austrian type-R

Guy, that is realy interessting what I heard of.

Japaneese racers are using lower spring rates in the rear like 12kg front / 8 kg rear while you US guys are doing the opposite. My tuner is leaning to the japaneese site without nowing what I knows (the world is splitted on spring rates )

Fact is, that higher spring rates in the rear will give very much oversteer. Why is there such a BIG difference on likeing spring rates? I don't understand it. I mean some one prefer 12kg/8kg more than 14kg/12kg, but doing the opposite on the rates is just confusing me.

Mike P.

There is some decent debate in the thread below on this subject:

https://honda-tech.com/zerothread?id=231870

Neo

You like controversy? Oh dear, God. Not this again...

Read the thread above, I mean really read it carefully, and then form your own opinion...


[Modified by Neo, 1:23 PM 11/12/2002]

fsp31

>>There is some decent debate in the thread below on this subject:
https://honda-tech.com/zerothread?id=231870<<

Dunno about y'all, but I gave up on that horrendous pile of horseshit after about 2 sentences. Here's the really scientific summary of my spring (highly subjective) rate analysis:

When I had low rates in back, the car pushed badly. Lots of push resulted in *slow* lap times. So, I raised the spring rates in back until I achieved *fast* lap times. What I ended up with were spring rates that are significantly higher in back than in front. Do I care that they are higher in back than in front? No. I just wanted enough oversteer to achieve the fastest possible lap times. If I ever switch vehicles, I will definitely have to repeat the process, and probably end up with different spring rates in the end.

As for how they do it on the other side of pacific, I'm clueless. Never gave it much thought...

Reid

Did you also change camber settings at these times?

Wai

One thing that the above thread didn't mention was the side effect of using spacers. By increasing the front track width and lowering ride height, load transfer would be decreased hence better front grip. BUT spacers would also retard the effectiveness of the springs (changing the motion ratio) so the front spring rates have to go UP.

In Asia, I've seen as thick as a 20mm (~3/4") spacer *each side* on a DC2R. Camber was set at around -4 with 195 slick so the top edge is still tucked in.

Raz1983

most japanese "tuners" or what not want a little understeer than any oversteer. me too, have seen alot of people put spacers in the 20mm's (i have F 10mm, R 5mm in mine)

taste difference i suspect.


[Modified by Raz1983, 8:13 PM 11/12/2002]

carl_aka_carlos

ok....from a purely physics stand point, both JDM and USDM FWD set-ups accomplish the same thing...albeit in a completely different route....my explaination will in no way be as detailed or precise as Wai's....but I think it holds true....if you all are interested in my conclusions, read on

my example concerns autoX and gymkhana set-ups, say for a ITR:
JDM:
gymkhana set-ups tend to run ridiculously <sp> high front spring rates...sometimes in the 4-digit range! how many of us have seen pics of CTR's pulling their inside front around tight turns? anyway, over here we instantly assume that set-up will produce massive understeer...but if you remember that weight travels along the diagonal ALWAYS you can start to see the logic in running ludacris front spring rates....also JDM set-ups usually tend to sport large rear bars as well. on more important factor is the LSD....I have noticed (this is pure speculation) that JDM seems to prefer clutch type diffs, which wont' unload if one of the drive wheels leave the ground.

USDM:
generally US autoXers follow this rule of thumb: the roll stiffness on the drive wheels should not be greater than the roll stiffness for the non-drive wheels....simple, run high spring rates in the rear. we have a term that I'm sure all of you have heard, "right wheel peel" or "inside corner-fire" when you roast the inside wheel on turns....following that weight travels along the diagonal theory running higher rear spring rates should help keep the inside rear tire planted. another factor in this is the type of LSD....US autoXers almost all prefer torsen or gear type like the quaife...these diffs work great, and seamlessly, but if one of the wheels leaves the ground, it instantly becomes an open diff and all the power goes to the unloaded wheel, so we have to keep that inside tire on the ground to keep the LSD effective.

ok, now that I have subjected my opinions on the matter to all of you I realize that I may get flamed, which is aiight with me. also solo-x has some pretty interesting ideas concerning setting up the suspension around the weight travels along diagonal theory...

austrian type-R

That spring fizzle is some confusing ****!

fsp31

>>Did you also change camber settings at these times?<<

I played with the rear camber some, but not much. My tire of preference is the Hoosier bias ply, and they're not very responsive to camber changes. I did fiddle with rear toe some as well, but I didn't want to go crazy with it since I still drive this car to events, and to work occasionally.

Right now, I've got 1.4 degrees negative camber in front and 1.3 degrees in back. Funny part is, I still wear the *insides* of my bias plys.

ZygSpeed

Oh yes Sir indeed!

solo-x

bias ply tires will favor a rear stiff setup purely because of the slip angles bias ply's run at.

i would like to mention that spring rates really don't mean much. wheel rates are what matters. and you can't just compare wheel rates among setups either, since the sway bars are a huge part as well. i've crunched the numbers on the jdm setup and the usdm setup and found that the jdm setup had a 40/60 roll couple distribution (ie stiff rear) while the usdm setup has a 30/70 roll couple distribution. (rr98itr's car was my example, 800fr/1100rr 24mmfr/26mmrr)(ie stiffer rear)(also of note, this is nearly the same roll couple distribution of a stock itr assuming the info i got on an itr's sring rates was correct) so this whole jdm versus usdm is rather dumb since the setups are nearly the same as far as which end is the stiff end.

furthermore, autocross and roadrace setups for a fwd car are different. period. in roadrace, you have to preserve your tires, particularly your outside front tire, for as long as you can. therefore, a small amount of front grip is sacrificed in the quest for better tire wear and temps. to offset this loss in grip, we reduce the rear grip (convenient that we can accomplish both goals by simply increasing rear roll stiffness) and thus have a car that has a lower overall grip, but a level of grip that is more easily sustained over extended periods. autocross, due to its short burst nature, looks for maximum grip at the front end and could give a damn over tire wear. therefore, we maximize front grip, then use toe and camber to "adjust" the cars cornering attitude. will the car "push" more? unlikely (assuming you AREN'T using bias ply's) since the original cause of the push was the amount of mass at the front of the car, otherwise known as the mass trying to go straight. remember, vertical loading on a tire increases grip (ie downforce) while the horizontal load uses up that grip. more weight=more horizontal load=greater slip angles=the feeling of push. has anybody figured out yet that this setup would suck over the long term roadrace??

my own conclusions are this. if you are running relatively soft spring rates (natural freq of around 2 cps) you need to run a rear stiff setup for autocross. if you roadrace, you need to use a rear stiff setup. (i would tend to stay closer to a 40/60 roll couple distribution purely because it seems right, imo. weight dist is nearly 60/40!) if you autocross, i think a roll couple dist of 52/48 or something similar is better, but again that is my opinion. personal taste does mean a lot here. either setup, if done well enough, can be equally as fast i think.

nate- who feels it best people not comment on how a setup is different until they really know what the numbers mean.

Namlak

I don't think this is correct. When you increase the stiffness at the rear, you are not reducing grip, you are translating more of the roll resistance to the rear (via the chassis) making the rear tires take a greater percentage of the overall *dynamic* load, relatively speaking. This is *increasing* the total grip because you are equalizing the total load on the tires. Oversimplified, on a prefectly balanced car in a steady state turn, the downforce (NOT "weight") should be the same on each outside wheel, thus they reach their respective limits at the same time creating a 4-wheel drift. Of course there are many many variables that could tip the balance - alignment, braking, off/on throttle etc etc.

I know when I stiffened up the rear of my car, I started noticing the rear tires screeching along with the fronts which never happened in stock trim.

solo-x

correct me if i'm wrong, but isn't the dynamic loading in the verticle plane? if it is, then you are reducing the verticle loading on the front tires, reducing their grip, while increasing the verticle load on the rear tires, increasing their grip. the slip angles that the tires are operating at will change due to the verticle loading, thus your squealing rear tires, but you haven't increased front grip. i'm no physics major and i don't claim to have more driving experience then will, but these are my ideas and thoughts. i might be completely off base and going in the wrong direction, but increasing the rear roll stiffness hasn't made my car any faster for me.

nate-who's jealous of certian cali. people who are getting my competition.

Namlak

By stiffening up the rear, you are reducing the roll couple at the front of the car and increasing it at the rear. With reduced roll couple at the front, the outside front isn't as heavily loaded and the inside front gets more downforce. That's another thing I noticed when going to a big rear bar - less inside-front wheel spin - think diagonally. If you recall, if you double the downforce on a tire you get something less than double the grip - so by reducing downforce on the outside front (by sharing the load with the inside-front and the outside-rear), you get proportionally more grip out of it. The truly useless wheel is the inside-rear, which is why you don't even notice when it's off the ground and stationary! (Except in extreme cases). The old adage about the rear tires of a FWD car being there just to keep the bumper from scraping the ground is completely ignorant (and usually quoted by RWD drivers).

But your analysis of the wheel rate and roll couple distribution is right on. I still can't believe how many people keep trying to compare the straight spring rate numbers without thinking of *wheel rate*. And then they ignore the sway bars! <shrug>

Doctor CorteZ

this will never end......

solo-x

at least there isn't any name calling in this thread.

will, i guess my stubborness in accepting how you put it comes from every time i've run a higher rear roll couple stiffness i've had MORE inside front tire spinnage. the only thing that makes sense to me is that i'm transferring weight off the inside front and onto the outside rear. i know, it goes against the grain, but it's the only thing that makes sense to me. i wonder if part of it might be the differences in suspension design between your car and mine. or it may even be the course designs: ie west coast more sweepers, east coast more hard transitions and slaloms. again

nate-who doesn't understand why we can't revisit a well discussed and very important topic

Namlak

You know in a competition forum, you only need to discuss springs once. <shrug>

Interesting difference in observation. It may have something to do with roll centers or camber control as our suspensions are indeed quite different.

Can't argue with your success, tho - congrats!

solo-x

too bad you couldn't make it. i would have settled for fourth to have met all the greats in sts.

nate

BigAl

just to add some further comment!
In Australia and new Zealand where Integras and Civics are also popular circuit raceing vehicles spring rates are very similar front to rear .
setup example
integra on slicks 16x8 rims
800front 750 rear spring rate
std front bar 22 rear bar
3.5 neg f 2.5 neg rear camber
2mm out front 0 rear toe

Civics , which are normally a little lighter as they run in the 1600 classs run slightly lighter springs alround

softer springs are often required particularly in the rear due to surface undulations in some braking areas

i am not trying to justify the setup , just that this is what we have found works best for us.