G8 GT underrated???
02-26-2008, 04:37 PM
#21
On The Tree
Thread Starter
iTrader: (3)
Join Date: Apr 2004
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
the 335I is definitely underrated, as it puts out 300rwhp much like an LS1 F-body, but its actually near 350hp, like the LS1 Vette. So good point Rayain! The Lexus ISF is another one that I suspect is a bit underrated, like its brother the IS350 which is documented to be underrated.
Hondanick and BigDaddy;
Good call on reading more on those threads and finding the octane numbers, I just read them and ran with the numbers. Still if the car is not tuned for the better octane, it might not react significantly enough to make it have the power levels I was saying it had. It definitely has an effect, but without a boost controller or a tune, I bet its not doing much.
As for my math, I have used that equation of the years and other websites like supraforums have too. Its pretty damn close to being right, the hard part is guessing the drive-train loss. Here are some examples of the math being accurate.
300rwhp LS1 Fbody - 300rwhp/.85= 352 crankhp
340rwhp LS2 GTO - 340rwhp/.85 = 400 crank hp
as you can see, its pretty damn close, and with 15% drive train loss from an M6 (100-15%=85), you cant deny thats pretty much nails it. You can take it with a grain of salt, but I will keep using it
As far as the drive-train loss with the GTR, it should be really high. Manual RWD cars the f-body's are around 14-16%. Auto RWD's are usually around 18-20%, hence the reason LS1 auto's dyno lower than M6's.
The real kicker is AWD; it has super parasitic drag because of all the moving parts. Even worse is that the GTR has two drive shafts and all of these crazy *** differentials which I wont get into, but I am guessing its much more than 20%. Other people on the other forums have said that M6 AWD cars lose as much as 25%, but I have no proof to back this up.
Either way, the car is underrated fo sho. Why do they do it? To beat other cars like the Z06 or the 911 Turbo and have supposedly less hp, and also to keep insurance, prices, emissions, and safety people off their backs. No one would be impressed if a GTR beat a 911 Turbo with 100 more hp
, that would not make for a fun article.
Hondanick and BigDaddy;
Good call on reading more on those threads and finding the octane numbers, I just read them and ran with the numbers. Still if the car is not tuned for the better octane, it might not react significantly enough to make it have the power levels I was saying it had. It definitely has an effect, but without a boost controller or a tune, I bet its not doing much.
As for my math, I have used that equation of the years and other websites like supraforums have too. Its pretty damn close to being right, the hard part is guessing the drive-train loss. Here are some examples of the math being accurate.
300rwhp LS1 Fbody - 300rwhp/.85= 352 crankhp
340rwhp LS2 GTO - 340rwhp/.85 = 400 crank hp
as you can see, its pretty damn close, and with 15% drive train loss from an M6 (100-15%=85), you cant deny thats pretty much nails it. You can take it with a grain of salt, but I will keep using it
As far as the drive-train loss with the GTR, it should be really high. Manual RWD cars the f-body's are around 14-16%. Auto RWD's are usually around 18-20%, hence the reason LS1 auto's dyno lower than M6's.
The real kicker is AWD; it has super parasitic drag because of all the moving parts. Even worse is that the GTR has two drive shafts and all of these crazy *** differentials which I wont get into, but I am guessing its much more than 20%. Other people on the other forums have said that M6 AWD cars lose as much as 25%, but I have no proof to back this up.
Either way, the car is underrated fo sho. Why do they do it? To beat other cars like the Z06 or the 911 Turbo and have supposedly less hp, and also to keep insurance, prices, emissions, and safety people off their backs. No one would be impressed if a GTR beat a 911 Turbo with 100 more hp
, that would not make for a fun article. 
02-26-2008, 05:52 PM
#22
LOL, I was hoping someone would mention "insurance rates" as the reason to underrate the power of these cars.
I wish I could post the info, but major insurance companies are not relying on manufacturer estimates for power like they did 40 years ago in setting their rates.
This is coming from an actuary with a MAJOR insurance company. It's a friend of mine's wife and I won't "out" a friend, so don't ask.
Because I can't post the info, take it with a grain of salt until someone can collaborate or verify what I stated.
I wish I could post the info, but major insurance companies are not relying on manufacturer estimates for power like they did 40 years ago in setting their rates.
This is coming from an actuary with a MAJOR insurance company. It's a friend of mine's wife and I won't "out" a friend, so don't ask.
Because I can't post the info, take it with a grain of salt until someone can collaborate or verify what I stated.
02-26-2008, 06:04 PM
#23
I'm only guessing b/c we don't know.
As for my math, I have used that equation of the years and other websites like supraforums have too. Its pretty damn close to being right, the hard part is guessing the drive-train loss. Here are some examples of the math being accurate.
300rwhp LS1 Fbody - 300rwhp/.85= 352 crankhp
340rwhp LS2 GTO - 340rwhp/.85 = 400 crank hp
as you can see, its pretty damn close, and with 15% drive train loss from an M6 (100-15%=85), you cant deny thats pretty much nails it. You can take it with a grain of salt, but I will keep using it
300rwhp LS1 Fbody - 300rwhp/.85= 352 crankhp
340rwhp LS2 GTO - 340rwhp/.85 = 400 crank hp
as you can see, its pretty damn close, and with 15% drive train loss from an M6 (100-15%=85), you cant deny thats pretty much nails it. You can take it with a grain of salt, but I will keep using it
As far as the drive-train loss with the GTR, it should be really high. Manual RWD cars the f-body's are around 14-16%. Auto RWD's are usually around 18-20%, hence the reason LS1 auto's dyno lower than M6's.
The real kicker is AWD; it has super parasitic drag because of all the moving parts. Even worse is that the GTR has two drive shafts and all of these crazy *** differentials which I wont get into, but I am guessing its much more than 20%. Other people on the other forums have said that M6 AWD cars lose as much as 25%, but I have no proof to back this up.
The real kicker is AWD; it has super parasitic drag because of all the moving parts. Even worse is that the GTR has two drive shafts and all of these crazy *** differentials which I wont get into, but I am guessing its much more than 20%. Other people on the other forums have said that M6 AWD cars lose as much as 25%, but I have no proof to back this up.
02-26-2008, 06:14 PM
#24
Either way, the car is underrated fo sho. Why do they do it? To beat other cars like the Z06 or the 911 Turbo and have supposedly less hp, and also to keep insurance, prices, emissions, and safety people off their backs. No one would be impressed if a GTR beat a 911 Turbo with 100 more hp , that would not make for a fun article.
, that would not make for a fun article.
Insurance (insurance industry), emissions (government), and safety (government) people all report to someone other than the manufacturer of the vehicle. Emissions and safety won't differ if the vehicle is 480 or 550hp.
02-26-2008, 07:35 PM
#25
On The Tree
Thread Starter
iTrader: (3)
Join Date: Apr 2004
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
LOL, I was hoping someone would mention "insurance rates" as the reason to underrate the power of these cars.
I wish I could post the info, but major insurance companies are not relying on manufacturer estimates for power like they did 40 years ago in setting their rates.
This is coming from an actuary with a MAJOR insurance company. It's a friend of mine's wife and I won't "out" a friend, so don't ask.
Because I can't post the info, take it with a grain of salt until someone can collaborate or verify what I stated.
I wish I could post the info, but major insurance companies are not relying on manufacturer estimates for power like they did 40 years ago in setting their rates.
This is coming from an actuary with a MAJOR insurance company. It's a friend of mine's wife and I won't "out" a friend, so don't ask.
Because I can't post the info, take it with a grain of salt until someone can collaborate or verify what I stated.
interesting story, but I bet power has more than we think to do with insurance rates! my camaro is killing my wallet and its only "285hp."
02-26-2008, 07:39 PM
#26
On The Tree
Thread Starter
iTrader: (3)
Join Date: Apr 2004
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
Again, we can only guess. What if the ECU/ECU/PCM/etc is tuned for knock retard and is set to retard timing at higher rpms? With higher octane fuel, there won't be any... see where I'm going?
I'm only guessing b/c we don't know.
I beg to differ ONLY b/c we read of "factory freaks" all the time on this forum. Read the dyno results of people wondering where their hp/tq is. I'm sure it will balance out then.
I would agree with the parasitic loss, but Nissan has stated otherwise. But, we really won't know the real data until someone takes one of these cars off the assembly line in the US, runs a dyno at the crank, then runs one at the wheels, unfortunately.
I'm only guessing b/c we don't know.
I beg to differ ONLY b/c we read of "factory freaks" all the time on this forum. Read the dyno results of people wondering where their hp/tq is. I'm sure it will balance out then.
I would agree with the parasitic loss, but Nissan has stated otherwise. But, we really won't know the real data until someone takes one of these cars off the assembly line in the US, runs a dyno at the crank, then runs one at the wheels, unfortunately.
its pretty common that LS1's dyno 300rwhp, well pretty damn common. if I was to make a post anywhere on this site, cz28.com, or a corvette forum, the overwhelming answer would be that LS1's make 300rwhp.
the only reason I used that example is to show how my formula works. if you dont like it, I dont care and I am not gonna go bouncing around the internet to prove it. But its a shorthand way of finding crank hp for sure without too much statistical discrepancy.
the bottom line is that AWD cars lose a phuq ton of power from powering all four wheels. stock evo 8's and sti's put down something small like 220-240awhp and they are said to have near 300crank hp. its pretty common knowledge, and there is no way of getting around it. a gearbox and a tranny is what it is, and having more gears and all that crap sux power.
03-04-2008, 08:04 PM
#28
Teching In
Join Date: Feb 2006
Posts: 6
Likes: 0
Received 0 Likes
on
0 Posts
Rasputin, your formula is correct... it is simple math and little algebra...
Follow me for sec,
if we have an engine with a known 300hp at the crank, and we placed it in a car with a known 20% driveline loss, we all can agree it would chasis dyno 240whp (20% of 300 is 60,,, so 300-60 is 240)
So Lets reverse the process and take our car to the chasis dyno and
and we get 240whp if we used Bigdaddybry's formula we might
think the engine had 288hp at the crank.... huh what? (20% of 240 is 48
or 1.20 x 240 = 288)
We are not gaining the 20% hp from whp to bhp we are losing it from bhp to whp...
So we need to divide the whp by 100% minus the driveline loss to solve for crank hp.
Here it is 240/(100%-20%)= crank hp or 240/.80= 300hp which is what we know we have.
Sorry to have a long explanation, but I think it is simple to follow.
Follow me for sec,
if we have an engine with a known 300hp at the crank, and we placed it in a car with a known 20% driveline loss, we all can agree it would chasis dyno 240whp (20% of 300 is 60,,, so 300-60 is 240)
So Lets reverse the process and take our car to the chasis dyno and
and we get 240whp if we used Bigdaddybry's formula we might
think the engine had 288hp at the crank.... huh what? (20% of 240 is 48
or 1.20 x 240 = 288)
We are not gaining the 20% hp from whp to bhp we are losing it from bhp to whp...
So we need to divide the whp by 100% minus the driveline loss to solve for crank hp.
Here it is 240/(100%-20%)= crank hp or 240/.80= 300hp which is what we know we have.
Sorry to have a long explanation, but I think it is simple to follow.
Last edited by geldingmakr; 03-04-2008 at 08:24 PM. Reason: fixed a typo
03-05-2008, 07:09 PM
#29
On The Tree
iTrader: (3)
Join Date: Oct 2005
Location: Myrtle Beach, SC
Posts: 178
Likes: 0
Received 0 Likes
on
0 Posts
One thing to consider is that GM uses SAE J1343 to rate the power in most all of their vehicles. http://media.gm.com/us/powertrain/en...2008/08car.htm The purpose was for all auto makers to use the same scale when rating power. When you put the engine on an engine dyno it should give you the SAE horsepower number.
Is the G8 GT underrated? If GM is true to SAE, No.
If our L76 makes an SAE 361 hp, and our drivetrain has a loss of 15%, should give us about 306 hp at the rear wheels.
Is the G8 GT underrated? If GM is true to SAE, No.
If our L76 makes an SAE 361 hp, and our drivetrain has a loss of 15%, should give us about 306 hp at the rear wheels.
03-06-2008, 04:19 AM
#30
Teching In
Join Date: Feb 2007
Location: Sydney, Australia
Posts: 25
Likes: 0
Received 0 Likes
on
0 Posts
I think it's also common knowledge that they're rating it with the lowest octane fuel available to the masses and it's likely tuned accordingly...put in some premium gas and/or maybe a good dyno tune once the software becomes fully available and this thing could really wake up as well. 
03-13-2008, 05:30 PM
#32
On The Tree
iTrader: (1)
Join Date: May 2004
Location: Chicago, IL
Posts: 108
Likes: 0
Received 0 Likes
on
0 Posts
rumors of GT-R engine making 600 hp at the flywheel are greatly exaggerated: http://www.autoblog.com/2008/03/13/n...nd-e92-bmw-m3/
Mustang dyno says: 406 hp to the wheels
Mustang dyno says: 406 hp to the wheels
03-13-2008, 05:37 PM
#33
On The Tree
Thread Starter
iTrader: (3)
Join Date: Apr 2004
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
rumors of GT-R engine making 600 hp at the flywheel are greatly exaggerated: http://www.autoblog.com/2008/03/13/n...nd-e92-bmw-m3/
Mustang dyno says: 406 hp to the wheels
Mustang dyno says: 406 hp to the wheels
03-15-2008, 06:31 AM
#34
Teching In
Join Date: Dec 2004
Location: New Jersey
Posts: 45
Likes: 0
Received 0 Likes
on
0 Posts
03-16-2008, 06:42 PM
#35
On The Tree
Thread Starter
iTrader: (3)
Join Date: Apr 2004
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
Does this help? http://www.g8board.com/forums/showthread.php?t=1282
327/.8= 408hp
327/.85= 385
I WIN!
03-16-2008, 07:38 PM
#37
Launching!
Join Date: Jul 2003
Location: Raleigh, NC
Posts: 259
Likes: 0
Received 0 Likes
on
0 Posts
yea, i saw that on the g8 board. If it already making north of 400hp, I hate to see what it will do will a tune. Damn!!!!!!!!!!!!!!!!!!!!!!!!!!!!
03-16-2008, 09:03 PM
#38
On The Tree
Thread Starter
iTrader: (3)
Join Date: Apr 2004
Posts: 189
Likes: 0
Received 0 Likes
on
0 Posts
they said the dyno is either plus or minus 10rwhp compared to other dynos which makes sense. Not only that, but the car needs to be broken in. It probably has another 10 left in it, and this was the auto . 330rwhp, sounds great to me. Intake and exhaust with a tune, a conservative 350rwhp daily driver, hell yeah!
. 330rwhp, sounds great to me. Intake and exhaust with a tune, a conservative 350rwhp daily driver, hell yeah!
03-16-2008, 09:17 PM
#39
Teching In
iTrader: (1)
Join Date: Feb 2007
Location: San Antonio
Posts: 25
Likes: 0
Received 0 Likes
on
0 Posts
Yeah riiiiiight...... So where do they get their info from? I know a thing or two about insurance companies, underwriting & actuary - these guys are not auto enthusiasts. They don't the difference between an LT1, LS1, L76, LS7, etc. Now, as far as physical damage costs - those are different, meaning the cost to repair the car after an accident, how well the car does in an accident, etc. Those are statistical based.
