240Z to 280Z differences...

[mtcookson]

What is the difference between the 240's and the 280's that adds nearly 400 pounds to the car? Has anyone ever figure that out?? I'm looking to get a 280Z for a VG30ET swap and was just curious what the difference between them were.

 

Speaking of the swap brings me to my next question... who all has done a VG30ET swap in here? If anyone has done it, how was it? Worth the time?

 

Thanks in advance guys!

[z-REX]

as for the vg30 look for ZR8ED's posts... he has one in his 280.

 

most of the weight went into beefing up the structure. the bumpers were pigs too, but it's mostly frame, sound deadening, stuff like that.

[Savage42]

From what I've read, it's about 130 lbs in bumbers & bumper "shocks" and the rest into chassis stiffening. I'll take the extra couple hundred pounds in stiffness in my 280 and with 400+ HP, the power to weight ratio stays pretty good!

[rreford]

Here is an e-mail I saved many years ago that takes a stab at quantifying the weight differences. All credit for this goes to Donn..

 

From: (Donn Vickrey)

Subject: <z> Reconciling the weight of a '70 240 to a '78 280

 

A number of people have asked what caused the weight increase from the

240 to the 280. Magazine articles attribute the weight gain to

bumpers, emissions devices, and luxury items. It appears that the car

gained weight every year, except '77-'78 when the car's weight

decreased by approximately 90 lbs. (according to Car and Driver).

What follows is a mixture of (1) data from magazine articles, (2)

personal observations (i.e., I, or someone else on the list weighed

them), and (3) educated guesses. Each source of data is listed below

with a number of 1-3 corresponding to the data type. When more than

one source of data is available, personal obserbvations are given

first priority below due to reliability.

 

Curb weight, '70 240Z (per Road & Track) 2,355

Air conditioning (2) 50

Bumpers (2) 40

Wheels and tires (3) (see a below) 45

R200 differential (1) 25

5-Speed transmission (3)(see b below) 15

Flywheel (3) 10

Stronger clutch components (3) 10

Suspension components (3) (see c below) 20

Additional soundproofing (3) 5

Upgraded interior pieces (3) 10

Catalytic converter (1) 25

Engine, stronger internal components (3)(see d below) 50

Miscellaneous underhood components (3) (see e below) 15

Larger gas tank (3) 5

Stronger frame, unibody (plug figure) 100

-----

Curb weight, '78 280Z (per Car & Driver) 2,780

=====

 

a. Wheels increased in width from 4.5" to 5.5" from '70-'78. If each

wheel/tire weighed 50 lbs. (a conservative, low estimate) then the

increase in weight will be approximately 1/4.5 X 50 X 4, or

approximately 45 lbs.

 

b. The car I am reconciling to is a '78 280Z equipped with a 5-speed.

The 5-speed must be slightly heavier due to an additionl gear,

synchros, etc.. It probably also is stronger than the original

4-speed on the 240 due to the increased torque requirements.

 

c. If the car weighs more, it will need heavier springs and other

suspension components. Also, the 240 had no rear anti-sway bar. This

weighs 10 lbs. alone.

 

d. Obviously boring the engine will reduce the weight of the block

minimally. However, add larger/stronger pistons, larger/stronger

valves, a heavier/longer crank, stronger/heavier engine mounts,

heavier/meatier head, and so on, and 38 lbs. seems entirely

reasonable. The figure could be closer to 50 lbs..

 

e. There are a number of underhood componenents that the 240Z did not

have to cope with. Included are fuel injection components, the odd

charcoal cannister, and other emissions equipment.

 

If these observations/guestimates are correct, it is interesting to

note that one could take a 280Z and, after weight reduction efforts,

wind up with a car very close in weight to a '73 240Z (2,450 lbs.),

yet with a larger engine and stronger body. One IZCC member reported

reducing his 280Z to an observed 2,575 lbs., including the A/C and

even larger wheels and tires. The car could have easily been brought

down to 2,500 lbs. without these two items. Given that most 240Z

owners tend to add weight to their cars through larger wheels/tires,

A/C, 5-speed, heavier suspension components, and occassional L28

conversions, in many cases, I wouldn't be surprised to see some

modified 280s and 260s that weigh less than modified 240s.

 

I'd appreciate feedback on the guestimates in particular to get a more

refined estimate of the weight increases. Consider these a good first

estimate, with refinements needed.

 

Donn Vickrey

'78 280Z (BSP),'90 300ZXTT

IZCC #443, ZCSD #56

[Michael]

The above post is probably the most detailed discussion of 240Z vs. 280Z weight that I’ve seen, but it still leaves open the question: “what is the weight difference between the 240Z tub and the 280Z tub� By that I mean, the “unibody†that remains after literally every bolt and bolt-on part is removed, including all glass, trim, sound deadening, etc.

 

The tub is reputed to weigh around 300 lbs – for a 240Z. A friend and I were able to lift one by hand – it was unpleasantly heavy, but not backbreaking. But does anyone have a more accurate estimate? If the 240Z tub indeed weighs 300 lbs (say), and the 280Z tub is 100 lbs heavier, that’s a 33% difference – definitely significant, with profound implications for increase in stiffness (not to claim that extra weight necessarily means extra stiffness, but presumably the tub weight increased largely because more metal was added in an effort to improve stiffness).

 

The point is that whereas a minor error (say, 20 lbs) in estimate of the tub weight is insignificant in estimating the total weight of the car, it’s definitely significant in trying to compare the unibody structure of the 240 vs. the 280.

[Clifton]

A stock VG30ET in a heavy 280 would be about the same as an L28ET in a 280ZX not too fast stock. I would use a 240Z or VG30DETT in the 280. 400lbs is alot of extra weight for basically the same car.

[Guest bastaad525]

280z's are quite a bit stiffer... 240's frame rails only go to just behind the seats!!! 280's frame rails go all the way back. There are reinforcements in the doors as well, and other stuff I don't remember all of it... if you're going for big power I see no reason to not go with a 280 over the 240.... 280's are much more plentiful, and should be cheaper.

 

My '72 weighed 2320lbs with about 6 gals of gas, my tools, jack and spare in it. '70-71's are 100-200lbs lighter even than that. 280's weight about 2800lbs give or take 100.

[Clifton]

240's are stiff enough for 400+ rwhp easily. I haven't had any weak chassis issues. I road raced mine for years in the street group with out a cage. Put a cage in which should stiffen it up a flexy body and the car was slower (more weight). I don't think the extra weight is proportianal to a stiffer chassis. They're unibody. I think those carrying the extra 400lbs would like to believe they are getting something they need out of it. If I was cutting the top off one I might use a 280 if those frame rails are longer.

[Guest Chris240turbo]

Tallking only STOCK cars here, but I've owned 6 280's and 4 240's,(not including the one I just bought for a song) as well as both an early and late 260, drive both cars, stock, back to back, and you'll soon realise that the engineers at nissan put the weight in the right places!

IMO, again just talking personal experience here, a stock 280, on the street at least, is much more solid driving than any 240 I've had anything to do with, the added weight went quite a long way in making a car that didn't jar your fillings out over rough streets, (although certainly shock valving, and possibly even more significant, tire design, played a big part in a better ride) as well as a car whose doors closed with a "clunk" rather than a restroom stall "clatter" and always seemed to shake and shimmy less, that said I truly think that a 280 makes a better pure "street" car than a 240.

I might add that I do not currently own a 280z, although I would certainly own another, given the right circumstances, and I don't suppose I'd worry much about the extra weight being much of a performance penalty, as witnessed by Rick Bowers recent 12.0x pass in the 1/4 mile with an admittedly well prepped "junkyard" engine.