nothere

iTrader: (23)

This thread is intended for those relatively new to suspension tuning who are interested to getting the most out of their car.
Hearing from the knowledgeable will be a real help.
The premise here is that there is more than one way to make a car handle well. So there will be some disagreements. The idea is not to argue which method but to increase the knowledge about your method.

First off, for most people the best method of getting your car to handle well is to hire someone to do it for you. Along those lines I can think of at least three very well known evom users who can get your car to a higher state. They of course have devoted many hours of work and energy to develop what they offer. Giving away what they sell is not fair.
On the other hand there should be a large number of drivers who see suspension tuning as a hobby or interest that they have a knack for. I am hoping that from this group a great deal of knowledge can be derived. If once in awhile one of the suspension masters wishes to step in that would be greatly appreciated.

Lastly this is intended as information for road course use, but since the vast majority of us can't bare the expense of a track only car, street ride quality shouldn't be ruled off topic.

vboy425

iTrader: (19)

Robispec ///

nothere

iTrader: (23)

So lets start off with tires, all the kings men can't put your car right without good tires.
I had one of the suspension masters set up my car several years ago. It was better than stock in every venue. But until I switched to track tires I was giving away about ten percent of the improvement. In fact that missing element made me decide to go to another coilover, in the mean time, just before the new coilovers arrived , I switched to some track tires and that one change made me realize how great the set up was.
All is not lost because now I can try to get my car to handle as well as it did, another hurdle, I mean hobby to master.

nothere

iTrader: (23)

Camber, pressure and load.

At the major track nearby a camber setting of 2.6 is about right. Across the state at another track 2.6 is too much camber for that track. This is determined by reading tire temperatures. By reading temps across the face of the tire you can see where the tire is working and not working. From inside to outside the temps should go from high to low. Such as 198, 195, 192. The temps will range relative to ambient too.ie 150 145 140

Those numbers would tell you that the camber was about right, the tire pressure was about right and the general load on the tire was about right. In that order. If the middle number was higher than the first number that would tell you the tire pressure was too high or that the camber wasn't set high enough. A series of numbers like 199 170 185 would be telling you the tire pressure is too low.

Now you would look at all the tires, looking to find the same spread ratio, of course on an evo the rears will read lower than the fronts. On a counterclockwise track the drivers side tires will read lower than the passenger side. The last big turn side will read warmer ...

nothere

iTrader: (23)

OK, time for someone else,
this time its shocks.

When adjusting shocks you hear people say I turned them all the way to hard and off I went.
This is indeed effecting overall ride but it is not adjusting the way the car handles the track.
If you want to make a difference you can't turn everything the same way the same amount.
You either give it more or less rebound or more or less bump. The deal being not the same to every wheel. If one end is loose make the adjustment there or the opposite adjustment to the other end.

Anyone have a cause and effect they could post here?

trinydex

iTrader: (12)

oh man... this last question is very not unadvanced :\

nothere

iTrader: (23)

well that was the intent of the thread. to let a wannabe suspension tuner know where to start. what to look for and how or why he should turn the knobs.

might be best to just suggest a good suspension book

Jeff_Jeske

iTrader: (66)

<---- This guy runs stock suspension plus.....

25mm rear sway bar
An aggressive alignment using front camber plates (-2F -1.7R)
255/40/17 sticky Falken 615 tires

Those few things have made my car handle MUCH better than stock.

For the 03/04 guys the next best thing would be a FLSD.

nothere

iTrader: (23)

thanks Jeff
you sound like you found somethng that really works for you!



well I'll try one again,
Another thought to consider is each segment of a corner wants different settings from your suspension.
Lets start with corner entry, in most cases you are on the brakes or just off of them. Weight is on the front, as you progress you come off the brakes or add gas, now weight is shifted to the rear, the front unloads. Further still into the corner you add more gas, the front is lighter still. All the while the outside tires are doing the majority of the work.


As you entered the corner the front was down. As you exit the back is down. Not long ago I watched a modified Audi running on the track. When he mashed on the gas coming out of a corner his whole car seem to squat down. I am guessing he had a lot of rebound in the front and not much bump in the back. ie, as he got on the gas the front couldn't lift because his front suspension was restrained form lifting by his shock setting. Meanwhile the back end was allowed to come down because the shock's bump setting was low enough it couldn't resist the load.
I couldn't tell you if this was the fastest setting for his car but it was fun to watch, he certainly looked fast.

trinydex

iTrader: (12)

tires are definitely the single most important thing on a race car. everything in suspension tuning is about maximizing tire performance. maximizing their grip through the largest percentage of the roadcourse.

you wanna know how important tires are? my awd evo kept spinning out at an autocross simply because my tires were not fit for the mostly rainy and cold pavement conditions (when it did dry). you know how embarassing that is?

so in competition, rain tires are JUST as important as race compound tires. all serious teams have both on hand.

of course with tires there's also the discussion of shouldering. more round shoudlers break away more slowly and evenly while sharper shoulders break away more quickly. the response on rounded shoudlers are slower, lazier and more crisp and firm with sharp shoudlers. that's why stretching tires over a thick wheel gives you more response and smushing a tire into a thin wheel gives you even break away.

rounded tires also warm up quicker.

trinydex

iTrader: (12)

there's four types of adjustments low speed compression and rebound and high speed compression and rebound.

adjust the low speed stuff will affect your turn ins. going stiffer will make your turn in more crisp or dull.

the high speed adjustment is where you'll need to damp out the springs compression and rebound forces at full tilt. so if you hit that bump in the middle of the turn after you've used your low speed compression you don't go flying out of the turn.

of course you have to have the right amount for your springing and this is where it gets complicated. techinically there's a very narrow range of where a damper in a certain adjustment is idealy working a spring. so turn the knob too much and you need to be swapping the spring.

now this is a final consideration, you want to have high speed understeer and low speed oversteer for most intents and purposes. this means you have to do some magic that i don't quite know how to explain yet.

trinydex

iTrader: (12)

ok so since we're talkin' about hte traction circle let's just come out and talk about it. according to skip barber you need to do some trail braking in order to not leave time on the table.

turn in, on brakes and trailing off. i've been practicing this lately to get the feel but check this out. as you brake towards the apex you should be lifting off the brake at the same rate you're turning the wheel.

so imagine full brake. then the moment you begin to let off turn in nad as you feed more wheel you let off more brake. if you guys kart at all this is that part of learning where you realize i don't wanna over brake into the turn, so lets just brake and then let off at the same time we throw the car into the turn so the actual turning scrubs off the rest of the speed. (at least this is how it was for me, as karts seems to have on and off braking. even tho i tried my darndest to modulate. and there's absolutely not throttle modulation.)

in the same way as you roll onto the gas you should be rolling out of steering, just as much roll outta steering as throttle input. that then gives you the most benefit of all the downloaded areas due to accel and decel.

they say in going faster that the skib barber instructors look for a nose dive, a smooth transition to the outside tires and then a squat coming in and out of certain critical turns and they make their students keep practicing until they get it.

trinydex

iTrader: (12)

this topic varies a little with driving style but the subject of front diffs was brought up and if anyone is using the quaife they know that that thing pulls you around.

you notice in the american touge 2 that the kazama drives john mueller's evo and says if you give it a little gas at the end it pulls the car out. this is of course because john has the quaife.

the style for driving with this unit is a bit different and for an amatuer learner like myself john recommends doing all my braking in the straight being in a high torque gear and easin' it into the turn on the gas so that the quife does its magic.

but you see for a pro like kazama he does his trail braking and then lets the quaife do its magic on the exit so he can get on the gas earlier and remove more steering earlier to get shooting straight earlier, maximizing his straight speed and minimizing his lap time.

nothere

iTrader: (23)

I am sure most people have noted that I know very little about suspension tuning, and that I am fishing for some experience tuners to clue us all in.

there is a good long dispute, I mean, thread elsewhere on evom as to to trail brake or not. For the most part novices should be instructed to get their braking done before entering the corner. Once the instructor is out of the car and doesn't have to fear the driver, no. Anyway.

So, for the most part anyone reading this thread will have a set of coilovers with bump adjustment, and perhaps rebound. Height adjustment is fairly straightforward, the limits of which are mostly set by road conditions. But one thought for rear height is to keep the lower rear suspension as near level as possible. Above level you might find the rear a little loose, but if that is what you are after I believe it is better to get loose via another method. ie, springs or bar or if close enough by shock adjustment.

Of course you have camber adjustment too, just remember if you change camber at the track you need to set toe, as one affects the other. Some guys will have their two positions marked so they can change camber at the track and know where (nearly) to set camber and toe.

Noob4life

Unless you are circle track racing, or on a course that has significantly more lefts than rights (or rights than lefts) that can justify an imbalance of tuning between sides, then you will always be making shock adjustments in pairs (front and rear).

The more-or-less accepted method for shock tuning begins with shocks set 50/50 (rebound/compression), which could mean equal rebound/compression or simply middle settings. With all the factors contributing to the overall handling of the car, you want to get a good baseline of the chassis first before you begin tweaking the shocks.

The process of making individual changes to rebound and compression depends on where the handling suffers (and of course, whether or not adjustments to fix this will affect where the car performs well - its always a trade-off).

Since shocks only affect handling during transition, we can divide up the "where" of adjustments into several phases, depending on how complex you want to get, with the most basic being corner exit, mid-corner, and corner exit. Keeping in mind that "tuning" for one phase will affect the performance in another, you begin with where the big problems are - and it is always important to nail down the exact, specific problem. Otherwise, you may be trying to solve for an issue that is actually the result of a more deeply rooted issue. eg. the car is loose on exit, but only because the driver goes in too hot and the car pushes. You'll end up chasing your own tail.

Until you get into the 3/4-way adjustable shocks, you are only looking at making general increases and decreases in rebound and compression. Despite what some say, turn entry is affected by the dampers, and is affected via changes in front damper compression and rear damper rebound. afaik, mid-corner behavior follows the same rules. Corner-exit is affected by front damper rebound and rear damper compression.

Hence, even a single-way adjustable shock can be used to tune the balance throughout all phases of a transition, but of course a 2-way adjustable would be more beneficial (assuming you can tune a 2+way adjustable damper).