I hope buddy doesn't spoil it lol
Originally posted by coryclifford
I run 1.5" wider tires on the front, and they're harder than the rear. Imagine 9.5" wide RM on front, and 8" wide RS on back. Cause they are just like that. 500 lb front spring with no sway bar, 450 lb rear spring with a 22mm bar. Car weighs 1695 pounds full wet. Idea for the skinny softer rears is to get some heat for ultimate grip. But it's mostly loose outta control until things settle in.
This set up is very autocross. Parking Lot racing where the speeds never really get too high. Very technical and lotta twisties around cones. These FWD cars will often run a bit of toe out in the rear to get that tail out there easier. With his described set up I don't think he has camber plates he makes no mention of wheel angles. if he did have then I wouldn't be surprised with about 1-2deg neg camber up front and crazy 2.5 to 4.5 deg neg camber in the rear, Toe out both up front and in the rear, decent amount up front but very small amount in the rear what I would equal to about -0.05 deg rear toe. Front will depend on the akerman bar so its hard to say, each car needs to be felt out zeroed out you can say.. Civic tho, Im guessing about -0.25 to -0.50 deg.
His set up is mechanically giving more grip to his front and also more grip with wider tires, but he keeps it in check with softer rear tire compounds. Its lose like crazy until the rear tires heat up and the car settles in...
Take the same car for circuit racing and maybe add a really really thin bar up front, zero out the rear toe, less aggressive on the rear camber and rear sway (too aggressive on a set up like that makes it much more difficult to trail brake) I would keep a bit wider tires on the front but run the front and rear with the same compound. Maybe a slight increase to caster angle.
The theory behind the set up is heavy front light rear attack the weight transfer at the opposite end for grip on front wheel focus and increased rotation. Front wheel drive the softer springs and softer sway (or no sway) bar up front give the front more grip, The stiff rear springs and sway make for less grip, & because weight transfer is handled as a total meaning whatever WT the front axle cant resist is handled by the rear axle. The stiff Rear end is maxed fast kicking out while the soft front maintains grip to steer through the corner with the tail end following along. This gives grip focus to the front as the front wheels steer and accelerate the car while also being on the heaviest side. If we were to attack the weight directly we would have stiffer springs where there is more weight and generate a car that under steers a lot with a heavy front.
Many of the 90's Gen FWD cars use Mac Pherson front struts with a multi link rear end on coil springs. A great way to set the springs up for performance when pushed but timid when not is to use progressive rear springs, so that when pushed they stiffen up but rather soft when not pushing it, BUT run Linear up front using the progressive rears to alter handling when pushed. More performance stiffer rear spring when pushed and more balanced when not being pushed. The multi link may confuse people with my statement as the spring rates on many of these cars look F>R on the low side but F=R on the high side, but the multi link set up vs the 1 to 1 MacPherson front end leverage factor turns that into more like F=R when not being pushed but F<R when being pushed because in FF cars a F<R set up is performance oriented for rotation... Without paying any real attention to his model Civic or whatever, I can say with confidence His SR set up of 500/450 F/R is more like F<R as far as stiffness after leverage.
A great example is the ITR, that uses this type of set up (MacPherson Strut up front with a multi link rear end on coil springs, running linear front and progressive rears the car will actually rotate more the harder you push it up to its limit obviously. IF both the front and rear were progressive and stiffness were F=R at all time then the car would under steer all the time as it would on a linear front and rear set up that's F=R....
Ifs funny how the bunch will like his post at GTP but cant tell you exactly why aside from a pic of his car in an auto cross. He also highlights a key point in TT or Auto-X vs Circuit Racing. His set up running softer compounds up front vs rear being crazy lose until it settles in is indicative of somebody Hot Lapping, the word HoT in the term is not about crazy hot fast, but hot tires. When a Fast single lap is the target we do Hot and Cold laps, the cold laps consist of us getting the tires optimum to start a Hot lap. Heating them up leaving the pits or cooling them down after a Hot Lap.
Circuit Racing we don't have the luxury of Cold Laps we race the whole race hot unless nursing a crazy lead and we don't have too. Certainly not if in 2nd or 3rd or 4th etc chasing a lead. The cars are set up a bit different considering the circumstances they will be driven in.. Tires are only cool leaving the pits but that's not a problem with tire warmers...