KingDatsun1

I'm talking about all the Z's in general. I think the 280zx has a top speed of 112mph
are the top speeds limited by the weight of the car and the drag? how fast would a light datsun be able to go? (completely stripped interior, light weight driver seat and aluminum dash)


Thanks
KD1

280zx2by2

my 2+2 has a top speed of atleast 120 cause i flew past a guy in a avalanche that was electronicly limited at 110

weight has less to do with top speed and more to do with acceleration

and your question kind of has no point... do you mean top speed w/ stock motor, just removing weight?

260zturbo

well weight has to do alot but aerodynamics is the biggest thing. the s30 in general is not a every aerodynamic vehicle. alot of discussion about this on hybrid with wind tunnel stuff. but also gotta look into gearing. but honestly how often do you go 120 mph?

duowing

Once you start to reach higher speeds I'd think it'd be less about weight. You'd have all the momentum and it's in motion so it's not really going to make much difference. It's going to be about the limitations of the engine, gearing, and most importantly aerodynamics. My friend was telling me how his Scion xB one day seemed to not want to go past 70. He had the pedal to the floor, and it was super windy. He was joking and saying how his car as far as shape goes is like a giant wind dam.

If you're looking at top speed in a Z you're probably going to want to start with a Z31 or later Z model as the aerodynamics kept improving. Either that or you're going to need some serious stuff done to an S30. The S130 is much more aerodynamic than the S30, and that's part of the reason why people don't like the styling of the 280ZX. Tony D who frequents HybridZ runs a S30 2+2 with a Gnose to do high speed runs down on the Salt Flats.

280zx2by2

the wind blew me into the next lane last thursday... scared the **** out of me, made me wish i liked trucks and not tiny *** sports cars...

snwbrderphat540

weight or mass has no effect on the top speed of **** unless its in free fall. its all about aerodynamics and power and gearing.

apollo

You're all wrong. The real question you should be asking yourself is how fast do you want to spend. The car will go as fast as your pockets are deep. DONE

hughdogz

I agree. Aero has the "ultimate say" on top speed.

From Newton's 3rd law, "Every action has an equal and opposite and reaction". Meaning, the faster your Z pushes the wind away to go through it, the more it will resist you doing so...

Einstein had a similar revelation: "The faster you approach the speed of light, the more your apparent mass becomes"

Remember, it is the same situation with a Z-car. The drag increases with the square of the velocity. It mostly depends on the frontal area of the rig in question, and a lot more to do with smoothing out the flow...downforce has a lot to do with it or else you could get airborne in no time...think about Kitty hawk taking flight at ~20 mph!!

hoov100

has anyone on here ever considered rolling resistance as part of the equation or did it just slip everyones mind? and yes weight has a HUGE part of speed as well as the weight of your wheels.

lww

WOW! Jake comes out of the wood work! I just hope my GZ is in the garage with all this rain!

He's right, top speed is primarily a combination of engine power and aerodynamics. Weight only affects how long it takes to reach that top speed.

Power determines your cars ability to overcome your cars resistance to the air pressure in front of your car.

Your car's cD (coefficient of drag) determines how easy it is to reach higher speeds.

snwbrderphat540

rolling resistance is very minimal. weight coincides with rolling resistance its what makes up the coefficient of friction and any friction is considered drag, BUT in a straight line like that it will never change unless the mass on the wheels changes its an induced drag unlike wind resistance which is parasitic and will increase as speed increases no matter what and IS the ultimate factor in speed along with the power you have and beyond that the gearing.




EDIT: awwww damn you LWW basically said what i just did in a smaller block of words while i was typing.... oh well.

280zx2by2

downforce isnt much of a help at 110-120 mph but like you said frontal surface area and the flow of air around it would be the bigest hinderance of speed... downforce just keeps you from turning that speed into a highspeed wreck (picture the F1 cars flipping 30 feet in the air)...

snwbrderphat540

did you just say downforce wont help at 110mph? lol i can take off a 1400lb aircraft at 35knts a 747 can take off at 120mph..... i think you might be seriously under estimating aerodynamics lol.....

apollo

Haha, yea. I try not to poke around here too much cuz it just makes me angry. Too many Z memories and lots irrelevant questions being asked.
And dont worry, The G is good and dusty in the car hole. Sucks too cuz i had Godspeed put new dunlops on before i parked it.

*Apologies for the threadjack*

lww

Well, those were the factory original tires, so they were about 8 years old... We need to get you back into a Z so you can test all the hypothesis being espoused in this thread... (bringin' it back on topic!)

Bleach

If only I could test these ideas... get an accurate top speed stock, then lower my 280ZX and put on the "g-nose" now available in the US and test again.

85mph speedo won't do the trick.

snwbrderphat540

GPS. its 100% accurate and every GPS i have come around does a storage of top speed average speed and miles covered since its been turned on, or if someone reset it. like i did when i took my dads did 110mph in my SX just to see if it would break 100 then reset it and had to get it to 85mph which was his previous max......

Bleach

ok thanks. I have a Navigon GPS. I'll look to see if it tells top speed.
then I have to find a place to do this test. Going 135mph in a stock 280ZX doesn't really seem safe

280zx2by2

and you do realize that planes have these things called wings that have 10X the surface area of a car... i thing your seriously under estimating the force of GRAVITY.... lol

snwbrderphat540

um.... no. the under side of a standard car is actually only about 1/3 the size of a cessna 172's wing area and they stall at 35knts and they are 1700lbs now we got a car 1/3 the size going 4 times that speed it adds up FAST. and im not saying your going to go flying in the air, im saying you will start to suffer from float though and that proper aerodynamics even if only minimal stuff is added will help the car greatly at those speeds.

280zx2by2

my z dosent weight 1700 lbs, and you still fail...

snwbrderphat540

my god your retarded sometimes.....

260zturbo

..........lol

lww

All cars carry a remote similarity to the shape of a wing. "Flat" on the bottom and "curved" on top. This generates lift. Although snw is correct, weight, an inefficient wing design and significant "flight instability" will usually keep a car on the ground, but you will get some lift at relatively low speeds that will grow as speed increases. A simple air dam and rear wing can add upwards of an additional 100lbs of down force at each end greatly improving the cars stability at speeds over 100mph.

The 1st generation Z cars are far less stable, but even my little air dam on my RBZ greatly improves it's high speed stability.



The much more significant air dam on my 280ZXT (a car that is already FAR more aerodynamic than an early Z) makes a HUGE difference, especially at speeds in excess of 100mph.

SHADY280

i know my wing and airdam helped tons on my car. you can actually feel it sink to the ground as speed increases. ive had my stock z to 180kph, but never went faster due to traffic, now that its modded, ive had it a little past 220kph. my brother had a very worn out lowered s130, he took it to 185kph, but man that thing felt scary at 100kph!!