The LT1 should have +15% more power than the LS3||||||
01-16-2013, 03:13 PM
#41
Haltech,
You make great engine management systems, and you guys know your ****. However, I think it would be beneficial to share additional light on the subject of expectations for increased hp in the new engine.
When estimating the increase in torque (and thus hp at a given rpm) based on increased compression ratio, first this needs to start with the efficiency actually gained from increasing the compression ratio. The efficiency is given by the equation:
E = 1 - (1/R^(k-1))
Where E is the thermal efficiency, R is the compression ratio and k is the adiabatic expansion for air, which is nominally 1.4.
The efficiency of using a 10.7 compression ratio is 61.25%. The efficiency of using an 11.5 compression ratio is 62.35%. The net increase in efficiency is 1.8%.
This assumes the same dynamic compression ratio. With direct injection, more air can be flow into the cylinders before detination becomes an issue due to the increased cooling effect resulting from the fuel being directly sprayed into the cylinders, and the ability to better time when the fuel is sprayed.
So, for clarification, the increased compression ratio only plays a small part in the overall increase in expected torque/hp. More significantly is the ability to inhibit the onset of detonation using direct injection in comparison to port fuel injection. The LT1's intake port and piston design also helps in this regard. This assumes that the LT1 actually flows more air into the cylinders than the LS3. It certainly does in the mid-rpm range due to VVT. At high rpm, I suspect the cam lobe positions will be quite similar. So, to acheive a 15% increase in torque/hp at high rpm, the LT1 need to flow roughly 13% more air into the cylinders. Hopefully it will do that, but other than Bigg_Gunz's comments in the LS1Tech thread (which are somewhat suspect), GM has not indicated this will be the case. Hopefully they are holding back information.
You make great engine management systems, and you guys know your ****. However, I think it would be beneficial to share additional light on the subject of expectations for increased hp in the new engine.
When estimating the increase in torque (and thus hp at a given rpm) based on increased compression ratio, first this needs to start with the efficiency actually gained from increasing the compression ratio. The efficiency is given by the equation:
E = 1 - (1/R^(k-1))
Where E is the thermal efficiency, R is the compression ratio and k is the adiabatic expansion for air, which is nominally 1.4.
The efficiency of using a 10.7 compression ratio is 61.25%. The efficiency of using an 11.5 compression ratio is 62.35%. The net increase in efficiency is 1.8%.
This assumes the same dynamic compression ratio. With direct injection, more air can be flow into the cylinders before detination becomes an issue due to the increased cooling effect resulting from the fuel being directly sprayed into the cylinders, and the ability to better time when the fuel is sprayed.
So, for clarification, the increased compression ratio only plays a small part in the overall increase in expected torque/hp. More significantly is the ability to inhibit the onset of detonation using direct injection in comparison to port fuel injection. The LT1's intake port and piston design also helps in this regard. This assumes that the LT1 actually flows more air into the cylinders than the LS3. It certainly does in the mid-rpm range due to VVT. At high rpm, I suspect the cam lobe positions will be quite similar. So, to acheive a 15% increase in torque/hp at high rpm, the LT1 need to flow roughly 13% more air into the cylinders. Hopefully it will do that, but other than Bigg_Gunz's comments in the LS1Tech thread (which are somewhat suspect), GM has not indicated this will be the case. Hopefully they are holding back information.
01-16-2013, 03:15 PM
#42
Melting Slicks
With 11.5:1 cr, bigger throttle body, probably better flowing intake, variable cam timing, bigger intake valves, 2 3/4" exhaust, better flowing exhaust manifolds, and of course direct injection it certaintly should make more power than just 20 or 14 hp over the LS3. The head ports look larger too from vidos I've seen. And then if it comes in a little lighter, and that's debatable, but assuming maybe 100# or so lighter this car might run almost as good as a C6 Z06. With the automatic, the right converter and sticky tires my guess is 1/4 miles times will be very exciting!
01-16-2013, 03:28 PM
#43
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St. Jude Donor '09
Haltech,
You make great engine management systems, and you guys know your ****. However, I think it would be beneficial to share additional light on the subject of expectations for increased hp in the new engine.
When estimating the increase in torque (and thus hp at a given rpm) based on increased compression ratio, first this needs to start with the efficiency actually gained from increasing the compression ratio. The efficiency is given by the equation:
E = 1 - (1/R^(k-1))
Where E is the thermal efficiency, R is the compression ratio and k is the adiabatic expansion for air, which is nominally 1.4.
The efficiency of using a 10.7 compression ratio is 61.25%. The efficiency of using an 11.5 compression ratio is 62.35%. The net increase in efficiency is 1.8%.
This assumes the same dynamic compression ratio. With direct injection, more air can be flow into the cylinders before detination becomes an issue due to the increased cooling effect resulting from the fuel being directly sprayed into the cylinders, and the ability to better time when the fuel is sprayed.
So, for clarification, the increased compression ratio only plays a small part in the overall increase in expected torque/hp. More significantly is the ability to inhibit the onset of detonation using direct injection in comparison to port fuel injection. The LT1's intake port and piston design also helps in this regard. This assumes that the LT1 actually flows more air into the cylinders than the LS3. It certainly does in the mid-rpm range due to VVT. At high rpm, I suspect the cam lobe positions will be quite similar. So, to acheive a 15% increase in torque/hp at high rpm, the LT1 need to flow roughly 13% more air into the cylinders. Hopefully it will do that, but other than Bigg_Gunz's comments in the LS1Tech thread (which are somewhat suspect), GM has not indicated this will be the case. Hopefully they are holding back information.
You make great engine management systems, and you guys know your ****. However, I think it would be beneficial to share additional light on the subject of expectations for increased hp in the new engine.
When estimating the increase in torque (and thus hp at a given rpm) based on increased compression ratio, first this needs to start with the efficiency actually gained from increasing the compression ratio. The efficiency is given by the equation:
E = 1 - (1/R^(k-1))
Where E is the thermal efficiency, R is the compression ratio and k is the adiabatic expansion for air, which is nominally 1.4.
The efficiency of using a 10.7 compression ratio is 61.25%. The efficiency of using an 11.5 compression ratio is 62.35%. The net increase in efficiency is 1.8%.
This assumes the same dynamic compression ratio. With direct injection, more air can be flow into the cylinders before detination becomes an issue due to the increased cooling effect resulting from the fuel being directly sprayed into the cylinders, and the ability to better time when the fuel is sprayed.
So, for clarification, the increased compression ratio only plays a small part in the overall increase in expected torque/hp. More significantly is the ability to inhibit the onset of detonation using direct injection in comparison to port fuel injection. The LT1's intake port and piston design also helps in this regard. This assumes that the LT1 actually flows more air into the cylinders than the LS3. It certainly does in the mid-rpm range due to VVT. At high rpm, I suspect the cam lobe positions will be quite similar. So, to acheive a 15% increase in torque/hp at high rpm, the LT1 need to flow roughly 13% more air into the cylinders. Hopefully it will do that, but other than Bigg_Gunz's comments in the LS1Tech thread (which are somewhat suspect), GM has not indicated this will be the case. Hopefully they are holding back information.
Actually, we have done dyno testing at Katech Engine Devlopment on our 429 motor running E85. The net gain on the engine dyno was 8 HP increasing static compression ratio from 12:1 to 13:1, with no other modifications whatsoever.
Haltech is the engine management folks, we are the Corvette Halltech Systems guys that manufacture induction systems for GM rides. I have around 10 years of tuning experience as well.
__________________
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"World Class Performance for your Corvette"
Intake Design and Engineering since 1999
Halltech Systems, LLC
262-510-7600
For service email:
orders@halltechsystems.com
www.halltechsystems.com
01-16-2013, 03:29 PM
#44
With 11.5:1 cr, bigger throttle body, probably better flowing intake, variable cam timing, bigger intake valves, 2 3/4" exhaust, better flowing exhaust manifolds, and of course direct injection it certaintly should make more power than just 20 or 14 hp over the LS3. The head ports look larger too from vidos I've seen. And then if it comes in a little lighter, and that's debatable, but assuming maybe 100# or so lighter this car might run almost as good as a C6 Z06. With the automatic, the right converter and sticky tires my guess is 1/4 miles times will be very exciting!
VVT usually advances cam phase in the mid-rpm range, but pulls it back to 0 at high rpms. So, unless the LS3 cam position was not optimized for peak hp, VVT will not help at peak hp, but it will provide significantly more mid-rpm torque, which GM's published graph indicates.
The more advanced head design should provide increased air flow, and the combination of the intake port/piston design should help reducing onset of detonation so more air can be consumed. Also, I suspect the intake port/piston design also may increase combustion efficiency a little bit more, but I don't see this having more than a 1 or 2% increase in efficiency. Perhaps combined with the increased compression ratio we may expect an increase of 2-4% in thermal efficiency.
01-16-2013, 03:34 PM
#45
Actually, we have done dyno testing at Katech Engine Devlopment on our 429 motor running E85. The net gain on the engine dyno was 8 HP increasing static compression ratio from 12:1 to 13:1, with no other modifications whatsoever.
Haltech is the engine management folks, we are the Corvette Halltech Systems guys that manufacture induction systems for GM rides. I have around 10 years of tuning experience as well.
Haltech is the engine management folks, we are the Corvette Halltech Systems guys that manufacture induction systems for GM rides. I have around 10 years of tuning experience as well.
Moving from a 12:1 to a 13:1 compression ratio should increase efficiency about 1.85%. So, I'm guessing the hp at 12:1 CR was around 432 hp, and with the 13:1 CR around 440 hp. Is this correct?
01-16-2013, 03:39 PM
#46
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St. Jude Donor '09
We are going to 14:1 CR with new Brodix heads and WCCH porting, and a different profile cam.
01-16-2013, 03:40 PM
#47
Ok, I'm just going to list some changes that I found for the LT1 that indicate beyond reasonable doubt, a power capability far beyond what is claimed.... This information summary was taken from:
http://www.gmhightechperformance.com...#ixzz2Aoe7eAxS
First, the obvious and factual power-increasing technologies...
1. Direct Injection. (less heat *cools top of piston* more ignition timing options,
2. 10.7:1 --> 11.5:1 compression ratio increase
3. Intake manifold with + 3.6 % dynamic flow and 50% less airflow imbalance intake runner design.
4. CVVT - Continuously Variable Valve Timing (62 degrees of camshaft phasing).
5. 4-into-1 short-tube headers similar in design to LS7, & LS9 units.
6. Electric power steering - (no parasitic loss of old unit)
7. Reversed intake and exhaust valve locations - resulting in a straighter air path into the combustion chamber.
Other indicators this engine is going to be higher output than claimed:
1. Forged eutectic aluminum alloy high compression pistons, optimized for DI.
2. stronger rods...
3. Forged 1538MV twisted steel crankshaft. - features induction hardened journals, with intermediate pin drills.
4. New upgraded Polymer Coated Bi-metal eccentric bearings, used for crankshaft and connecting rods.
5. Stronger nodular iron main bearing caps. (Reduces crankshaft flex)
5. Oil squirters underneath each piston. Usually on overbuilt boosted applications. ie. twin turbo supra, LSA / LS9, etc...
And more:
Statements that the engine will not need to be run on premium fuels indicate this engine is special.. Think about it for a second. A 6.2 liter 11.5:1 cr engine without needing premium fuel to make over 450+ hp has got some major wiggle room for power output when conditions are right....
Something's not adding up. This engine is being built to take a beating and we are surely not being given the actual hp output estimate when all modern technology points to a substantial gain limited only by an ECM programming.
It's all speculation, but when we speak of realistic expectations, lets get real......
Thoughts?
http://www.gmhightechperformance.com...#ixzz2Aoe7eAxS
First, the obvious and factual power-increasing technologies...
1. Direct Injection. (less heat *cools top of piston* more ignition timing options,
2. 10.7:1 --> 11.5:1 compression ratio increase
3. Intake manifold with + 3.6 % dynamic flow and 50% less airflow imbalance intake runner design.
4. CVVT - Continuously Variable Valve Timing (62 degrees of camshaft phasing).
5. 4-into-1 short-tube headers similar in design to LS7, & LS9 units.
6. Electric power steering - (no parasitic loss of old unit)
7. Reversed intake and exhaust valve locations - resulting in a straighter air path into the combustion chamber.
Other indicators this engine is going to be higher output than claimed:
1. Forged eutectic aluminum alloy high compression pistons, optimized for DI.
2. stronger rods...
3. Forged 1538MV twisted steel crankshaft. - features induction hardened journals, with intermediate pin drills.
4. New upgraded Polymer Coated Bi-metal eccentric bearings, used for crankshaft and connecting rods.
5. Stronger nodular iron main bearing caps. (Reduces crankshaft flex)
5. Oil squirters underneath each piston. Usually on overbuilt boosted applications. ie. twin turbo supra, LSA / LS9, etc...
And more:
Statements that the engine will not need to be run on premium fuels indicate this engine is special.. Think about it for a second. A 6.2 liter 11.5:1 cr engine without needing premium fuel to make over 450+ hp has got some major wiggle room for power output when conditions are right....
Something's not adding up. This engine is being built to take a beating and we are surely not being given the actual hp output estimate when all modern technology points to a substantial gain limited only by an ECM programming.
It's all speculation, but when we speak of realistic expectations, lets get real......
Thoughts?
01-16-2013, 03:44 PM
#48
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(actually read every post in this thread so far ha) - so with all that has been said - when do you think GM will release these guarded FINAL HP/TQ numbers.. realistically...
I mean has anyone heard when the very FIRST c7 will make it to a customer .? June? .. July? ... so it MUST be with in a month or two from now (for the numbers to come out) right ? .... what do u guys think/ have heard ?
I mean has anyone heard when the very FIRST c7 will make it to a customer .? June? .. July? ... so it MUST be with in a month or two from now (for the numbers to come out) right ? .... what do u guys think/ have heard ?
01-16-2013, 03:46 PM
#49
CrystalRedMetal ZR,
Good point, I forgot to factor in the ability to advance ignition timing when using DI.
Good point, I forgot to factor in the ability to advance ignition timing when using DI.
01-16-2013, 03:48 PM
#50
Melting Slicks
LS3s 1/4 mile better than a 12.3. Take a look at the 1/4 mile C6 challenge list. Might take good air but a 12.3 would be very disappointing. If this engine makes the torque of a Z06 up to 4000 rpm then 60' should be greatly improved. I'm going over 20 mph in my 08 LS3 before reaching 4000 rpm. Assuming the car holds traction of course.
01-16-2013, 04:04 PM
#51
Le Mans Master
I agree with the op the new C7 should have around 490hp. With that sais what will the new Z06 have? 575hp? Do you think they will give out the real HP numbers Saturday at the Barrett Jackson auction?
Last edited by DRLC5; 01-16-2013 at 04:07 PM.
01-16-2013, 04:05 PM
#52
LS3s 1/4 mile better than a 12.3. Take a look at the 1/4 mile C6 challenge list. Might take good air but a 12.3 would be very disappointing. If this engine makes the torque of a Z06 up to 4000 rpm then 60' should be greatly improved. I'm going over 20 mph in my 08 LS3 before reaching 4000 rpm. Assuming the car holds traction of course.
I agree in that I hope the C7 is faster than those initial numbers. But at this point GM has not given any confirmation to the contrary.
01-16-2013, 04:07 PM
#53
Burning Brakes
EDIT: Nevermind, I've gone back and read some earlier stuff. I assume you're talking about the Caddy example and whatnot.
EDIT 2: I also gotta say, if you're right and the LT1 produces anywhere close to 500 hp while ALSO delivering 26 combined mpg? And it didn't even have to resort to cutting cylinders and forced induction??? My god... SCIENCE BLESS AMERICA.
Last edited by RocketGuy3; 01-16-2013 at 04:15 PM.
01-16-2013, 04:25 PM
#54
LS3s 1/4 mile better than a 12.3. Take a look at the 1/4 mile C6 challenge list. Might take good air but a 12.3 would be very disappointing. If this engine makes the torque of a Z06 up to 4000 rpm then 60' should be greatly improved. I'm going over 20 mph in my 08 LS3 before reaching 4000 rpm. Assuming the car holds traction of course.
Hail Science!
Last edited by Jawnathin; 01-16-2013 at 04:27 PM.
01-16-2013, 04:31 PM
#55
Instructor
I would say on 93 Octane... Base 490, Mid ( Z06 rep ) 625 with supercharger, and Max 750+ with twin turbo. The port move seems to have been to accommodate a twin turbo setup. Why put in high flow injectors ( enough for 1xxx hp ) unless you plan to use them. I tend to think Bigg_Gunz was on point. If these numbers were announced today what would the current inventory of new Corvettes be worth..a lot less $$ for sure.
01-16-2013, 05:01 PM
#56
The times I posted were in one of the videos posted herein (I think the C&D video). They were interviewing people involved in the C7 development, so I don't think they will be far off. Of course, these are probably nominal figures and in certain situations may be improved upon. Then again, GM may be sandbagging the figures for now in order to keep their competitors off guard.
I agree in that I hope the C7 is faster than those initial numbers. But at this point GM has not given any confirmation to the contrary.
I agree in that I hope the C7 is faster than those initial numbers. But at this point GM has not given any confirmation to the contrary.
While interviewing corvette chief engineer Tadge Juechter, at 1:12 into the video C&D posts the estimated weight of the C7 is 3350 lbs. At 1:43 into the video, C&D posts an estimated 0-60 time of 3.9 sec. and an estimated 1/4 mi. time of 12.3 sec. @ 118 mph.
Are they sandbagging. I don't know. But other than GM's statement that 0-60 will be less than 4 sec., these are the numbers we currently have. Moreover, C&D had a sit down interview with Tadge, and estimated these numbers based on that interview. I don't think they are going to be far off...
01-16-2013, 05:18 PM
#57
Acutally, they are estimating 30 mpg highway driving.
For hp, let's take the LS3 as a reference point. I believe it has 436 hp.
Here are the numbers we know: Add an additional 1.8% thermal efficiency for the increased compression ratio and add 3.6% for the increased dynamic air flow (based on CrystalRedMetal ZR-1's post).
Let's make a SWAG (scientific wild a$$ guestimate) as to the increase in thermal efficiency from the port/piston design and the potential ability to advance ignition timing using DI. let's assume these add up to an additional 3% of hp.
That puts us around an 8.4% improvement in peak hp. 436*1.084 = 472 hp.
I think the final hp number will very close to 470, maybe +/- 10 hp. Since there will be no parasitic losses due to a hydraulic steering system, maybe assume another realizeable 2-3 hp (guess on my part).
For hp, let's take the LS3 as a reference point. I believe it has 436 hp.
Here are the numbers we know: Add an additional 1.8% thermal efficiency for the increased compression ratio and add 3.6% for the increased dynamic air flow (based on CrystalRedMetal ZR-1's post).
Let's make a SWAG (scientific wild a$$ guestimate) as to the increase in thermal efficiency from the port/piston design and the potential ability to advance ignition timing using DI. let's assume these add up to an additional 3% of hp.
That puts us around an 8.4% improvement in peak hp. 436*1.084 = 472 hp.
I think the final hp number will very close to 470, maybe +/- 10 hp. Since there will be no parasitic losses due to a hydraulic steering system, maybe assume another realizeable 2-3 hp (guess on my part).
Last edited by C8forT; 01-16-2013 at 05:26 PM.
01-16-2013, 05:20 PM
#58
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St. Jude Donor '05
3.6 0-60,
11.9 1/4 mile
That is what this car should do,
Not 12.3 and 3.9.... that is way too close to c6 speed specs!!!
11.9 1/4 mile
That is what this car should do,
Not 12.3 and 3.9.... that is way too close to c6 speed specs!!!
01-16-2013, 05:28 PM
#59
01-16-2013, 05:52 PM
#60
Safety Car
So no teaser info on the z06 engine then? 
One thing that I don't understand is how C&D is coming up with that 3300lbs. est. The 2012 base c6 weighs 3208lbs. With the 136lbs in weight reduction (not accounting for any additional increased due to interior upgrades) that would put the car at 3072lbs.
Add maybe one hundred pounds of "stuff" and that is c6 z06 stock weight territory. Now add a hp rating close to 500hp (460hp-490hp) and well, you have a car that IS faster than a grand sport but not just as fast as a stock c6 z06.
No problems here!
One thing on the tuning... the new pcm is supposed (according to BG) to have two parallel software environments that communicate and verify the current calibration (and what the sensors are seeing) to a set of redetermined parameters. A key is necessary to access it.
Given that and what I've heard from some of my software engineer friends... well, I'm sure the race to uncrack the pcm is going to be fun to watch. Also, BG also eluded that the high pressure fuel pump is dangerous if messed with. I find that hard to believe in the hands of smart and capable people given that Di (and Diesel HO fuel pumps) have been tuned for years now and I've never heard of explosion due to messing with the HP fuel pump cal.
All we need is time I guess but for sure this decade is going to bring a new level of automotive performance. The aif flow modeling seems to be a big point with the vette which we got a glimpse of with the ZL1. I can only imagine what these cars would look like in 5-7 years from now.
One thing that I don't understand is how C&D is coming up with that 3300lbs. est. The 2012 base c6 weighs 3208lbs. With the 136lbs in weight reduction (not accounting for any additional increased due to interior upgrades) that would put the car at 3072lbs.
Add maybe one hundred pounds of "stuff" and that is c6 z06 stock weight territory. Now add a hp rating close to 500hp (460hp-490hp) and well, you have a car that IS faster than a grand sport but not just as fast as a stock c6 z06.
No problems here!
One thing on the tuning... the new pcm is supposed (according to BG) to have two parallel software environments that communicate and verify the current calibration (and what the sensors are seeing) to a set of redetermined parameters. A key is necessary to access it.
Given that and what I've heard from some of my software engineer friends... well, I'm sure the race to uncrack the pcm is going to be fun to watch. Also, BG also eluded that the high pressure fuel pump is dangerous if messed with. I find that hard to believe in the hands of smart and capable people given that Di (and Diesel HO fuel pumps) have been tuned for years now and I've never heard of explosion due to messing with the HP fuel pump cal.
All we need is time I guess but for sure this decade is going to bring a new level of automotive performance. The aif flow modeling seems to be a big point with the vette which we got a glimpse of with the ZL1. I can only imagine what these cars would look like in 5-7 years from now.