dizwiz24

Just curious why its heavier

Crabs

The heads are MUCH bigger than SBC.
Don't forget 4 camshafts, 32 valve springs, 32 lifters, 12 feet or so of heavy duplex chains, an 11 quart oil capacity and a 60 flywheel all add up.

'Crabs
'90ZR1 #792

Tom400CFI

With all of the above (especially the heads) but the flywheel, since they're functionally the same.

The LT5 also has a heavy steel or iron ladder structure in the bottom end to support the crank.

Also the entire intake system. LT1 intake probably only weighs 20 lbs? IDK what an entire LT5 intake weighs, but I'd bet it's around twice as much.

I think mostly, the engine is just very strong, and weight is a consequence.

mike100

I have heard The full compliment of LT5 headbolts alone weigh 20 lbs.

Z51JEFF

Cant believe you guys fall for this BS.To the OP,getting slow over in O.T.?

Tom400CFI

What BS? Are you saying the LT5 is not heavier than an LT1 or L98??

dizwiz24

I am offended. I am a diehard c4 guy been here 10+ years.

Do you really think i associate with those holes over there?

Z51JEFF

Why do you think it's heavier?

jss06c6

L98 = 3330
ZR-1 = 3465


Both coupe, both 6 spd.

?? Sure looks like LT-5 adds a little weight, but overcomes it with better power and higher redline.

bb62

The LT5 engine is certainly a contributer to the differential, but to know exactly what is driving the difference, you would also need to know what options are available in the L98. The ZR-1 is fully optioned up while the L98 weight may be just the base car.

Some other considerations beyond the engine:
- The weight of the wider body work
- The weight af the larger doors
- The extra weight of the 11" wheels
- The extra weight of the wider rear tires
- The larger rotor size for the ZR-1 front wheel braking system
- Power seat weight (an option not picked up by all L98 cars)
- The weight of the electronic heater controls (not much but automakers do look at everything in categorizing vehicles by EPA weight classes)
- Delco bose speakers
- The performance (3-way) shocks and associated hardware

Point here is that it's not as simple as pointing to the engine. That 135 pound vehicle differential may not even have a majority of the differential explained by the engine change.

ZR1Bob

I recall reading somewhere that the LT5 engine weighed 714 pounds. Maybe in the Heart of the Beast, but I can't remember. Edit: Can't find the 714 number anywhere. Additional research surprisingly doesn't yield a clear answer. I have found numbers of 596 pounds and 602 pounds in various publications. Surprised that there is no authoritative source that can specify engine weights on a consistent basis. I don't know what a current LT4 weighs with supercharger. --Bob

illenema

Lt5 is a Large engine. Heads, cams and chains, intake.+++

http://i261.photobucket.com/albums/i...psdv0hlkez.jpg




You want heavy, that avatar pic engine has it beat weight wise by 300+

Mr. Gizmo

THe plennum and injector housings together are probably close to 60lbs. I took the plennum off my 91 Lt5 and that sucker was heavy.

93Rubie

FYI, a 93 Z07 LT1 ZF6 coupe with basically every option that adds weight is about 3300lbs.

A LOT of the weight IS the LT5. It makes the weight bias go up a point up front so that kinda signals its the engine. Also, a LT1/L98 car is a bit more nimbe due to less weight on the nose and better Z51/Z07 suspension. The ZR1 really had soft springs more of a HIGH SPEED grand touring car than a track/auto-x car. Since few Corvette owners care about track/auto-x (especially in stock-ish form) what does this weight thing really matter?

dizwiz24

The weight doesnt matter.

I remember lots of bragging about the 'all aluminum' lt5

An ls3 is all aluminum but weighs less.

In trying to understand what parts made it weigh more. More valves, gears, chAins i understand.

What i learned new was the 11 quart oil capacity (wtf? Is that just to punish the owner during oil changes?) and the 60 lb flywheel.

I think heavy flywheels are dumb as heck especially on an engine designed to rev high like the lt5.

Sure a heavy flywheel makes the car easier to drive for golf course types in heavy stop and go traffic, but it is undesirable in every other racing situation (including drag racing, but thats my opinion and not every one here is going to share that).

Someone had a point that an lt5 car is going to have every option by default vs a lower optioned lt1/l98 coupe. So thats part of the added weight.

This post was by no means a knock on the zr1. Trust me it excites me more than the c6 zr1.

If i had a c4 zr1, Itd be a 415 twin turbo.

Oh, and id ditch the heavy flywheel

Tom400CFI

The flywheel is not 60 lbs. I already said that in post #3. The flywheels of ALL 6 speed C4's are functionally the same, and virtually the same weight; about 37 lbs. THAT weight was documented in the link, in post #12.




.

FASTAZU

It has an oil cooler behind the radiator that holds about 3 quarts of the extra oil.

dizwiz24

Oh! Cool. Useful!

Stuff like hat prob helped it out during the tommy. Morrison? Endurance at bridgestones fort stockton tx track

DRM500RUBYZR-1

SOME DO, MANY DON'T; YOUR CHOICE.

Marty

dizwiz24

This is the post that is stating the dual mass on the zr1 has a 60 lb flywheel.

Later posts disputed that. I didnt notice the later posts which is why i assumed the zr1 had a heavy flywheel.

Again, i think heavy flywheels serve no purpose other than to make the car easier to drive (less chance of stall) for non racers or people learning to drive stickshift.

Ive had it both ways and i will not go back to a heavy flywheel.