Top Speed of r33gtst

[Cubes]

gR33ddy,

When I had the SAFC hooked up my tacho also reads higher than the digital readout from the SAFC. By 4000rpm my dash tacho was reading 200rpm higher.

[JaFF]

same here cubes.

[halz]

I have exactly the same results. The Apexi RSM + PowerFC read the exact same speed (as expected), but the dash is reading ~ 5km/h more ( edit: got mixed up :Oops: ) at 100km/h. Would love to know which one is correct as well!

[Abo Bob]

My dash reads more. I thought that all analogue speedos were out a bit. I've been in a few cop cars with radar (it tells your speed and the speed of the car it's pointed at) and at top speed. Never did the speedo show less than the radar, in fact it always showed 10 to 25 km more. Cop speedos are also re calibrated after they leave the factory every now and then to make them more acurate but as you can see it's still hard.

[igor]

:burnout:

[Bass Junky]

I doubt a resonably stock skyline would crack 250klms easily.

Remember that the for every k/ph more, the energy is multiplied by four, or something like that.

The average car uses about 8kw to stay at 100kph. 150 would be more like 30 kw, 200 more like 150kw, 250 probably about 300kw or something similar.

A 300kW HSV could only crack 256 at a high speed test bowl in controlled conditions flat out.

Pick any supercar, they are slick through the air, have bulk grunt and the media gets excited when they can crack 300 kph.

I genuinely estimate my car to hit about 240kph with 200 at the wheels. Anything I would be veyr pleased with, but not really expecting to any better than that.

Anyway, I've been wrong once before, but I've never taken my car over the legal speed limit anywhere, so I'm just speculating.

BASS OUT

[quincy777]

How can u get 240 with exhaust and airfilter wat bout the ecu it doesnt allow that speed correct me if im wrong?

Sorry for late reply, Gee some of you guys talk some crap. As stated 240km with GTST with only exhaust and air filter. You need good blocked off road, which I arranged.

Standard ecu will limit you at aprox 185km so yes of course you need to mod this.

I used RSM which is always about 5% less than speedo. RSM read 240 and speedo which is just standard was about half way to 'Kmh' from 180.

Hope this helps with your enquiry...

[IanH]

230rwkw got me to 180mph (UK car so roughly 290kph in Australia) but I've only got a good picture at 165mph (265kph) as the airfield was a bit bumpy for the cameraman (I'm in the RAF so got free access to an airfield at weekends!)

[Sydneykid]

The R32 GTST is doing 235 kph at the end of the straight at Eastern Creek, that's with 220 rwkw. It's still accelerating of course, but we do have to turn left:cheers:

PS; I have no doubt that given a long enough downhill straight, with a tailwind, it would hit the rev limiter in 5th, that's ~290 kph.

[performance-wise]

I thought we were tryin to get a top speed for a r33gtst??

any one know why the speedos are different to apexi commanders or RSM? Someone wrote previously that they both are connected to the same speedo reading source?? Does tyre/rim size affect the speed readout??

[benm]

This friends R33.. Was it dead stock? or had the usual exhaust?

FMIC, full 3" exhaust, ex cam gear, k&n panel filter, stock ecu (rsm with speed cut), stock turbo (at 7psi didnt bother with 12psi so about 180rwkw give or take 2rwkw), firm suspension struts etc, standard tyres/rims, sideskirts and low rear bumper.

How did it go towards around 235-250km/h. Torque would have been dropping off at that point so I would have to assume the last 10km/h were slowish.

Quite quick up to about 210km/h then it gradually slows down to about 235km/h then from 235km/h -> 254km/h it was still moving but slower again. If his private road was longer it certainly without a doubt would have gone quicker, easily another 10km/h i'd say (altho would have taken longer again than the previous 10km/h).

Pulling hard is subjective.

Sorry by that I meant the speedo needle was never sitting still it was continuously moving up n up n up.

[Sydneykid]

A few insites to start off with...

Speed is a measure of distance over time, kilometres per hour, feet per second etc

Speedos don't measure either distance or time, they simply count the revolutions of the driven wheels. Like a tacho counts the revolutions of the engine.

This means they are subject to errors of input, the most obvious being the circumferance of the tyres. Even new tyres of the same marked size have different radii. To that add the wear of the tyre over its life and the resulting decrease in circumferance. Smaller circunferance means less distacne travelled for the same tyre rpm, so you get optomistic speedos (read higher that real speed). This can be as much as 3-5% depending ion the tread depth.

In addition car manufacturers build in some optimism into speedos, they are not perfectly accurate, there are manufacturing tolerances, so they allow a small percentage (~2 or 3%). They do this so you are actually travelling slightly slower than you think you are, ie; so you can't sue them for speeding due to a pessimistic speedo.

If you add the two factors together it is not unusual to see a speedo read 100 kph when the car is actually doing 92 kph. And that's an accurate one.

Now for the differences between a needle (speedo) and a digital display (Commander, RSM etc)....

They both use the pulse generator in the gearbox, so they are both subject to the "errors" as above. They can still read different values however due to their contruction method and manufacturing tolerances. Speedo needles are heavily damped, otherwise they would jump around a lot and you woudln't be able to read them easily. Plus they coverted pulses into a needle rotation, this is subject to all sorts of errors, stuff like battery voltage, current drain, temperature, parallex error etc.

The digital read outs (Commander, RSM etc) have the potential to be more accurate as they don't translate pulses into needle movement. They have a timing chip and simply relate the pulses counted (distance travelled) to the timing signals from the chip (time). But they can suffer some of the same problems (as the speedo), temperature stability, voltage shift etc.

So neither of them is accurate either, but how do I know what speed I am really doing?

I find the best way to check my speedo accuracy is to time the car over one of those 5 kilometre speedo check markings. Simply note the time taken to travel the 5k's. Divide 5k's by the time and you have the average speed (ie; a proper speed measure of distance over time). If you kept the speed constant, you will be able to work out how accurate your speedo is.

If your speed according to the speedo was a constant 120 kph and it took you 2.5 minutes to travel the 5 k's then you speedo is accurate. 5 / 2.5 X 60 = 120 kph.

Hope that makes sense:cheers:

PS; just because the oddometer is accurate (shows 5.0k's over the measured 5k's) doesn't necessarily mean the speedo is accurate.

[INASNT]

Sorry for late reply, Gee some of you guys talk some crap.  As stated 240km with GTST with only exhaust and air filter.  You need good blocked off road, which I arranged.  

Standard ecu will limit you at aprox 185km so yes of course you need to mod this.

I used RSM which is always about 5% less than speedo.  RSM read 240 and speedo which is just standard was about half way to 'Kmh' from 180.

Hope this helps with your enquiry...

So where in Melbourne is this street again???

[Col-GTSX]

I see mention above power outputs and how this is a factor for top speed....

Ok on a race track like eastern creek, yes this will help you achieve a higher top speed at the end of the straight... But on a perfectlly flat straight road like a salt pan... (controlled conditions) The power of a car has absolutly no factor in top speed (other than wind drag) but it all comes down to ratios...

Like a said above a dyno is the only way to confirm top speed. Because there is no wind drag on a dyno. Power will get you to the top speed faster yes, but will not increase that top speed. Considering you have a rev limiter, if you bounce the car off it in 5th gear youd get to around 267kph by my calculations. The guys at the local dyno tuning shop said it would be ir-responsible to test this on a dyno cause it would be very dangerous, he said speeds over 220kph could dammage an average dyno.

So i guess its impossible to tell. Take the air strip for instance, a tail wind would help in achieving a greater top speed then going into the wind. However in this case more power would help going into a head wind in achieving a greater speed over a stock 33.

This logically. 7000rpm is standard redline on a 33. At 3500rpm you can be doing about 134 acording to many dyno print outs i have seen. So double that figure. 7000rpm would be roughly 2 x 134 = 268kph..... Take an extra couple of rpm till rev limiter kicks in then you may be able to achieve 275 or so....

I have put a lot of time into thinking about this topic and i appoligise about the "flux cap" comment above but i was in a joking mood....

Anyways in conclusion its all about the drivetrain ratio.....

[Col-GTSX]

Before i cop flack about this reply i will also say...

The original topic is asking about top speed on an R33... Im assuming it means a stock manual box and stock diff ratios on a stock 184kw motor....

Personally i dont believe a r33 could reach 275kph in stock form....

[Cubes]

Before i cop flack about this reply i will also say...

The original topic is asking about top speed on an R33... Im assuming it means a stock manual box and stock diff ratios on a stock 184kw motor....

Personally i dont believe a r33 could reach 275kph in stock form....

So it boils back down to having the power to overcome the wind drag.

[Col-GTSX]

Yes in the testing conditions we have on hand.... yes....

My point refered to perfect controled conditions which is impossible to get so yeah i say off the top of my head 250kph is most likely achievable..... After allot of thinking im pretty confident. Although i have never and will never travel in a car at these speeds... As im a little bit$h....

NOTE: I must say for those of you who dont know me. I was in a accident at 210kph back in 1999 as a passanger in a magna. I spent 2 weeks in hosipital and the driver spent over 6 months in rehab.... The guys in the back were up and about 2 days later.... I will never allow someone to drive when im in the car at those speeds again.... Its just crazy... Cause you have NO control....

When i say NO control, i was not driving and you cannot control other cars on the road...

[knore]

Yes in the testing conditions we have on hand.... yes....

My point refered to perfect controled conditions which is impossible to get so yeah i say off the top of my head 250kph is most likely achievable..... After allot of thinking im pretty confident. Although i have never and will never travel in a car at these speeds... As im a little bit$h....

NOTE: I must say for those of you who dont know me. I was in a accident at 210kph back in 1999 as a passanger in a magna. I spent 2 weeks in hosipital and the driver spent over 6 months in rehab.... The guys in the back were up and about 2 days later.... I will never allow someone to drive when im in the car at those speeds again.... Its just crazy... Cause you have NO control....

When i say NO control, i was not driving and you cannot control other cars on the road...

Well said,

Its not hard to hit 250 on a private track, but at this speed and above things are very unpredictable and VERY dangerous. If anything were to go wrong it would be certain death. Going fast isnt cool, its all about how fast you get to that certain speed. So who cares about going 250-300km/h, its stupid and unless you have a test track to do it on, then do not attempt it anywhere.

[RNS11Z]

After a race with a motor bike, he passed me because i hit rev limit in 5th. I later asked him what speed he was doing when passing... approx 280k. Id say top speed is between 260-270k for a skyline.