I've recently started tracking my car and i can honestly say that it's been the most fun I've ever had with it. I'd like to thank the forum for the wealth of (mostly ) good info here, especially in the stickies. Since we have no circuits in my country, i have to board a ferry to Italy to get to a track, but money and time permitting, I look forward to doing this more often. Till now I've been to two of the three tracks available in Sicily and have been joining a local club as a day member to participate in their timed events. The tracks I've frequented are the following:

Autodromo Di Pergusa in Enna


Autodromo Di Siracusa in, you guessed it, Siracusa


You can click on the pics for a better view.

The car is mostly standard but has the following modifications (amongst other things):

Avon ZZR tires 225/45 front 255/40 rear 17 inch on Mugen mf10
Spoon clutch + Flywheel, no clutch delay valve
Ferodo DS2500 brake pads Goodridge brake lines and Silkolene Pro-Race 2000 DOT 4 Brake Fluid
Cusco front and rear brace (not that I've noticed much improvement)
Spoon/J's racing exhaust system (currently cat back is stock)

BTW, car is an AP2 but in Europe we get the 2.0l engine and drivetrain.

I'm no Aryton Senna, but I'm getting quicker with every event I attend. Which leads me to some issues I have with the car, and which I would like to pick your brain on.

Issue 1

The car becomes skittish in the rear when braking from 180kph-200kph even though I heel and toe. It is particularily noticeable at the end of the long straights in Siracusa and before the chicanes at Pergusa. It doesn't help my confidence and as such I started braking earlier into the turns. The tarmac on both tracks is pretty good, but better at Pergusa. I tend to brake hard before entering the corner whilst the steering is still mostly straight so it must not be an effect of trail braking. Is there something I could do, possibly in my alignment to improve this?

Issue 2

Last time I went to Siracusa i forgot my cg lock and I was almost riding the door in the 180 degree turns. The car rolls a lot in corners, and I would like it to corner flatter. Also it has a tendency to understeer heavily in the tighter corners before the rear will come loose. It is very noticeable in the chicanes at Pergusa and the two successive 90 degree bends at Siracusa. I would like the car to be more neutral in corner entry and not to roll as much. I have looked at posts regarding sway bars but they are almost all about replacing the front bar with a stiffer one -which would make the car push more?

These are the reults of my last alignment, they are basically UK alignment with some added camber:



I also tend to keep hot tire pressures at around 2 bar front and marginally higher in the rear. Any higher and the car is all over the place, and loses grip much quicker.


Your thoughts are appreciated.

*edit* BTW - my car

 

Issue number 1 is due to brake bias and general setup of the car (alignment, tires, etc.). But as long as it stays under control it's not necessarily much of a problem.

Issue number two is similar -- you will quickly find the "UK alignment" is much too tame for hard track use. But also you will find that understeer suddenly shifting to oversteer is a basic characteristic of the car, and has been all along.

Also, most novice drivers take the slow corners too fast and the fast corners too slow. It could well be that you are just trying to get the car through the corners too quickly, and thus it is responding with understeer.

 

I like those Ferodo DS2500's but when you realy start braking hard on track they tear up - I changed to Carbotechs and they are much better. If you can't get them I think ferodo to do a DS3000 that might be better for track.

On my old car with uk alignment it would it push at the limit then let got at the back in a scary way. Most people here recomend to max camber front and rear. 0.20" toe in each side at the rear and 0 toe in front then max out caster after thats all set.
My 03 with this alignment is much less scary

I would go for that don't worry about tire wear - I used to chew up the outside edge of tires before the car was alinged because I hadn't enough camber now its more even

 

@mikegarrison and dan_uk

Thanks for the input guys. I noticed between sessions that the outside edges of the tires, particularily the front have the most wear. Something I forgot to mention since they are not very common in the US, the tires are what you call R compound. I think I'll have a go at increasing the camber and rear toe. What effect would increasing front toe-in have?

I also understand that the car basically pushes first then transitions to oversteer, my concern is that I would like it to push less. I have been thinking of possibly replacing the rear sway bar with that of an ap1 car since it is thicker and in theory should reduce roll and increase oversteer, but I haven't come across others that have done this. so don't know if it's a good idea.

Regarding the brake pads, I'm not too happy with the DS2500, I might have a look at the Carbotechs. I think I may have overheated the brakes as I started getting a spongy pedal towards the end of the session. Also my discs aren't cracked or worn down significantly, but they've been overheated and have turned purple/blue and i suspect they may be slightly warped - should I change them or have them turned?

By the way, regarding the slow corners fast and fast corners slow, this is something I suspect I was guilty of doing on a number of occasions. I have onboard video evidence that can prove it it's something I'm improving with every trackday.

 

More tire wear, among other things. Fronts should have zero toe. Rears should have as little toe in as you can get away with.

 

Camber and caster on the front are related in that the more caster you give it the less camber you can give it. So you want to get your camber up around 2.25 and then max your caster from there. With the stock suspension and swaybars you will really need to max the camber in order to get the tire to contact the ground in the corners.

You are right that all things equal a heavier front swaybar will cause the car to push more. But it's not always that simple. A heavier swaybar also limits camber changes, so if you can make it so your car doesn't roll over on the outside tire, you will get less understeer, not more. One of the big limitations of the S2000 is the lack of front camber adjustability. It's hard to get much over 2 degrees in my experience, especially as you dial up the caster. So a bigger front sway may help you.

The best solution is to change the tire stagger since that is where everything starts. 225/245, 235/255, 245/255 or 255/255 depending on what wheels you have. Since you have MF-10s I doubt you want to change wheels. I don't know what size your fronts are, but if they are 7.5" you could run 235/255, although a 235 tire on a 7.5" rim is a bit at the edge and you lose some of the feel of the tire. It probably doesn't sound appealing but 225/245 maybe your best bet.

 

Don't forget that thing which aren't that simple are not that simple either, and everything has compromise. The big anti roll bars do reduce the camber change in roll, but they have negatives; increasing the roll resistance will increase lateral load transfer, decreasing the overall cornering force that is available. It also compromises the car's balance over bumps.

 

Thanks, at my next alignment I'll make it a point to max camber then work my way from there regarding alignment. I don't use the car much on the road anymore so I'm not too concerned about wear or comfort.

Regarding the rims and tires, yes the fronts are 7.5 inches and the rears 8.5. I went for the widest tires I was told would be safe. The tires still have a few more track days in them and I'm not too keen to change either them or the rims just yet because of cost.

Hmm regarding sway bars maybe I think I won't fiddle with the sway bars just yet, it looks like it may be less simple than i thought. It's probably best to leave them as is at this stage since it is not a modication I can alter at the track if i don't like the result.

BTW can anyone chime in regarding my brakes question? Come to think about it, I' ll probably just change the rotors as well since I'd like to try out a set of Carbotechs. However for future refence, if the rotor gets heavy discoloration (a blue/purple wavy pattern) does it need changing or turning?

 

Mike, never experienced that. where do you get this conclusion from?!

what year of car are you talkin about?

 

^ he's talking about the the AP0 and AP0.5, 1989-1998 if I'm not mistaken