unfortunately all 0-60's vary, especially with a v-tec. It depends on how high you rev before you let the clutch slip, touchy feet can turn a low to mid 5, sloppy spinners or rpm droppers turn a 6 and up.

 

[QUOTE]Originally posted by Railroad Bob
[B]
My '99 Suzuki Hayabusa GSX1300R runs it easily in 2.6.

 

You can get EXACT acceleration times.

If you measure from one speed to another in a given gear. Those repeat to a few hundredths of a second most of the time. No shifting, no launching. Great way to compare mods.

Some magazines do many 0-60s and then publish the best one. I'm not sure that is a good idea. Often the best time is a few tenths faster than the average time.

Here is an example of this sort of variation from a review of the Z3 3.0 -

"Performance tests show that this new 3.0 is significantly quicker than the 2.8. In several runs from a standstill to 60 mph, the BMW averaged 5.69 seconds, with one run at 5.31 seconds backed up with a 5.45. That's a half a second quicker than the 2.8. Using only third gear, the 3.0 could run from 50-70 mph in just 3.34 seconds and up a steep grade only slowed it 3.0 to 4.59 seconds. Using second and third gear would have cut these times by at least two tenths of a second. The new 3.0 performance levels are near identical (it's only a couple of ticks behind) to the M version which uses a 3.2L engine of 240 hp."

I'd call that car a 5.7 second 0-60 machine. Some would call it a 5.3 second car. Notice that the in gear times don't even need averaging. This also shows why you can't use a g-tech to tune your car...cuz the run to run variation is likely way larger than the improvement or loss coming from your mod. Interestingly, this guy also repeats the 50-70 test up a hill...and some cars are hurt more than others in that test.

Stan

 

Honda claims in their advertising that the S2000's 0-60 mph time is approximatley 5.8 seconds -- if you can believe them!

 

You know, there are a lot of phrases in the english language that may not be considered proper but are widely used none the less. For example, "You are stupid". And the responce, "No I'm not". According to proper english, "No I'm not" is a double negative and therefore becomes the same as saying, "Yep, I'm stupid". However, ask any college level english teacher and I'm sure you'll find that "No I'm not" is widely accepted as meaning "I AM not". So I say once again, relax buddy. You really have zero chance of making a difference so let it go. Thank you for your time and happy motoring to you all.
VTECnology

 

---------------------------------
You can get EXACT acceleration times.

If you measure from one speed to another in a given gear. Those repeat to a few hundredths of a second most of the time. No shifting, no launching. Great way to compare mods
---------------------------------
I disagree. There's no such thing as EXACT acceleration times. All these things influence the times whether they are standing or rolling starts:
- weight of the driver
- Solo run or with a passanger? (ie. more weight variance)
- Amount of fuel on boad (ie. even more weight variance)
- What the temperature/humidity of the air is. Different conditions have a direct effect on how much power the engine is producting.
- wind strenght and direction.
- Whether you have roof UP or DOWW.
- How much traction the road/tyres have.

All of these things have a big effect on acceleration times and will sill easily introduce 0.5 - 1 sec variance.

ps. The 'in gear' acceleration time seem to have only a small variance beause you're dealing with a very short amount of time - more often then not we're talking about 3 - 4 secs instead of 6 - 15 secs. That means that 0.2 variance in a rolling start is still the same percentage of variance as 0.4 sec in a 0-60mph time.

 

[QUOTE]Originally posted by Railroad Bob
[B]The car magazine guys, and the generally accepted figure I've seen many times for the S2000,

 

To UTAH S2K:

OK, we're talking STOCK bikes, not one-off rebuilds. I don't like to exaggerate about my machines, so I went a little low on my specs. First gear on the Hayabusa would probably go to 80, not 75. The radar-gunned top speed of the 1999 'Busa was 191 by Cycle World and 194 by Motorcyclist. It was the fastest PRODUCTION MC to date. Special machinery, like your Big Pappa, is not included. The '00 and later 'Busas were slowed down by a chip, as you know. Those could be modified in a number of ways to go faster, but I'm just talking bone stock.

We're splitting hairs here, bro...everyone knows it's a fast bike. What's to argue? Have fun with your rides!

 

 

>>>I disagree. There's no such thing as EXACT acceleration times. <<<

Well that is okay. Maybe some examples will help explain my POV.

Maybe we need to define "exact". You can't get chassis dyno runs to repeat exactly at all RPMs every single time. If nothing changed on a car with about the S2Ks power level if you are within a couple ponies then you are doing fine. That's around 1%.

When you do ANY test you have to keep things as constant as possible. You know the old "Scientific Method". So for example my weight of 175 stays pretty much the same, and an extra 5 pounds around Christmas doesn't affect things on today's cars. Same amount of fuel is important, but not to the gallon. Good tire pressures. etc. At a given test session, the in one gear numbers repeat again and again to a few hundredths of a second. UNLESS something changed such as a heat soak, or a mod, or something. Heat soak goes away in a minute or so of driving, and tends to be low with large low specific output torquey motors.

In one test session on my 4 cyl M3 I did four 60-80 MPH tests in 3rd gear. The results were 3.31, 3.34, .3.31. and 3.33 seconds. Around 1% variation, same as a chassis dyno. How about that? Just floor it in third at about 55 MPH and the 'puter measures 60 - 80 MPH time. I feel VERY confident that if I had run the car a fifth time that it would do in the low 3.3s. About 5 minutes later I tried some 0-60s and found 5.75 seconds with a very good but not great launch and a good 1-2 shift. And a 5.9 and a 6.3 with a bad shift or launch. Once the car was in gear, the accel was identical. Cuz you just look at the data logs for every 1/100th of a second. The 5.75 is my best result to date and very good for that car. Looking at the datalogs, if I combined my best launch with my best shift I could knock off another tenth or so. .Each 0-60 had identical 40-60 MPH times to a few hundredths of a second. Cuz you were in 2nd gear floored, no skill. The variation came almost entirely from the launch and 1-2 shift. Small engined cars need awesome launches to run the best times. Roughly a half second variation. Quarter mile runs ranged from 14.17 to 14.65 in a different session. Again lots more variation, about 1/2 second. About 16-18 times the variation in time compared to the in gear tests. With in gear tests you can see improvements when you change oil viscosity.

And when you do a chassis dyno test you are doing an in gear test. Think about it.

If you run a speed to speed test a week later with comparable temp, barometric pressure, and so forth...they repeat!! If you want, you can apply SAE correction factors to help with weather issues. You can get close enough data for that from weather .com and knowing your local altitude within a hundred feet or so.

Again IMHO, 0-60 and 1/4 miles are too skill and condition dependent and vary from run to run enough that you can't really come up with a good comparison or final 0-60 figure. The best you can do is to do a bunch of runs with the best launch technique, throw out some outlyers and then take an average and note the conditions. Many of the magazines don't explain their approach very well..some take averages and some print the single best results even if it was way better than the average. But you can get MUCH closer with in gear tests. Also bear in mind that motors don't always put out the exact same output each time. They vary a bit too.

So above we see what varies on a given car. One unkown factor is how much different examples vary. You'd probably need to test something like 50 cars to get some confidence in that variation. And another factor is that cars change a bit year to year or more often. Often ECU programs are reflashed during service at the dealer with the latest tweaks.

Since in gear tests repeat as closely as chassis dyno tests if both are performed properly and nothing actually changed, I rest my case.

Stan