Koni Adjustables/ARB trackday settings

The great Mr Prost, drove very smoothly and very quickly, all about using the controls right

The one great thing I found with my first trackday car was the difference tyre pressures made. Like GVK said, its free to do, just take a little time and a pressure gauge. Gary and I were doing this at the same time, we were aiming for 25 (whats the key stroke for degrees again?) hot, so that was about 19 cold. You need to be aiming for a even pressure all round to start with, and then for that pressure to be consistent all session. The higher the pressure, the more greasy the tyre will get - this means you will start squealing and skating more as the session progresses.

As for the suspension ARB question, I can only pass on what I know.

As has been said before, the harder springs, will lessen the need for ARB's. The problem with doing this is that spring sets are expensive, and cost time and effort to change at a trackday to experiment with.

So, an easier way to effect the same as harder springs is with ARB's. What I mean by this is that it achieves the same aim, ultimately that of better tyre control, the contact patch that Golden mentions above.
From personal experience, I used to have a very similar powered Golf to GVK, and we are at a similar level with our driving skills (unless he's been sandbagging ). The cars were our only difference, mine being on lowered fixed suspension (damping and height), Gary being on fully adjustables, and having Eibach ARB's. The end result was that I was understeering and losing ground on anything but fast corners, and losing time to him hand over foot.

I now have eibachs on a road golf, and when I drive my missus' standard one (the only difference between the two are the ARB's) the difference is very marked. What I am trying to say here is that they will make a real difference to your on track experience. They wont be a substitute on an all out racer, but they are good for guys like us who are out there to have fun and enjoy.

If it was my money (and I have just done something similar to this) I would buy a slightly thicker front bar (an ibiza 23, tapered to 20mm at the ends to fit in the standard ends) and a neuspeed rear bar. You have the choice of a 25 or 28mm, and the benefit of both of these are that they are adjustable, 3 position. They are 70 and 175 respectively (front and rear) I beleive. The neuspeed being from Awesome Gti Store, the UK importer.

At the end of the day though, its up you in what you want to spend and achieve. The advice is out there (in other places from here) its up to you how to use it

I hope that garbled post help you

Chris

P.S. Did you go anywhere with the cams btw???
Edited by: ChrisP

 

Remember.. a professional tennis player will beat you with any racket...



So we should all accept that Mr Apex could whoop our arses on any track in his lardy mk3... so ignore his posts.



Golden just writes too much, but i'll sum up what he says.

"ARBs DO NOT make you car handle better... but they alter the way your car works and that makes it handle better.... so the ARB's have nothing to do with it. Despite the fact that if they weren't there you wouldn't get the outcome you do if they where. (Confused!?? I hope so )



GVK is bald and mad... so he doen't count. But when i didn't have ARB's i couldn't get close to him on corners. Now i have them he holds me up




Chris is tall......
Edited by: Tubthumped

 

Sorry prof, just re-read that and it's about as clear as mud!

The point I was trying to make was that although, as you say, traditonal wisdom would suggest that fitting a rear bar would increase oversteer that is on vehicle that has reasonably stable dynamic geometry. If you stiffen the rear on an otherwise standard car you may reduce overall body roll a little but this could actually increase the yaw angle at the front and induce even worse dynamic camber change.

The key thing to remeber is that antiroll bars do not improve overall grip levels. It's just that on a McPherson strut FWD they help to minimise an inherent fault with cheap pooe suspension.

 

Due to financial reasons I'm now doing the engine in two stages. Stage one is a blueprint and ported head with std injection and twin exhaust cams. Stage two will probably involve twin carbs or TBs and around a 276/278 cam. I have a friend of a friend who (as his wife says) makes car parts, actually he works for the company that produces exhaust manifolds for the Toyota F1 team. He is looking into if he can produce a cam for me.

 

well, a car is quite a lot more complicated device than a tennis racket!!

every race driver is confident almost to the point of arrogance, altho i try and keep myself in the confident zone! my mkIII would beat a push bike at the mo as its broken, but seriously, i don't think it would lap anywhere near as quick as your (and gvk's) mkII's...its a standard car still pretty much. what i wouldn't mind doin tho is having a car swap with one of you for a session.

 

Sorry Golden, but if prof's was mud, yours is tar.

How can you increase yaw angle at the front of the car?

 

The mud comment refered to my post not profs you doughnut.

Thats the best way I can describe it, it's the swaying angle change at the front of the car.

Why do you find it necessary to try and pick holes in every post I make, I don't have time to write an entire book on suspension in reponse to every post on here.

You've already proved you know about as much as stoned Nova driver.

Now if you don't have anything costructive to say, please don't waste my time and the space on this site.

 

Doh! Realised that upon re-reading. Asking for that one really.

Genuinely interested as to what you mean, the theory and application behind it. When you say things like "change of yaw angle at the front of the car" it makes little reference to what you mean. Yaw is the angle the car is pointing in, in relation to the momentum of the car. How can it be at the front only? Unless you are talking about something different! Thats why I questioned it.

Admittedly my knowledge is mainly studied rather than practical so am asking these questions from people who have done this for real. I could post some topics with one-sentence questions? Asking if I should do something or not, or whats the best, but this doesn't really teach you much and you end up with a list of facts but still non the wiser.

This is why I probably come across as "stoned nova driver". Rather than being contented with what you have said, I either want more information or question certain things you have posted, and may seem like I am pulling apart your or female doging about little points in your posts. This is not because I think your making up excrement, rather I am asking why?

 

That was better than yesterday's joke

You think i'm gonna let someone who think's they're invincible drive my car round Mallory just to prove a point????..
Edited by: G_V_K

 

Ahh, reading Golden's and Jettin's posts tells me *why* we don't have such discussions

 

Right - here it is

how many people here have driven a car round a track with basically std suspension and just eibach arb's front and rear?



(puts hand up) it's great, really really a world better than std.



who's driven one with totally std suspension, std front arb and eibach rear?


(hand up again) - it's not so great - the photos look great, inside rear wheel well up - but!!!!! as golden said it just means huge body roll at the front, appaling camber change, and the car would either understeer badly, or snap into oversteer - not balanced.

 

http://forums.vwvortex.com/zerothread?id=621342

golden grap a 6 pack and have a look through this lot, amid the ramblings srsvw and oldman TDI seem to make some good points...what do you reckon?

 

To Jettin'

Ok, I'm sorry for being short, you just seem to have a nack for windding me up

I've tried writting an explaination to this 3 times and can't think of an understandable way to explain what I mean.

I can picture it in my head but can't explain it very well. I think what I was trying to say is that if you stiffen the rear, weight will still try to transmit through the springs, so if you increase stiffness at the rear more of the weight will try and transmit through the front outter corner, increasing load on that tyre but also casuing just as much body roll, which is what tips the wheel over and stuff the tyre contact patch.

This was why I made the point that it's very vehicle specific. If you were to stiffen the rear on a vehicle with quite very little body roll already than it would have the effect prof mentioned, but on a car with alot of body roll it will acheive next to nothing as you still end up with the high camber change at the front.
Edited by: Golden

 

i managed to explain *exactly* what you are saying to prof earlier - but can't remember how



basically it's what happened at donny - rear arb only *causing* understeer


too many comments and generalisations are made about suspension. *everything* affects *everything* else.


nothing works in isolation - so no change can be considered as truly "independent"

 

I know, and most of its unintentional. I will put more thought into my posts in future as I am not a person who intentionally tries to annoy people.

Anyway, I get what you mean now with regard to only having a large rear ARB, it causes more torsional twist through the body shell, and the front of the car is the place that this is most pronounced.

I think at track level the bodyshell become a much bigger factor and if you start trying to force a handling balance (over / understeer) that is quite different to stock you are going to be putting alot more stress on the shell and can only lead to reduced grip and unpredictability with the handling.

 

oi - shut it! i don't think i'm invincible, i just know a thing or two about drivin fast.

 

One thing i want to look at is the difference the make of suspension hs on the car's handling.

Me and Gary are almost identical set-up wise... but GVK seems to kick the back out more than LET... maybe it's his better driving, but i suspect his FK's give the car more of that charecter than my SPAX do....?

 

I skim read it prof, I wouldn't trust a yank to tune a piano let alone a suspension setup.

Seriously though, there are a few good points in there but nothing that hasn't been said on here before. They seem to only be able to talk about suspension in vehicle specific terms, rather than understanding the bigger picture.

The basic points mentioned though are worth mentioning again.

ARB's do not directly improve grip levels but by reducing camber change from body roll there is a net improvement.

Don't lower the car to the point that the lower arms go past verticle, this screws the roll centre and causes all of the sprung weight of the car to be transfered through the springs/bars causing excessive body roll.

ARB's (if you ignore the fact that on VW's body roll screw the camber) are only a tuning aid to balance the car to the drivers taste or driving style.

prof was there a specific bit you wanted me to look at on that thread?

 

i am so sorry golden, but i had to do this...

Vertical Wishbones? it'll never catch on...

 

thing is tho, there's no such thing as identical cars. even if you have exactly the same kit, set up identically, there's always slight differences in the chassis that makes the cars handle slightly different. for example if one cars had a crash it could have fractionally bent the chassis.

we once took all the suspension and the wheels of one nova and put it on another. the first one oversteered loads, the other then understeered a little!
Edited by: acf8181