SCCA STR 370z Progress Thread.... It can be done!

j-rho · 04-14-2015, 02:10 AM

In Street trim I was pretty happy with the balance. Ran Hankook RS3v2 front, v1 rear. The v2s were fine at room temp, the v1s needed heat - so the car would go from loose to understeer over the course of a run. That's some of what you see in my Street-class videos from last year - that, and I had just bought the car and was still getting used to it. Having a 305 out back sure was sweet!

Now in STR am down to 255s (245s at the Pro, all I could get in the Bridgestones). In San Diego things were a mess. Some of that was the surface, some was the tires, a lot was the driver, but the setup was off too. I think the car was pushing a ton on entry, which I wasn't picking up on. I was over-turning the wheel, so the car would quickly get loose on the power. The move to better tires and a better surface helped a lot between SD and the ET Pro, but so did changing the setup to something more neutral.
For the next event I plan to stiffen the rear bar (to free it up in steady-state) stiffen rear bump and rebound (to help liven it up a bit in transition and entry) soften front bump (try to keep from overloading the front tires on entry and getting into a push) and stiffen front rebound (to keep the transitionnal balance from getting out of hand). Spring rates will be leaving alone at 1100front, 700rear.
The quaife has been great thus far. A clutch type would only be making the problems I'm already dealing with, worse - even if it might be the slightly faster ultimate solution. The big front bar in street cut down most of the inside wheelspin, but even in a non-wheelspin situation, there is definitely something to be said for how a real diff distributes torque, vs a viscous or open diff.

Also have a couple electronics tweaks in mind which I believe should improve the car's lift throttle and trail-braking behavior.

j-rho · 05-18-2015, 12:01 PM

PPE long tube headers installed, bit of work involved...:
PPE Long-Tube Header install « J-Rho's '67 Camaro Z28 STX build

05-18-2015, 12:01 PM	#2 (permalink)
j-rho Base Member Join Date: Jul 2014 Location: San Diego Posts: 154 Drives: 1967 Camaro Z28 Rep Power: 12	PPE long tube headers installed, bit of work involved...: PPE Long-Tube Header install « J-Rho's '67 Camaro Z28 STX build carlitos_370z likes this.

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04-14-2015, 02:10 AM	#1 (permalink)
j-rho Base Member Join Date: Jul 2014 Location: San Diego Posts: 154 Drives: 1967 Camaro Z28 Rep Power: 12	In Street trim I was pretty happy with the balance. Ran Hankook RS3v2 front, v1 rear. The v2s were fine at room temp, the v1s needed heat - so the car would go from loose to understeer over the course of a run. That's some of what you see in my Street-class videos from last year - that, and I had just bought the car and was still getting used to it. Having a 305 out back sure was sweet! Now in STR am down to 255s (245s at the Pro, all I could get in the Bridgestones). In San Diego things were a mess. Some of that was the surface, some was the tires, a lot was the driver, but the setup was off too. I think the car was pushing a ton on entry, which I wasn't picking up on. I was over-turning the wheel, so the car would quickly get loose on the power. The move to better tires and a better surface helped a lot between SD and the ET Pro, but so did changing the setup to something more neutral. For the next event I plan to stiffen the rear bar (to free it up in steady-state) stiffen rear bump and rebound (to help liven it up a bit in transition and entry) soften front bump (try to keep from overloading the front tires on entry and getting into a push) and stiffen front rebound (to keep the transitionnal balance from getting out of hand). Spring rates will be leaving alone at 1100front, 700rear. The quaife has been great thus far. A clutch type would only be making the problems I'm already dealing with, worse - even if it might be the slightly faster ultimate solution. The big front bar in street cut down most of the inside wheelspin, but even in a non-wheelspin situation, there is definitely something to be said for how a real diff distributes torque, vs a viscous or open diff. Also have a couple electronics tweaks in mind which I believe should improve the car's lift throttle and trail-braking behavior.