any1 know the top speed of a 300zx n/a 1992 300zx

The speedo information is partially incorrect.

 

Legally a car speedo cannot under read at all, or over read by more than 10% - so the tolerances are -0%, +10% of the actual road speed. That is what leads to all speedos over reading - the amount of over read is usually quite modest - generally around 5%. So if you have a portable GPS and a straight section of road expect to see that level of over reading. This is also why fitted car GPS do not display speed..... (because it would contradict the speedo!).

 

The usual tolerance for prosecution for speeding is greater than 10% - as that is comfortably into the 'illegal' area - but there have been successful prosecutions at much less as this 'speeding tolerance' is not written into law.....

Wind resistance is the differance there. the vec is much more aero dynamic than a zed.

 

Ive been 165 got there quick and had plenty more and that was on a stock engine. only done it once but still wanted more :devil:

 

Is it? Mine looked like a brick compared to the sleek shape of the zed.

 

EDIT: Your right mate. Vectra b has a drag co of 0.28 and the zed is 0.31. Very surprised by that :blink:

Edited May 30, 201213 yr by Steams

Is it? Mine looked like a brick compared to the sleek shape of the zed.

 

Vauxhall vectra cd :0.26

Zed 32 cd: 0.32

 

Obviously, the lower the number the less drag there is. 0.26 is actually a very low figure for production cars. The zed may look sleek but its quite wide (ie.: large frontal area) and has a relatively short rear which does not help aerodynamically.

Vauxhall vectra cd :0.26

Zed 32 cd: 0.32

 

Obviously, the lower the number the less drag there is. 0.26 is actually a very low figure for production cars. The zed may look sleek but its quite wide (ie.: large frontal area) and has a relatively short rear which does not help aerodynamically.

 

Yeah, I did a quick search on the drag of both and was surprised by the results I found.. Shows what I know about it. lol

yes stu still have blue 300 but some1 wants to swap a silver n/a 300 on a 1992 plate

In regards to Aerodynamic Drag. Most cars have a Drag Coefficient of 0.30 - 0.35. The Z was pretty good at its launch, but cars are becoming more aerodynamic as manufacturers race to improve fuel economy.

 

The 300zx TT is quoted as 0.32 and the NA as 0.31.

 

For the Vectra GSI its 0.30

 

When it comes to Manufacture quoted Drag Coefficients, unless specified separately, they are always for the base model, as it has the lowest Cd. The performance models, like the GSI have a higher Cd.

 

Vauxhall have a history of making low drag production cars. The Base model calibra had the lowest Cd of any production with 0.26 for 10 years!

 

Cross sectional area is important, but you cant really just look at the shape of a car to guess its Cd. Its a bit of a misconception that frontal Area is a the main dependent of Drag Coefficient. The drag coefficient is determined by Profile drag and Skin friction drag, which are affected by pressure differences around the vehicle body. Aspects such as ground clearance, floorpan shape, grill openings, window rake, tailgate/hatch slope..(any many more)....all affect how the air interacts about the body, which alters the Cd.

 

One of highest speed production cars in the world, the Bugatti Veyron, has a drag coefficient of 0.41 - 0.36, depending on its ride height setting.

 

.....and F1 cars have a Cd of around 0.7 to 1.0 (depending on setup).

Edited May 30, 201213 yr by Yowser

quick look on utube and found this if his speedo is correct(pinch of salt there) he's doing 186mph

 

 

I don't necessarily believe that - I don't think he passed the lorry quick enough to actualy be travelling at near 186mph!!

Edited May 30, 201213 yr by RichardS

OK I was pretty sure it was 10% when comparing Sat Nav GPS speed to dials on the latest cars I've had in the last 3 years ST500, Megane Cabriolet, DS3 and Ibiza FR.

 

But I know you cant be prosecuted for 32 in a 30, its defo minimum of 33. maybe thats where I got my 10% from.

 

Will have a looky up on the tinterweb and see what info I can find.

 

Speedo tollerances will vary a lot from car to car; with many being pretty accurate up to about 60mph and then over-reading by an increasing margin thereafter.

 

My ZX for instance (since I fitted the 18 inch wheels with 265/35/18 tyres) is almost bang on to my sat nav. Up to 70 on the speedo, it is identical to the GPS, at 100 on the speedo, the GPS is reading 97, they move back in line at 110mph and don't start separating again until after 120mph. Although I have not seen the variance at more than 5-7mph - all tested on a track and certainly not on the public roads!!

 

Julia's Rav-4 is pretty accurate until over 60mph and then the speedo starts to over-read so that by true 80mph (per GPS) the speedo reads 87!!

 

My previous (black) SLK350 was bang on at up to about 80, and then the speedo would start to over-read by 3mph. Never anymore than that though - even at 120mph+ on the autobahn, it was still 3mph out. I haven't used the GPS in my silver SLK though - it has Command - but I have no reason to doubt it would be much different from the old one.

 

Richard:balloon: