ZR1 vs.... What they overlook.
 

Consistently there are threads that pit one car vs another, one engine vs another, etc. The ZR1 vs seems to be a very common comparison in this circle. Lets narrow this vs to the LT5 engine.

LT5:
quad cam
dual intake runners
16 fuel injectors
coil pack spark
aluminum block
aluminum head
timing chains(not belts)
(385-405 hp 350ci)
1.157hp/ci for 93-95
.....

Most other engines(of the GM performance type)
single cam
single intake runners
8 fuel injectors
coil pack spark
aluminum block
aluminum head
timing chain
(430hp 376ci)
(505hp 427ci)
1.18hp/ci for LS7

Now what arguments come up most often. HP comparison and technology comparison. HP is easy, so lets talk about technology. The LS7 has 20 years of engine design advantage to pull from. Primary improvement areas are cylinder heads and intake manifold designs. So for all this improvement after 20 years, the LS7 has 1.183 vs 1.157 hp/ci. To put that in perspective, that is about a 2% power increase per cubic inch. I don't know about the rest of you, but that gets me excited. That would be even more impressive on a graph(just kidding). So all that technology and we gain a couple percent and lighter weight(gotta be fair).

Now lets think about what can be done to the LT5 without buying new parts(other than gaskets, etc) and what can be done to the LS7 without buying new parts. Lets assume both cars get optimum exhaust and intake systems. We will also not discuss displacement changes since we can keep the discussion simple by referencing hp/ci.

Porting polishing stock parts(heads, intake runners, etc., retaining stock cams):
LT5 approx. 500hp(properly done) or 1.43hp/ci
LS7 approx. 560hp(properly done) or 1.31hp/ci

Porting polishing with upgraded cams and springs:
LT5 approx. 560hp(stage 1) or 1.6hp/ci
LT5 approx. 600hp(stage 3) or 1.71hp/ci
LS7 approx. 630hp(moderate cams and porting) or 1.48hp/ci
LS7 approx. 675hp(extreme cams and porting) or 1.58hp/ci

So what does all this mean. Stock to stock, newer cars might be faster, but think twice when comparing technology before establishing superiority. The LT5 is a masterpiece that almost throws cost benefit analysis out the window. The LS engine is a great engine that tries to balance performance with cost and feasibility. Imagine the new LS engine with 4 cams and dual intake runners. Does the image of a +700hp 427 come to mind. That would be nice, but what would they sell next year. Also, would the average buyer be willing to pay for the technology. Due to cost and market, we likely won't see the LT5 equivalent in a new American sportscar. There are just cheaper ways to meet minimum standards and sell you a car. Tragedy yes, but I'll take my 90 368 over a c6 anyday and its not about money.

I'd be wary of this kind of argument. Take it too far and we should all go get S2000's. Regardless of hp/liter, the LS7 gets it done with a smaller size, less weight, and similar fuel economy.

It's fun to think about the LT5 that could have been, especially as they were pretty close to doing it with the "1995 MY" design (not the 1993-built engines that went in '95 MY cars). And the engines are really something special, with a lot of potential even by modern power expectations.

But the LS7 is the real deal. If you've ever driven one, I think you'd pay that car its due for what a totally stock, totally emissions compliant, totally warrantied engine can produce. I was blown away when I test drove one.

dont drive a Z06 and you will be ok.

If GM made the car perfect, it would have looked like this.

http://i7.photobucket.com/albums/y292/kpie/DSC_0521.jpg

The LS7 is about as good as it gets for that displacement and technology. If you did decide to use S2000 technology on an LT5 (which you could not do on an LS) but scaled up to LS7 displacement (assuming it is theoretically possible to do so), you would have 840HP, over 500 lb-ft peak torque and over 400 lb-ft from 2500 RPM. The S2000 was difficult to drive (meaning inadequate torque) because the engine was so darn small. There would be no torque issues at higher displacements. And the power would be monstrous.

The fact that there are higher displacement LT5s pumping out LS9 power but naturally aspirated should give one a clue as to the power potential that was left on the table when Chevrolet walked away from the architecture.

Nice PIC Kevin

Could not agree more.....

If Ford does the Coyote engine to 6 liters in a mustang or??(mystery car that doesn't weigh a lot) I'll be the biggest blue oval fan boy you have seen- especially since I'm a GM guy.

The LS engine is lightweight and compact- that will not be outdone.

Ford is showing that if you make enough engines across multiple model lines by the 100's of thousands, the economy of scale will be there to benefit the consumer. The aftermarket will come too.

I'm torn on what future GM cars should have for engine tech- I like cheap, but eventually they will have to offer something more sophisticated.

You've basically made my point. You can talk that up, but the reality is the Z06 delivers 505 real horsepower, and the S2000 only delivers 240. Honda has never shown it can "scale up", and they have barely broken the 300hp mark with production engines.

The LT5 definitely has a sweet spot with intake/head porting and some headers for power/dollar. But an LS7 isn't exactly hard to make big power from either, and gets pretty good gains from cheap mods too.

While I love the LT5, and it was absolutely the right answer at the time, I think GM has shown it wasn't necessary to push the horsepower envelope (witness ZR1, Z06, CTS-V, and the forthcoming ZL1). While it might not be a 100% fair comparison, look at what GM did with the S/C Northstar vs what they did with the LSA and LS9. The Northstar cars (STS-V, XLR-V) are no slouches, but they are no bargains either. Prices were $70-100k. And the cars were heavy. The CTS-V and ZL1 aren't exactly lightweights, but a 3,800 lbs car built on the C6 platform is surprising. I think the engine architecture takes some of the responsibility.

Though in their V6's and I4's, DOHC is really impressive. The little turbo Ecotech is really something. I think it's just waiting for the right car to get dropped into. The Sky/Solstice was close, but a bit too heavy and pricey.

This conversation really cant get started until the well uninformed stop by to grace us all with their vast misinformation.IBTL.:D

I've owned everything from Blue Flame's to Big Blocks and love the feel of the LT5's power range. Each has their own unique characteristics. The feel of a Big Block and a 4-speed is incredible if you like tire spin and brute power.

I test drove a new Z06 back in 2008.....simply INCREDIBLE. I really need to own one of these or a new ZR1 one day. I was extremely impressed at just how precise GM had made the car's performance and the shifter was perfect.

You just have to own one of each if you can.

Owning both a ZR-1 and a ZR1 would be the best of both worlds... ALL Day.. Every day :iagree:

GM had some DOHC engine on paper that got scrapped during the recent bankruptcy didn't they? I bet they will gain some steam again soon.

Couldn't agree more :eek:


Strongly agree... But that engine belong's in the car Kevin !:D

Yes, I think it was called the "Ultra" program or something similar. All of the "premium" cars that used the Northstar are gone now. The Lucerne, DTS, and STS. The need for a N* replacement is about at its lowest.

The 3.6L V6 is becoming more prolific (only engine offered in grocery getters like the Impala now). And they are expanding that lineup (3.0L version, rumors of a turbo version).

GM is having success with DOHC motors in areas where their pushrod motors were lacking. The 3.9L "high value" V6 is a POS in my opinion. A descendant of the fun but leaky 2.8L Chevy V6. They haven't had a pushrod I4 for years now (thankfully), but those were always crap.

In those areas the Ecotech (and new smaller variants) and the Caddy V6 have really done well.

Against the LS motors, the Northstar has not. I think at least part of the problem is that V8's are inherently balanced. So the "smoothness" aspect isn't a real factor. And of course the power vs size favors the LS. Like the LS4 that fit in cars a FWD Northstar never could have, and made more power with better economy. Though now the FWD 3.6L makes even more than the LS4, and with even better economy.

I have to think, for the time being, the DOHC V8 is done at GM. Though, just like in the mid 80's, there may come a time when they need it again.

I don't see a Coyote going that big. A kit is out to go to 351" which requires sleeves and a stroker crank. The Coyote has a 3.9" bore spacing and 3.63" factory bores compared to a 4.4" bore spacing on Chevy small blocks and 3.9" bores on the LS1 and LT5. It will still be interesting to see where the aftermarket takes the Coyote. I have never been a Ford guy but a fox body powered by a Coyote with big cams backed by a T56 with a nice track oriented suspension under it would be an awesome toy.

The LS motors make great power with fewer moving parts which could be argued as a more advanced design. Having modded a LS motor the beauty is the simplicity of the motor and that they respond to a few mods. The aftermarket was in part won over due to a readily available platform, that responds very well to the basic intake, exhaust and 1 cam.


I'm torn as well, the LS is so simple and inexpensive but a DOHC V8 spinning some serious RPM would be fun.

Now THERE is an idea... Put an LT5 in a C6. Talk about "best of both worlds"!! Think about the crowds that might draw on any given cruise night!?:D

That's more or less what the XLR-V was. :cheers:

I believe it was also the first GM car to cost more, inflation adjusted, than the ZR-1 did.

My 68 Mustang use to be the center of my universe. Then I got my 90 ZR-1 and that was the end of my love affair with the stang. If I get a C6 ZO6 is there a possibility the same thing might happen to the ZR-1? Maybe. But fortunetly I've already driven a 2008 ZO6 and didn't loose interest in the Z. So I've passed that temptation test. I do agree my money would be better spent making HP out of the ZO6. Easier in many ways. And thats just the way it is.
http://i301.photobucket.com/albums/n...tar25856_1.jpg
Now the Mustang is up for sale. There is a good chance that a C6ZO6 will be sitting in its place before long.

It would have to have cam phasing or I don't want it. I would not be opposed to an optional trick high-tech multi valve engine option in the C7 (except for the part about it being too expensive for me to buy).

Having owned a 1991 zr1 and a 2009 Z06, I will say that the torque of the LS7 is incredible and down low compared to the lt5.

However when looking at the LS7 versus the LT5 the LT5 is an artful masterpiece and beautiful to view under the clamshell hood. the LS7 looks just like the engine you find in a chevy pick up.