Ecotech? Ecotec engine family is a GM I4 engine line. If you mean Ford, you probably are meaning the "Twin-Force" engines. I for one prefer naturally aspirated engines. The thing I have a problem with is one a company has to resort to forced air-induction because they can't get decent power out of their engines without it even after taking the higher technology approach just to stay competitive with the old school engine designs. Ford seems like they have had to resort to this a lot in recent history and that makes me loose respect for them when they do this instead of taking more natural approaches to upping the power. To me, it is like overusing a trump card or diplomatic immunity to cover an error. You can say that about Chrysler using cubic inches, but the issue is there is they built that engine because none of their V8s at the time could produce enough power to make the Viper competitive for the Supercar arena and making an exclusive V10 engine was what made the Viper stand out. The thing to me that proves that route is the better route is the fact that the power has been over doubled when people like Hennessey do add forced air induction. This leaves more room for us later to modify our cars. Also I have heard that GM might not be doing that smaller V8 approach so let's not count our chickens before they hatched.

 

RLSH700 you put it the way i think it Thats my point exactly Thanks.

 

Your welcome! You actually did quite a good job at it yourself.

 

Actually, it's ECOBOOST, my mistake. I have a couple of big inch muscle cars and I do enjoy them(including my '71). Again, displacement is a power adder also. It all depends on what approach you are going to use. With the new CAFE rules it will be difficult(or impossible) to make a large engine and get it to comply with MPG rules. Turbo or supercharging is one way to still get performance and some mpg. I like the N/A stuff also, just looking at from another perspective. I will still be picking up a Challenger regardless. :-)

 

That's right, I forgot about that nameplate. The other reason why I view larger displacement as a more respectable route is it provides a lot more peak potential. I can't remember who did it, but one of the magazines took modified Vettes, Vipers, and GTs against each other and the Vipers produced a whole lot more than any of the rest of them. Although there still is modification room left after a car has been supercharged or turbocharged, it certainly limits how much more you can get out of the engine since it already is depending on that blower.

I'm not sure if I completely agree that forced air-induction is going to be all that better than displacement when it comes to fuel economy. If you look at the high performance turbo I4s, they really don't get any better fuel economy than V6s that produce similar hp. The same is true between turbo V6s and V8s. Part of the reason why is you need to provide these engines with shorter gearing to let them wind up faster to get the full effect of the boosting. Just look for example about the Crossfire, it got about 22mpg on the highway on the SRT-6 version. GM has been able to get 26-27mpg with the Corvette automatics that has just under double the displacement. The fact of the matter is that when you increase displacement and up the power, you can make the gearing taller and normally get better fuel mileage.

The idea to use GDI is a great plan. It will improve both fuel economy and power. The use of multi-displacement systems is also a great route for improving fuel economy now that technology can successfully implement it. Using forced air-induction I'm afraid has too many drawbacks and probably never will replace larger displacement engines unless something dramatically changes that makes it more practical. The other thing is forced air induction has been tried so many times now to replace larger engines and each time it never does. I just don't see that ever happening under the current circumstances, but I appreciate an outside perspective. Thanks for bringing it up.

 

RLSH700 I just enjoy the conversation. Just to make it clear I am not pitching for any one thing in particular. I agree with you on most points except usually with the supercharger or turbo you are using less gearing due to the big torque increase under boost. My old 1987 Grand National used a 3.42 axle ratio and it performed the best with it. I had a vortech supercharged 1993 Mustang with a 302 and it was geared at a 3.55. My Cobra is also a 3.55 gear. Looking at the physics of it, 400hp is 400hp. It will take the same amount of fuel to produce it no matter how many cylinders you have. This being said a 4cyl turbo and a V8 NA both making the same power will use the same amount of fuel at full throttle. The difference is when you are at cruising speed the smaller engine will then show an advantage in fuel economy as it will be out of boost. I've been highlighting the boost thing but let's look at NA. The advantages I like about big inch NA is you don't stress the engine as much and it usually has a more linear curve. What you stated about gearing on this type of set up is true, you won't need as much compared to a smaller NA engine which will help in the fuel economy dept. I will give GM credit as far as fuel economy goes, the LS engines do get excellent fuel economy for their displacement and power. Again, your statements about the Corvette are very true. The LS-7 makes 505hp and is rated at 24-25mpg on the highway out of 427 inches. The 3100pd weight helps though. I have driven a modified 5.7 here in a Magnum and that car performed outstanding. I don't see any Challenger fan being disappointed with the performance of these cars. Thanks for your view points also.

 

Another thing that is important to remember is that GM generally sets up their engines and transmissions to use taller gearing than most other manufacturers so this isn't too surprising. Although you may be correct about when they are just cruising it will yield an advantage, the issue at hand is that will do very little to help them with the CAFE standards from what I understand. The CAFE standards are based significantly off of the "official" EPA sticker ratings. If those ratings say it does no better than a V8, it's not going to help them. Will it help the customers who drive them? If what your saying is correct, then yes. The other thing is under current use of technology the forced air-induction systems are not being paired up with a multi-displacement systems, and that has the same basic effect of when not being used at full power it really can yield some significant advantages. Our administrator has mentioned many times about how his in-laws were able to get 30mpg with a 300C, but that does little to help Chrysler with the Government because their system says 25 (or 23 by the new standards). Also I have talked to many owners of the last F-body cars (Firebird and Camaro owners) and many of them have claimed that the old ratings they had up to 28mpg was accurate, so I don't know how much better off a person would be with the forced air induction route anyways. I don't know any one who owns the current Vettes or any other models so I can't testify about those per say. I will admit I don't know enough results of forced air inducted cars to make a judgment call about what mileage they get so someone else will have to add that one.

I believe part of the reason why the LS engines do so well in fuel efficiency besides weight and gearing is the compression ratios. The LS2 had a 10.9 to 1 compression, the LS7 has about a 11.1 to 1 or 11.0 to 1 (depending on the source). The 5.7L Hemi currently has a 9.6 to 1, the 6.1L has a 10.3 to 1 in comparison. The Viper's V10 improved significantly from 19 to 22 (using the new standards) thanks to the VCT, the increased compression (from 9.6 to 1 to 10.2), and the updated TR-6060 from the old T-56 transmission, despite the slight displacemen

 

Like the old adage goes, "there is not replacement for displacement".

With a beefier engines comes a stronger engine with a bigger crank, 4-bolt mains etc. and that means it take take a lot more abuse.

Now add a forced induction system on top of that and you get one heck of a monster. Turbos are better with fuel economy than
a supercharger because there is no parasitic drain on the engine everthing else being equal.

 

Agreed, the only problems are they aren't as consistent throughout the band in terms of power and they can be harder on the engine than a supercharger. I just think that should be reserved for the aftermarket and larger displacement should be for the production model.

 

Can you elaborate on what you mean by that?



Why not have both.........then you have a real monster on your hands and a more reliable engine since it can withstand the stress.