Kozy.

They measured the inner pick ups of the front LCAs as not being parallel to either plane which affects the axis of rotation and subsequently the toe and camber curves. My model has these modelled as parallel as I did not measure the rear pick up locations which could cause varying degrees of inaccuracy if they in fact not parallel as per the RSX. Unfortunately I am unlikely to get under the car to check this until mid March now (it's currently sat in the garage buried under the cardboard remains of Christmas morning) so I am unlikely to progress on this for a while.

SHG_EasyE

I just posted that in reference to the effect of the RCA's between the double wishbone and strut suspensions, because, per that report they are effective on the DC5/EP3 chassis.

Interested to see what comes of re-measuring those planes... Maybe someone else could supply Komodo with the measurements?

94eg!

iTrader: (2)

Okay......Yes making the LCA rotational axis angled can have several effects. A vertical change would be Anti-dive geometry (usually angle is raised at the rear). A horizontal angle is called sweep. At least that's what we call it in RC car racing. Very advanced stuff. Sweep can be used to increase/control camber throughout suspension stroke as the steering turns.

Here is a very interesting RC-related thread I found with lots of test data:

http://forum.teamxray.com/viewtopic.php?t=618

94eg!

iTrader: (2)

Okay guys, this is coming together for me. Thanks!

I went back and inserted those DC5 suspension coordinates into AutoCAD and all I can say is HOLY SHIZ! Viewed from above, the LCA has 16.8* of rearward sweep to it. That's bonkers. The rear LCA bushings are 8.8" closer together than the front ones.

It also has 2.5* of anti-dive angle in the LCA.

It would really be interesting to compare these measumments to those of redesigned (06+ I think) RSX suspension to see exactly what Honda altered. I know the tie-rod positioning is completely different.

SHG_EasyE

All model year RSXs had the same suspension geometry. They seemed to have addressed all the issues with the DC5 packaging with the 06+ civic. They changer rack position, caster angle, rear shock is mounte further outboard for better control, among I'm sure a laundry list of other not so obvious changes

94eg!

iTrader: (2)

I didn't realize the RSX didn't make it to the revisions that the Civic did. Thanks.

Wish we had OEM renderings of the EG/DC suspension like those shown above. I could easily extract all measurements from that (given good enough resolution).

Kozy.

Would the drawings on the Honda EPC be any good? Might only be hand drawn actually, so maybe not...

SHG_EasyE

I wouldnt waste my time with drawings I wasnt 100% sure were accurate. Better off getting these measurements yourself, or by a trusted source. Ill be plumb bombing and taking measurements for our DC5 once the car is in assembly phase.

Any idea how the user with the DC5 specs found his "CG" point to measure for X and Y axis?

94eg!

iTrader: (2)

Unfortunately no. The picture I posted above are perfect flat plane 2D images set exactly perpendicular to one another. From that you could easily extract x, y & z coordinates. Those parts drawings are isometric, and you have no idea if they are drawn with perspective or even scale. Extracting coordinates would be impossible.

It's funny, but compared the image of the 2001 Civic image, the points I plotted for the DC5 LCA into AutoCAD look EXACTLY the same. Same massive 16* of sweep and subtle 2.5* of anti-dive. Pretty cool.

BTW: Has anybody done plumb-bob work? I can't imagine it's very easy to find the exact rotational center of bushings and ball joints with a string.

apwhat

Great thread.. gives me a car nerd chubby, thinking this could be a good article to setup, get some more info going here..

would like all of your input.. but how can the home garage based tuner apply this to their build... once they understand the functions/why this important

SHG_EasyE

Yeah the 2001-2004 civic/rsx had identical suspension components and geometry. The 05-06 RSX was modified slightly with inverse wound front springs with different rates, larger front ball joints, different front shock tower angle, larger rear sway bar, re valved shocks and struts etc

I think the easiest way would be for one of the users here with CAD capabilities to take accurate measurements, and plug the info in to find at what ride height these parts actually do make a positive affect on geometry and handling. Only then can you tell someone if the part will be worthwhile in their application.

VERY useful information to have so hopefully someone can have the time to accurately measure the pick up points... I would be happy to do it but I no longer own a double wishbone car.

Kozy.

I have the car and the CAD model already set up, just need some nice weather, a free weekend and something better than a tape measure to start measuring with...

94eg!

iTrader: (2)

Here is an RC setup guide. It will give you a good idea of how to work on setup. As you can see we start with several "conditions":
- under-steer
- over-steer
- straight line stability
- steering response

The first two conditions are broken up into 4 categories:
- Corner Entry
- Mid Corner
- Corner Exit
- Braking

The cornering categories are then broke down into 2 sub-conditions:
- Off-Throttle
- On-Throttle.



So once you've identified your problem on the track, only then can you begin to fine tune your suspension. If you follow a given row across you will find changes listed that range in order of importance for both the front & rear suspension. It's important to note, that some changes (ie sway-bars) have a huge impact on every aspect of the turn. Therefore sometimes you will want to avoid messing with them because they may screw up something else. Once you've identified a possible change you would like to make, you can follow the column up and down to see what other impacts that change will have on your setup. Sometimes you can find a more subtle change that will produce the results you desire without effecting EVERY other aspect of the turn.

So lets say we are having trouble with Over-steer on corner entry, when off-throttle (typical for FWD): The number 1 response would be to stiffen the front sway and/or soften the rear sway. But by following the sway-bar column up & down, you can clearly see that making such a change is going to change every other part of the cars cornering that we weren't having trouble with. Now if you follow the row a little further, you will see that raising the rear "downstop" (reducing rear suspension droop) should have a significant effect on this problem (labeled as 3 on importance) without severly altering any other aspects of the corner (labeled as 7 & 8 most everywhere else in that column).

Now it's time to make the desired changes and get back on the track.

On the subject of Roll Center:
As a side note, you'll notice that the #1 change that "raising" the front roll center produces is increasing the steering response. Everything else is reducing oversteer (adding understeer) to every aspect of the turn. It also has a minimal effect of increasing straight-line stability.

apwhat

That's gold.

Hmmm.. i wonder how i can add to this, my focus is on the s2000, so maybe i could show products, techniques, etc... good stuff..

Actually even better, i should make a video.. kids attention span is insanely low. However, put all this information in a video format, add in some speech so nobody has to read..
the more we can educate people the less people will be proned to buy cheap taiwan coilovers without a clue why, understanding more creates a better environment for progression in the hobby as well...

Going to start this little project this week!
If anyone wants to help i can create a project mailing list and keep everyone updated with progress/topics for input, etc..

Kozy.

By all means help out the motivated, enthusiastic individuals with the drive and interest to learn with these resources, but I wouldn't waste my time dumbing it down to spoon feed those that are too stupid or lack the attention span to understand, because in most cases, they simply don't care.

I'm interested in helping out though. Might these be of interest?

http://www.ek9.org/forum/suspension/...-transfer.html

http://www.ek9.org/forum/suspension/...s-dampers.html

apwhat

i agree, but my inner scientist wants to test it to prove if i'm wrong hehe

great links, the tricky part is not to dumb it down to the point its useless or none functional..

teaching this can only work if you can actually apply it.. or else it becomes a story.

Thanks for the help, will keep you updated.

Kozy.

Well I can certainly see where you are coming from. Have fired you a PM about the website.

94eg!

iTrader: (2)

Thanks! I'm finding that this RC related stuff holds more and more true for 1:1 racing. The amazing thing about RC is that adjustments and testing can take place in minutes rather than hours. Every suspension point is shimmed so you can add and take away by simply removing 1 or two screws. Once you develop a "method" to tuning your specific chassis, you don't even need the setup guide any more. And the setup sheets that come with the chassis make it really easy to keep tract of your changes & conditions.

If you take a close look at my 4WD touring car, you can start to get a feel for just how many adjustments can be made (a lot more than what's shown on that guide):









BTW: Good luck on your project. Educating people can be a monumental task. Everytime someone new steps in, it starts all over with the same questions... lol

Somalie187

iTrader: (1)

Hey guys love where the thread has gone can't believe one question could open up such a 'forum' of scientific review regarding the aspects of suspension geometry and theoretical application.

Kozy.

Yes, nice to see some mature technical discussion here without the condesending attitude that is usually so prevalent on this forum!

00IntegrAllmotoR

iTrader: (1)

How does the on/off throttle work into the rest of the graph?? The black squares saying what you should be doing during those certain points??

also do u have any books to suggest on suspension. that are not to dry and some1 that doesnt have a degree in suspension theory can understand. Really trying to get knowledge of all this. Been tracking my car alot lately and would love to dial in my suspension.

Great post btw!!

94eg!

iTrader: (2)

It's supposed to be where you are having the problem. If your on-throttle, entering a turn, and experiencing over-steer, you would follow that row across to figure out how to cure it.

I don't really have any books for 1:1 scale. All my suspension tuning know-how comes from RC cars. I know a few sources for tuning if your interested...

4th one down is the "Hudy setup book" pdf in english. This is where I got that chart from. Very interesting stuff.
http://www.teamxray.com/teamxray/pro...b3bd271ae41ed8

This link also has some interesting car info. The suspension tab to the left is full of useful info...
http://users.telenet.be/elvo/

Somalie187

iTrader: (1)

Hey guys wanted this sent TTT.

Still think there is a lot to be discussed on the subject when regarding the eg chassis.

Thanks All!

grumblemarc

iTrader: (4)

There is? Funny. Nothing has been discussed since January. Thread looked pretty dead to me. If you're going to bump it at LEAST come back with something to add to it.

Sung@MM

On-Off throttle..Vehicle Dynamics is ALL BASED ON TIRE DATA. the TIRE,TYRE is the very most important tool on the vehicle. Everything you do with the car always ends at the tire. Vehicles are tuned based upon each tire.
Tires with more vertical load will heat up more and also increase lat. or long. "grip".
simply put, Weight Transfer.
On throttle on a FWD vehicle will decrease tire contact patch or verticle load since the vehicle is pitched back.
Off throttle, weight transfered to front
In the case of your RC car, there is more of an effect b/c the RC car is decelerating or braking. more weight to front tires.
Think, Top Fuel Drag Cars, they have ALL the WEIGHT to your driven tires during launch. AND THEN SOME.

To understand why you need to modify Roll Center, You have to understand what it is. Roll Center adj. can be seen as "stiffness" and how the weight is transfered to each tire.

ok...im getting tired. can't tell you guys everything.
go research