Gen V announcement
12-03-2011, 08:40 PM
#22
Melting Slicks
....sort of! I think that qualifier about being "able to disable" is key, and I wonder if that will be the case. I think it is more likely that the start/stop feature would be used in calculating fuel economy and emissions requirements on the prescribed test cycle, and therefore be a mandatory full time feature. 
12-03-2011, 10:45 PM
#23
Im glad they are improving on the pushrod vs going with overhead cam multiple valve tech. A Z06 gets almost 30 mpg on the highway if driven conservatively. With DI that could bump 5mpg and maybe get another 30-50hp. Start/stop is BS but probably adds a lot of mpg credit to the city mpg numbers.
A lot of people knock the pushrod but you will never see a lighter/smaller package for power. The 5l Ford looks the size of a big block and the top half of the motor is almost bigger than the bottom. Its and ugly, inelegant design. A great comparison is the GM pushrod to the 911. Both are hailed as inferior designs and have been around forever. The engineers have worked miracles with both of those products. 100 million motors cannot be wrong.
A lot of people knock the pushrod but you will never see a lighter/smaller package for power. The 5l Ford looks the size of a big block and the top half of the motor is almost bigger than the bottom. Its and ugly, inelegant design. A great comparison is the GM pushrod to the 911. Both are hailed as inferior designs and have been around forever. The engineers have worked miracles with both of those products. 100 million motors cannot be wrong.
12-03-2011, 11:55 PM
#25
Burning Brakes
More GREENIE bullcrap. Really?? You buy a 450-500+HP car and worry about saving a couple of drops at the stop light? Political correctness has ruined America. If they do this to any performance car, time to move on to something else, or hang onto the cars you have now. What's next, hybrid BS in the Corvette??
12-04-2011, 12:27 AM
#26
The Consigliere
Member Since: May 2006
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Well that is A real shame.
That will drastically limit the tuning potential of the engine with out yanking out the motor and tossing the stock crap.
If the really want to make more power and be more efficient they should of gone with an overhead cam design... Not Di, but that is normal for gm, instead of modernization of the 1930's design, they take the cheap route and avoid any real engineering, then claim triumph.
That will drastically limit the tuning potential of the engine with out yanking out the motor and tossing the stock crap.
If the really want to make more power and be more efficient they should of gone with an overhead cam design... Not Di, but that is normal for gm, instead of modernization of the 1930's design, they take the cheap route and avoid any real engineering, then claim triumph.
You do realize that OHC tech was deployed in the 1920s, right? It ain't new tech. It's just different tech. And heavy, and bulky. They both (OHV and OHC) have their plusses and minuses. But let's dispense with the "old tech", "new tech" pablum. Neither of them is new tech.
12-04-2011, 12:35 AM
#27
Racer
You do realize that OHC tech was deployed in the 1920s, right? It ain't new tech. It's just different tech. And heavy, and bulky. They both (OHV and OHC) have their plusses and minuses. But let's dispense with the "old tech", "new tech" pablum. Neither of them is new tech.
12-04-2011, 05:13 AM
#28
Le Mans Master
12-04-2011, 06:49 AM
#29
Instructor
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2016 C6 of Year Finalisof Year Finalist
I know somebody who works in GM's testing and development for their engines from I understand it's still going to be a 6 L direct injection the funny thing is is the new model name for the engine will be LT1 and the LT4. The LT4 is a supercharged engine. that's what He told me. He actually has had hands on both motors breaking them down inspecting and everything. So that's what he told me and he also told me that the pictures that were recently posted of what the C7 is go to look like he set me a text saying you Want to know what the C7 is going to look like and he sent me those picture so I am quite sure what he says is true.
12-04-2011, 09:37 AM
#30
Well that is A real shame.
That will drastically limit the tuning potential of the engine with out yanking out the motor and tossing the stock crap.
If the really want to make more power and be more efficient they should of gone with an overhead cam design... Not Di, but that is normal for gm, instead of modernization of the 1930's design, they take the cheap route and avoid any real engineering, then claim triumph.
That will drastically limit the tuning potential of the engine with out yanking out the motor and tossing the stock crap.
If the really want to make more power and be more efficient they should of gone with an overhead cam design... Not Di, but that is normal for gm, instead of modernization of the 1930's design, they take the cheap route and avoid any real engineering, then claim triumph.
The downside to overhead cams is weight. For example, compare the weight of other manufacturers V-8's of similar size to the LS3 with overhead cams. For example, Nissan's DOHC V-8 is more than 100 lb. heavier. In a mid-engine car, it is probably worth the tradeoff but , imo, not in a front engine car. The acceleration of the Z06 and ZR1 already is traction limited, not hp limited. Adding more weight to the nose of the car will only make that worse. Moreover, much of the additional weight added with an overhead cam engine is at the top of the motor, which would raise the center of gravity, which is not good for handling. In addition, DOHC V-8s are larger than their push-rod counterparts, which creates fitment issues.
Implementing VVT with a push-rod motor seems to me like the way to go for a front engine car, like the Corvette, and the evidence that I have seen seems to suggest that is the direction GM is going. If this is the case, I say "good job."
I am now going on my second built motor in my G35 and, to a certain extent, getting high HP levels out of a DOHC V-6 is kind of like beating your head against the wall. Some of my buddies already have ditched the VQ35 engine and moved to the LS2, and for good reason... RELIABILITY. Don't get me wrong, I love my G35, but it is going to become a weekend track car and a C7 will be my next daily driver.
12-04-2011, 10:05 AM
#31
Drifting
I know somebody who works in GM's testing and development for their engines from I understand it's still going to be a 6 L direct injection the funny thing is is the new model name for the engine will be LT1 and the LT4. The LT4 is a supercharged engine. that's what He told me. He actually has had hands on both motors breaking them down inspecting and everything. So that's what he told me and he also told me that the pictures that were recently posted of what the C7 is go to look like he set me a text saying you Want to know what the C7 is going to look like and he sent me those picture so I am quite sure what he says is true.
12-04-2011, 11:00 AM
#32
Burning Brakes
Spoken like a true west coaster. If you are worried about saving fuel, buy a PRIUS or VOLT. Leave the sports cars alone, there are plenty of petite, light on the environment, cars already. Why else would you do this other than politics????!!!!
Last edited by dboz; 12-04-2011 at 11:52 AM.
12-04-2011, 11:42 AM
#33
Racer
The Volt is definitely politically motivated; electric cars wouldn't exist without all the subsidies. But that really isn't the case with hybrid technology. It's just another way to improve gas mileage or, in some cases, to improve performance. Same with start stop or the use of lighter materials. If it improves fuel economy without impacting performance, and you can disable it, what's the issue?
12-04-2011, 01:11 PM
#34
Direct injection allows higher compression for a given octane of gas, which is actually quite nice. Give it a bit of time, and aftermarket fuel injectors will come out to allow after-market tuning.
The downside to overhead cams is weight. For example, compare the weight of other manufacturers V-8's of similar size to the LS3 with overhead cams. For example, Nissan's DOHC V-8 is more than 100 lb. heavier. In a mid-engine car, it is probably worth the tradeoff but , imo, not in a front engine car. The acceleration of the Z06 and ZR1 already is traction limited, not hp limited. Adding more weight to the nose of the car will only make that worse. Moreover, much of the additional weight added with an overhead cam engine is at the top of the motor, which would raise the center of gravity, which is not good for handling. In addition, DOHC V-8s are larger than their push-rod counterparts, which creates fitment issues.
Implementing VVT with a push-rod motor seems to me like the way to go for a front engine car, like the Corvette, and the evidence that I have seen seems to suggest that is the direction GM is going. If this is the case, I say "good job."
I am now going on my second built motor in my G35 and, to a certain extent, getting high HP levels out of a DOHC V-6 is kind of like beating your head against the wall. Some of my buddies already have ditched the VQ35 engine and moved to the LS2, and for good reason... RELIABILITY. Don't get me wrong, I love my G35, but it is going to become a weekend track car and a C7 will be my next daily driver.
The downside to overhead cams is weight. For example, compare the weight of other manufacturers V-8's of similar size to the LS3 with overhead cams. For example, Nissan's DOHC V-8 is more than 100 lb. heavier. In a mid-engine car, it is probably worth the tradeoff but , imo, not in a front engine car. The acceleration of the Z06 and ZR1 already is traction limited, not hp limited. Adding more weight to the nose of the car will only make that worse. Moreover, much of the additional weight added with an overhead cam engine is at the top of the motor, which would raise the center of gravity, which is not good for handling. In addition, DOHC V-8s are larger than their push-rod counterparts, which creates fitment issues.
Implementing VVT with a push-rod motor seems to me like the way to go for a front engine car, like the Corvette, and the evidence that I have seen seems to suggest that is the direction GM is going. If this is the case, I say "good job."
I am now going on my second built motor in my G35 and, to a certain extent, getting high HP levels out of a DOHC V-6 is kind of like beating your head against the wall. Some of my buddies already have ditched the VQ35 engine and moved to the LS2, and for good reason... RELIABILITY. Don't get me wrong, I love my G35, but it is going to become a weekend track car and a C7 will be my next daily driver.
It is not a fuel injector that would be a hold back to tuning, There are already many aftermarket choices for direct injectors. (Lets not forget DI is not THAT new) It is the compression ratios. If you have a 12:1+ compression ratio in an N/A motor no matter what fuel injector you use you are seriously limited in your tuning ability without exotic race fuels. You will not see bolt-on 300+hp with a simple supercharger kit. Building the block to lower the compression ratio will become nessicary at much lower power levels than you have in the LS1/2/3 motors.
Nissan's DOHC V8 is heavier than the LS3, but not just because of the heads and cams; or it's DOHC design. DOHC designs do not add that much weight; for example Ford's 5.0L V8 Coyote motor (out of the BOSS 302) is 444lbs, for the complete long block, Vs. the LS3's 418lbs for the complete long block, that is just 26lbs. Granted the Ford motor is not exacly the model in which all other's should follow. It has more than it's fair share of issues... and it needs a lot more work, but it is leaps and bounds closer than the gen IV ls motors.
100hp per liter is nothing crazy anymore, in fact 150hp per liter is nothing crazy anymore. If GM is serious about producing powerful and raise the MPG of the motors they are going have to revisit the design itself, and stop producing 6+ Liter motors that only produce 400/450hp....
If you are having issues getting high HP levels out of a built DOHC v6, then you are doing something wrong. There are plenty of VQ35's putting down 800+ or even 1000+hp. I had no problems at all putting down 800+ out of my stock motor 2JZGTE, and once built well over 1000hp.....
Try calling Sound Performance in Chicago, Ask for Larry. He will help you figure it out.
12-04-2011, 01:28 PM
#35
You do realize that OHC tech was deployed in the 1920s, right? It ain't new tech. It's just different tech. And heavy, and bulky. They both (OHV and OHC) have their plusses and minuses. But let's dispense with the "old tech", "new tech" pablum. Neither of them is new tech.
DOHC designs are not that much heavier (if at all) if designed properly. GM V8's is just overdue for a major overhaul, and time is running out for them to catch up to the rest of the auto industry.
I loved my Z06’s LS6, I have no real complaints about the LS2 in my GTO, and I am shopping for an LS3 GrandSport currently. I am not a "hater" by any means, but if I compare the VQ38DETT in my GTR, and the 2JZGTE in my Supra to the LS V8's I have; Well truth be told, I made more power, and got better fuel economy.
I truly hope GM stops band-aiding it's design with bolt on tech, and starts to produce a truly modern engine so it will be able to compete over the next few years. They have a lot catching up to do, and a lot of american jobs depend on it.
12-04-2011, 02:51 PM
#37
Auctually.... No... on all of your points.
It is not a fuel injector that would be a hold back to tuning, There are already many aftermarket choices for direct injectors. (Lets not forget DI is not THAT new) It is the compression ratios. If you have a 12:1+ compression ratio in an N/A motor no matter what fuel injector you use you are seriously limited in your tuning ability without exotic race fuels. You will not see bolt-on 300+hp with a simple supercharger kit. Building the block to lower the compression ratio will become nessicary at much lower power levels than you have in the LS1/2/3 motors.
Nissan's DOHC V8 is heavier than the LS3, but not just because of the heads and cams; or it's DOHC design. DOHC designs do not add that much weight; for example Ford's 5.0L V8 Coyote motor (out of the BOSS 302) is 444lbs, for the complete long block, Vs. the LS3's 418lbs for the complete long block, that is just 26lbs. Granted the Ford motor is not exacly the model in which all other's should follow. It has more than it's fair share of issues... and it needs a lot more work, but it is leaps and bounds closer than the gen IV ls motors.
100hp per liter is nothing crazy anymore, in fact 150hp per liter is nothing crazy anymore. If GM is serious about producing powerful and raise the MPG of the motors they are going have to revisit the design itself, and stop producing 6+ Liter motors that only produce 400/450hp....
If you are having issues getting high HP levels out of a built DOHC v6, then you are doing something wrong. There are plenty of VQ35's putting down 800+ or even 1000+hp. I had no problems at all putting down 800+ out of my stock motor 2JZGTE, and once built well over 1000hp.....
Try calling Sound Performance in Chicago, Ask for Larry. He will help you figure it out.
It is not a fuel injector that would be a hold back to tuning, There are already many aftermarket choices for direct injectors. (Lets not forget DI is not THAT new) It is the compression ratios. If you have a 12:1+ compression ratio in an N/A motor no matter what fuel injector you use you are seriously limited in your tuning ability without exotic race fuels. You will not see bolt-on 300+hp with a simple supercharger kit. Building the block to lower the compression ratio will become nessicary at much lower power levels than you have in the LS1/2/3 motors.
Nissan's DOHC V8 is heavier than the LS3, but not just because of the heads and cams; or it's DOHC design. DOHC designs do not add that much weight; for example Ford's 5.0L V8 Coyote motor (out of the BOSS 302) is 444lbs, for the complete long block, Vs. the LS3's 418lbs for the complete long block, that is just 26lbs. Granted the Ford motor is not exacly the model in which all other's should follow. It has more than it's fair share of issues... and it needs a lot more work, but it is leaps and bounds closer than the gen IV ls motors.
100hp per liter is nothing crazy anymore, in fact 150hp per liter is nothing crazy anymore. If GM is serious about producing powerful and raise the MPG of the motors they are going have to revisit the design itself, and stop producing 6+ Liter motors that only produce 400/450hp....
If you are having issues getting high HP levels out of a built DOHC v6, then you are doing something wrong. There are plenty of VQ35's putting down 800+ or even 1000+hp. I had no problems at all putting down 800+ out of my stock motor 2JZGTE, and once built well over 1000hp.....
Try calling Sound Performance in Chicago, Ask for Larry. He will help you figure it out.
I closed decked my new 4.0L motor (similar to the VQ38DETT in the GTR), and added a billit girdle and main caps. Hopefully this should make it handle 750 hp for a good period of time. We'll see once it is running. I know SPR, they are good guys and very knowledgable. I have purchased parts from them.
The Ford Coyote motor is smaller than the LS3, 3.9" bore spacing vs 4.4". A DOHC LS3 sized motor would be noticably heavier than the Coyote (and would probably put the LS3 sized motor over 500 lb.).
You are correct that it makes it more difficult to safely tune for forced induction on a high compression motor. Meth/H20 injection will help, but yes, building the short block with lower compression certainly would be advised to add another 300 hp. My new motor is 8.5:1 compression for a twin turbo setup.
Last edited by C8forT; 12-04-2011 at 07:14 PM. Reason: update weights
12-04-2011, 05:11 PM
#38
If you are having issues getting high HP levels out of a built DOHC v6, then you are doing something wrong. There are plenty of VQ35's putting down 800+ or even 1000+hp. I had no problems at all putting down 800+ out of my stock motor 2JZGTE, and once built well over 1000hp.....
Regarding FI, by the time you go with turbos, & if you are wise, forged internals, the cost gets pretty steep. Steep enough to question if it is worth it or simply get another car with over 400hp stock.
12-04-2011, 05:20 PM
#39
^^^
+1000
VQ motors are very expensive to modify. I have a billit crank, forged rods and forged pistons, and they definitely were not cheap.
+1000
VQ motors are very expensive to modify. I have a billit crank, forged rods and forged pistons, and they definitely were not cheap.
12-04-2011, 05:38 PM
#40
Burning Brakes
The Volt is definitely politically motivated; electric cars wouldn't exist without all the subsidies. But that really isn't the case with hybrid technology. It's just another way to improve gas mileage or, in some cases, to improve performance. Same with start stop or the use of lighter materials. If it improves fuel economy without impacting performance, and you can disable it, what's the issue?
Furthermore, why worry about making a limited niche type car be the bearer for fuel savings? Does it really matter that 6-10,000 cars save a drop or two at a stop when most are limited use vehicles anyway. I doubt you will be able to just turn it off either, what would be the point? No one buys a CORVETTE for MPG savings.
Again, you bought the wrong car. Sure, it is all good if you can improve MPG without harming performance, but having your engine cut out at a stop is not one that makes much sense, nor seems very practical. How much could it possibly save anyhow. Cylinder shutoff at cruising speeds would make more sense, since the car is probably moving 95% of the time vs. just sitting there. Way more chance to recover and improve MPG on the go vs. on the stops.
I would also be concerned with the engine shutting down and having less oil pressure available when the it comes time to nail it and it takes a second to build back up, but what do I know?