[ZR1] Whats the ZR1s GROSS horsepower?
09-29-2010, 12:30 PM
#1
Whats the ZR1s GROSS horsepower?
Hello,
In the 60s and early 70s the muscle cars were measured in gross horsepower. During their decline they switched to net horsepower and a few years back we switched again. My question is, what would a ZR-1 make with a gross horsepower rating?
750? 800?
Thanks,
Miller
In the 60s and early 70s the muscle cars were measured in gross horsepower. During their decline they switched to net horsepower and a few years back we switched again. My question is, what would a ZR-1 make with a gross horsepower rating?
750? 800?
Thanks,
Miller
09-29-2010, 02:03 PM
#3
Safety Car
Gross horsepower is measured from pressure developed inside the cylinders (using an engine indicator), but it's a theorectical number assuming a frictionless engine. Probably a pretty good reason why it's no longer used or mentioned.
I'm sure you're already aware the flywheel or net horsepower is 638, and the typical ZR1 will make 500-550 horsepower at the rear wheels (true or effective horsepower).
So, I guess that effectively doesn't answer your question
I'm sure you're already aware the flywheel or net horsepower is 638, and the typical ZR1 will make 500-550 horsepower at the rear wheels (true or effective horsepower).
So, I guess that effectively doesn't answer your question
Last edited by ZaneO; 09-29-2010 at 02:05 PM.
09-29-2010, 04:20 PM
#6
Melting Slicks
Here's some info I found on hp ratings:
SAE gross horsepower (pre 1972)
Prior to 1972 most American automakers rated their engines in terms of SAE gross horsepower (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance muscle car engines were frequently understated.
hp (SAE) net (1972-2005)
In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use hp (SAE) to indicate the net power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.
Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972, US carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.
SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.
Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines shows a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be understated) and a net rating of 375 hp.
SAE-certified horsepower (2005 on)
In 2005, the Society of Automotive Engineers introduced a new test procedure for engine horsepower and torque.[6] The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".
SAE gross horsepower (pre 1972)
Prior to 1972 most American automakers rated their engines in terms of SAE gross horsepower (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance muscle car engines were frequently understated.
hp (SAE) net (1972-2005)
In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use hp (SAE) to indicate the net power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.
Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972, US carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.
SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.
Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines shows a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be understated) and a net rating of 375 hp.
SAE-certified horsepower (2005 on)
In 2005, the Society of Automotive Engineers introduced a new test procedure for engine horsepower and torque.[6] The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".
09-29-2010, 04:31 PM
#7
Premium Supporting Vendor
18% is often what's used by guys standing around a car determining who has the most power. The reality is 8-15% depending on whose dyno you're on.
09-29-2010, 06:02 PM
#9
Pro
The Thread Starter may be interested simply in the comparison power of a ZR1 and a 1970 or earlier muscle car...
Maybe Jason from Katech or someone with any of these could weigh in on this comparison:
A new ZR1 dynos rwhp at something like 530 ...On the same dyno as these...
What does a STOCK 1967 427/435 dyno at rwhp? Same dyno brand
What does a STOCK LS6 SS Chevelle dyno at rwhp? Same dyno brand
What does a STOCK Hemi Cuda 1970 or 1971 dyno at rwhp? Same dyno brand
These answers may shed some "real world" rwhp comparisons between cars...and does "corrected" standardize density altitude and temperature?
Maybe Jason from Katech or someone with any of these could weigh in on this comparison:
A new ZR1 dynos rwhp at something like 530 ...On the same dyno as these...
What does a STOCK 1967 427/435 dyno at rwhp? Same dyno brand
What does a STOCK LS6 SS Chevelle dyno at rwhp? Same dyno brand
What does a STOCK Hemi Cuda 1970 or 1971 dyno at rwhp? Same dyno brand
These answers may shed some "real world" rwhp comparisons between cars...and does "corrected" standardize density altitude and temperature?
09-29-2010, 10:25 PM
#10
The Thread Starter may be interested simply in the comparison power of a ZR1 and a 1970 or earlier muscle car...
Maybe Jason from Katech or someone with any of these could weigh in on this comparison:
A new ZR1 dynos rwhp at something like 530 ...On the same dyno as these...
What does a STOCK 1967 427/435 dyno at rwhp? Same dyno brand
What does a STOCK LS6 SS Chevelle dyno at rwhp? Same dyno brand
What does a STOCK Hemi Cuda 1970 or 1971 dyno at rwhp? Same dyno brand
These answers may shed some "real world" rwhp comparisons between cars...and does "corrected" standardize density altitude and temperature?
Maybe Jason from Katech or someone with any of these could weigh in on this comparison:
A new ZR1 dynos rwhp at something like 530 ...On the same dyno as these...
What does a STOCK 1967 427/435 dyno at rwhp? Same dyno brand
What does a STOCK LS6 SS Chevelle dyno at rwhp? Same dyno brand
What does a STOCK Hemi Cuda 1970 or 1971 dyno at rwhp? Same dyno brand
These answers may shed some "real world" rwhp comparisons between cars...and does "corrected" standardize density altitude and temperature?
Yes you hit the nail on the head, many people talk about the muscle cars of yore, however different testing measurements were used (My Charger was rated at 375 horse but there is no doubt a new Challenger R/T would dust it). I was wondering just how far we have come over the last 40 years.
09-30-2010, 07:06 AM
#11
Race Director
Here's some info I found on hp ratings:
SAE gross horsepower (pre 1972)
Prior to 1972 most American automakers rated their engines in terms of SAE gross horsepower (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance muscle car engines were frequently understated.
hp (SAE) net (1972-2005)
In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use hp (SAE) to indicate the net power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.
Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972, US carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.
SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.
Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines shows a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be understated) and a net rating of 375 hp.
SAE-certified horsepower (2005 on)
In 2005, the Society of Automotive Engineers introduced a new test procedure for engine horsepower and torque.[6] The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".
SAE gross horsepower (pre 1972)
Prior to 1972 most American automakers rated their engines in terms of SAE gross horsepower (defined under SAE standards J245 and J1995). Gross hp was measured using a blueprinted test engine running on a stand without accessories, mufflers, or emissions control devices. It therefore reflected a maximum, theoretical value, not the power of an installed engine in a street car. Gross horsepower figures were also subject to considerable adjustment by carmakers: the power ratings of mass-market engines were often exaggerated, while those for the highest-performance muscle car engines were frequently understated.
hp (SAE) net (1972-2005)
In the United States the term "bhp" fell into disuse after the American Society of Automotive Engineers (SAE) recommended manufacturers use hp (SAE) to indicate the net power of the engine, given that particular car's complete engine installation. It measures engine power at the flywheel, not counting drivetrain losses.
Starting in 1971 automakers began to quote power in terms of SAE net horsepower (as defined by standard J1349). This reflected the rated power of the engine in as-installed trim, with all accessories and standard intake and exhaust systems. By 1972, US carmakers quoted power exclusively in SAE net hp. The change was meant to 'deflate' power ratings to assuage the auto insurance industry and environmental and safety lobbies, as well as to obfuscate the power losses caused by emissions-control equipment.
SAE net ratings, while more accurate than gross ratings, still represent the engine's power at the flywheel. Contrary to some reports, it does not measure power at the drive wheels.
Because SAE gross ratings were applied liberally, at best, there is no precise conversion from gross to net. Comparison of gross and net ratings for unchanged engines shows a variance of anywhere from 40 to 150 horsepower. The Chrysler 426 Hemi, for example, in 1971 carried a 425 hp gross rating (often considered to be understated) and a net rating of 375 hp.
SAE-certified horsepower (2005 on)
In 2005, the Society of Automotive Engineers introduced a new test procedure for engine horsepower and torque.[6] The procedure eliminates some of the areas of flexibility in power measurement, and requires an independent observer present when engines are measured. The test is voluntary, but engines completing it can be advertised as "SAE-certified".
You nailed it. My dad and I owned some of those Gross power rated cars.
09-30-2010, 08:23 AM
#12
Pro
One other "measure of horsepower" may be 1/4 mile Trap Speed...
I have been reading ZR1's are running 128 to 130 to 132 mph ...11.5 seconds AND QUICKER
So... STOCKHemi Cudas, LS6 Chevelles, 427/435 Stingrays etc, that may be running 102 to 107 mph is an interesting comparison regarding horsepower...Though the gross weights differences are significant on some, a 427/435 Corvette from 1967 would not be alot different than a new ZR1...
Those muscle-car auctions make LESS sense to me when guys are paying 60,000 or more for 14.5 sec (or slower) Z28's or Boss 302's or paying even MORE for 428 Mach 1's or LS6 Chevelles that may run 13.50's at 103 mph...
Sure seems to me the ZR1 and new Vipers are King when talking about horsepower...gross, net, or REAL WORLD.
I have been reading ZR1's are running 128 to 130 to 132 mph ...11.5 seconds AND QUICKER
So... STOCKHemi Cudas, LS6 Chevelles, 427/435 Stingrays etc, that may be running 102 to 107 mph is an interesting comparison regarding horsepower...Though the gross weights differences are significant on some, a 427/435 Corvette from 1967 would not be alot different than a new ZR1...
Those muscle-car auctions make LESS sense to me when guys are paying 60,000 or more for 14.5 sec (or slower) Z28's or Boss 302's or paying even MORE for 428 Mach 1's or LS6 Chevelles that may run 13.50's at 103 mph...
Sure seems to me the ZR1 and new Vipers are King when talking about horsepower...gross, net, or REAL WORLD.
09-30-2010, 04:23 PM
#14
Team Owner
One other "measure of horsepower" may be 1/4 mile Trap Speed...
I have been reading ZR1's are running 128 to 130 to 132 mph ...11.5 seconds AND QUICKER
So... STOCKHemi Cudas, LS6 Chevelles, 427/435 Stingrays etc, that may be running 102 to 107 mph is an interesting comparison regarding horsepower...Though the gross weights differences are significant on some, a 427/435 Corvette from 1967 would not be alot different than a new ZR1...
Those muscle-car auctions make LESS sense to me when guys are paying 60,000 or more for 14.5 sec (or slower) Z28's or Boss 302's or paying even MORE for 428 Mach 1's or LS6 Chevelles that may run 13.50's at 103 mph...
Sure seems to me the ZR1 and new Vipers are King when talking about horsepower...gross, net, or REAL WORLD.
I have been reading ZR1's are running 128 to 130 to 132 mph ...11.5 seconds AND QUICKER
So... STOCKHemi Cudas, LS6 Chevelles, 427/435 Stingrays etc, that may be running 102 to 107 mph is an interesting comparison regarding horsepower...Though the gross weights differences are significant on some, a 427/435 Corvette from 1967 would not be alot different than a new ZR1...
Those muscle-car auctions make LESS sense to me when guys are paying 60,000 or more for 14.5 sec (or slower) Z28's or Boss 302's or paying even MORE for 428 Mach 1's or LS6 Chevelles that may run 13.50's at 103 mph...
Sure seems to me the ZR1 and new Vipers are King when talking about horsepower...gross, net, or REAL WORLD.
You don't understand why people are paying big dollars for old Muscle Cars that run 13's etc???...No, you don't understand.
09-30-2010, 04:43 PM
#15
Instructor
Interesting that the group keeps including the '70 Chevelle LS6 and not the '71 Corvette LS6. Probably, most posters don't know there WAS a corvette LS6. It was the same 454, but rated at 425hp, not the 450 hp rating in the Chevelle, even though it is essentially the same engine. GM was getting afraid of the ratings and further under-rated the '71. Both cars (70 & 71) are said to be under-rated, as many muscle cars in 1970 & 1971. There were approx 6,000 1970 LS6 Chevelles, 180 1971 LS6 Corvettes.
You can look at all kinds of test and extrapalations, but real quarter mile times tell a story. These old LS6s would run a quarter mile on bias ply, crap tires in near 13 seconds. I have both Chevelle & Corvette, and they are very strong and quick. Put radial tires on them and they run with many current generation cars. Not the ZR1 or ZO6 though. King is King!
Enjoy the life!
You can look at all kinds of test and extrapalations, but real quarter mile times tell a story. These old LS6s would run a quarter mile on bias ply, crap tires in near 13 seconds. I have both Chevelle & Corvette, and they are very strong and quick. Put radial tires on them and they run with many current generation cars. Not the ZR1 or ZO6 though. King is King!
Enjoy the life!
09-30-2010, 05:55 PM
#17
Pro
A muscle car back then...a "has-been" today...
Also... stock Hemi Cudas or LS6 Chevelle don't/CAN't spin its tires for an 1/8 mile...you are Wrong sir! Trap speeds of low 100's tell how much power they really had, compared with today's Z06 and ZR1 Corvettes...
Last...don't forget they had a distinct GASOLINE advantage back then...100 octane or more...Imagine a NEW Z06 tuned to run on 100 octane...without cat. converters...
I think your 69 Camaro is beautiful...I also do not feel they are worth what a new Z06 is worth...
Last edited by JBHunter; 09-30-2010 at 06:20 PM.
09-30-2010, 05:56 PM
#18
Team Owner
Interesting that the group keeps including the '70 Chevelle LS6 and not the '71 Corvette LS6. Probably, most posters don't know there WAS a corvette LS6. It was the same 454, but rated at 425hp, not the 450 hp rating in the Chevelle, even though it is essentially the same engine. GM was getting afraid of the ratings and further under-rated the '71. Both cars (70 & 71) are said to be under-rated, as many muscle cars in 1970 & 1971. There were approx 6,000 1970 LS6 Chevelles, 180 1971 LS6 Corvettes.
You can look at all kinds of test and extrapalations, but real quarter mile times tell a story. These old LS6s would run a quarter mile on bias ply, crap tires in near 13 seconds. I have both Chevelle & Corvette, and they are very strong and quick. Put radial tires on them and they run with many current generation cars. Not the ZR1 or ZO6 though. King is King!
Enjoy the life!
You can look at all kinds of test and extrapalations, but real quarter mile times tell a story. These old LS6s would run a quarter mile on bias ply, crap tires in near 13 seconds. I have both Chevelle & Corvette, and they are very strong and quick. Put radial tires on them and they run with many current generation cars. Not the ZR1 or ZO6 though. King is King!
Enjoy the life!
09-30-2010, 05:57 PM
#19
Team Owner
What's to understand...They don't go by today's standards, they don't stop, and they don't handle, and the NEW one does...and looks better too... your 69 Camaro warming your garage, used to be a favorite...What you'd have to convince me of is this...How did such a sharp guy as yourself get seperated from all that money for that 69???
A muscle car back then...a "has-been" today...
A muscle car back then...a "has-been" today...