That is impressive then UnhuZ, no underbody kit, no significant body modifications, and the original Honda engineering got you up to that speed.
What's the fastest you have driven your NSX?
- Thread starter mknmoves
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160mph at 2am.
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Steveny: I fully agree. Highways are a lot more fun without speed limits. And if you blow by a cop at that speed, it doesn’t matter. It’s legal!
Shawn110975: I have a 1991 USDM 3.0 liter 5-speed. If I don’t turn off the traction control, the car hits a kind of speed limiter at about 7500 rpm in fifth gear. If I turn the traction control off, the TCS failure light comes on instead at that speed and the car can accelerate further.
I don’t agree that the instrument cluster is more accurate than a sat nav. However, if you look at the rpm in the picture above and multiply that through with the gearing, you get to the same speed as is shown in the sat navs in posts #9 and #20.
I find that decent GPS devices do show the speed quite accurately when their antennas get a clear signal. Cellphones are typically not decent GPS devices. Apple iPhones, Sony Ericsson phones, etc. often use “assisted GPS” chipsets that can quickly determine your location to within 100 meters or so based on signals from cell phone towers, even if you’re indoors. However, the actual GPS portion of the receiver that sees the satellites is miserable. It seems to me that even a cloud passing overhead can cause them to go blind. And if they can’t accurately determine your position, they can’t accurately calculate your speed.
If you had a TomTom, Garmin, etc. device mounted on your windshield and the speed shown was usually 6 mph off compared to your instrument cluster, then I would suspect that your instrument cluster is off. If you got your GPS readings from a cellphone, then that may well be the cause of the discrepancy.
Isn't the 5sp only geared for 186mph?
http://www.nsxprime.com/FAQ/Technical/gearratios.htm
And your speedo must be much more accurate than the 02+ cars, as ours show almost 180mph when we are timed at ~165mph
Hi,
yes it is really impressive... but i can do it in a subtil downhill... while Greenberet can do it in a flat zone... so, his aerodynamics and little engine mods give him the same effect as a downhill for me :wink:
Nuno
yes it is really impressive... but i can do it in a subtil downhill... while Greenberet can do it in a flat zone... so, his aerodynamics and little engine mods give him the same effect as a downhill for me :wink:
Nuno
When my colleague took the picture in post #27, I asked him to focus on the tachometer since I figured the speedometer would be inaccurate. Looking at how the needles were pointing, it seems the speedometer is quite accurate after all. When your speedometer was showing almost 180 mph, did you happen to note what rpm your tachometer was showing? That would be interesting to cross check.
Regarding the gearing: 186 mph is an excellent approximation of how fast a 5-speed NSX with stock tires should be travelling at 8000 rpm. I don’t know whether I need to go on from there, but in case I should:
How fast you are actually travelling depends on your tire size, how much slip they are generating, how worn down they are, how much they have grown due to centrifugal forces, and how fast the engine is actually spinning. When tires transmit torque to the road, they slip. How much they slip depends on how much torque they are transmitting, how much weight is pushing them onto the road, the friction coefficient of the road (asphalt vs. concrete), etc. With all those variables, you can’t know exactly how fast you are travelling based on your engine rpm.
Stock 225/50 16 rear tires should have a circumference of 78.09 inches, so that is how far the car should travel for every revolution of the hub. With stock 5-speed gearing (0.771 fifth gear ratio and 4.062 final drive ratio), every revolution of the engine will cause the hub to complete 0.319 revolutions. At 8000 rpm, the engine is spinning 480 000 revolutions per hour, causing the hub to spin at 153 266 revolutions per hour. With stock tires, that should give you 11 969 270 inches per hour, or 188.91 miles per hour. However, that doesn’t take into account tire slip, tire wear, whether the tires were produced exactly to specification in the factory, etc. The 186 mph in the NSX Prime FAQ assume the car is travelling 1.5% slower than it theoretically should be at 8000 rpm. That is an excellent assumption, but it is a rule of thumb based on how worn down they assumed your tires are, what road surface you are driving on, etc.
Furthermore, that is at 8000 rpm. In my car, the fuel cutout comes a bit after 8000 rpm according to the tachometer. I hit the rev limiter when the needle of the tachometer obscures the lower dark portion of the 8, if I remember correctly. At the TDi dyno day in 2008, your NSX seems to have hit the fuel cutout at 8080 rpm, not at 8000.
So 186 mph is an excellent estimation of how fast a 5-speed NSX on stock tires should be travelling at 8000 rpm, but if your tires are worn down less than assumed, your engine is spinning a bit faster than 8000 rpm, etc. you may hit a different speed.
I consistently take 200mph turns on highway onramps.
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Ours touch around 170mph on the limiter in 5th, which equates to 160mph through timing beams - same as predicted on link. It may be that the speedos became inaccuarate with various wheel changes over the years.
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That wasn't quite the limiter. Had a few more mph to go before changing into 6th. I can assure you that a standard 02 Coupe is not accelerating quickly enough at 160 to make a difference
This is slightly different
http://www.evo.co.uk/news/evonews/251362/9ff_gt9r_crash.html
Too bad about the GT9R, but seriously, who tests a new braking system on a top speed run?
At an indicated 8000 rpm, the tachometer needle is perfectly centered between the upper and lower dark portions of the 8. In your picture, the needle looks like it’s pointing at about 8010 or 8020 rpm. If you can go about 6mph quicker before hitting the rev limiter, the needle would be pointing at around 8300 rpm. Does that sound about right? Since your car actually hits the limiter at 8080 rpm according to TDi, your tachometer may be a bit optimistic. My car runs into the limiter well before tachometer shows 8300 rpm.
The speedometer can be calibrated, so it can probably get out of calibration as well. I don’t know whether the tachometer can be calibrated. Maybe Honda changed the calibration of the instruments over the years or for different markets or maybe there is just a production variance between individual cars.
drifting?
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I don't think the revcounter moves much more, but will check the vid later
Both Paul and my cars showed the same
Looking at the calcs, I reckon a standard 02 (with 0.30 drag) would need around 287bhp at the wheels to do 189mph. So maybe around 360bhp at the flywheel.
http://www.pumaracing.co.uk/TOPSPEED.htm
The 02 press car did 171 round the Millbrook bowl IIRC, so around 178 on the flat, but this had a special engine. The 1997 model did 159 IIRC.
According to the NSX Prime FAQ, NSXs show about 11 - 13% driveline losses: http://www.nsxprime.com/wiki/Performance_Measurements. A car with a transversely mounted mid engine transmits power to the rear wheels much more efficiently than cars with longitudinally mounted engines, than cars with 4WD, etc. So 287 bhp at the wheels should require about 320 - 330 bhp at the flywheel in an NSX.
According to the same page of the FAQ, NA1 engines with Comptech headers, airbox, exhaust, cams, and heads should be putting about 265 - 270 hp to the wheels. In addition to those modifications, I had my intake manifold extrude honed and my engine management chip custom programmed with the car on a dynamometer as per Comptech’s recommendations to make more power.
When the pop-up headlight NA1 came out, Honda stated its top speed was 270 km/h (168 mph). When the fixed headlight NA2s came out, Honda stated they had a top speed of 280 km/h (174 mph). According to Detlef, who has good contacts to Honda Racing, both NA1 and NA2 engines produced more power than officially stated and the cars went faster than officially claimed. But that's hearsay.
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I don't think both these statements can be true. On the hub mounted dyno at TDI, NA1s got around 240bhp and NA2s 256bhp. Maybe that dyno is very pessimistic.
In all the tests that I read, only the infamous 02+ car reached more than claimed. The rest did around 160mph around the bowl, so ~165mph on the flat. This ties in with what I've seen at Vmax compared to other cars when mine was standard (slightly slower than Cayman and E46 M3).
You’re right. Given the rear wheel horsepower figures in the NSX Prime FAQ, either the driveline losses are 11-13% or the crank horsepower are above 270-280 hp.
Detlef told me all the NA1s that were built up for the ADAC GT Cup in Germany showed at least 281 ps (277 hp) at the flywheel in stock form. If the NA1s tested in the US had that crank hp figure and then put 235 horsepower to the wheels, that would imply 15% driveline losses. The five additional horsepower the NA1s showed at TDi may have been caused by not subtracting the rolling resistance of the tires from the wheel horsepower figures.
However, I’m leery of the accuracy of rear wheel measurements anyhow. A Clayton Hydrokinetic dyno measured my car as putting 408 horsepower to the wheels. With the car in the same state of tune, a Bosch FLA-203 measured 270 hp at the wheels. Great. The Bosch dyno also measured driveline losses of 10.4% for my NSX, while a Maha dyno measured 24.0% for Detlef’s at the same wheel speed. Almost no dynos are regularly calibrated, so although they are very good for showing the relative power of cars at a dyno day, the absolute horsepower figures may or may not be correct.
The numbers an uncalibrated dyno generates are of dubious value when predicting a car’s top speed. If the opportunity presents itself, I think you should drive to Germany with a decent GPS device and do a two-way run. At Bruntingthorpe, that 9ff was still 50 km/h down on its real top speed.
Detlef told me all the NA1s that were built up for the ADAC GT Cup in Germany showed at least 281 ps (277 hp) at the flywheel in stock form. If the NA1s tested in the US had that crank hp figure and then put 235 horsepower to the wheels, that would imply 15% driveline losses. The five additional horsepower the NA1s showed at TDi may have been caused by not subtracting the rolling resistance of the tires from the wheel horsepower figures.
However, I’m leery of the accuracy of rear wheel measurements anyhow. A Clayton Hydrokinetic dyno measured my car as putting 408 horsepower to the wheels. With the car in the same state of tune, a Bosch FLA-203 measured 270 hp at the wheels. Great. The Bosch dyno also measured driveline losses of 10.4% for my NSX, while a Maha dyno measured 24.0% for Detlef’s at the same wheel speed. Almost no dynos are regularly calibrated, so although they are very good for showing the relative power of cars at a dyno day, the absolute horsepower figures may or may not be correct.
The numbers an uncalibrated dyno generates are of dubious value when predicting a car’s top speed. If the opportunity presents itself, I think you should drive to Germany with a decent GPS device and do a two-way run. At Bruntingthorpe, that 9ff was still 50 km/h down on its real top speed.
but was that with TCS on or off?:biggrin: If a stock NSX could pull to it's redline in 5th gear with only 270 hp, that would be truly impressive.
BTW, let's see your calculation.
The cool thing is, it can. Not as a two-way average, but one way, if you have enough of a tailwind or a downhill slope, yes.
In the video in post #20, my car got up to a two-way average of 186 mph driving in both directions on the same stretch of Autobahn. If that Opel Zafira hadn’t pulled into the fast lane in the second part of the run, my two-way average might have been a bit higher. But it would never have been 189 mph. In the still pictures in posts #9 and #20, shot during or after one way runs, my car did pull to the rev limiter at 189 mph in top gear. Since that is faster than my two-way average, a tailwind or a downhill slope must have been helping the car along.
Assuming Honda’s statement regarding an NA1's top speed is correct, they can achieve a two-way average of 168 mph in stock form. To run into the rev limiter at 189 mph, they would need about a 25 mph tailwind at ground level. Or a hill. Attached is a simplified spreadsheet (just remove the .pdf ending from the filename) to calculate how much of a hill you need to reach a targeted speed. To be more accurate, the calculation should also take into account the shape of the engine’s power curve, the density of the air, etc. However, the spreadsheet should still give you a good ballpark figure. As you can see, if you find a stretch of road that’s angled about 2.6° downhill, that should allow a stock NA1 to get pretty close to the rev limiter in top gear.
I did 170mph plus in a standing mile down in Miami.
This was not my stop speed, just the speed I got to in a one mile distance.
I also did 178mph in the back roads of nevada a few years ago.
My car is boosted with a different fuel settings. I would like to do a full top speed run one day!
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This was not my stop speed, just the speed I got to in a one mile distance.
I also did 178mph in the back roads of nevada a few years ago.
My car is boosted with a different fuel settings. I would like to do a full top speed run one day!
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