http://www.egmcartech.com/2010/06/30...l-make-440-hp/

 

If it's going to basically make the same power as an LS3 I'll be expecting a relatively big boost in the MPG...it would be reallly cool to see a Corvette with 35mpg on the window sticker (probably not reasonable but it would be cool if the Corvette ended up with Civic like fuel efficiency and dragster like power )

 

I dunno, this design is growing on me. at first I didn't really care for it, but over time it's beginning to look more and more like the right direction, but without the split window and maybe a somewhat different rear-end treatment.... I do like the stingray logo, this is the first time I've really noticed it.

 

There's no new information here. They're still sticking to that "5.5L" story though.

 

I think that article is pretty much just a bunch of dated guesses.

Hasn't the 5.5L issue been put to bed (i.e. it won't be a 5.5L) by some people in the know around here?

If the car drops even more weight (it is already commendably light by modern standards), 440 hp would probably be enough. But with DI and other things added to increase efficiency, I'm guessing we'll see more than 440 hp.

 

That is what I'm thinking, maybe they will get a 30mpg hwy rating out of it. There is only so much HP you can put in these cars. I think we have hit the ceiling, all the new improvements will go towards making them more efficient instead of increasing HP. 440HP leaves room for a 550HP Z06 and 650+HP ZR1.

They say 5.5L, but a lot of people in the know around here have been saying the only two displacements will be 5.3L an 6.2L. So would I be correct in guessing the 440HP number is for the 5.3L in the Corvette? I wonder how the Vette guys will feel about such a large drop in displacement. Maybe they will not care as long as the car is as fast or a hair faster than the LS3 Vette.

We are also running out of LS_ numbers. What will the new series of engines be named?

 

Why do you keep assuming the 5.3L displacement will be a performance application? It's a truck motor.

 

The current 6.2L is already 436HP. With SIDI and all the other upgrades coming I expect that displacement to be putting out close to 480-500HP. If 440HP is to goal I would expect that to come from a 5.3-5.5L size engine. 10 years ago we got 405HP from a 5.7L, so 440HP seems realistic for a DI VVT 5.3-5.5L.

 

Just give the 6.2 DI and call it a day, don't decrease the size of the engine. Big displacement FTW!

 

Pulling out the old HP/Liter thinking.

I don't claim to have any inside information of my own, but I don't see GM using the 5.3 anywhere else but in trucks. To me, the 6.2 would be used exclusively in performance applications with better fuel economy across the board, and direct injection and superchargers spread around the lineup.

 

I am going with that line of thinking, but I also feel others are too when they underestimate the 5.3L. You may have your own reasons, but I feel like just because the 5.3L has never put out more than 315HP people think it is a truck engine and couldn't be a 400HP+ sports car engine. Give it the right heads and cam along with DI and the latest VVT and it is a 440HP V8. Ford is getting 440HP out of the new 5.0L in the Boss. Why can't Chevy with the 5.3L?

Of course then the 6.2L becomes a 500HP+ V8. Is that too much HP for a base Corvette?

 

It isn't that they couldn't, but I'm wondering if there are emissions considerations, or a limitation with the traditional 2V setup at that displacement.

The 6.2 doesn't have to have 500+ HP just because of its displacement and new technologies we assume are coming. My guess is that fuel efficiency is going to be the real news with the next 6.2 in the Vette, not so much pure horsepower gain.

 

I think it was Geoff Chadwick who said we were going to see some big jumps in HP with the new Gen V V8's.

 

Well, first thing is first - the L92 is equipped with GM's prototype variable cam timing OHV setup. What other LS series engines are equipped with that technology? Why is it that when GM puts the DoD technology on an engine, does it get a cut to max rated hp? Those are two questions to think about.

The L92 sports a rating of 404hp on 87 octane. The intake manifold & heads on the L92 are for a truck (~330cfm at max lift if my memory is okay) and that's great for a truck - but what would happen if you slapped an LS3 intake manifold and heads on there? Nobody *actually* knows how such an engine would come rated from the factory, because they have not made it for SAE rating.

There was an L92 DI prototype running around in a Cadillac back in the fall of 2007, a solid 3 years ago:
So assuming the L92 continues on to a DI version, a 6.2L engine should be good for "well north of 450 horsepower." - but what does that mean? If we look at the gains other companies (and GM) have had in hp/liter by transitioning to DI and VVT from their 'non' engines, I could see GM (who currently is getting ~71hp/liter with the LS3) up to ~80hp/liter - which fits with the power gains (higher compression ratio, higher max RPM).

For today's displacements, that would make a (4.8L doesn't get these toys as its the 'cheapy' V8) - 5.3L for 420hp, a 6.2L for 496hp, and a 7.0L for 560hp (And the mythical 4.9L for 392hp and a 5.5L for 440hp). For adding the tech they're talking about (variable cam phasing, direct injection, higher compression, higher max rpm, etc) 10% peak gains are pretty reasonable.

And that doesn't even include replacements for the LS9 and LSA, which are also on the table somewhere under someone's coffee cup.

There is wiggle room for more mpg versus power, but DI's main benefit is increased efficiency (which also allows the engine to stay in DoD more often, netting another tiny bit to mpg). It's not like you can trade 10% peak power for 5% more mpg - but some smaller camshafts might get 1 extra mpg, and that might be worth it. Will they go that route? Possibly, but I'm not sure. They could always just de-tune the engine from the factory so in two or three years they can bump the rating without any re-work.

If you look at Corvette's mpg ratings since the LS1 - she's gotten more aerodynamic without really putting on a lot of weight. She should be getting better and better MPG - but the bigger displacement engines are coming at a penalty.

But does it really matter? When you put all the factors into your giant spreadsheet, the people who buy a V8 over a V6 in a car want more power already and are willing to sack MPG for it. You could offer two V8's, but you're increasing complexity costs dramatically just for that option. Would people take the smaller V8 over the bigger one? Would it make a significant impact on CAFE? GM has already asked these questions and is proceeding accordingly. With 300hp V6's becoming the norm, a V8 under or around 400hp only makes sense in a truck where you need the torque.

There is a huge list of potential engine displacements for the GenV (4.8L, 4.9L, 5.3L, 5.5L, 6.0L, 6.2L, 7.0L and more) that were all on the table with and without boost when the design process was in full swing. They have narrowed it down to just a couple of them for cost and complexity. Anyone who claims to know the final displacements likely doesn't - as the final decision getting public would allow the competition time to prepare and counter-attack. Anyone who DOES know shouldn't say, for that very same reason.

Personally, I would rather have a smaller V8 that revs like an LS7 - a Z06 sounds like heaven, but you can only legally redline it in first gear, which is such a waste when you slam to second and quickly realize you can't keep going and need to find the next onramp/offramp combo to hear the engine at top end again!

 

edit: ^^agree. That's what I get for not refreshing the page before I post, heh.

I don't see how you can expect a big jump in efficiency leading to economy and not see a significant jump in power, unless you assume that they are going to use an odd economy scheme for cam phasing... this is of course assuming constant displacement (as in the 6.2L).

As far as the 5.3L, it depends on how it ends up. Cam phasing and DI (with increase in SCR and DCR) would be helpful. Another good question should be what the bore size (and also stroke) would be since that would be important in answering your questions about power. Is the next 5.3L going to have a 96.01 mm bore and 92.00 mm stroke? How good is the info that 5.3L and 6.2L are going to be the only displacements? The 5.5L stuff may or may not be true, but seemed to show up after the 5.5L motor for the C6R GT2 which is supposed to be Gen V related. The displacement for a racecar motor has nothing to do with production motors at least in that series though.

edit2: Part of the AFM/DOD limits are allegedly imposed by the collapsible lifters imposing a lower redline than the standard hydraulic lifters. However, given that the LS3 peak rating is at 5900RPM and that an L92 or L99 could easily rev at least that high the real culprit is the cam choice with the cam phasing over a wide area of timing retard. Hence why every aftermarket cam installation is installed with a limiter. Both the L92 and L99 also have valve reliefs which lower SCR a little.