the way my car is set up now i have the konis 3/4 stiff in front and back with same psi in front and back. at my last autox event i noticed quite a bit of understeer. how can you tell if you are coming into the corner too hot or if its the suspension. would you recommend making any adjustments to the front (softer setting on shocks/ air pressure)?

 

I'd wager it was a bit of both.
Solutions:
Lift/Brake earlier: http://www.dmvrscca.org/topten.htm
Go full stiff on the rear damping.

 

try playing around with tire pressure too

 

I run my rears considerably stiffer than the fronts. You probably need less damping in the front to get more turn-in grip. What are your spring rates and what is your swaybar setup front and rear?

 

Try about 3-5 pounds more air in front than rear, rear shocks at 1/2-full stiff, fronts at full soft or just a tad up from there and see what happens.
You just have to keep messing with the adjustments till you find a sweet spot. But no matter what your settings are the car WILL understeer if you enter way too fast.

 

rates are 430f/500r no sway bar f or r at this time. so i would be on the right track by softening up the front and letting some air out of the front tires? question, i have the gc coilovers and the way the car sits the f/r are pretty much level. would it help if i lowered the front some as well, or could that be a mistake? just thinking it would apply more grip as well to the front tires under braking and turning. please help guys im new at autoxn and your help is appreciated. but from my last autox event and last weekends test n tune understeer is my bigest problem.

 

thats a nice setup... ihave a similar set up... maybe it could be your driivng?

 

There are a lot of things which could contribute to the problem. If you feel the push is already starting at corner entry, try braking earlier and/or harder to bleed off more speed before starting the turn.

From what I see in your setup, my recommendations would be to try swaybars (small F/large R) and to pay careful attention to alignment. What is your alignment now? The small details can make a huge difference.

Ride height difference F to R does make a difference, but not for the reason you are thinking. Raising the rear relative to the front will make the car looser, but I'd recommend getting the springs/bars/alignment/pressures/shocks down first before messing with that. In general, our Civic has a lot more roll rear roll stiffness bias, a lot more tire pressure bias (higher front), a lot more shock bias (stiffer rear), and it is very well balanced, not loose or tricky to drive at all. The devil is in the details.

Don't try to many things at a time, and find someone more experienced/faster than you to ride with you and see if it is a technique issue. These are the things that have worked for me.

HTH,
Peter





Modified by PoweredbyCamry at 6:53 AM 4/11/2006

 

on my past civic, i had 500/750 on f/r and no sway bar rear full stiff and i still had oversteer only with trail braking. a rear sway bar will help you a lot. and you can dial the oversteer with tire pressure and shock adjustment

 

my alignment may be an issue as well. i'm sure the alignment shop adjusted it for tread wear/longevity of tires. i really didnt mention it was for racing purposes at the time i was unaware of the importance of alignment.

 

If the previous advice doesn't work, try doing the opposite. Assuming you have the single adj. Koni yellows, try stiffening the fronts and softening the rears instead. These shocks control only the rebound damping and by doing this you'll make it easier for your car to transfer more weight from the rear wheels (providing for less grip) to the front wheels (to achieve more grip) and keeping it there longer. The softer rebound in the rear is what will allow the car to place more weight on the front wheels going into a corner. While the stiffer rebound in the front will help to transfer less weight off the front wheels once you get back on the gas and hopefully reducing a little understeer on corner exit. If you have corner entry understeer, you can also try trail braking more aggressively (which also plays on the weight transfer process mentioned above), with the changes to the shocks making the car respond even more to this. This is all assuming your front tires are not overwhelmed by too much loading to begin with, but given the springs you have, this shouldn't be the case. If you have shocks that also control compression (bump), then yes stiffen the end you want to reduce grip on and soften it where you want more grip.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by cheesebox &raquo;</TD></TR><TR><TD CLASS="quote">i'm sure the alignment shop adjusted it for tread wear/longevity of tires. i really didnt mention it was for racing purposes at the time i was unaware of the importance of alignment.</TD></TR></TABLE>
Be careful how you present it and what you tell your alignment shop. Some may not carry out your instructions in fear of potential law suits if they deviate too much from the "normal" street specifications for your car and something happens to you.

 

i kinda understand the theory of the last post but where were the others that posted getting their info? were they assuming i had shocks other than ots koni's? out of the suspension tuning articles i have gathered info from most say softer front/stiffer rear. is the above post saying to try the other way first and if it isnt better to try the stiff front/soft rear? just kinda getting confusing to me. thanks for your help guys

 

When you adjust a shock, you have to clarify what it is that you are adjusting, be it compression (aka bump) - the movement of the wheel upwards as the spring compresses, or rebound - the movement of the wheel downwards as the spring decompresses. (Then you can get into high and low speed bump/rebound adjustments, but that’s not the case here.) I just wanted to point out that the same changes done to one adjustment will not produce the same result as it would if done to another adjustment. In this case, going up in compression produces a different effect than going up in rebound. Also keep in mind, shock changes can really only influence a car's handling during weight transfer. This is occurs at corner exit, corner entry, or in transitions such as slaloms. If you have understeer during the turn - when weight transfer has stopped once the outside tires are at maximum load - there is not much a shock adjustment can do. It’s the spring rates and sway bars that affect a car's balance now during steady state cornering, and the "soften for more grip; stiffen for less grip" generally does apply here. I think we just assume this to be a universal rule and apply it to everything else, and not always correctly. Just wanted to point out in this specific case that doing this may make your understeer problem even worse, at least on corner entry. Then again, there can be many other variables in play. For example, if a car could use more spring, then you might do a tradeoff and not go as soft (if at all) on the adjustment to achieve the best compromise on balance.

But since you have these shocks, probably the best advice I can give is to send an IM to "CRX Lee" on here since he works for Koni and perhaps he can help you out with a couple of tips. Good luck.

 

I'm my own experience this is what I have found at Auto-x

94 Civic Si
GC 450F/600R
Koni Yellows
Stock front Sway bar
no rear sway bar.
Front toe: .125 out
Rear toe: 0
front/rear camber (whatever camber I got from lowering no camber kits or adjustments)
Car is lowered 1.75" from the stock height.
Tires all the same at 40 psi

With the front shocks on Full Soft and the rears on Full stiff..
the car was rather loose under braking.
dialing out some of the rear shocks and some stiffness into the fronts helped a lot.

But like it has been mentioned before, if you are going to fast into the turn, you will most likey push right through the outer cones.

If you can brake early, get turned you will be in a much better position.


If I were you I would try running:
Full soft in the front,
3/4 Stiff in the rear (that sounds gross doesn't it.)

I think you will be surprised what a difference the adjustments on the shocks make.

Also get your aligment done, this could be a problem too.


But MOST IMPORTANTLY

Fix your driving,

if you hear your tires screaming, your are probably going to fast into the turn.

 

i have now adjusted the fronts to all the way soft and rear 3/4 stiff air pressure is the same in all for tires and will use this as a baseline for this weekends autox. will plan on adjusting air pressure if needed and maybe front stiffness. while autox i have never noticed any tire squeel so would that be an indication that i am not entering the corner too fast? from evaluation of my in-car video from last weeks test n tune it appears that things get squirley towards the middle/exit of the corner and not entrance. hope these adjustments help this weekend. all in all i was able to finish 2nd in the last autox so i hope this helps and doesn't harm.

 

There's a good article in the latest GRM about shock tuning. They have a list of handling problems and the solutions you can use to fix them. I don't have it with me so I can't quote them right now, but it's worth checking out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nonsense &raquo;</TD></TR><TR><TD CLASS="quote">There's a good article in the latest GRM about shock tuning. They have a list of handling problems and the solutions you can use to fix them. I don't have it with me so I can't quote them right now, but it's worth checking out. </TD></TR></TABLE>

With all due respect to the article writer and subject, I highly recommend that the people here not pay too much attention to the tuning tips in that GRM article because of the frame of reference that the information comes from.

It was written by a respected Formula Vee driver about a respected shock tuner but it does not clearly convey that the tuning information is much more going to apply much more toward a lightweight formula car generally with an race optimized suspension geometry and a fair amount of aero downforce and lots of grip potential from sticky racing slicks on very smooth racing surfaces. There is much more emphasis being put on compression damping adjustment in a effort to keep the chassis very stable and level for the aero needs. There is very little emphasis put on rebound tuning as the cars they are drawing the experience from are comparatively very stiff and light sprung body weight with limited suspension and body motion. Playing with the compression damping a lot will push the limits of grip potential but these cars have gobs of it to start with.

The cars that this group here are normally talking about are going to be 1800-2500 lbs, production based, street and production compromised geometry, non-aero downforce, high sprung vs. unsprung weight balance, much less optimal tire grip potential and run on less optimal surfaces. After I read the article, I was immediately concerned that readers who see this information and not see that it's specific context does not apply to their own street derived cars and the info may be very, very wrong for them. I also have this concern when people take suspension information derived from Pro-rally cars that work mostly on extremely bumpy and even jumpy and loose surfaces ajnd apply it to smooth surfaces and stiffer cars using less overall suspension stroke. Please remember that not all information applies everywhere when in fact the more specialized the application the greater the risk if you try to apply it across the board.

I mean nothing ill to the writer or the the subject, just that I think it risks greatly confusing the issue for some more than clarifying it if readers are not clear about the application.


To the original poster of this thread, balancing your rear rebound damping to a higher level than your front is going to be an important tool to move the car away from understeer toward neutrality and maybe even a bit of oversteer. I would recommend that for the autocross course (not the street) that you keep your rear biased balance but move both ends higher up the adjustment range. Take the front shocks to about the mid range (about 3/4-1 turn from soft) and the rear to about max (don't force it) or half a turn off max. In an autocross situation, the car will benefit from the general increase in roll stiffness as you move up in the adjustment range. The Konis are twice as firm at the max setting as they are at the min setting so going from soft to mid-range will be helpful in highly transitional autocross. For the street, I suggest that you might leave the front at mid-range or softer and then set the rears back down to a similar setting as the fronts. Good luck and have fun.

 

What!!! No cliff note.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Lee &raquo;</TD></TR><TR><TD CLASS="quote">With all due respect to the article writer and subject, I highly recommend that the people here not pay too much attention to the tuning tips in that GRM article because of the frame of reference that the information comes from. ...</TD></TR></TABLE>

I agree. I went home and read the whole article last night and I can see now that the sidebar of tuning tips can be misleading. They should have noted that those tips are based on a formula car.

Thanks for the writeup Lee, but let me pick your brain a little.

I'm running 450lb front and 400lb rear springs on my 99 Civic Coupe. I run the front shocks at 1.5 turns from full soft and the rears at .5 turn from full stiff. The ride is stiff, but I find that going lower makes the car seem bouncy. I haven't tried going much lower than that because I'm afraid that it'll just bounce all over the place. Am I overdamping for the street or are my rates high enough that the shocks need to be turned way up to compensate?

The ride gets better with a full tank of gas vs an empty tank, which leads me to think that the rear is what causes the "bouncyness". Maybe I'm just over sprung in the rear for my street driving taste?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nonsense &raquo;</TD></TR><TR><TD CLASS="quote">I'm running 450lb front and 400lb rear springs on my 99 Civic Coupe. I run the front shocks at 1.5 turns from full soft and the rears at .5 turn from full stiff. The ride is stiff, but I find that going lower makes the car seem bouncy. I haven't tried going much lower than that because I'm afraid that it'll just bounce all over the place. Am I overdamping for the street or are my rates high enough that the shocks need to be turned way up to compensate?

The ride gets better with a full tank of gas vs an empty tank, which leads me to think that the rear is what causes the "bouncyness". Maybe I'm just over sprung in the rear for my street driving taste? </TD></TR></TABLE>

from your fuel comment, it seems to me that you may simply be over sprung at the rear for your tastes. Probably the first thing that i would check would be zip ties on the shock rods to as a travel indicator to make sure that you are not constantly whacking the bump rubbers based on ride height or their length. Generally I would say that those settings are probably on the high side for those spring rates based on my own experience but if the car seems to be less pleasant if you soften then it is relating to something back upstream in the springing and bump rubbers.

The term "bounciness" is really confounding as it can be used to explain bith an underdamped and an overdamped situation. One way I find it easier to judge is to see if you can islolate what is bouncing vs. otehr parts. If you feel that teh bouncing is often rather short and sharp and can often be your body bouncing on the car seat in maybe a different rate or energy wave pattern than the entire body of the car, then this leads me to beleive that you are overdamped and the car is not moving enough to keep you in sync with it. if you feel like the car and you are bouncing or oscillating together but just too much, then that is wwhen you are likely underdamped and need more rebound.

My gut feeling is that so long as you can prove that the car is not regulalry smacking the bump rubbers casuing a functional spring rate spike, I'm thinking that you are probably both overdamped and maybe rear oversprung for your tastes and your usage. My CRX sits outside my office on 400f/325r with a very livable but aggressive rife qality and the shock set about 3/4 turn from soft.

 

OP, lower the shocks to a softer setting. Do you have a rear sway bar? Front sway bar? What car?

The addition of a rear sway bar REALLY helped me to get rid of some understeer.

 

no sway front or rear at this time. saving up for the asr setup. softened up the front to .5 from full soft and rear is at 3/4 to full stiff and it seems perfect. i think this was the problem. i havent been able to thrash it yet but i can tell the rear wants to turn out more when throttle is released. turn in also seems to be alot more smooth. thanks guys for the help. i know my suspension is by no means fixed but i feel i can push the car a lot harder without as many ill effects. i cant wait to try it this weekend. thanks

bryan