dcbingaman

Cruising about the Web, I compiled the following engine spec. table to better inform our discussions. Many engine spec.s are relatively easy to get, except for dry weight. Engine weight is a key factor but is hard to nail down since the mfg.s really don't like to talk about it, and in some ways it is comparing apples to oranges to pomegranates. For instance, is an intercooler a radiator and not included in the engine weight, or integral, as in the Eaton TVS superchargers on the LT4 and LT5 ? There are no good answers. I estimated LT4 and LT5 weights from the LT1 weight and the Eaton TVS weights for the respective superchargers used.

In any case the comparisons are interesting. If anyone has data to fill in the "TBD's", send it to me and I'll update the chart.

JD_AMG

You should specify how dressed the engines are for a fair comparison. GM weighs their engines with the flywheel and clutch assembly attached for whatever reason (unless they specify the weight is with the flex plate) while other manufacturers do not to my knowledge. That is usually 60+lbs of weight right there.

Here are some for you:

LS7 crate engine weight:
https://ls1tech.com/forums/generatio...ls7-crate.html

Ive attached a PDF file from a crate engine site, I feel like it was GMperformanceparts but I don't remember. Weight of engines include the crate and packaging material (which they note to be 30lbs here) and you can see the weights are all over the place for practically the same engine because the engines are in different levels of dress, some near fully dressed to completely undressed, and it doens't specify which is which but its pretty easy to tell.

Rkreigh

Jerri I feel the desire for pushrod motors as I love my z06. but for tighter emissions variable cams, turbos, and smaller displacement will be the only way to meet both hp and emissions targets.

durability, compact, lightweight, and especially low cost typifies the LS architecture

I turbo the little beasties and I haven't found a need for more than 1k hp on the street which they produce comfortably

pushrods aren't bad, and dohc isn't necessarily hard to work on as you might think. I have torn down and worked on a few LT5 motors and they aren't that complex.

now a hot v tt engine like you see in the caddy is whole step up

I think the vette will see a larger version of this engine with the turbos on the outside.

don't be hating 800+ HP that lives and has a nice wide powerband just my 02 of boost

Rkreigh

that's true, but a ms3 pro as and additional injector controller just doesn't cost that much or you could be stuck in the mud with ONLY 780 hp with the gm kit and a decent exh

Work arounds are available. GM spends quite a tidy sum on driveability, why not take advantage of that and just add the fuel needed up top when you want more power?

it's not rocket science, pooters is stooopid

RapidC84B

Foosh

I'm going to be shocked if the intro base model doesn't debut w/ a NA LT1 variant. Later MYs may involve a switch to another engine for CAFE reasons.

RapidC84B

z06801

I would agree for sure but that's why I suggested the Katech LT1 427 which should be a much more straight forward.

BillY2KFRC

The prospect of a mid-engine C8 with their 427 motor is exciting, however, it may also be challenging if the C8's ECU cannot be tuned as with the ZR1. My hope is that since the C8 will be a high volume, high visibility car, the incentive to be the first to hack the ECU will be much higher than it has been with the ZR1.

Tom73

Shaka

The only sure way is to weigh and measure everything yourself, especially if you build cars and race 'em. My two roadster are almost identical except one has a modified 96 LT4 and the other has a modified LS1. I purchased a LS3 for my new car. Each have injection, ignition and water pumps and 100 AH alternators. No PS or air. Each has a T56 6 speed attached. My highly modified C6Zs LS7 weighs less than my LS3. The LS3 weighs more than the LS1. There have been many internal mods to these engines. They all weigh more than my 96 LT4. Even though they all have the T56, the gearboxes have different weights. The Z T56 at the rear is the lightest, the one behind the LS3 is the heaviest. It has much bigger gears in first and second. The one behind the LS1 is different to the one behind the LT4. The extension housings are all different lengths. The parts are not all interchangeable. The clutch hydraulics are all different. The LS1 and LS3 T56s have internal hydraulics. The fly wheels and clutches are all different and vary in weight.
The dimensions are all different also. Different to what has been published here. The LT4 is the smallest. I had to move the LS1 forward by 3 " in the same frame that was designed for the LT4. I had to raise the hood and revise the coil/over placement and lots of other stuff. The worst thing is, the LS1 and LS7 required huge radiators and oil coolers. That means more oil and coolant. The LT4 and the LS1 had the same 400 HP, but the 96 LT4 had no cooling problems or oil surge problems. I couldn't get the LS1 to run cool, fixed the LS7 for 610 HP in the C6Z and the crate LS3 car has yet to be driven.
When you design a car, you gotta weigh everything that is going into the car. It is critical for placement of all the components. The computer, even early 95 CAD programs, will give you the exact weight of the chassis as you design. To move the engine and gearbox after the chassis has been designed and built, simply Fs Up the design. Did I cuss at the Chevy engineers? It took many years to fix that LS engine.

Dominic Sorresso

Dominic Sorresso

Shaka

It has had many design changes since the GM engineers, and not the Lotus engineers began designing this engine in 92. They had carte' blanche with this design. They entertained OHC but chose the OHV and it was not because of budget. They began with the LT5 gen.3 block. The cylinder head bolts are an integral part of the structure on the aluminum LS engines. It has taken many years to get this engine right. My LS1 was a disaster. Cooling was a problem from the beginning. The OEM radiator manufacturer dude who helped me with the cooling issue, said it was an internal design error which turned out to be true. The LS engine they will use will be the best yet. There was talk of 2 cams side by side in the block and even a vari single cam. Will have to ask Tadge what became of this idea. My LS7 is at it's reliable limit at 6500 rpm and 600HP with a hell of a lot of cooling. Better results with the truck cast iron LS engines.

NICK YOSKIN

100% agreed. Older crowd will most likely disagree though.

Dominic Sorresso

Tom73

jefnvk

I'm 32, hardly old. As long as it is putting up the numbers it needs to, which it currently is and I have zero reason to suspect it won't in the future, I couldn't care less if it is DOHC, OHV, a boxer, or a rotary.

Ok, maybe not a rotary. Point is, no, the average Corvette owner doesn't care about the engine internals. I bet the majority of buyers couldn't even tell you what DOHC stood for, let alone what it is. Most care about HP, displacement, and maybe torque, roughly in that order. If you REALLY care that much about a car needing to have DOHC are you willing to defect and buy a Mustang, to put your money where your mouth is?

JD_AMG

I guess I gotta post this again, which will again leave you with nothing to reply to.








You essentially wanting to use a big block that makes small block power for the Corvette, have fun adding all that weight and hurting all around performance and making the car more expensive.

RapidC84B

I'm 37 and I'll gladly take a cam-in-block OHV motor over a DOHC motor. They're physically smaller, lighter, and more simple. Try putting a set of headers on a the 4.6 DOHC Mustang Cobra I used to have vs. any Corvette. It's a lot easier to have fun and mod a LS/LT (admittedly they did a few things that make the LT harder than the LS) than a DOHC motor. Would I not buy a C8 if it comes with a DOHC "blackwing" derived motor? No, but I really don't want a twin turbo one. I've had enough headaches with our Twin Turbo Mercedes diesel.