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My Tarett monoballs make a clunking noise when getting on the power coming out of turns.. but it's been essentially the same (you might say stable since installation for 9 track days. Is this what you were experiencing Joe?
Congrats Joe on the new PB!!! I guess I need bigger turbos
You just need to come out to the track!
Originally Posted by 2fnquik
My Tarett monoballs make a clunking noise when getting on the power coming out of turns.. but it's been essentially the same (you might say stable since installation for 9 track days. Is this what you were experiencing Joe?
Most of the clunk happens running over minor bumps on the road, but you can hear it during transitions in turns on track. It started with a clunk and then the squeak started. Was relatively stable the first 4 months, but then got much worse over the last month. Sounded like something was broken in the suspension. Monoballs should not make noise. Tarret has a bunch of bad monoballs out there. QC is a problem. If mine fails again, I'm going to replace with RSS
The track has some very fast turns and as much as I can feel the understeer in the medium speed stuff (50-60mph-ish) it seems not to be an issue at higher speeds (95mph+).
I don't know if it is me just not pushing it hard enough when going faster (fear slows me down) or if there is some influence of aero on the general balance of the car at higher speeds.
As to the tire wear here's how the CS2s look after 180 miles of clockwise track action + some wet laps and 3500 leisurely street miles.
The track has some very fast turns and as much as I can feel the understeer in the medium speed stuff (50-60mph-ish) it seems not to be an issue at higher speeds (95mph+).
I don't know if it is me just not pushing it hard enough when going faster (fear slows me down) or if there is some influence of aero on the general balance of the car at higher speeds.
As to the tire wear here's how the CS2s look after 180 miles of clockwise track action + some wet laps and 3500 leisurely street miles.
Wow, spa looks like such a beautiful and fun track! Thank you for sharing. Very nice driving!
Understeer on slow corners cannot be totally dialed out on this car, but med/high speed turns can be addressed with simple sway bar setting changes.
Your tire wear looks appropriate for a car that was driven well/hard on track. The outer edge wear is slightly accelerated due to stock alignment settings. I would expect the tires to look like that after 250 miles of track use with camber settings in the -2.7 range. As expected, the rear tires look just fine.
Day 2 on my latest and hopefully final setup on the GT4.
I took the car back to Laguna Seca and was able to beat my prior best lap time by 0.8 seconds.
Looking at my data from my prior best lap of 1:39.2, my time was gained by getting on the throttle much sooner and harder at T4 and using a single apex for T2.
1:38.4 in blue and 1:39.2 in red
I was able to run 1:38.4 and 1:38.7 back to back. If you look at the video, in the first lap I did a single apex and the 2nd lap was a double apex. The data below shows about 0.5 seconds faster because of higher exit speed with the single apex vs the way I did the double apex. In the first lap, there was a yellow flag at dirt at T5, which made me brake earlier and caused a slight slide in the corner. This costed me 0.5 seconds. The 2nd lap I lost 0.5 seconds by doing the double apex and gained 0.5 seconds by entering T5 faster and smoother. I think if I switch to single apex alone I can dip into 1:37. I'm clearly not using the entire track on exit still, which means I can be more aggressive with power and track out. In the right hands and conditions, I'm fairly certain the car can do 1:36. I'm shooting for 1:37 next time. Here is the graph of my 1:38.4 (blue) vs 1:38.7 (red)
The 20" RE71R are holding up fine so far. 10 heat cycles on them and 230 track miles. The rears look like they are even. The fronts still have some beveling of the middle band and the outer edge is still wearing faster than the inner edge, but at a slower rate than before the tarett springs. I would love to get 25 heat cycles out of these without having to flip the tires on the wheels. Let's see how it goes.
Front left:
Front right:
Rear:
Front right tire shot at angle to show the beveling and edge wear
Day 2 on my latest and hopefully final setup on the GT4.
I took the car back to Laguna Seca and was able to beat my prior best lap time by 0.8 seconds.
Looking at my data from my prior best lap of 1:39.2, my time was gained by getting on the throttle much sooner and harder at T4 and using a single apex for T2.
1:38.4 in blue and 1:39.2 in red
I was able to run 1:38.4 and 1:38.7 back to back. If you look at the video, in the first lap I did a single apex and the 2nd lap was a double apex. The data below shows about 0.5 seconds faster because of higher exit speed with the single apex vs the way I did the double apex. In the first lap, there was a yellow flag at dirt at T5, which made me brake earlier and caused a slight slide in the corner. This costed me 0.5 seconds. The 2nd lap I lost 0.5 seconds by doing the double apex and gained 0.5 seconds by entering T5 faster and smoother. I think if I switch to single apex alone I can dip into 1:37. I'm clearly not using the entire track on exit still, which means I can be more aggressive with power and track out. In the right hands and conditions, I'm fairly certain the car can do 1:36. I'm shooting for 1:37 next time. Here is the graph of my 1:38.4 (blue) vs 1:38.7 (red)
The 20" RE71R are holding up fine so far. 10 heat cycles on them and 230 track miles. The rears look like they are even. The fronts still have some beveling of the middle band and the outer edge is still wearing faster than the inner edge, but at a slower rate than before the tarett springs. I would love to get 25 heat cycles out of these without having to flip the tires on the wheels. Let's see how it goes.
Front left:
Front right:
Rear:
Front right tire shot at angle to show the beveling and edge wear
...med/high speed turns can be addressed with simple sway bar setting changes.
Your tire wear looks appropriate for a car that was driven well/hard on track. The outer edge wear is slightly accelerated due to stock alignment settings. I would expect the tires to look like that after 250 miles of track use with camber settings in the -2.7 range. As expected, the rear tires look just fine.
Will try to do one more trackday this year (weather permitting) on stock settings. We'll see what's possible in the camber department with factory parts over the winter.
In terms of pressures I find the 29/33 f/r setting to be spot on. The rear can take some more but anything above 30 up front spoils the fun for me.
For those of you that are running the RE71R. What ideal cold / hot temps are you running front and rear?
I tried 28 PSI all around and tires got very greasy 20 minutes in.
25F/26R seemed to be pretty good for me. Just got a full track alignment / corner balancing (-2.5 camber up front too) and RSS toe links so let's see how the tire Heats up now.
For those of you that are running the RE71R. What ideal cold / hot temps are you running front and rear?
I tried 28 PSI all around and tires got very greasy 20 minutes in.
25F/26R seemed to be pretty good for me. Just got a full track alignment / corner balancing (-2.5 camber up front too) and RSS toe links so let's see how the tire Heats up now.
Are you talking cold temps? Sounds about right.
I've been running 32/33 hot
Joe, what are your thoughts on the stiffer springs?
I drove a GT4 on Monday at Thunderhill with the stiffer springs and loved how stable it felt at turn in (very flat). I wish I could have tried it on the street to feel the trade off on bumpiness...
10-08-2016, 07:58 PM
since installation for 9 track days. Is this what you were experiencing Joe?
