I also reckon your spring rates 160-170 are way to soft. You must be getting some body roll when cornering which will definately effect the handling. I personally think you would need to run 300Ibs min if you want your car to go around corners at max speed.
This is something that drifted across my mind yesterday, as I remember the original poster made a post a while ago trying to sort out his bodyroll. Did this issue ever get sorted to start with, or is this thread the extension (in a manner of speaking) of the previous one?
In reality you cant give advice on spring rates, camber and castor etc.... without knowing some key things like for starters, the cars weight, ride height, drive line, tyre sizes, weather the koni's have been revalved, weather the rack and steering knuckles were modified to take a V6 chev engine, was the cross member modified to do any suspension relocation during the engine swap.
Yes, it is true you can't give EXACT figures without knowing exact details, but what you can do is give a guideline of a ballpark figure for a starting point, and an idea of what areas to look at to start improving the issues being detected. You can do all the maths you like to work out the 'perfect' suspension setup, but ultimately the person behind the wheel may not like it, and want something different anyway.
I was talking to a mate who races nationally (and competitively) in Formula Ford the other day, and he was talking about this exact fact - there are a small handful of people in the field who use 10psi more than the 'accepted' figure in their tyres, and it works for them to the point that they can post times in the top part of the field. Doesn't work for him though. That's just one example he gave, but there are apparently other people who run suspension settings that have the rest of the field scratching their heads and asking 'How the ___ does that work?', and again they make it work. At the end of the day though, they all started from a guideline figure of a REASONABLE handling car, and worked out from there what they needed to suit their strengths and weaknesses (including tyre management).
People, IF YOU DON'T KNOW WHAT YOU ARE TALKING ABOUT - DON'T POST! Angry
I DO NOT want to see in-accurate information posted on this site.
Erm... sorry to everyone on here, but I actually agree with Lurch on this one, I feel the same way about it, and have the same problem on the Alfa club site.
The easiest way to put this, is to use a Zed manual conversion for example. People will swear black and blue that you HAVE to change the whole pedal box. I know for a fact you can simply swap the pedals themselves over in a late car at least. Now, if you are paying a mechanic to do the conversion for you, and he isn't too bright at working things like this out, he's going to look around for how to do it. Whats he going to be told? Pull the whole pedal box out, and so away he goes. 3 hours of labour and a lot of swearing later, he's done. However, he could have done that part of the job in 30mins by swapping just the pedals, and guess who pays for the extra 2.5 hours of labour, at $90 an hour? Thats right - YOU do.
Now thats only a couple of hundred, but imagine if you go and buy a reco gearbox from some other model car because someone tells you it will bolt straight in. A thousand or so later, you discover that there is no possible way to fit it. Or someone tells you that you need to buy extra special race tyres at $600 each and its guaranteed to fix your understeer, and you put them on to find these tyres are actually more sensitive to the pre-existing setup issue in your car.....
Gentlemens ,great response so far,hopefully by the time we collate ,decipher and eradicate we will have some concrete and accurate race suspension requirements for the beginner to motor sport.Now to answer some queeries.Tyre temp. after 5 laps of Winton long track , recording 1min 50 sec.laps,inside temp. 47 degrees ,outside 53 degrees. The wear pattern was pretty even across tyres slightly less inside, outside had scollaping and eventually chunked off pieces 1cm down side wall , only on left tyre.The tyres were completely stuffed after approx. 200kms of which 130 were track wear.My Z is running a 3.9 lsd diff. The springs are 160lbs front and 170lbs rear. The only time I could get any rear drift was steering around the long left hand sweeper with throttle, the set up then was fully hard front and half a turn less on rear konis,which seems to be a... about .I feel that the starting point should be 3 to 4.5 degrees neg. camber, lowest front sway bar setting.Does anyone know about toe out ?
The tyre temps definitely suggest more negative camber would be helpful, although I'd personally shy away from going towards 4 degrees you suggest for two reasons:
1. I suspect that to get that much you would require some fairly extensive mods to your front struts, meaning a lot of money, and I think it should be possible to get a well handling car which will be awesome fun on the track without needing to spend that much - someone mentioned slotting the holes where the strut tower bolts to the body, which is definitely a cheap place to start, although I don't know how much camber that will actually give.
2. If you use it on the road as well for a semi daily driver, it will probably be a pain to drive, and if you have normal road tyres for this use, they will be destroyed pretty quick with that much camber.
The left tyre wearing considerably more is interesting, whether that could be attributed simply to a combination of bad setup and the fact that about 2/3rds of Wintons corners are right handers, or whether its a pointer to something else I don't know.....
Finally, I know a group S alfetta which has been dual entered for 4 sprint days with Bridgestone RE55s on it, and those tyres are only just starting to lose their outer edges. I don't care how cheap and crappy your tyres are, if you can kill a brand new set of semi slicks in one track day, something is very wrong.