What is the difference between ZR1 LS9 and LT4 C7 Z06?
06-17-2016, 05:47 PM
#161
Agreed. Good post.
Ehh, I don't think we've seen compressor maps for both blowers yet to really make that claim. Yes, the 2.3L is spinning slower, but that's not the only variable here. The 1.74L is a newer generation with shorter lobes and other efficiency improvements designed to spin faster and be more efficient at that range. Everyone talks about the "small blower being over-spun" but it's not like GM just slapped a different pulley on the blower to spin it faster and called it a day. They worked with Eaton on the TVS 1.74L to get the efficiency range where they would be using it.
That said, I agree the total power potential of the 2.3L is higher, but to say the 2.3L is more efficient, just because it's larger displacement/rev is ignoring a lot of key variables in blower performance. I'm not claiming the 1.74L is definitely more efficient, just that we don't have the data necessary to make a claim either way without the compressor maps. The data we do have (IAT1 vs. IAT2) actually suggests the 1.74L works great in the stock application.
The other thing is that the intercooler on the LT4 is claimed by GM to be an 11% improvement over the LS9's. From what I've seen/heard, unless there's something wrong (like air bubble in the intercooler system) the Z06 overheating issues are oil and coolant temperature, not IAT1 vs. IAT2 (Heat soak), so at stock/near stock power levels, the talk of the 1.74L being inefficient and overspun is really overblown and hasn't been backed up with actual data, just people making guesses based on the displacement/rev variable. Based on results of people swapping the radiator out being minimal improvements, it seems to be more of an airflow issue than a radiator heat rejecting capacity issue, as well. So any engine making this much power would likely have issues with the same airflow/heat exchanger setup.
Take a gander at this thread too though,
https://www.corvetteforum.com/forums...er-setups.html
You have to be looking for pretty high power numbers to make the 2.3 worth it, it seems.
Ehh, I don't think we've seen compressor maps for both blowers yet to really make that claim. Yes, the 2.3L is spinning slower, but that's not the only variable here. The 1.74L is a newer generation with shorter lobes and other efficiency improvements designed to spin faster and be more efficient at that range. Everyone talks about the "small blower being over-spun" but it's not like GM just slapped a different pulley on the blower to spin it faster and called it a day. They worked with Eaton on the TVS 1.74L to get the efficiency range where they would be using it.
That said, I agree the total power potential of the 2.3L is higher, but to say the 2.3L is more efficient, just because it's larger displacement/rev is ignoring a lot of key variables in blower performance. I'm not claiming the 1.74L is definitely more efficient, just that we don't have the data necessary to make a claim either way without the compressor maps. The data we do have (IAT1 vs. IAT2) actually suggests the 1.74L works great in the stock application.
The other thing is that the intercooler on the LT4 is claimed by GM to be an 11% improvement over the LS9's. From what I've seen/heard, unless there's something wrong (like air bubble in the intercooler system) the Z06 overheating issues are oil and coolant temperature, not IAT1 vs. IAT2 (Heat soak), so at stock/near stock power levels, the talk of the 1.74L being inefficient and overspun is really overblown and hasn't been backed up with actual data, just people making guesses based on the displacement/rev variable. Based on results of people swapping the radiator out being minimal improvements, it seems to be more of an airflow issue than a radiator heat rejecting capacity issue, as well. So any engine making this much power would likely have issues with the same airflow/heat exchanger setup.
Take a gander at this thread too though,
https://www.corvetteforum.com/forums...er-setups.html
You have to be looking for pretty high power numbers to make the 2.3 worth it, it seems.
Someone started that talk and many swore to it. No facts, no compressor maps, no IAT's, no manifold temps, No logged data at the time because no one had a friggin car.
And the rumor still persist.
Yes a 1.74 will run out of air long before a 2.3 but that point is beyond what most of us will mod our cars to need. There are those who will need a 2.3 or a whipple because they want power levels beyond a 1.74s capability. That capability is probably around the upper 700hp at the crank. But even if you put a bigger blower on it, to make the power gain worthwhile and take advantage of the extra air you are forced to do a whole lot more to the motor than just adding a bigger blower.
Last edited by dar02081961; 06-17-2016 at 06:09 PM.
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CPhelps (06-17-2016)
06-17-2016, 07:01 PM
#162
Le Mans Master
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C6Z never ran out of power. I can tell you that. What it lacked vs the C7Z or even the Stingray is being unable to put it down as efficient as the 7th gen Vette can. You are talking about increasing power but have you thought about putting it down? You can bet your *** the MPSC2 won't do that for you. They might help but they are not capable of miracles.. Then you have 150lbs of lift at 124mph.. No power increase of cup tires will help with that. 
06-17-2016, 07:07 PM
#163
Le Mans Master
I love how people talk about how "efficient" the TVS-2300 is over the TVS-1740 without looking at a compressor map, or knowing the boost ratio, or really having any idea whatsoever.
Just because a blower is bigger doesn't make it more efficient. The high efficiency area on a compressor map is an island, and you can be outside of it in multiple dimensions, both too big, too small, too much boost, too little boost, and so on. Spinning it slower does not necessarily increase efficiency.
But the unending ZR1-worship just assumes that since the blower was bigger it must be better.
The reality is probably that it's what was available in an off-the-shelf part from Eaton at the time, whereas the C7 got a custom piece.
Just because a blower is bigger doesn't make it more efficient. The high efficiency area on a compressor map is an island, and you can be outside of it in multiple dimensions, both too big, too small, too much boost, too little boost, and so on. Spinning it slower does not necessarily increase efficiency.
But the unending ZR1-worship just assumes that since the blower was bigger it must be better.
The reality is probably that it's what was available in an off-the-shelf part from Eaton at the time, whereas the C7 got a custom piece.
Last edited by davepl; 06-17-2016 at 07:08 PM.
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3 Z06ZR1 (06-18-2016)
06-17-2016, 07:29 PM
#164
Le Mans Master
?
My comment was Lt's, CAI and a tune, maybe 50 HP at the wheels....I didn't say a supercharger to add 150+ HP. The C7Z generates far more TQ down low where mechanical grip is most needed, if anything the C7Z is at a disadvantage down low for grip. The C6Z is ~400 lbs lighter than C7Z so MPSC2's will yield higher gains on a lighter car than a heavier car...fundamental physics from Newton's Laws. There are over 170 turns on the Ring so weight transfer has a huge influence on why the 505 HP C6Z was able to turn a lap only 3 seconds slower than a 638 HP ZR1 that weighs ~200 lbs more. I'm not talking miracles...just physics.
As a matter of basic Physics, that I have done a simple Lab. on, more weight everything else being equal gets you more traction, and friction, but, it slows it. You want the car to stay flat and not be upset by bumps or hills.
MR does a good job of allowing for all the different variables needed in an all around GT street car. IE Stiffness doesn't transfer weight optimumly from a dig!
J.
Last edited by johnglenntwo; 06-17-2016 at 10:29 PM.
06-17-2016, 07:33 PM
#165
Team Owner
I love how people talk about how "efficient" the TVS-2300 is over the TVS-1740 without looking at a compressor map, or knowing the boost ratio, or really having any idea whatsoever.
Just because a blower is bigger doesn't make it more efficient. The high efficiency area on a compressor map is an island, and you can be outside of it in multiple dimensions, both too big, too small, too much boost, too little boost, and so on. Spinning it slower does not necessarily increase efficiency.
But the unending ZR1-worship just assumes that since the blower was bigger it must be better.
The reality is probably that it's what was available in an off-the-shelf part from Eaton at the time, whereas the C7 got a custom piece.
Just because a blower is bigger doesn't make it more efficient. The high efficiency area on a compressor map is an island, and you can be outside of it in multiple dimensions, both too big, too small, too much boost, too little boost, and so on. Spinning it slower does not necessarily increase efficiency.
But the unending ZR1-worship just assumes that since the blower was bigger it must be better.
The reality is probably that it's what was available in an off-the-shelf part from Eaton at the time, whereas the C7 got a custom piece.
When they selected the 2.9L and the 4.0L blowers, did they do so deliberately so they would be slower than the Fords.
And before you reply, I'm aware they used a Whipple.
If the 1.74L blower is so wonderful, why did Callaway go with the 2.3L? Couldn't they too have used the Eaton 1.74L rotors in their from-the-ground-up new supercharger where they picked up 107 horses above GM's little 1.74L unit(and still is 50 state emissions legal).
Last edited by JoesC5; 06-17-2016 at 07:44 PM.
06-18-2016, 12:02 PM
#166
Interesting...
But no I'm not clueless, I understand the reasoning behind why it's faster. But stock for stock, no way id choose an LT4.. Not to mention they're breaking completely stock.
Dunno if I have even seen a LS9 explode yet lol. Although I'm sure some have somewhere.
But no I'm not clueless, I understand the reasoning behind why it's faster. But stock for stock, no way id choose an LT4.. Not to mention they're breaking completely stock.
Dunno if I have even seen a LS9 explode yet lol. Although I'm sure some have somewhere.
Last edited by Mikeyfitz; 06-18-2016 at 12:02 PM.
06-18-2016, 12:20 PM
#167
Le Mans Master
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I love how people talk about how "efficient" the TVS-2300 is over the TVS-1740 without looking at a compressor map, or knowing the boost ratio, or really having any idea whatsoever.
Just because a blower is bigger doesn't make it more efficient. The high efficiency area on a compressor map is an island, and you can be outside of it in multiple dimensions, both too big, too small, too much boost, too little boost, and so on. Spinning it slower does not necessarily increase efficiency.
But the unending ZR1-worship just assumes that since the blower was bigger it must be better.
The reality is probably that it's what was available in an off-the-shelf part from Eaton at the time, whereas the C7 got a custom piece.
Just because a blower is bigger doesn't make it more efficient. The high efficiency area on a compressor map is an island, and you can be outside of it in multiple dimensions, both too big, too small, too much boost, too little boost, and so on. Spinning it slower does not necessarily increase efficiency.
But the unending ZR1-worship just assumes that since the blower was bigger it must be better.
The reality is probably that it's what was available in an off-the-shelf part from Eaton at the time, whereas the C7 got a custom piece.
1. GM used a smaller blower for hood clearance to meet pedestrian laws in Europe.
2. GM needed to maintain or increase engine output for next Gen C7Z. The TVS 1740S is more efficient due to subtle improvements in blower housing intake, heat exchanger and other areas.
Without question the GM TVS 1740S is an improved design over the outgoing GM TVS 2300. Designing the 1740 to be smaller and ~20 lbs lighter is space and weight efficiency. Output in the design window of power range is improved and more efficient. Comparing GM products whether entire cars or components from one generation to the next we should see design improvements.
Both units use Eaton rotors of the 160* helix design. The size of rotors and housing is where the changes exist. A 2300 by volume alone will pump more air but due to blower housing improvements the 1740 will have a better input to output ratio however still falling short of the larger 2300. The LT4 engine is an evolution of the LS9 but it is not without compromises in some areas. That is The Good, The Bad and The Facts.
06-18-2016, 01:02 PM
#168
Team Owner
Interesting...
https://youtu.be/gRF0Lb2oOds
https://youtu.be/KQWk3x-3WIE
But no I'm not clueless, I understand the reasoning behind why it's faster. But stock for stock, no way id choose an LT4.. Not to mention they're breaking completely stock.
Dunno if I have even seen a LS9 explode yet lol. Although I'm sure some have somewhere.
https://youtu.be/gRF0Lb2oOds
https://youtu.be/KQWk3x-3WIE
But no I'm not clueless, I understand the reasoning behind why it's faster. But stock for stock, no way id choose an LT4.. Not to mention they're breaking completely stock.
Dunno if I have even seen a LS9 explode yet lol. Although I'm sure some have somewhere.
Engine to engine NOT ZR1 to C7Z
SHEZZZ can you understand that the LIGHTER weight helps the ZR1.
SWAP engines between the two and the ZR1 wins BY A MILE
650 > 638 650>604
then a load more under the curve.
HOPE THAT HELPED LT4 > LS9
Last edited by 3 Z06ZR1; 06-18-2016 at 01:04 PM.
06-18-2016, 01:10 PM
#169
Academic arguments
The power and speed of both cars is very high. Highly technical differences between the two would seem to have little impact of the brutal reality of their power. The Camaro and Vette have always sold into very different markets. Describing the characteristics of the average Camaro owner vs average Vette owner would sound like I was being very disparaging toward the former.
IMO the Camaro is just plain ugly. It resembles an animated cartoon car from a video game or action movie aimed at teenage boys. That is, IMO, precisely why it sells well. The Vette has class and attracts buyers, no matter their age who appreciate it. As such, I don't care what is under the hood of the Camaro. I write it off as a result of just looking at it.
IMO the Camaro is just plain ugly. It resembles an animated cartoon car from a video game or action movie aimed at teenage boys. That is, IMO, precisely why it sells well. The Vette has class and attracts buyers, no matter their age who appreciate it. As such, I don't care what is under the hood of the Camaro. I write it off as a result of just looking at it.
06-18-2016, 01:23 PM
#170
Le Mans Master
Different horsepower target. If GM was shooting for 750 or 800, they would have had to. But you (nor I) know the effects if any at low speed, emissions, fuel consumption, and so on.
As we've seen there's even still room to pulley up the 1740 by at least 18%
As we've seen there's even still room to pulley up the 1740 by at least 18%
06-18-2016, 01:36 PM
#171
Team Owner
Then like GM is going to cut a hole in the hood?
Why did Callaway cut a hole in the hood? Because the blower didn't fit!
Then if you put the ls9 in one car and the exact same car only with the lt4.
The car with the lt4 out preforms the ls9 with the smaller blower.
Why did Callaway cut a hole in the hood? Because the blower didn't fit!
Then if you put the ls9 in one car and the exact same car only with the lt4.
The car with the lt4 out preforms the ls9 with the smaller blower.
06-18-2016, 01:42 PM
#172
The Consigliere
Member Since: May 2006
Location: 2023 Z06 & 2010 ZR1
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When team Corvette releases the C7 ZR1 or Zora or whatever they're going to call the C7 top dog, the very DNA of some in this sub may unravel.
Internet Brands may have to open numerous grief counseling portals.
Internet Brands may have to open numerous grief counseling portals.
06-18-2016, 01:42 PM
#173
Le Mans Master
That's the thing - the LT4 outpowers the LS9 and the parts that the LS9 has that are "stronger" don't fail on the LT4, so where's the win?
What makes it better, other than being amenable to future upgrades? Sounds like nothing, so far as I can tell.
What makes it better, other than being amenable to future upgrades? Sounds like nothing, so far as I can tell.
06-18-2016, 07:41 PM
#175
I still doubt it. Less than 200lbs isn't going to make that huge of a difference. And the ZR1 can do it back to back to back many more times without overheating.. Can't say same for the LT4. Sorry man.
06-18-2016, 07:42 PM
#176
Le Mans Master
SWAP engines between the two and the ZR1 wins BY A MILE
Last edited by davepl; 06-18-2016 at 07:44 PM.
06-18-2016, 10:48 PM
#177
Burning Brakes
My LT4 runs all day at the track without overheating even on hot days. Or did you mean the LS9 overheats?
Which way? Put the more powerful LT4 in the old body you mean? Yes, that'd make the ZR1 faster, though ordering a crate motor for a ZR1 would be silly, just buy the C7Z. Not the other way around though because the LS9 makes less power.
Which way? Put the more powerful LT4 in the old body you mean? Yes, that'd make the ZR1 faster, though ordering a crate motor for a ZR1 would be silly, just buy the C7Z. Not the other way around though because the LS9 makes less power.
06-18-2016, 11:26 PM
#178
Considering the C7Z currently has the quickest and fastest 1/4 and 1/2 of any stock Corvette to date and tied the ZR1 for a 1 mile trap... it kinda makes me wonder if you are a troll or a really bad troll. Pick the one that suits you...makes no difference to me.
Last edited by Lavender; 06-18-2016 at 11:34 PM.
06-18-2016, 11:29 PM
#179
Interesting...
https://youtu.be/gRF0Lb2oOds
https://youtu.be/KQWk3x-3WIE
But no I'm not clueless, I understand the reasoning behind why it's faster. But stock for stock, no way id choose an LT4.. Not to mention they're breaking completely stock.
Dunno if I have even seen a LS9 explode yet lol. Although I'm sure some have somewhere.
https://youtu.be/gRF0Lb2oOds
https://youtu.be/KQWk3x-3WIE
But no I'm not clueless, I understand the reasoning behind why it's faster. But stock for stock, no way id choose an LT4.. Not to mention they're breaking completely stock.
Dunno if I have even seen a LS9 explode yet lol. Although I'm sure some have somewhere.
I won't even comment the speedometer videos because frankly this is just.. don't know how to call that. Comical at best might fit but Id say its not enough still.
06-19-2016, 12:45 AM
#180
Scraping the splitter.
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