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Chassis strength


Guest yatsen

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Guest yatsen

Hello everyone,

 

I'd like to know whether the chassis and drivetrain of the 79-83 era ZX is much sturdier than the earlier Z's. Almost a decade after I totalled my ZX I'm starting to get the fever again after having owned a couple of muscle cars and a European car. Currently I'm looking around for a decent Z/ZX. Since my last name isn't Gates it might be wise to get a sturdier car that can handle a strong engine instead of spending a lot of $$$ on chassis mods. I'm aware I'll have to put a little on the side for that anyhow. I'd like to modify the engine and I'm also thinking of dropping in something from Detroit.

 

Thanks.

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The condition of the specific vehicle you are looking at is of more importance then whether its a 1970 240 or a 1980 280ZX. Rust, the enemy of all these cars, is your biggest concern. Purchase as rust free a vehicle as you can afford.

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Guest yatsen

I forgot to mention another reason for posting my question: I have the option to buy a 240 in very good condition and a '79 280zx that's also in very good condition. Both cars are nearly rust free but the body panels of the 240 look nicer. I'm planning on using lots of fiberglass, however.

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The drivetrain of both cars are basically the same, except the 280ZX probably has a R200 diff which is better if you're pushing over 300hp. The 280ZX chassis is stronger then the 240Z chassis but it also weighs from 300 to 700 lbs more. depending on which 240 and which 280ZX you're comparing.

 

Ultimately, you're trying to base an emotional decision on logic and that never works. Buy the car you "like" the best.

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Guest yatsen
Ultimately, you're trying to base an emotional decision on logic and that never works. Buy the car you "like" the best.

 

As far as making an emotional decision, well, if I had the resources I'd buy them both :wink: I did survive a frontal collision with a Ford Ranger while cruising in my '83 ZX, which is something to keep in mind ... Basically I want to buy the car that willl cost me the least amount of money to prep into something strong and nasty.

 

BTW, how much abuse (traction + torque) can a R200 take?

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Basically I want to buy the car that willl cost me the least amount of money to prep into something strong and nasty.

 

That would most likely be a 240/260/280Z because lots of folks have done exactly what you want to do. Everything is figured out and its almost just a matter of following the instructions (JTR book). Fewer people have done the work on the 280ZX chassis so there's more "figuring & fabrication" involved.

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Guest BigWhyteDude

If i were in your shoes i would buy the 240. Simply b/c they are so much spiffyer looking to me. i just love the body lines of the eirly z cars. :)

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Pro's for 240Z:

Classic design and nicer body

Less weight in 240 (280Z and Zx weight are almost the same), hence more nimble

Faster and better response

Better steering feedback

Much more aftermarket parts, therfore often cheaper parts

More information available on modifications (mostly for suspension and brake related set ups)

 

Pro's fo 280ZX:

Stiffer chasis

Better aerodynamics ( Z's Cd was 0.467, for the 280ZX they spent six months refining the design using a wind tunnel to get the Cd down to 0.385. Additionaly lift was reduced by 60% and sidewind stability was significantly improved)

Safety related to chassis, stronger doors, real bumpers and increase in weight. Given equal platforms and design, the damage sustained to a car is related to the difference in weight squared. So if a 4000lb car hits a same design 2000lb car the damage sustained to the lighter car will not be twice as much but 2 squared which is 4 times as much.

Less significant benefits: T-tops, better AC, better doors,.locks, power mirrors....(which can all off course be seen as negatives based on personal perspective and track vs. daily use...)

5 spd tranny and R200 diff. (half shafts on turbo model)

 

Personally, if I was to put in a V8 I would opt for the 240Z because of classic design, much more aftermarket parts and more info on mods. I would also then consider a cage for safety mostly (what can I say, I'm getting a little more conservative with age and parenthood)and also for chassis stiffening (specially fro V8 ).

As a turbo addict, I recently got a 280ZX turbo ( i had turbo swapped a Z before and had another 280Zxturbo) because everything was already there (turbo, half shafts, R200 ....) and then started further modifying it.

If I was to keep the original engine I would definitely get the 240Z over the 280ZX. But I would still rather get the 280ZX turbo (it's very different from the non-turbo) over the stock 240Z (because of power/torque)

Most of these comments are obviously subjective and can be viewed differently based on personal preference, and priority (speed vs handling, track vs street use, daily driver or not...). In the end both cars properly modified will be a blast and they both have well proven track records.

As JohnC already mentioned, the most important factor relates to the car with the least amount of rust (i.e. cancer). Make sure you check the chassis carefully.

In terms of cost, it's always more than anticipated, but in my highly biased opinion, it's worth every penny :-D .

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Afshin, you also forgot to mention the ZX's have four wheel disc brakes. I have a 280ZX that I am stripping paint off of right now. I love the way it drives. Since my car is nothing to look at and I overpaid, I always find myself looking at the first gen Z's. I would go with a 280Z or 280ZX if I were going with a high power setup because of the added strength and safety. I am going with a more mild L28 setup so I think the first gen would have been better for me. I will forget all about the first gens once I get paint on my ZX. :-D

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Guest thinkmonkey

.467 Drag Coefficient! That's very suprising to me, I always thought of the Z as slippery... Hard to believe that the new G35 sedan is coming in well, well below .3

 

-David

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You're right Z driver, I can't believe that I forgot to mention the four wheel disk brakes as a plus, it must have been past my bedtime.

I know what you mean David, I never would have guessed that the Z was about as aerodynamic as a brick. But my understanding is that cutting thru the air (i.e. sloped nose) is a small part of aerodynamics, most important is turbulence and drag from creating a vacuum in back of the car when moving forward. The Z was never tested in a wind tunnel and there are many modern large grilled four door sedan these days with Cd's in .27-.29 range because of low turbulence above and below (quite important) the vehicle and little drag in the back.

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Oddly enough, the 240Z was tested in wind tunnels, at least from what I can tell. I have a coffee-table book on Z history, with several pictures of wind tunnel tests. One can only conclude that either there was something wrong about those tests, or the Z’s aerodynamics were knowingly sacrificed for better looks. Regarding the former, I’ve seen a photograph of the 240Z in a wind tunnel test section, with its wheels on pylons off the tunnel floor. And probably that tunnel had no boundary layer splitter/suction upstream of the test section. Two things are wrong here: moving the car away from the floor or ground plate will give a completely wrong result in terms of ground effects, and not sucking the tunnel boundary layer will throw off the data regardless, because the test section isn’t getting clean, uniform air.

 

This winter I toured the 9-meter low-speed wind tunnel in Ottawa, Canada, where they do a lot of NASCAR-type testing. Roush Racing had some full-scale models. In fact, they were actual race cars, with the engines removed and tufting added to the bodies. Technicians would roll a car into the tunnel, take data, then roll it out and replace it with another one. Anyway, in that tunnel, the car sat on a turntable flush with the tunnel floor, but there was a giant boundary layer suction lip upstream of the test section. Underneath the turn table was the balance, which measured lift (or downforce) and drag. A technician showed me two nearly identical cars, but with different-sized bulges over the front fenders. Evidently the car with the more bulbous fenders was for more downforce (shorter tracks, tighter turns perhaps), while the car with the more gently curved fenders was for lower drag (probably for tracks will longer straightaways). Anyway, the point is that a bad wind tunnel test is no better (and maybe worse) than no test at all, while a good wind tunnel test can reveal things that completely slip one’s intuition.

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One thing to remember when comparing the CD of various cars is that the force applied to a moving car by drag is determined by a function that uses the CD, the frontal area of the car (height x width), and the speed it is traveling. That is why the simplest way to lower the drag induced on your car is to lower it. It is very possible for a large car with a low CD to have more drag than a small car with a higher CD.

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Oddly enough, the 240Z was tested in wind tunnels, at least from what I can tell. I have a coffee-table book on Z history, with several pictures of wind tunnel tests

 

I just rechecked my Z books, in Brian Longs book on the ZX there is only mention of the ZX being tested in the wind tunnel and in Millspaugh's book Z car a legend in it's own time he specifically says the the 280ZX was the first Z to be tested in a wind tunnel. I know the Z has been in wind tunnels, that's how we know how poor the CD is. So I think it was tested after it was produced and the info might have been used for racing modifications as opposed to during the development of the production car.

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Guest tom sixbey

aerodynamicly, the early cars were in bad shape for 2 main reasons

1 - the intake area in front of the radiator is has poor diffusing capabilities.

2 - the angle of the rear hatch causes a large amount of separation in the airflow over the top of the car.

 

We have to understand that this time period produced cars that were designed for looks and not necessarily aerodynamic performance. The top of an automobile is essentially an airfoil. Unfortunately the airflow characteristics of an early zcar's roofline are similar to those airflow characteristics of an airplane wing that is on the verge of a stall. There is simply too much camber to permit smooth airflow over the top of the roof, and the "eddies" that are produced by separation in this low pressure zone are very detrimiental to our drag coefficient - and it also reduces the effectiveness of rear spoilers and wings. This cannot be changed unless the angle of the hatch is to be altered with respect to the relative wind.

The intake ram can however be modified to improve our aerodynamic performance. The "lip" created by the edge of the hood and the valence areas is a very poor diffuser for the intake ram. Airflow seperation happens inside the front opening behind the sharp hood edge, and causes a substantial amount of drag. This also reduces the airflow velocity at the font of the radiator. There is an entire science devoted to the design of submerged ducts. - i recommend that you read "tune to win" and "engineer to win" if you are intrested in how this relates to cars...

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Seeing we have drifted off topic ;) I recall that there was an article in a long ago US magazine, Road & Track?, where they tested the fitting to a 240Z of a flat, angled alumium plate fixed at the back of the hatch. Apparently it made a significant improvement without any additional drag.

 

Can't recall the size, angle, etc but it was about the size and angle of a whaletail.

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