If it had the benefit of all the PCM, sensor, airflow and materials technology that's available now.

Just an idle thought.

I was reading "The Heart of the Beast", which is about the ZR-1 and the LT5 (mostly the LT5), and was pondering the power that the LT5 could lay down with all the new technologies that are available... titanium valves... direct injection... etc...

The LSx series motors are quite the amazing pieces of technology themselves, but I guess part of me would like to see the General do a full-bore DOHC massive displacement V8... maybe just as a demonstrator.

Imagine a scaled up naturally aspirated 7.0 liter LT5-type DOHC motor... 600hp? 700hp?

Sure, it would be big and heavy... but Lordy, Lordy would it lay the smack down.

 

The next generation Northstars (Ultra) will be bigger and have all the new tech goodies.

Who needs a 7.0L LT5 when you could have a DOHC 7.5L V12

 

At $3.00 for a gallon of midgrade gas...

 

It would be a seriously bad *** motor. Maybe make it spin to 7.5 or 8k. Would be awesome. Probably would jack up the price of the z06 substantially as well.

 

I would happily pay admission to watch it in action

 

Somebody who can't package the extra length.

 

Displacement on Demand = V12 power with LS1 economy.

Ok... you got me there

 

Didnt they put an LT4 and an LT5 into a set of vettes so GM big shots could drive both and tell which they liked more, before they began LS1 engineering? After the LT4 felt stronger, they were sold, and when they found out it was also cheaper, simpler, and smaller, it was a done deal? I thought I read that in an history-of LS1 book.

Either way, Im sure it would be 'neat' but Id rather see what their next few pushrod ideas do.

 

Wasn't the LT-5 the first engine to have Varible Valve Timing? I thought I read that somewhere in one of my Chevy books.

 

I'm not convinced that this would have made a whole heck of a lot of difference. What's the nastiest DOHC V8 on the market right now? The new AMG 6.3 L. And how does it do compared to the LS7? And right there lies my point.

I could also point to the fact that the Ecotec has yet to match the power output of the Quad 4 in naturally-aspirated form, but maybe that'd be excessively snarky.

An all-out attempt that placed four-valve heads and an absolutely killer intake manifold on the LS7 lower end would be interesting, but assume for a moment that the 475 lb-ft torque peak could be held all the way to the 7000 RPM redline. That'd be "only" 633 HP. I'm guessing that the aftermarket will coax 600 HP from the LS7 with little beyond a cam swap and valve springs. Making more horsepower would mean making more torque (somewhat unlikely given that this engine already makes 1.1 ft-lb per cubic inch), or revving the engine higher while maintaining peak torque (highly unlikely given that 7000 RPM is already damn fast for an engine with a 4" stroke and relatively massive pistons).

Seems to me that the best move would be to scale up the GenIV into big-block dimensions (which would also put it at about the same size as a DOHC small-block).

 

PacerX--in that bookyou read did it talk about valve sizes?

I read somewhere that some idiot at Chevy said it must have the 4.4" bore centres. Someone told him (an enginer?) that they would have to use smaller valves and would compromise power.

Awesome engine though---I'd love to put one in a 3rd gen Formula or IROC.

As for the Ecotec not matchng the old Quad 4---yeah paek hp it doesn't but its a way better engine and is alot cleaner and more torque down low. Not to mention...smoother. I am sure there is more potnetial locked up.

The redlines gettin' up there again----6750rpm.

And I am sure the LT5 did not have variable valve timing BUT had two stage induction on the intake manifold.

 

What kind of airflow numbers did the LT5 heads put out stock? How about a good port job on them? Honestly even with the 4" stroke, I think with the titanium connecting rods they could pull the redline of a 4-valve DOHC LT5 type motor at least another 500rpm reliably, at least. There would be no more worry about hydralic or solid lifters, and having to keep readjusting the valvetrain. Not to mention reduced wear on springs. If the heads could/would flow up that high, and an intake was designed for that kind of rpm, I think this motor would be a beast.

 

The ZR1 Corvette isn't exactly a stirling example of a great car.

The car was hyper expensive for it's day. The engine was beyond hyper expensive (even today). Once the Corvette collectors got their copy, the cars gathered dust in showrooms.

Sure, it was a cool engine in that GM made an engine every bit as sophisticated and advanced as anything else on the planet, but the fact that the new LS6 and LS7 with the so-called "outmoded" pushrods instead of sophisticated dual OHC put out numbers that rank among the top of the worlds most powerful engines, with fuel economy to boot.

LT5s might put out impressive numbers with today's technology, but I doubt fuel economy of the high revving engine or the cost of the engine per horsepower is going to make it very practical in anything that doesn't cost (at minimum) on par with a Ford GT, with ditto horsepower IMO.

 

Come on theres plenty of room for a V-12 ... in the silverado.

Gm and Falconer got together back in the mid 90's and made a V-12 Z71. It was based on a 400 ci SBC, it was alum head and block had 600 ci and made 700 hp and 750 ft lbs.

Didnt the LT5 cost 20k per engine? So whats that in todays dollars? I think the LS series are doing just fine.

 

Fuel economy and the cost of engine per horsepower aren't really significant factors in the sort of market sector where a modern day LT5 equivalent would fit, are they? And a four valve head does not necessarily produce an engine that needs to be revved higher than an 2 valve design of similar displacement.