Kai SRT10
Enthusiast
I got a chance to take my car to the local track to test my new Quaife differential and SSR wheel/Pilot Sport Cup tire combination.
Ideally, if I was committed to objective testing, I would have run with the runflats so that I could distinguish between the Quaife and the new tires/wheels. However, I didn't. So, some of the differences may be difficult to ascribe specifically to the new diff or the new tires.
Here are my observations.
Wheels/Tires:
First thing I noticed was the difference in ride quality. Driving to the track I travel on some pretty beat up roads. Even with my Motons stiffened up for a track day outing, the handling of the car with the Sport Cups and SSR wheels is noticably more compliant and much less bouncy and hard. This has to be due to the non run-flat tires and reduction in unsprung weight. I expected some differences, but was very surprised at the level of difference. On the track, there is one big bump that can really unsettle the car. This bump was much less of a problem with the new set up.
Grip: The Sport Cups do not seem to have as much grip as the stock runflats when they are cold. During the warm up laps, the Sport Cups didn't seem to grip as well as the stock tires, and they took longer to warm up. However, when the Sport Cups got some heat in them (took 4 or 5 1.8 mile hot-laps,) I really noticed the additional grip. Once warmed up, the Sport Cups really stick to the track well. In addition, the grip is more linear. When the Sport Cups get taxed beyond their ability to hold, they tend to slip more gradually, as opposed to breaking loose altogether. Controlling slip was much easier than with the stock runflats, and I was more confident I could keep the car under control with the Sport Cups while teetering on the edge of adhesion.
Quaife:
Where I noticed the new Quaife differential most was in tight corners. The stock lsd has a tendencey to **** a bit on these corners. The Quaife is much smoother, with no jerking or noticable wheel spin or hop. I could get on the gas quicker coming out of the corner (also likely due to the tires.)
Overall, the combination of the Quaife dif and the new wheels and tires felt significantly faster and smoother than my stock set up. I didn't have anyone timing me, but hope to go back and get some times for a more objective test.
One thing which I noticed is that I was needing to up-shift significantly sooner than I normally do on that particular track. It almost felt like I had shorter gears than the tall 3.07s. I didn't have the stock gearing changed, so perhaps I was just that much faster. I'm a little skeptical, however, because the change was quite significant, and I can't imagine I was really going that much faster. Any way that changing the diff would have the effect of lowering gear ratios? Anyone out there with a stock car that can tell me how many mph they go in 2nd gear at 2000 rpm? I'd like to compare it with my modified car.
Overall, I was very happy with the results. For everyday driving, I'm not sure that these differences would be worth it. I certainly wouldn't recommend the Pilot Sport Cups as daily driver tires, and the Quaife's qualities really only become apparent when pushing hard at the track. However, for track days, the new mods really seem to have paid off.
The improved ride quality of the wheels/tires also have convinced me that somewhere down the line, I'm going to replace the stock wheels and run-flats with some ultra-light wheels and lighter, non run-flat tires.
p.s.
I had my Quaife installed by Taylor Race Engineering in Texas. My local shop pulled the diff (housing and all) and sent it to Taylor. A few weeks later, they sent back the new dif. Cost of the Taylor part of it (parts and labor) was just under $3000.
Ideally, if I was committed to objective testing, I would have run with the runflats so that I could distinguish between the Quaife and the new tires/wheels. However, I didn't. So, some of the differences may be difficult to ascribe specifically to the new diff or the new tires.
Here are my observations.
Wheels/Tires:
First thing I noticed was the difference in ride quality. Driving to the track I travel on some pretty beat up roads. Even with my Motons stiffened up for a track day outing, the handling of the car with the Sport Cups and SSR wheels is noticably more compliant and much less bouncy and hard. This has to be due to the non run-flat tires and reduction in unsprung weight. I expected some differences, but was very surprised at the level of difference. On the track, there is one big bump that can really unsettle the car. This bump was much less of a problem with the new set up.
Grip: The Sport Cups do not seem to have as much grip as the stock runflats when they are cold. During the warm up laps, the Sport Cups didn't seem to grip as well as the stock tires, and they took longer to warm up. However, when the Sport Cups got some heat in them (took 4 or 5 1.8 mile hot-laps,) I really noticed the additional grip. Once warmed up, the Sport Cups really stick to the track well. In addition, the grip is more linear. When the Sport Cups get taxed beyond their ability to hold, they tend to slip more gradually, as opposed to breaking loose altogether. Controlling slip was much easier than with the stock runflats, and I was more confident I could keep the car under control with the Sport Cups while teetering on the edge of adhesion.
Quaife:
Where I noticed the new Quaife differential most was in tight corners. The stock lsd has a tendencey to **** a bit on these corners. The Quaife is much smoother, with no jerking or noticable wheel spin or hop. I could get on the gas quicker coming out of the corner (also likely due to the tires.)
Overall, the combination of the Quaife dif and the new wheels and tires felt significantly faster and smoother than my stock set up. I didn't have anyone timing me, but hope to go back and get some times for a more objective test.
One thing which I noticed is that I was needing to up-shift significantly sooner than I normally do on that particular track. It almost felt like I had shorter gears than the tall 3.07s. I didn't have the stock gearing changed, so perhaps I was just that much faster. I'm a little skeptical, however, because the change was quite significant, and I can't imagine I was really going that much faster. Any way that changing the diff would have the effect of lowering gear ratios? Anyone out there with a stock car that can tell me how many mph they go in 2nd gear at 2000 rpm? I'd like to compare it with my modified car.
Overall, I was very happy with the results. For everyday driving, I'm not sure that these differences would be worth it. I certainly wouldn't recommend the Pilot Sport Cups as daily driver tires, and the Quaife's qualities really only become apparent when pushing hard at the track. However, for track days, the new mods really seem to have paid off.
The improved ride quality of the wheels/tires also have convinced me that somewhere down the line, I'm going to replace the stock wheels and run-flats with some ultra-light wheels and lighter, non run-flat tires.
p.s.
I had my Quaife installed by Taylor Race Engineering in Texas. My local shop pulled the diff (housing and all) and sent it to Taylor. A few weeks later, they sent back the new dif. Cost of the Taylor part of it (parts and labor) was just under $3000.
