using as an example pretty much the whole time. As mentioned earlier, it was about 2.6 front and 2.4 rear.

Unless you're talking about his interesting yet crazy idea to use 1200 lb springs.

 

ST Civics are typically in the 1.8hz F and 3hz+ for the R.


Put that in your pipe and smoke it.


You can't compare frequency setups from car to car unless the following things are exactly the same:

CG
Track Width
Wheel base
Camber/Toe/Caster change per degree of roll.
Weight Distribution


Thats your starting point, until you know all those variables then all the internet engineering masturbation is completely useless.



Put something on your car, drive it. Discover shortcomings. Fix them. Drive again.

Rinse and Repeat.

 

I think turning a front wheel drive economy car into a very fast autocross car is the exception because you have to do ridiculous things in order to get it to rotate. A ~50/50 weight distribution rear wheel drive sports car, on the other hand, should require a setup that is much closer to the one internet engineering masturbation will come up with. Especially for one that doubles as a daily driver.

I'm actually curious what internet engineering would come up with for the civic after doing all the roll centers and everything.

Anyway, no one's saying internet engineering is the be all and end all, or saying that you even need it. It's a good way to get a starting point, it's a good basis for understanding for what's going on when changes are made, plus whoever said masturbation has to have a purpose anyway?

 

Define Ideal.

There are just way too many variables to say "X setup" is the perfect one. If you are waiting for someone to tell you how to set up your car and haven't noticed that 18 months and 3100 posts later that there is no clear consensus, I don't know what to tell you. Everyone is going to have their own opinions on what could/should work best based on their personal preferences and experience. The only way you are going to find what you like is to try it. There is no magical solution here, there is what works for you, and you have to find it. No one here can tell you what it is. They can share what has worked/not worked for them, but you can see there are plenty of differing opinions on certain set up choices for those that have tried them.

For example, I tend to be in the same camp as Nick on the rear bar thing, but imstimpy(who runs in my region) likes the bar on his car. So who is wrong? No one. I was able to run within 0.3sec of my time on a 38sec course in one run in imstimpy's car. The variance is within driver noise, it's just whatever makes you most comfortable behind the wheel. I feel like I can more consistently drive my car at the limit without the bar, so I leave it off.

There are plenty of ST Civics with different spring and bar setups within the trophy finishers at Nats this year. And most of them will likely try different things again this year to try and make their cars faster.

 

I don't believe that Dennis was being FWD specific. He has an AWD Eclipse. One reason to have a higher natural frequency in the rear is to prevent pitching when the car encounters a bump -- it delays the response of the front suspension relative to the rear so that they both rise together rather than one at a time. I don't know if that's how Dennis selected those frequencies.

Critical = critical damping. If you don't know what critical damping is, it's worth learning the physics of the damped harmonic oscillator (which has the same mechanical elements as each corner of your suspension).

 

.........^^^^That's my method, but with my results, it might not be a good example. Maybe Jim's is. From the thread where he shared his setup, he did not come across that he over thought things.... but look at his and his co-driver's results. Very impressive!

I'm not saying this cool engineering stuff is a waste... not at all. I find it fascinating and hope those that understand all of it would translate for us dummies. Until then... trial and error for me.

-Dave

 

Ride comfort data point

For a daily driver I have reached the limit on spring rate with 850 in the front. It was very livable at 750 in the front. Back end is at 600, considering 700 or 750. I have to soften up rebound all the way in the front and live with some under damping to make it through the week commuting. The roads are pretty bad on the way to work, lots of ridges. I found myself wanting to go 80 MPH (50 MPH local road) to smooth out the ride.

 

Do some research on the Olley Flat Ride Principle for street driving comfort levels. The increase to 850 on my car actually made the car ride better at certain MPH than the 700s. Front spring rate has very little to do with comfort believe it or not (unless travelling under 15mph)

 

Well after lurking on this thread for about a year, I suppose it is time for me to jump in now that I bought a car to really prep for the year.

I wanted an 06+ for flash pro but budget constraints for this year made me have to pick up a cheap 05.

The car will be prepped by myself and with the assistance of a few friends (and better drivers) in the DFW area including David Whitner, Thomas Hiromoto, Ken Orgeron, and others who want a codrive or two.

Car setup is most likely going to look something like this to start
AST 5100/5200 price range shocks
Gendron or Saner front bar
Tire rack wheels (will become the spare set/rain set when I can spring for a lighter option)
255s of course
Camber joints if needed
I will worry about power after the handling is getting dialed in.

Needless to say the car is going to have a very merry Christmas.

In the mean time I would like to thank everyone for your contributions to this thread it has been very good reading and helpful.

The only question I have for now is about fluids. I am going to be doing a full fluid transfusion, and am curious what everyone has been running.

From my reading and just previous experience I was going to run

Motul 5w30 oil
Motul RBF 600
Not quite sure yet on the diff fluid.
Maybe GM synchromesh with friction reducer for the trans

Thanks and I look forward to running into some of you at a few tours etc... And hopefully nationals.

Greg Laver

 

Greg, stock brake and trans fluids will be more than enough for autocrossing. I run Mobil 1 10W-30 for the engine.