KLR

There's no question that it's significant. Particularly when it comes to passing. However, I would not have guessed that losing 11% of my rwhp in a low power car would only cost me 0.8% of my lap time.

ubercooper

Im still skeptical of this. The "lap time triangle" would be 3/3 in the widow's favor, plus the slushbox in the battlewagon... I think if you had the same seat time in the widow as the wagon you could have shaved that time a bit more

I was quite puzzled by that at first but then realized power really doesnt matter that much in a momentum car (generally speaking) since you rely on the fact that you dont have a lot, so you dont usually scrub as much speed off as some of the higher hp/weight cars.

However you cannot dismiss that HP doesnt effect lap times because it clearly does. I know for a fact that the same S2000 that runs a 1:50 at LS can get into upper 1:30s with a massive turbo, some slicks/suspension/aero (Icemans triangle coming into play). With that logic it would seem that horsepower equates to about 1/3, maybe 1/4 if you count spoilers/spitters, of the potential lap time of your car.

These are from fastestlaps, not the pinnacle of sources but the trend speaks for itself.

Thunderhill

Pos Make / Model Time Speed (km/h) Year Power (hp) / Weight (kg) Driven by
1. Porsche 996 GT2 2:00.00 145 '00 460 / 1430 Sports Car Internati
2. Dodge Viper ACR 2:04.00 140 '99 466 / 1525 Sports Car Internati
3. Ferrari 360 Modena 2:07.65 136 '99 400 / 1390 Road and Track
4. Chevrolet Corvette C5 Z06 2:08.39 135 '03 385 / 1430 Road and Track
5. Chevrolet Corvette C5 Z06 2:08.39 135 '01 390 / 1414 Road and Track
6. Ferrari 550 Maranello 2:09.25 134 '96 486 / 1690 Road and Track
7. Porsche 996 Turbo 2:10.73 133 '00 420 / 1540 Road and Track
8. BMW Z8 2:13.30 130 '00 400 / 1585 Road and Track
9. Acura NSX-T 3.2 2:14.15 130 '96 294 / 1435 Road and Track
10. Mercedes SL 500 2:16.05 128 '98 306 / 1795 Road and Track
11. BMW Z3 M Roadster 2:17.28 127 '97 321 / 1350 Road and Track
12. Porsche 986 Boxster S (248bhp) 2:17.46 126 '99 252 / 1295 Road and Track
13. Honda S2000 2:17.66 126 '99 239 / 1260 Road and Track

Portion of Leguna Seca lap times

22. Shelby Mustang Cobra GT500KR 1:44.72 124 '08 540 / 1773 Motortrend
23. Porsche 997 Carrera (2008 facelift) 1:45.00 123 '08 345 / 1415 Car and Driver
24. Jaguar XFR 1:45.37 123 '09 510 / 1960 Motortrend
25. Chevrolet Camaro SS 2010 1:45.70 123 '10 432 / 1750 Motor Trend
26. Lotus Exige 240R 1:45.82 123 '05 247 / 941 Motortrend
27. Toyota Supra RZ 1:45.87 122 '94 284 / 1640 Kurosawa Motoharu
28. BMW 135i Coupe (E82) 1:46.00 122 '07 306 / 1485 Motortrend
29. Nissan Nismo 370Z 1:46.50 122 '09 355 / 1500 Motortrend
30. Porsche Cayman S 1:47.58 121 '05 295 / 1406 Motortrend
31. Mitsubishi Lancer Evo X MR 1:47.71 120 '08 295 / 1585 MotorTrend
32. Chevrolet Cobalt SS/TC 1:47.75 120 '08 260 / 1352 Motor Trend
33. Mitsubishi Lancer EVO IX 1:47.93 120 '05 290 / 1482 Motortrend
34. BMW 335i Coupe 1:49.04 119 '06 306 / 1610 Motortrend
35. Porsche 997 Carrera S 1:50.00 118 '04 355 / 1420 Motortrend
36. Mazda 3 MPS 1:50.38 117 '06 260 / 1485 Motortrend
37. Mazda RX-8 1:50.42 117 '02 231 / 1400 Motor Trend
38. Honda S2000 1:50.74 117 '99 239 / 1260 Motortrend
39. Mini Mini Cooper S Works GP Kit 1:51.73 116 '06 218 / 1180 Motortrend
40. Mini Cooper S (Mk II) 1:51.98 116 '06 174 / 1206 Motortrend
41. Mazda MX-5 Grand Touring 1:52.20 116 '09 160 / 1165


Feel free to shred me on any of this, just going off what I know from experience/witnessed at the track

IcemanG17

Cooper
Without a doubt I am a better driver now vs when I did the lap in the Widow....for example I felt that car was a low 2:00 car....probably 2:02 the way it was setup in the 2:09 video..... If you listen to the videos (using stereo left or right) you can tell that the Estate is being pushed HARD...vs the Widow that is barely squealing the tires.... I like to think I am near the potential of the Estate....I don't think there is many more seconds to be found in its current setup.....maybe 1 for a top level driver....

Brian

Sterling Doc

What's very interesting is that Neal really isolated what HP does, for our cars, and its not as much as I would have guessed either. That's not to say it's insignificant, but less than I anticipated.

What made the S2000 faster in the example above is very muddy, because many variables changed at once. How much any one part contributed is complete speculation.

To give this some perspective, I have run my 944 Spec car in two classes at NASA Nationals two years in a row. Each time, the only change was going from 225 Toyos to 245 Hoosiers or Hankooks. Each year that was worth between 1.5 and 2 seconds (1.4 to 1.9% of lap times at that track), over several days of back to back testing with the same car, same (consistant) driver.

So a tire change on our cars is worth significantly more (approaching double) than an 11% HP loss, on pretty firm data. This backs up Neal's assertion that chassis & tire is worth more than quite a bit of HP (on a percentage basis). Not surprising, but interesting to see quantified.

ubercooper

That would explain it... I had a feeling you were only 7/10ths on that lap. Just wanted to make sure the you were giving the widow the credit it deserves because that thing is quite badass, not to say the estate isnt

Yea sorry, that wasnt the clearest explanation. My point about the s2000 was only to demonstrate that even with a brilliant chassis and nice suspension, hp is still about 1/3 or 1/4 of the equation (apart from driver obviously) of how fast a car can potentially get around a track.

I completely agree with you about tire upgrades, there are hundreds of test which prove that it does make a massive difference. However assuming you have the optimum tires for your car and track (2-4 second improvement) and you add another 100-300hp, the results will be just as drastic (until the car becomes practically undriveable)

Better example than S2000- Top gear lap times with vettes, essentially the same car, one has more hp/tq

Corvette ZR1 1.20.4 (pretty damp, so assume 1.18-1.19s easily)
Corvette Z06 1.22.4 (completely dry)

Convert that to a larger track like VIR and the difference of ~100hp becomes just as important as nice tires.

again, mostly speculation with some data thrown in. Feel free to correct me, I'm always tryin to learn more.