[ddeflyer]

Originally Posted by ja1217

I was wondering if you could take a quick look at some data for me.

This weekend I was in time trials with NASA Mid Atlantic at Summit Point Main. I ended up coming in second place in my class but I was off the pace of 1st by just about 2 seconds. Now, the guy who came in first did set a new track record, but I feel like I shouldn't be this far off the pace. I'm trying to figure out how much of this gap is due to driver skill vs car. My car (13 FR-S) has Ohlins R&T suspension, Essex AP Sprint BBK, DSS CF Driveshaft and ACT Pro Lite Clutch. Other than a tune from Delicious and a drop in K&N filter the rest of powertrain is stock and I am competing on 225/45R17 Hoosier R6's. Last week I dyno'd at 184.5whp (dynojet) and my race weight is about 2900 lbs. (driver included). The guy who came in first place drives an E36 M3 that I think dyno'd aroud 205whp and weighs a bit over 3200 lbs and he runs on 225/40R17 R6's.

Given that our power to weight ratios are very close and we are running on roughly the same tires I would not have thought that there would be such a large gap between us. Looking at the data (which my competitor kindly sent me a copy of his) to my untrained eye I seem to doing what I can to take advantage of my lighter weight by braking later and carrying more speed through most of the turns (I could improve on turn 3), but it seems to me like his car simply overpowered mine coming out of the turns. Its quite possible that I'm over driving the car by being too aggressive entering corners and compromising my exits, but I'm just not experienced enough looking at the data to be sure. I did notice that I seem to be getting a fair amount of inside wheel slip in a lot of the corners (at one point my inside rear wheel was going 10mph more than the outside in turn 9) so I'm sure thats not helping my corner exits either. I think a clutch type LSD will probably on my list of things to do for next year.

Any way, I'd really appreciate it if you could take a quick look at my data. I'm going to be up against the same driver in October at VIR and would like to give him more of a run for his money than I could at Summit.

(I am the red line in this image)


Here's the video of my fastest session:

Data:
https://drive.google.com/file/d/0Bz6...it?usp=sharing

Thanks!

I really am talking out of my ass here so take this with a pile of salt, but I would suspect that he is cornering harder and spending alot less time at neutral throttle. At the same time he is not all THAT much slower than you in the corners. Notice the gyro channel in the data, he gets alot of rotation very fast and much earlier. I am not sure but he is probably doing an aggressive slide through the corners where he is going to a lower speed but is near full throttle for much longer. In essence he is probably sacrificing some speed mid corner in order to get the car aligned in a way to use more traction from all four tires as he gets into the apex. In other words, he is probably diamonding the corners.

Also he probably has a good torque advantage since I believe that car has a straight 6 (he should be putting down AT LEAST 200 ft/lbs vs you probably doing something like 130 or 140 ft/lbs). This helps both the straight line pull and also it should help him push the tail end of the car out for diamonding the corners.