LT4 Hot cam
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Burning Brakes
Joined: Jan 2004
Posts: 1,243
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From: Rowlett Texas
That is one lopy idle! Sounds great
Burning Brakes
Joined: Jun 2014
Posts: 1,020
Likes: 51
From: Connecticut
Agreed. Let's for a minute think of this in a logical sense. My Z put down just a hair less than a C5. C5 OD that year was "rated" at 350/365. If is a safe assumption that a manual tranny car loses roughly 15 percent, give or take, from the drive line. What is 293/350 and what is 303/365? Math works out to about 16%/17%, respectfully. My Z with its stock rating only lost roughly 7%/9%, respectfully.
Yes, go get exact you need to do engine and then chassis. However, you won't be exact there either because you WILL NOT be able to duplicate the exact atmospheric conditions. So your theory of it as an exact science is shot to hell.
General assumption (quite well known and respected) is the 4L60 eats about 18-20%. With those numbers my car actually performed quite well. I attribute it to the bogus hp ratings that it left the factory with.
But let's step away from the ratings. The 01 LS1 is slightly different than the 2000. Intake, heads (not enough to say so from 853-241), smaller cam, bigger injectors, block slightly revised. Of those things GM rated the Vette at 5 hp and 15 tq more. Since both cara used the same dyno on the same day with the same conditions, you would and should expect to see a mub larger gap if the ratinga from GM were accurate. As we all know, the ratings were not.
Yes, agreed that it would take more than this bench racing to get actual drivelind loss, but one would expect that two cara with very close engines to produce the same hp/tq figures within a certain delta. Which we clearly have. The only issue is the "ratings" they came with. The ratings were bogus for the f-body. That is a fact. So ce the Vette put down right about what it should for well accepted drive line loss I would say the dyno was pretty accurate. It may not be set up and spec'd but its pretty close.
Your science of on the engine dyno and chassis dyno would be ideal if you could duplicate the exact atmospheric conditions. Since you can't.....well, that argument holds as much water as a spaghetti strainer.
Yes, go get exact you need to do engine and then chassis. However, you won't be exact there either because you WILL NOT be able to duplicate the exact atmospheric conditions. So your theory of it as an exact science is shot to hell.
General assumption (quite well known and respected) is the 4L60 eats about 18-20%. With those numbers my car actually performed quite well. I attribute it to the bogus hp ratings that it left the factory with.
But let's step away from the ratings. The 01 LS1 is slightly different than the 2000. Intake, heads (not enough to say so from 853-241), smaller cam, bigger injectors, block slightly revised. Of those things GM rated the Vette at 5 hp and 15 tq more. Since both cara used the same dyno on the same day with the same conditions, you would and should expect to see a mub larger gap if the ratinga from GM were accurate. As we all know, the ratings were not.
Yes, agreed that it would take more than this bench racing to get actual drivelind loss, but one would expect that two cara with very close engines to produce the same hp/tq figures within a certain delta. Which we clearly have. The only issue is the "ratings" they came with. The ratings were bogus for the f-body. That is a fact. So ce the Vette put down right about what it should for well accepted drive line loss I would say the dyno was pretty accurate. It may not be set up and spec'd but its pretty close.
Your science of on the engine dyno and chassis dyno would be ideal if you could duplicate the exact atmospheric conditions. Since you can't.....well, that argument holds as much water as a spaghetti strainer.
This is a loose guesstimation at best.
As you know not every motor produced is dyno'd. A few or even one sample is used to perform all testing and is given the rating for the rest of the line.
With that said, how can you prove that your or any other motor is making the given OEM spec'd rating without first testing the motor? Answer: you can't. Each engine is different as tolerances vary from part to part and since it takes many parts to make a whole, these differences add up substantially across a given platform. So how exactly can you make the assumptions made above with no real data? By the way, I have a cold fusion reactor in my basement. It worked last night....
When you can prove the driveline loss percentages you so strongly believe in scientifically and accurately then perhaps I will believe in them as well. However, since you can't, I guess I will keep holding the strainer as it seems you're still holding the bag.
-- On top of the above;
1. You are using the uncalibrated chassis dyno HP number and then adding in a made up percentage to get an estimated flywheel HP.
2. You are taking that estimated flywheel HP number (made up essentially) and comparing that to the OEM HP numbers which are an estimate for the entire production line derived from one test mule engine.
3. You are deriving your driveline loss percentages based on a ratio of the above stated OEM test mule motor HP numbers compared to the uncalibrated chassis dyno numbers of an individual car.
So which science doesn't hold water again?
Last edited by kg4fku; Jul 6, 2015 at 05:42 PM.
Team Owner
Joined: Oct 2007
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From: PA
And you are still trying to compare factory engine dyno numbers to individual uncalibrated dyno numbers in order to form a delta for all driveline loss.
This is a loose guesstimation at best.
As you know not every motor produced is dyno'd. A few or even one sample is used to perform all testing and is given the rating for the rest of the line.
With that said, how can you prove that your or any other motor is making the given OEM spec'd rating without first testing the motor? Answer: you can't. Each engine is different as tolerances vary from part to part and since it takes many parts to make a whole, these differences add up substantially across a given platform. So how exactly can you make the assumptions made above with no real data? By the way, I have a cold fusion reactor in my basement. It worked last night....
When you can prove the driveline loss percentages you so strongly believe in scientifically and accurately then perhaps I will believe in them as well. However, since you can't, I guess I will keep holding the strainer as it seems you're still holding the bag.
-- On top of the above;
1. You are using the uncalibrated chassis dyno HP number and then adding in a made up percentage to get an estimated flywheel HP.
2. You are taking that estimated flywheel HP number (made up essentially) and comparing that to the OEM HP numbers which are an estimate for the entire production line derived from one test mule engine.
3. You are deriving your driveline loss percentages based on a ratio of the above stated OEM test mule motor HP numbers compared to the uncalibrated chassis dyno numbers of an individual car.
So which science doesn't hold water again?
This is a loose guesstimation at best.
As you know not every motor produced is dyno'd. A few or even one sample is used to perform all testing and is given the rating for the rest of the line.
With that said, how can you prove that your or any other motor is making the given OEM spec'd rating without first testing the motor? Answer: you can't. Each engine is different as tolerances vary from part to part and since it takes many parts to make a whole, these differences add up substantially across a given platform. So how exactly can you make the assumptions made above with no real data? By the way, I have a cold fusion reactor in my basement. It worked last night....
When you can prove the driveline loss percentages you so strongly believe in scientifically and accurately then perhaps I will believe in them as well. However, since you can't, I guess I will keep holding the strainer as it seems you're still holding the bag.
-- On top of the above;
1. You are using the uncalibrated chassis dyno HP number and then adding in a made up percentage to get an estimated flywheel HP.
2. You are taking that estimated flywheel HP number (made up essentially) and comparing that to the OEM HP numbers which are an estimate for the entire production line derived from one test mule engine.
3. You are deriving your driveline loss percentages based on a ratio of the above stated OEM test mule motor HP numbers compared to the uncalibrated chassis dyno numbers of an individual car.
So which science doesn't hold water again?
The easiest thing to point out is that IF rating s were correct my 310 hp ls1 should read lower than a 350 ls1 since they were both tested on the same dyno, same day, same conditions.
Again, I agree they are best guesses at the actual "crank" hp. But you can't deny that the rating for F-body LS1's is a joke. They produce very similar numbers to the Corvettes engine.
So lets throw away the whole thing regarding guessing the crank hp, ok? But explain to me why the engines put out very similar power though one is rated at 40 hp and 30 tq more? Whatever the calibration was on the dyno, if the actual ratings of the engines were real, you would see a much larger delta between the two cars.
So, is the LS1 in both cars "certified" like you say or does GM have an impact on the way the engines are rated? BTW, that would my original quaestion.
Let's try to say it another way in case you had three packets of sugar in the last cup.
Let's say the dyno is way off. As it was used for two cars, with the same settings, both cars would still carry a delta related to the factory ratings. Since they don't, please explain why. Thanks.
And your "Run sat dere engine on a dyno and then on a chassis and prove to me the drivelind loss!" Doesn't work because like I said, atmospheric conditions. The last engine I had on an engine dyno was an 010 block with worked 461 heads, .30 over with a 400 crank, Air Gap intake, and a custom cam. It made surprisingly good numbers. The car two years later thru a 3k stall and a 10 bolt 8.5 with 3.90 gears lost rough 23% compared to the engine dyno run. Of course the car was slightly warm and I had changed to the next smaller set of keys, it had about 40 1/4 mile runs in leicester, ny. So maybe it was the converter eating the power, maybe the smaller jets (don't think so, dropped my et with the smaller jets), or maybe the engine was heat soaked. Could be a lot of factors.
My blown C6 would lose 50+ hp when heat soaked. Went from 582-525 when warm. The torque dropped from 611 to 555.
Yes, I have had my share of vehicles, spe g a ton of money on dyno time both engine and chassis, but the fact remains that some ratinga are bullcdap from the factory.....regardless if you want to believe it or not.
I am NOT saying the LT4 was underrated.
Burning Brakes
Joined: Jun 2014
Posts: 1,020
Likes: 51
From: Connecticut
Good day sir.
Race Director
Joined: Dec 2002
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From: SCMR Rat Pack'r Charter Member..Great Bend KS
