ZR-1 Net Registry Forums - View Single Post - Gross Horsepower LT-5

tpepmeie · 11-23-2012

Ok I found the article. March/April 1998 Legend magazine. Page 14 is an article by Graham describing the 93MY changes.

"405 bhp was realized in GM Test 1 spec, which means with full vehicle inlet and exhaust system,

in GM Test 20 form, ie., dyno headers and no inlet restriction the 1993MY engine produced 445 bhp with optimized spark and fuel (LBT/MBT)."

So we have two different GM test specifications, with a 40bhp difference with headers and optimized tuning. What I don't know is what atmospheric correction factor GM uses for each of these tests. I believe it is probably 77F / 990mbar (SAE J1349) conditions, but I can't certain.

Doesn't really answer the original poster's question, but offers some insight into the difference with open headers/intake.

11-23-2012	#38
tpepmeie Join Date: Aug 2005 Location: Fishers, IN Posts: 813	Re: Gross Horsepower LT-5 Ok I found the article. March/April 1998 Legend magazine. Page 14 is an article by Graham describing the 93MY changes. "405 bhp was realized in GM Test 1 spec, which means with full vehicle inlet and exhaust system, in GM Test 20 form, ie., dyno headers and no inlet restriction the 1993MY engine produced 445 bhp with optimized spark and fuel (LBT/MBT)." So we have two different GM test specifications, with a 40bhp difference with headers and optimized tuning. What I don't know is what atmospheric correction factor GM uses for each of these tests. I believe it is probably 77F / 990mbar (SAE J1349) conditions, but I can't certain. Doesn't really answer the original poster's question, but offers some insight into the difference with open headers/intake.