The 2005 Generac 500 was the seventh race for the 2005 American Le Mans Series season held at Road America. It took place on August 21, 2005.

Official results

Class winners in bold. Cars failing to complete 70% of winner's distance marked as Not Classified (NC).

Pos	Class	No	Team	Drivers	Chassis	Tyre	Laps
					Engine
1	LMP1	2	ADT Champion Racing	Frank Biela Emanuele Pirro	Audi R8	M	72
					Audi 3.6L Turbo V8
2	LMP1	20	Dyson Racing	Chris Dyson Andy Wallace	MG-Lola EX257	M	72
					MG (AER) XP20 2.0L Turbo I4
3	LMP1	1	ADT Champion Racing	Marco Werner JJ Lehto	Audi R8	M	72
					Audi 3.6L Turbo V8
4	GT1	4	Corvette Racing	Oliver Gavin Olivier Beretta	Chevrolet Corvette C6.R	M	71
					Chevrolet 7.0L V8
5	GT1	3	Corvette Racing	Ron Fellows Johnny O'Connell	Chevrolet Corvette C6.R	M	71
					Chevrolet 7.0L V8
6	LMP2	10	Miracle Motorsports	Jeff Bucknum Chris McMurry	Courage C65	K	69
					AER P07 2.0L Turbo I4
7	LMP1	12	Autocon Motorsports	Bryan Willman Michael Lewis	Riley & Scott Mk III C	D	69
					Elan 6L8 6.0L V8
8	GT1	35	Maserati Corse Risi Competizione	Andrea Bertolini Fabrizio de Simone	Maserati MC12	P	69
					Maserati 6.0L V12
9	GT2	31	Petersen Motorsports White Lightning Racing	Patrick Long Jörg Bergmeister	Porsche 911 GT3-RSR	M	69
					Porsche 3.6L Flat-6
10	GT2	23	Alex Job Racing	Timo Bernhard Romain Dumas	Porsche 911 GT3-RSR	M	69
					Porsche 3.6L Flat-6
11	GT2	45	Flying Lizard Motorsports	Johannes van Overbeek Jon Fogarty	Porsche 911 GT3-RSR	M	69
					Porsche 3.6L Flat-6
12	LMP1	16	Dyson Racing	Butch Leitzinger James Weaver	MG-Lola EX257	M	68
					MG (AER) XP20 2.0L Turbo I4
13	GT2	43	BAM!	Mike Rockenfeller Wolf Henzler	Porsche 911 GT3-RSR	Y	68
					Porsche 3.6L Flat-6
14	LMP2	19	Van der Steur Racing	Gunnar van der Steur Ben Devlin	Lola B2K/40	D	67
					Nissan (AER) 3.0L V6
15	GT2	50	Panoz Motor Sports	Bill Auberlen Robin Liddell	Panoz Esperante GT-LM	P	67
					Ford (Elan) 5.0L V8
16	GT2	24	Alex Job Racing	Ian Baas Darren Law	Porsche 911 GT3-RSR	M	67
					Porsche 3.6L Flat-6
17	GT2	51	Panoz Motor Sports	Bryan Sellers Marino Franchitti	Panoz Esperante GT-LM	P	67
					Ford (Elan) 6.0L V8
18	GT2	44	Flying Lizard Motorsports	Lonnie Pechnik Seth Neiman	Porsche 911 GT3-RSR	M	67
					Ford (Elan) 5.0L V8
19	GT2	79	J3 Racing	Justin Jackson Tim Sugden	Porsche 911 GT3-RSR	P	66
					Porsche 3.6L Flat-6
20	GT1	71	Carsport America	Michele Rugolo Tom Weickardt	Dodge Viper GTS-R	P	66
					Dodge 8.0L V10
21 DNF	GT1	5	Pacific Coast Motorsports	Alex Figge Ryan Dalziel	Chevrolet Corvette C5-R	Y	61
					Chevrolet 7.0L V8
22 DNF	GT1	63	ACEMCO Motorsports	Terry Borcheller Johnny Mowlem	Saleen S7-R	M	58
					Ford 7.0L V8
23 DNF	LMP2	37	Intersport Racing	Clint Field Liz Halliday	Lola B05/40	G	13
					AER P07 2.0L Turbo I4
23 DNF	LMP2	8	B-K Motorsport	Guy Cosmo Jamie Bach	Courage C65	G	2
					Mazda R20B 2.0L 3-Rotor

Statistics

• Pole Position - #16 Dyson Racing - 1:53.042
• Fastest Lap - #2 ADT Champion Racing - 1:54.569
• Distance - 291.456 miles (469.053 km)
• Average Speed - 105.489 mph (169.768 km/h)