Bens handling the big issues.. N12 Coilovers (56k + drool)

[Callumgw]

Hi Glenn,
No I hadn't, but I just had a look. Most of the returns didn't look like they'd work for ours. By that I mean their layout only, not looking at trying to bolt one up. This page gave a couple of good looking option though:
http://www.cardomain.com/shoplist~b~NRG ... e%2520Bars

and the Subaru H layout may work, but the rear of the two cross bars may need carefull consideration to make sure it does interfere.

One of the issues we have that these boys don't is getting past the exhaustFor my car the lowest metal bits on the front of the car is the tow points and the exhaust at the front bend. We certainly couldn't go under that, we'd have to go round it.

C

[Callumgw]

found another article I've previously red:

http://www.whiteline.com.au/docs/articl ... race%22%22

[The Renegade]

Yeah, I'd never paid much attention to the lower bracing stuff before, just noticed it. But I couldn't even picture in my head what the underside of my Exa looks like, so I've no idea what would fit and what wouldn't. Might crawl under it on the weekend though and have a good look.

[The Renegade]

found another article I've previously red:

http://www.whiteline.com.au/docs/articl ... race%22%22

I just had a read of a bit of this and liked it.
So I've saved the whole thing! I'm going to have a read of it tonight.

Do you have the links to the other parts of that?

[Callumgw]

I remembered to drag out those books I mentioned. One is called "Carroll Smith's Engineering in your pocket" a great littl flip book for problem solving. Here's an example:

Corner entry understeer: Car won't point in and gets progressively worse.
-Driver braking too hard, too late
-Relatively narrow front track width
-Excessive front roll stiffness (spring or bar)
-Relative lack of front download (excessive rear download)
-Incorrectly adjusted packers or bump rubbers (car rolls onto packers)
-Insufficeient front toe (in or out)
-Insufficient Ackermann effect in steering geometry
-Front roll centre too high or too low
-Insufficient front damper bump force
-Insufficient front toe (in or out)
-Excessive dynamic positive camber on laden (outside tyre)

An interesting quote from Milliken (out of - Race Car Vehicle Dynamics) is:

pg41 section11 paraB
Adjusting the anti-roll bars is a common way to change the stability of a car in a steady turn. This works through the load sensitivity of the tyres-apair of unevenly loaded tyres has degraded lateral force performance compared to the same tyres with the same total load split evenly between them. Thus, to degrade lateral force capability of the front [rear] end of a car the anti-roll bar is stiffened on that end. This works until the inside front [rear] wheel is off the ground and the front [rear] track can provide no additional roll moment.

This brings me to a interesting point, increase the track width and reduce the effect forces on that end of the car and thereby improve the roll performance! I did this on mu Starion by fitting "wide body" Starion suspension to my Aussie narrow body car!

After saying all that I didn't find the specific comments I was looking for, but the para above aludes to it: I think the spring rates mostly effect turn in rate and final roll angle, whereas the sway bar have greatest effect on proportioning the laod between the tyres for any given angle, thereby providing the "balance".
Note though that there is coupling between the effects of the sway bar and springs...so things are not quite this black and white, but ok as a rule of thumb.

C

[Ben Hewitson]

hey Callumgw, yeah i was going to say that i have too much camber in a turn. i can feel the front wheels digging 'under' the car and i'm shredding the outsides of my tyres. I believe that i dont have enough camber on teh turns.. so i'm going to have it adjusted soon and then use my strut brace to fine tune the camber.

also to note is my car is about 55mm lower at the front and 50 at the rear. the sills sit flat with the ground and i have abotu 10mm above my 195/55/15's and the lip of the guard. the eyebrow height is about 330 on the front and 320 on the rear..

i'll definately take on board what you mentioned about the camber though. i think this could be my problem.

also those under body braces are very cheap..? is it just me or is that cheap..?... i reckon we could go all out and i dare say to get the car to handle well we'd all have seam welded chassis', 6 point roll cages, and a whole host of other stuff... but for the road, its all too much..

[Wes]

[quote="Ben Hewitson"]hey Callumgw, yeah i was going to say that i have too much camber in a turn. i can feel the front wheels digging 'under' the car and i'm shredding the outsides of my tyres.quote]

Ben, i think you meant toe in at the front?

Oh, hows this guys, my rear end was..... (noting that the amount of toe in should be 3mm each side!) but mine was chewing the SHIT outta my Yokie C-Drives outter half of the tyre and wasnt handling well at all and so EASILY step out the rear end in the wet.....all coz i had a total rear end TOE IN of OVER an INCH! :S:S:S:S:S:S:S:S

It was 8.4mm on on side and 16.7 on the other!!!
Needless to say i had to get it sorted and did, but they said the bushes were still ok (????)
Anyway i just said ok, die grind out the bolt holes and relocate where its needed to gain some positive camber back and to get the toe back out to where its meant to be again.
He said it would vastly help handling over all and of the front end and it def has!

Wes

[Paul Smith]

Ben, do you think it's possible your front springs are too stiff?

[Ben Hewitson]

Ben, do you think it's possible your front springs are too stiff?

there is every possibility but i dont think so. they are fairly suple on the corners and the bumps. and they aren't too much like jack hammers. i've driven up the freeway next to my car (driving gf's car and she's driving mine) and noticed how it rides. it definately looks like a skyline with the little stammers and heavy spring movements that it makes, but it still rides up more than 2" of float on the smooth stuff.

i'm thinking that i have the springs set too soft, as Shane86 has his set about 1 to 1.5 turns stiffer than i do. he also has the hard-soft settings about 1 click softer than i've got mine.