The Dark Art of Suspension Setup

Suspension Tuning is a critical part of getting the ultimate performance package, it is even possible to have a more competitive car then a rival with superior upgrades by having a well-balanced set up, which maximises the available grip levels. It all comes done to extracting the best from what components we have and making sure they are well set up for circuit conditions.  

Lancia Delta HF Integralie 16v- Richard Thurbin- Italiano vs Inglese All comers Race

With our upgraded suspension components, we have the potential for increase cornering capacities, by fine during the overall suspension balance and even help to eliminate weaknesses in the car chassis or handling characteristics. Suspension tuning can be used to change the way the car behaves on different conditions, playing to your car´s strength to gain a competitive edge.

Lancia Delta HF Integralie 16v- Richard Thurbin- Italiano vs Inglese All comers Race

We can reduce understeer and oversteer characteristics with the adjustments of anti-roll bar (sway bars), bump and rebound, ride height, spring rates, corner and static weights. The combinations are extreme and the more adjust-ability you have with suspension upgrades, the more the need to get the suspension tuning correct. The suspension´s main role is to keep the tyres in contact with the road surface for as long as possible and to optimise the contact patch of the tyre. We can increase acceleration, braking and cornering forces by manipulating suspension adjustments.  

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Setup is always a compromise between wet and dry. In the wet the quickest car is soft, compliant and is able to move the cars weight around by loading up the tyres more, generating heat and enabling the car to slide in a predictable, smooth and compliant manor. In the dry the car needs to float and dance around an apex with every driver’s input being immediately transmitted in to the tyres and tarmac with the corresponding response sent back with the same haste. Corrections on the edge need to happen without thinking in a way which is only possible when the inputs and corresponding feedback is instant. As a result, the car needs to be agile, the rear very light, always wanting to to swap ends on corner entry and the apex and exit controlled through liberal use of power.  

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 As a benchmark we started the car with slow & high speed rebound on full soft, rake level, front camber -3.5 degrees, rear camber -1 degree, front tow -1 degree, rear tow parallel and caster was set to make the car as long as possible. Tyre pressures are set to arrive hot at 31PSI. We had three sets of springs with us and put on the medium set. This is our standard wet setup and proved very effective allowing us to dominate the two wet races we have taken part in, “beasting” our competitors by seconds per lap.  

We had some help from Rob Wheldon from Raw Motorsport who drove the car and helped hone down the setting changes needed. We completed 6 sessions in total and made the following changes to the car:  

Session 1 

– All Round 

  • Slow Speed Compression: Full Soft 
  • High Speed Compression: Full Soft 

 Session 2 

  • All Round 
  • Slow Speed Compression: Full Soft + 6 
  • High Speed Compression: Full Soft + 20 

 Session 3 

  • Front 
  • Slow Speed Compression: Full Soft + 12 
  • High Speed Compression: Full Soft + 20 
  • Rear 
  • Slow Speed Compression: Full Soft + 6 
  • High Speed Compression: Full Soft + 20 

 Session 4 

  • Front 
  • Slow Speed Compression: Full Soft + 9 
  • High Speed Compression: Full Soft + 20 
  • Rebound: Full Stiff -12  
  • Rear 
  • Slow Speed Compression: Full Soft + 6 
  • High Speed Compression: Full Soft + 20 

 Session 5 

  • Front 
  • Slow Speed Compression: Full Soft + 9 
  • High Speed Compression: Full Soft + 20 
  • Rebound: Full Stiff -20 
  • Rear 
  • Slow Speed Compression: Full Soft + 6 
  • High Speed Compression: Full Soft + 20 
  • Rake: + 5mm up 

 Session 6 

  • Front 
  • Slow Speed Compression: Full Soft + 9 
  • High Speed Compression: Full Soft + 20 
  • Rebound: Full Stiff -24 
  • Rear 
  • Slow Speed Compression: Full Soft + 6 
  • High Speed Compression: Full Soft + 20 
  • Rake: + 10mm up 

 In short, the car is overall much harder, the rear harder still and slightly lifted higher than the front. The difference in driving characteristics is astonishing and it made the car over a second a lap quicker in the dry than the baseline wet setup. Corner entries can be attacked much more confidently with a fidelity not present with a softer car. Apex speeds are also up and power can be applied earlier and harder leading to the all important corner exit speeds increasing. As a consequence, a driver is able to make smoother, smaller inputs in to the brakes and steering, this in turn puts less peak load through the tyres, reducing sliding and increasing their life before going off over a race distance. 

It isn’t perfect through. Through the slow to medium speed exits the car rolls too much and causes tramping when loaded through a corner exit and on hard power. A stiffer anti-roll bar is on the shopping list over the winter and given there are no off the shelf parts it will be a custom job for a metal bender. Anyone who has seen a standard anti-roll bar will know how hard a job this will be! 

rthurbin

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