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Quickest way to change balance?

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m roj
(@rojid)
Estimable Member
Joined: 11 months ago
Posts: 95
Topic starter  

i need to induce some understeer into my car before my next outing (track day next week). 

here's my current setup: 

image

after i first drove it last month, the turn-in is pretty near exactly how i like it but on throttle mid-apex the rear is loose, and i need to induce some push-understeer back into the setup.

what's the quickest way to do this? Tyre pressures, wings, or dampers? 

With the wings, i find the way it's been worded in the manual confusing and poorly worded, or i'm being really thick (which is possible). 

In the base setup sheet in the manual, it says "Main, 3 out of 4" holes (from the bottom). 

So does that mean the 2nd hole from the top?! Which means the baseline setup in the manual sets the wing at a shallower angle?  So if i want a bit more understeer, i could increase angle of the main wing and set it at........1. Which would be 1 hole from the bottom. 

 

How about stiffening the front dampers/soften the rear? And by how many clicks? 

in the manual, referring to rebound, it says (Paraphrasing)

"more rebound resistance on the front = reduce mid-corner understeer". 

I want to Increase mid-corner understeer, so that means i need to do the opposite of what it suggests above. In order to do that, which way do i need to turn the rebound knob?

I think it's anti-clockwise - turning it anti-clockwise opens the rebound, and therefore makes the damper extend quicker, thereby reducing the rebound resistance, thereby increasing mid-corner understeer..........right?!

So then the logic is....if the rebound stroke is Less resistant, the weight is transferring away from the front quicker, and that's why it's increasing understeer. Correct? 

Conversely with Compression, if I make the compression stroke stiffer at the front, there'd also be less weight transfer to the front, also giving me more understeer. 

Therefore the conclusion is i can do 3 things at the track next week:

1. Increase the angle of the rear flaps, main and flap

2. Turn the front rebound a few clicks anti-clockwise, to reduce the rebound resistance, so the rebound stroke is quicker, thereby removing weight off the front quicker and giving me understeer on-throttle

3. Turn the front high/low speed compression a few clicks clockwise to stiffen the compression stroke, so less weight transfers to the front. 

Or have i just got all this completely wrong, and the rebound/compression adjustments only really affect the car over bumps and doesn't have much of an effect on car balance.....What do you guys think? What's the SR3 most sensitive to? 😀 

 

From the Intrax website: 

A: Rebound:
Close the rebound, by turning clockwise, until resistance is felt, the rebound is closed now. Turn anti clockwise and
count the clicks until our advised clicks or your own setting. We close the rebound first to be sure all dampers are
working from the same starting point. When you increase the rebound is, the shock will return slower.

B: High speed compression:
Turn anti-clockwise (to minus) until end, this is the softest position. Turn clockwise (to plus) and count the clicks until
our advised clicks or your own setting. With the high speed compression adjuster you adjust the way on high speed
compression movements.

C: Low speed compression:
Turn anti-clockwise (to minus) until end, this is the softest position. Turn clockwise (to plus) and count the clicks until
our advised clicks or your own setting. By turning clockwise low speed damping will increase which will make the car
have less movements.

 


   
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Rod Bender
(@rjbender)
Reputable Member
Joined: 4 years ago
Posts: 178
 

G'day @rojid 

As a first step, and without wanting to change too many things at once, I would change your rear springs to the front and vice versa... see what that does.  I'm running 110 fronts and 100 rears and I thinks its fantastic.


   
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John Parsons
(@parsonsj)
Prominent Member
Joined: 4 years ago
Posts: 573
 

One of the racers here gave me a tip about this exact thing. Remove the upper front dive plane, leaving everything else alone. That change transformed my SR8 from a spin machine to something in which I have complete confidence. 


   
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DavidF
(@davidf)
Reputable Member
Joined: 2 years ago
Posts: 222
 

Rake plays a significant role in the understeer/oversteer characteristics.  More positive rake (when rear ride height is greater than front) results in less understeer or more oversteer at high speeds.  Less positive rake has the opposite effect by increasing dynamic pressure to the rear, resulting in understeer.

I am familiar only with Gen 3 & 4 model SR3s and the setup process is very well described.  The earlier models appear to have different numbers for default ride height, at least according to the owner's manual.  

The damper setup can be a little confusing at first, but all adjustments are made from fully closed position.  Closed means fully tight until it stops turning by hand, the same direction as tightening a jar or bolt with standard threads.  So for example, 0 means fully closed, and -5 means five clicks from fully closed.  This applies to each of the three adjustments, and does not matter whether the damper is upside down or right side up -- tight is tight.

For wing setup on SR3, (gen 3 & 4) I never use dive planes in dry conditions; my main wing is set to 3 out of 4 from the bottom, and sub wing is set either to 5 or 6 from the bottom.  5 from the bottom is a little less sub wing than 6, and it is noticeable on the track.  Often I will start with 5 in the morning, and add wing in the afternoon when the track surface warms and track has less grip.

Note that if you modify: ride height, camber, or the spring perch adjustment, then you will need to do a full setup with corner balancing.  You can modify settings for toe, wing & dive plane, change ARBs (nick links), and damper settings without having to re-do the full setup procedure.  


   
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