ZZE Track Guide

[SuperDave]

Suspension

Coilovers are only a requirement if you intend on doing setup work. If you aren’t going to do setup work, then just buy springs and struts. Bolting coilovers onto the car and not adjusting them is likely to result in going no faster, or even slower. Car companies have actual race drivers help them with setup work, yes even in mundane cars. The function of the stiffer springs and higher dampening is there to help the tyre keep better contact with the road surface, so adding more negative camber helps out, explained in more depth further down.

Cusco supply their off-the-shelf kit with 7kg/mm spring rates at the front and 5kg/mm spring rates at the rear. To understand these numbers it’s best to break them down. A unit of weight per distance means that if a weight of x was placed on the spring it would compress by 1 unit of distance. So in this case 7kg would compress the spring by 1mm. Why is the front spring rate ‘heavier’ than the rear? Well in the Corolla’s case it has been blessed with very poor weight distribution, about 65:35 http://au.toyotaowne...corner-weights/

So with this information it’s easy to work out how much the suspension will compress by under the self weight of the car. With the numbers from that link; FL: 50mm, FR: 62mm, RL: 46mm, RR: 40mm. As can be seen the coilovers will need to be set at different lengths to achieve a level height once sitting stationary.

As for setup work, you can adjust the dampening, rebound, ride height, toe and camber. Not all adjustments may be available depending on the coilovers or spring/strut combination purchased.

Dampening is the absorbing force. Before I mentioned that the spring will rest at a certain height with a certain load. You’ll note I didn’t mention anything about the strut. The strut is there to absorb the energy and to ‘dampen’ the oscillations of the spring. Too stiff and the car won’t absorb the bump and have a rough ride and likely damage something. Too soft and the spring will keep bouncing along well after the bump has occurred. Rebound is similar, but in the opposite direction.

Ride height can be used to set the car level, or at an angle front to rear, called ‘rake’. Dropping the rear relative to the front will shift weight rearwards, and vice-versa. I’ve found the car likes the rear to sit about 50mm higher at the back than the front. But only setup work will yield a setup that suits your car and driving style.

Camber, throw as much in the front as you can get. The Corolla rolls heavily under lateral load and you’ll find your shoulders are worse for wear after a couple of sessions. -5* or so should do it, but you’ll have to think outside the box to get it at the front. For the rear you can use less, but as it isn’t adjustable, you’ll have to get creative there as well to get some adjustment. -2* at the back should be plenty.

Toe, think of the tyres as your feet. When you stand with your toes together, that’s toe-in, and vice-versa. I like the car with zero toe, but you might like it different.

To save explaining the cause and effect I’ll link to a copy of Carroll Smith’s excellent guide from his books http://www.ftw.com.a...ause_Guide.html

Anti-roll bars

No they aren’t sway bars, they don’t do any swaying. Now that that is out of the way we can move on. Anti-roll bars, by name, don’t do what they are called. The anti-roll bars are there to trim the oversteer and understeer characteristics of the car. The springs should be used to control the roll. On the front, the stock anti-roll bar will be fine, but it depends on what your setup data reveals and could be worth trying out to gain valuable tenths. I found the thicker front antiroll bar reduced the inside wheel spin out of slow corners, but at the expense of a little apex speed.

The rear anti-roll bar in stock form (for the Sportivo at least) doesn’t cut it. It is 19mm in diameter, while the normal Corolla has a 21mm item. Anything thicker will improve the corning ability of the car at the detriment of increased lift off oversteer. The sportivo with its extra power is more prone to lift off oversteer in stock form than the normal Corolla, hence the different bar thicknesses. But on a track car you of course know better than the factory’s development driver (note sarcasm). Once you have some experience with the car on the track and find it is understeering, you need to increase the thickness of the rear anti-roll bar. 23/24mm is probably what I would recommend. Selby’s and Whiteline can custom make to order if you are willing to wait.

Brakes

Rotors

Now you don’t need slots and cross drilling and whatever else in between. All that is needed is the selection of the correct pad temperature range for the application, covered below. Back to the rotors; first you need to understand why the slots and drill holes are there in the first place, and what they bring to the table in terms of effects. The drill holes allow gases produced by the pads to enter into the central vanes and be expelled. The downside to cross drilling is the small radius is a stress raiser where cracks form and the rotor is likely to fail. I have seen it happen. If you have a close look at a Porsche Cup car, the rotor will have hairline cracks around the cross drilled holes. The holes need to be offset from each other or else they are likely to cause uneven pad wear. The purpose of slots is to resurface the pad to remove a thin trip from the surface. This effectively removes any glazing that has formed on the surface of the pad. These slots are also stress raisers as the material is thinner in these areas, and is prone to cracking. I have also seen this occur. My recommendations are plain rotors, plus they are cheaper too.

Pads

I can’t say it enough, select a pad that is fit for purpose. If the car is a street car, go for something up to 400*C, if the car sees the odd short burst and the brakes aren’t applied all that often and has a chance to cool down aim for anything up to 500*C. For the track and mountain runs look at the 800*C range. Before I mentioned glazing and outgassing, if you refer to Carroll Smith’s wonder list posted above, this will give you an idea of the affect and cause. I don’t recommend buying pads based on brand, it is always better to buy based on the specs of the pads. Would you buy a computer without looking at the specs to know what you are getting? Why should brakes (which are vastly more important) be any different? If the manufacturer doesn’t provide that information, ask them, and if they still don’t look elsewhere. I am surprised brake pad manufacturers don’t freely give this information out, unless they have something to hide ;) While looking at the specs you’ll see a funny looking ‘μ’ symbol. That is our Greek alphabet friend, physicists use, for the coefficient of friction. A higher the number the more friction there is (think skin on asphalt) while the lower the number the less friction there is (think ice on a plate). Just like an engine power curve the peak number may not occur at the peak of the heat range. That is why it’s worthwhile trying out a couple of different pads to get an idea of where this occurs. Or better still ask the pad manufacturer for the coefficient of friction curve. You’re unlikely to get it though.

Setup work

Before you embark on gathering setup information there are a number of rules to follow. Make sure you are consistent in your lap times. If your lap times vary by 1s each lap either the car is a pig or you’re not as good as you thought you were (traffic/rain/oil excluded). To fix this problem more track time is the solution. If testing on semi slicks or slicks, keep in mind they can improve or degrade depending on the number of heat cycles and tread depth, so this will throw another variable into the mix.

I like to approach testing by having a baseline setup. This setup will be one I use each time I go testing, until I have found my preferred setup. Head out and set a time on your base line setup. Then make one (1) adjustment, anything you want, as long as it is the one change. Head out again and note the times. Keep repeating until the day is done. Or until conditions change that testing data can no longer be gathered, eg. fluid down or rain et cetera. Each time you go out to test make sure you go back to the baseline setup to compare all the data between different days any conditions to each other. This will allow you to apply factors to the peak, average lap, and standard deviation. Yes I like to compare the times in those three ways. A car might have a fast undriveable setup giving a good peak time, but poor average time. The standard deviation is useful I find to compare, peak, slowest, and average times to each other (plus it’s a good check of how well you are as a setup driver, a low number means you are doing well). Repeat the process as long as it takes to achieve the best setup for your car and driving combination. Every now and again it’s still worthwhile trying something different to see if your data still matches your skill level as you gain more experience or change parts over time. Tyres can have a big effect on the data, so be very careful in this regard.

With all this new information you can now venture forth and conquer your foes on the track!

[david.]

Oh wow that was a good read, some very valuable information!

[4ABHGE]

Interesting read, not sure i agree with much of it though.

for example being 50mm higher in the rear is gonna make it plow on turn in and slide on exit. there is way too much of a height difference! and especially if the weight is a 65:35 distribution!!

[Kenshin X]

he did say that he liked that more and it depends on how u drive ur car on the track

my rear sits slightly lower than the front because i like people to think my car FWD can launch like a bombadore :P

but when the weight goes off from the back (seats spare tyre etc) car will raise abit more from the back but still a little lower than the front. This is when i brake heavily on the track the car will nose dive a bit therefore making the car level. i use different dampening on the track than i do on the road too so thats a factor. and last time i ran slicks too.

i'm missing the track dearly. and i will be hitting it soon as well. gotta get a few things sorted out first :)

but a good read SD. :D

[GHOSTIVO]

interesting read and a lot of useful information SD.

[ben yip]

excellent, my 2 cents about brake

http://www.myturbodi...q/brake_FAQ.htm

http://www.raceshopper.com/tech.shtml

http://www.zeckhausen.com/Testing_Brakes.htm

My next rotor is plain as well as the slotted one does not seem to have performance improvement, eating my pads and more expensive, thus the above article also recommened it

Edited October 10, 2012 by ben yip

[SuperDave]

Interesting read, not sure i agree with much of it though.

for example being 50mm higher in the rear is gonna make it plow on turn in and slide on exit. there is way too much of a height difference! and especially if the weight is a 65:35 distribution!!

It's all personnal preference. I've tried various levels of rake and I've found that works best for my setup and driving style.

It's an open debate, so feel free to point out where you disagree, I might learn something from it.

[4ABHGE]

Just saw this thread again.

Youre compensating with ride height because you have too much rear grip, which means your rear springs and/or sway bars are too soft.

From my understanding the tivos like an even spring rate front to rear. 7/5 is too soft IMO. If you run 10's all round the car will be easier to drive on the track (if you run semis)

This will also reduce a lot of body roll and you'll be able to run less front camber too which will aid in straight line and braking grip. If you have an open diff the car will pull better out of the corners thanks to the stiffer springs too, you may even be able to run a smaller sway bar which will give more front grip yet again!

Edited November 23, 2012 by 4ABHGE