ALFAGTV6.COM

[Mats]

Last races I hade the opening closed on my car just as an experiment and noticed a big increase in air quality in the cabin. Seems like the hole in the window is a very effective way to draw air in through every opening available in the car such as through the floorpan and the bootlid. Used to be a black spot in my balaklava where I breathe through it... Now not so much.

So focus on getting fresh air into the cabin. Carbon Monoxide will make your brain sloooooow...

[kevin]

First set of doors on car and fit well. Domingoes decided to put window guide from old doors in. Im going try with out.

[kevin]

Just like MD, Im also going through my share of problems on the 'rear' end of car. Come to think of it I did not have one problem when I had a standard 2.5 V6 in and raced whole season on same clutch and box. Must be a morale there somewhere.
Even though last race was relatively trouble free I could not get car into reverse when left track to go home. Started with the usual suspects of gaerlever touching body, shifting linkage housing etc. Eventualy I pulled the box out for the !@# time and found a roller bearing from the pinion stuck in the reverse gear. How it got there is vitually impossible as it would have to travel from back of the box through a tiny hole in the central housing(miss all the gears) and get stuck. Secondly how I could I race on a broken roller bearing. In order for bearing to travel to front it would have had to come out of its bakelite housing on assembly. I guess I should have checked this box before I put it in. Got it sent out from UK in good shape. Look in pic for bearing stuck in reverse gear and missing bearings out of cluster.

[kevin]

Race report - The ventilated rear discs with slots worked to well. I found the front of the car was very skittish uner heavy braking. The owner of AP racing UK(here in SA)concluded that the extra rear bite on brakes make the front lighter thus resulting in this problem. Two solutions were either I put in a brake bias or dial in more bump into the front shocks. Im going to video car next race to watch how its weight transfers under load. The car needs to squat evenly under braking. Its all getting to hectic for club racing but its still fun and making sense.

[Mats]

Race report - The ventilated rear discs with slots worked to well. I found the front of the car was very skittish uner heavy braking. The owner of AP racing UK(here in SA)concluded that the extra rear bite on brakes make the front lighter thus resulting in this problem. Two solutions were either I put in a brake bias or dial in more bump into the front shocks. Im going to video car next race to watch how its weight transfers under load. The car needs to squat evenly under braking. Its all getting to hectic for club racing but its still fun and making sense.

Plesae tell me how the car behaves under heavy braking without using slang.

If the car is starting to wag the tail it is definetly time to put a bias valve in to get less brake force on the rear.
You can not brake more on the rear and make the front end lighter, that is physically impossible, weight transfer is only dependant on CG height and deceleration. Is that AP guy in sales perhaps?

[kevin]

Mats, lets try figure this out. The back is stable under heavy braking , its the front that is - try slang here - moving left then right, twitchy(not itchy) . The only thing I have changed are the rear calipers which are working harder and I have brought the camber in to 2.5 deg from3.5 as I am running slicks. The problem is im not an expert so I am trying to listen to every one. Maybe the back is not working harder but I am no longer glazing rear pads due to slots in ventilated calipers on rear. I know glazing can occur from' trailing 'your braking,not bedding in pads properly . The back is not locking up but that does not mean its working harder than before.
Maybe the only way is to put in a bias and do a whole lot of emergency stops and annylise unless I can find out what the temperature difference between front and rear should be. I have not had this problem on front before so yeah im searching for answers.
Could also be a shock but there is no sign of leaks and Castors arms are solid.
Back to another point if you are using the front much more the car will dive more. This is the point the AP chap was trying to explain so if you are using front less there will be less of a nose dive thus front been technicall(marginally) lighter.
Please insight welcome from anyone thats why im posting this.
Cheers
kevin

[Mats]

Interesting. Sounds like you have outboard calipers, right?
One very important fact in this is that what I said in my last post is true, CGH and decel is the only thing (if wheelbase is the same) that change the loading of the front end. You can not change weight transfer by changing brake bias! Body attitude has really nothing to do with it, zero.

I would definetly try less braking power on thr rear axle as the first thing. Sounds very familiar in behaviour...

Just get an adjustable bleed valve and do laps at you favourit track, adjust it until it works. Simple.

[kterkkila]

What kind of pads are you using? Big vented rear discs may loose their temperatures on long straights and if pads are temperature sensitive, you may end up to unlogical behaviour. Doesn't mean that this is the reason for your problems, but one guess.

[MD]

Kevin,

You need some hard data about what's happening.

Beg ,borrow,steal one of these:

http://indonetwork.net/Andhika_Trade1/6 ... rtable.htm

[kevin]

Thanks guys. Point taken from Kimmo that these pads do need temp as they are ferodo ds 3000. As Kyalami is not as intense and heavy on brakes as our smaller tracks i can suspect less heat build up with the new ventilated discs is mostly the problem.Thus they are not biting as temp is to low. Mats I will put in adjustable bias but you got to to be a master at this to do adjustments while racing as you can lose focus of what you are doing.
Mats,Kimmo, MD do you set your car up before in practice or make continuos adjustments in race. Lets assume its a dry track conditions.

[Mats]

During training/setup before race.
Might be needed to adjust during race if the weather changes though (drying track).

Totally agree on the focus issue, wilwood also have used the worst labelling ever for the knob.

[MD]

Kevin,

I do have an in-line rear bias adjuster but it is all the way out and basically the rear pressure is full bore. By the same token I run Skyline R32 turbo brakes all round and locally made racing pads. This is a beautifully matched set up for the weight and balance of my car. I just cannot fault these brakes. They are awesome. Don't use a vacuum booster at all.

Sorry that this is not much help to you.

If you are experimenting with settings and pad formulations, then you need to measure the differences with a deceleration meter as I have suggested. Having a good hunch is fine but good data is better.

[kterkkila]

Usually we do the rough adjustment on warm up and some fine tuning during the race if needed. If it's dry all the day, there isn't much need to touch on bias. If pads were new (only bedded in) on start up, they may still change some on race. If weather changes, then the adjustment is must, as Mats also said. Our typical races last 6h, so the conditions use to change more than on short sprints.

[MD]

What I should ad Kevin is that my settings are for dry conditions only. Our tracks are predominantly dry as opposed to ciruits around the planet and I basically have a personal rule which is that I only sprint in dry conditions. I dont even have windscreen wipers to save weight.

[ALFA GTV6 GP]

Chicken-footed duck scared of water

A Chinese farmer is baffled after he bought a duck that has feet like a chicken and is scared of water.

Sound like anyone MD

HA HA

I have the same personal rule.
John