So I would say I am an average tuner so I know bits. Anyway I have been turning a Holden and I have also tried an Aston Martin and they both wheel spin loads and I can’t seem to tune this out and wondered if anyone else ah come across this?
Just some more details its not from the line its spinning up to 3rd or 4th gear, I presume it has something to do with the power and the grip or something like that. I have got racing tyres on etc but I am at a bit of a block if anyone has any pointers or have come across this before.
Not bothered about spinning off the line because I can control that its during or after corners. I thought it might be the diff but I have all but taken it down to nothing and its still spinning up.
If I coast around a corner and drop it to say 2nd gear to keep the revs up then put the power down the tyres light up and then even if i quick shift to 3rd its still spinning up.
If you have any room to work with, reduce bump stiffness. if that causes bottoming out raise the ridehight a bit.
this allows more weightshifting towards the rear of the car which should give you a bit more grip. Although it might effect on the cornering ability of the car elsewhere in the corner.
How ever never smash the throttle from no throttle to full throttle. The problem might solve itself just with smoother throttle control.
Try adding a healthy amount of negative camber on the rear and loosen the rear a little via the roll-bars and spring stiffness - also the bump as HLR Jugg mentions above. Also, try lowering tyre psi on the rear a little.
Is it happening in a specific gear, or at a specific rev range? I recently spent a LONG time toying with the suspension on a celica trying to combat understeer, only to realise the problem was with my gearing mainly, even under smooth throttle control
Well i only race the Lotus E21 but i recently started racing with no tcs so i had trouble getting the power to the tires, so what i did was lower the spring rate until i noticed i was bottoming out the raced it just a few clicks above that then kept the rear about 10 lbs stiffer then the front for turn in, and also your gearing plays a part longer gears seem bad but if your in your torque band its not a problem i run mostly 4 gear tunes in the Lotus now and i have alot of top 5s on the leaderboard hope this helped also ill leave this reference guide i use when i tune
Tires give their best grip around 32.5-34 psi on warm tire. 28 psi sounds fairly reasonable, IF they “inflate” bit over 4 psi, from cold tire to warm tire.