wow.i read car and driver today and they said they were punchin out the vette engine to 6.3 liters. i was hopin with all the technology they would have upped the 5.7liter, just cause its been around so long :boxing

 

There's no replacement for displacement. The bigger the better! :smash: :smash: :smash:

 

:withstupid:

 

6.3L = 383 CID. I wonder if they will go 3.9x4.0 or 4.1x3.62? Hmmmm.......

Keith

 

:_dupe:

 

I haven't received my July C and D yet, but I don't thing the 6.3 is correct. We may actually have better info on this forum in the form of an "unauthorized" list of engine options that was posted a month or two ago, but had to be removed by management.

This list refers to a "LS2 6.0L" and a "LS7 6.4L". The 6.4L engine was discussed on the record with Hot Rod Magazine about 18 months ago, and GM Powertrain confirmed that it has two cams, but were mum about the number of valves (meaning that two inlets and one exhaust are a possibility). They did show dyno sheets and this engine was making about net 450/450 torque/power in emission trim.

Since GM reduced the bore of the LS1 aluminum Corvette engines to 3.90" to accomodate the iron liners, it remains to be seen if the 6.0 will have a full 4" bore as does the cast iron 6.0L truck engine or whether the displacement increase will be made with increased stroke. The 6.4L (quoted by GM Powertrain as 389 CID) engine will have longer than the current 3.625" stroke.

Keep in mind that a stroked engine will only make more peak power if breathing is improved via better porting or valve timing, so this bodes well for improved heads or variable valve timing (or both) as 450 HP from a stroked 6.4L engine is marginally higher than the LS6' 405 HP from 5.7L.

Recent rumors have placed this engine at 500 HP. I doubt that this power will be available immediately, but with development it may be possible, and I think GM would want to keep a little in reserve for a future upgrade in a few years.

Although the 6.4L engine will likely have two cams, it's not clear if the 6.0L engine will. The likely reason for two cams is to implement independent variable valve timing on the inlet, exhaust, or perhaps both. Variable valve timing on a single cam engine has marginal benefits because the inlet and exhaust valve timing cannot be independently varied, which is the best scheme for optimizing the combination of emissions, fuel economy, and torque bandwidth.

Duke

 

:withstupid:

 

Man SWCDuke, every time I read one of your posts I learn something new, great info thanks. :thumbs:

 

Oops, small error. I went back and looked at my notes. GM Powertrain quoted the bore and stroke of the "twin cam" LS7 to Hot Rod as 4.06" x 3.78", which yields 391.49 CID, or 6.418 liters. Considering that the bore centers are probably still 4.4" it will be interesting to see the bore construction/material details.

The article was in the October 2001 issue of Hot Rod, and I repeat that the information was provided "on the record" by GM Powertrain. It was NOT speculation on the part of the Hot Rod editiors.

The current 3.90" bore with a 3.78" stroke yields 361.25 CID or 5.92 liters. Just thought I'd run that calculation to see what it would yield. ;)

Duke

 

Duke, given the technology shown in the V-16 engine and the statement that a single cam can do about 80% of what the two cam will do, do you think that the LS7 will still have two cams? I believe you as to what the Power Train people said at that point in time. However, the possibility exists that economics dictates holding off on the two cam/three valve engine, if the single cam two valve can do a reasonable job. :cool:

 

At this point it's anybody's guess as it appears GM is covering all bases. There's no doubt that the engine GM Powertrain discussed with Hot Rod had two in-block cams. The reasons why were not discussed, but implementation of indendently variable inlet or exhaust vavle timing or both is the only logical reason. GM and other OEMs have already done this on DOHC designs since the two (or four on V-engines) cams are already there.

About the only thing I think we can take to the bank now is a base 6.0L engine (despite continued reports that it is 5.7), and an optional 6.4L about a year later, with the base engine at about 400 HPand optional at 450 HP. I'm not counting on 425/500 at this point so as not to set myself up for a letdown.

A "twin cam" would obviously be a substantially redesigned block to accomodate the two cams, and how they will achieve the 4.06" bore is also a mystery at this point. Maybe the optional engine will have a competely different block with the base engine having a similar to current production single cam block. Again, it's anybody's guess.

We've got a pretty good idea now what the cars will look like now, but the Corvette Group and GM Powertrain have managed to keep a real tight lid on the new engines. Maybe they're so good they want to keep it a secret for as long as possible to knock the competition for a loop and send them scrambling back to the drawing boards.

Duke

 

Thanks SWC. That explains the 2 cam motor and seems like a very likely scenario. I recall someone here reported seeing a 2 cam block at GM over 2 years ago. More to dream about :cheers:

 

Do truck engines need a two-cam design with separately variable intake and exhaust timing?

I ask this because there doesn't seem to be a very broad market for the C6 motors in cars, what with the XV12, revised Northstar, high-feature and high-value V6s, and the XV8. I know we might be tickled pink with the thought of Corvette not sharing its powerplant with any other vehicle in whole or in part, but that would be quite a departure from past practice.

Is dual-cam wasted in a truck motor, adding cost and complexity where larger displacement might provide a cheaper route to power? Do trucks need a broad RPM operating range that reaches beyond 6000rpm the way a sports car does? Are there other benefits of this technology applicable to trucks?

Has Corvette finally reached the point where it gets a complete engine to itself? (And perhaps a coattail-riding limited-production hotrod from another division.)

 

The truck "horsepower wars" are heating up, but customers appear to be paying more attention to fuel economy, and a number of high-end SUVs have DOHC V-8s. From a marketing standpoint GM needs something to counter. A three valve per cylinder two-inblock cam V-8 might be the answer. The two cams enable independent inlet and exhaust valve variable timing, which is beneficial to the torque curve, fuel economy, and emissions.

GM keeps reinventing pushrod technology, and I expect them to take it to the next level in the near future.

Duke


[Modified by SWCDuke, 8:19 AM 6/7/2003]

 

You mean like the GTO perhaps? If its supposed to be competing with other cars in the ~30K price range it couldn't hurt to have something like that up its sleeve right? Needless to say it wouldn't get it the first year, and if/when it did it would be an option.

I have friends that keep insisting that the Camaro/Firebird is coming back in a few years, but can't seem to produce any proof of it. Anyway the point is that if the F-body returns it might be a platform that would benefit from the twin cams.

 

"The current 3.90" bore with a 3.78" stroke yields 361.25 CID or 5.92 liters."

Interesting, as this duplicates the Chevy SS 6lt engine shown at the Detroit Auto Show. That engine was reported as being a stroked Gen III of 6lt displacement, giving 430hp and 430lb-ft of torque. In fact the photos show 6lt in script on the engine covers.

About increased breathing from the XV16 announcement:

"The XV16 has cylinder head ports and a combustion chamber that have been analytically optimized to provide smooth, quiet and complete combustion. The advanced combustion system reduces emissions and improves fuel economy simultaneously. Sequential multipoint fuel injection is utilized in conjunction with precisely targeted injectors to minimize engine-out emissions. Spark is delivered by high-energy ignition coils for a clean, fast burn. The engine-management system monitors mass airflow to accurately control fuel and spark delivery under all operating conditions."

"GM Powertrain engineers benchmarked the port geometry of racing engines in designing the XV16. The result is a two-valves-per-cylinder engine with airflow characteristics that rival four-valves-per-cylinder engines."

The XV16's valves are titanium alloy, an extremely lightweight material. The engine also employs titanium alloy valve springs, which are 40 percent lighter than comparable steel designs. The titanium helps increase the springs' natural frequency by 28 percent to allow for higher engine speeds."

". . .variable cam phasing further enhances the XV16's fuel economy, emissions and power output. An electro-hydraulically actuated position controller varies the camshaft timing relative to the crankshaft. The use of cam phasing also eliminates the need for an external exhaust gas recirculation (EGR) system to control engine-out NOx emission." "The cam phaser enables increased torque at low speeds by positioning the camshaft with an earlier inlet valve closing to trap more fresh combustion mixture. It also can be used to modify the "effective" compression ratio, allowing for increases in initial compression ratio for improved fuel economy and performance. A phaser authority of greater than 40 degrees allows for overall optimization of power, fuel economy and emissions."

So, it would seem as though Chevy has another option; a stroked Gen III of 6lt with the technology from the XV16, that yields 430 x 430.

The plot thickens. :cool:


[Modified by I Bin Therbefor, 4:25 AM 6/8/2003]


[Modified by I Bin Therbefor, 2:13 AM 6/9/2003]

 

on the topic of the fbody's return could it be possible that only the camaro would retun, but paired wiht the GTO, that means a GTO and comaro built on the same platform, now im no expert on GTOs but werent they built on the same platform as firebirds way back when. given the 400s in them were large and incharge as compared to the firebird but it is a possibility that we will see the fbody now being the comaro and GTO. that could make it fun. no proof here but just a thought. now i did see a pic of a possible comaro today, i wasnt sure if it was someguys rendition of what it should look like if it came back or if it was a GM drawing, i think the first, but it looked like it was matched body wise with the GTO, again no proof just thought

MAtt

 

In case anyone is interested and wasn't sure about the details of
the valve geometry in the XV8 (LS7??), try clicking on the top
picture at this website.
http://www.carcraft.com/techarticles...GM/index3.html


Part of the motivation for this design is that apparently
stringent Euro 4 emissions levels due to come into force in 2005.

http://www.orbeng.com.au/orbital/abo...f/0142news.pdf

A 6.4L version, if extrapolated, would put out 445HP. Another thing,
what distinguished the C4 ZR-1 from the rest of the C4s was a
more powerful engine with more valves and "sophistication." If
the GenIV LS2 is the next generation beyond the GenIII then
this dual camshaft, trivalve set-up XV8/LS7 would be a perfect
way to reintroduce the ZR-1.
http://media.gm.com/events/productse...s/stephens.pdf

Trivalve engines are clearly on the way (page 17 of the above .pdf file)

[Modified by Runge_Kutta, 2:10 AM 6/12/2003]


[Modified by Runge_Kutta, 2:11 AM 6/12/2003]


[Modified by Runge_Kutta, 2:13 AM 6/12/2003]

 

GTO's were built on the TEMPEST frame .. the firebird was much smaller.. :steering:

 

The Camaro and firebird shared the same platform from day 1. The first hot firebird was the Firebird 400 in '67, which was essentially a GTO engine. The Trans Am came later. These were unitized bodies with sub frames.

The GTO was based on the intermediate GM chassis which included the Chevelle, LaMans, Cutlass, and Regal (SS396, GTO, 4-4-2, and GS performance models). These larger cars remained body on frame throughout their Muscle Car years.
:thumbs: