RED MX5

Instead of speculating the way you're doing, why don't you just post a dyno plot of an MX5 that YOU find acceptable. Obviously you don't believe me when I tell you both the plots I posted are typical for the cars. It would actually be stupid if the MX5 didn't make more torque within it's powerband, for reasons I've already explained. If you have dyno plots indicating anything to the contrary, post them; I'm not always right. But unless you have better data, lets drop the speculations and stick with the hard data we have. OK?

RED MX5

Regarding the power "on the street," if you find that the S2000 does not have enough power to blast away from traffic, you're in the wrong gear. That's a fact. If you need even more than what you need to blast away from traffic, then you must be racing, and any driver worth his salt can get the car into VTEC almost instantly. That's why this kind of comparison doesn't make sense to me.

Looking at the gearing David posted, it is clear that the S2000 has lower gearing (numerically higher gearing), which is what you'd expect, given the difference in red lines. The lower gearing produces more thrust for a given amount of torque, and if the dyno charts posted earlier are typical, it looks like the acceleration of the two cars, in first gear, from a slow roll, up to the MX5's redline, is going to be very close. The MX5 clearly produces enough thrust to scoot away from traffic as easily as the S2000. If the difference mattered under any circumstances I could imagine I'd do a spreadsheet of thrust vs RPM for both cars, but IMO it's more trouble than it's worth.

Does anyone here (who downshifts when the need arises) ever have trouble keeping up with traffic during normal driving "on the street?"

DavidM

Instead of speculating the way you're doing...

Aren't we all speculating here? That's why I was hpping that someone could post the actual acceleration numbers for an S2000 when driven off the line with the clutch engaed from very low revs (or even in 2nd gear from low speeds). I can source these kind of number for the MX5.

Though, I'm more than happy to hear / read any insight here.

don't you just post a dyno plot of an MX5 that YOU find acceptable

That's the thing ... I don't think any of them are acceptable for the purpose of finding out how quick the car accelerates. The differences in the settings, how hard the car is tied down, wheel alignment, tyre pressures, etc is just so variable that the numebrs that the dyno tells us are not that important/reliable.

ie. Here's one ...

http://www.bellengineering.net/Image..._MX5_Stock.jpg

if you find that the S2000 does not have enough power to blast away from traffic, you're in the wrong gear.

How can you be in a wrongh gear if you're in the 1st gear? Does anyone take off the lights in any other gear but 1st?

it looks like the acceleration of the two cars, in first gear, from a slow roll, up to the MX5's redline, is going to be very close

That's what I'd suspect as well. Would love to have it verified though.

smurf2k

in summary, s2000 is better than mx5 in every way

HMFIC

dude.......david.....dats alot of Stars!!!!!

RED MX5

No. I'm looking at hard data and trying to answer your questions.

The BS is harder to address than the speculation. You claim to be talking about "normal street driving," yet you are talking about the time it takes to get to VTEC, and that's just BS. If you engage VTEC in any of the first three gears, on the street, you are guilty of exhibition of speed. If you engage VTEC in any of the upper three gears, you are guilty of speeding (at least here in the USA). Hence, time to VTEC is not an issue on the street, unless you are street racing. Let me give you a few hard facts. It does not matter whether you are driving an MX5 or an S2000, you can easily keep up with traffic, without ever reving the engine above 6,000 RPM, and you can IN FACT accelerate hard enough to get pulled over for exhibition, without ever exceeding 6,000 RPM. So saying that time to VTEC is an issue in "normal street driving" is just BS. If you're trying to beat others away from the light, and they're trying to prevent you from doing so, then that's racing, whether you call it that yourself or not. If you can't blast away from traffic without pushing the car to 6k or more, then either the car is not running properly, or you don't know how to drive it. More facts. An E320 Benz will stay with a stock S2000 until the S2000 hits VTEC, after which the S2000 scoots away. Now if the S2000 is lame below VTEC, then so is an E320 Benz. But in FACT, if you can't pull away from traffic on the street in an E320, you're not pushing on the gas pedal hard enough (or your car is broken). NOBODY has ever complained about an E320 lacking torque or low end grunt, yet it is no faster from a slow roll than the S2000. One more FACT. An RX300 can't even come close to keeping up with an S2000 from a slow roll, or under any other circumstances, and yet it still has MORE THAN ENOUGH grunt and power to scoot away from traffic EFFORTLESSLY.

The idea that the S2000 falls short in this area is total BS. It is no torque monster, but it has more than you can use, legally, in "normal street driving."

Your claim that time to VTEC matters for normal street driving is total BS, and if you are having to get into VTEC in your normal driving then your car is not running properly.

I don't mind discussing the acceleration of the car or any other aspect of its performance, but crazy talk about crazy things like using VTEC in normal driving is not condusive to a productive discussion.

IF YOU TELL ME that you actually have to use VTEC in NORMAL STREET DRIVING, I'll have to take your word for it, and I will, but privately, I'll think you're a liar, because I can blast away from traffic in an RX300, Fiat 128, or first gen Miata (1600cc), effortlessly, and so can anyone else who knows that you have to push the gas pedal to go fast.

OK, I can understand your interest in the data, but you need to be honest with us, and admit that you aren't using VTEC in normal street driving. If you're trying to beat others away from a red light, just go ahead and admit it. If you're not concerned about street racing, then just admit that you don't use VTEC in normal street driving. If you can just be that honest with us we might be able to make more progress.

What I don't understand is your biases here. How is measuring force with inertia or a brake any different from measuring force with an accelerometer? How is the average GTech owner more qualified to calibrate his instrument than the average GTech owner? There are a number of things in your questions and comments that make no sense at all (to me at least ), and this is one of them. Your strong preference for one type of data doesn't make sense to me.

It is not a matter of speculation that the various methods of measurement are equivalent. (Not identical, but equivalent.)

BTW, I personally use accelerometer data to measure the performance of my cars, so don't get the idea that I think there is anything wrong with the data they produce. I just know (as opposed to speculating) from experience that the accuracy of an accelerometer is not any better than the accuracy of a dyno. The accuracy of either one is totally dependent on the calibration and is in the hands of the person running the tests. I don't trust anyone else's numbers on face value alone, and I don't post my own data because it's not really useful to anyone who doesn't understand how the measurements were made and how the equipment was set up and calibrated. IOW, I use acceleometers myself, and still, I can't understand why you feel they're any better than a dyno (in terms of accuracy).

I'm glad you said that, because I was starting to think that you were just trolling. Sorry if I don't believe you when you indicate that time to VTEC matters in normal driving, and sorry I can't get you to understand that measuremets are equivalent, but I have tried.

Don't take this wrong ... I have to ask ... How much actual experience do you have in performance measurement with different devices?
I've been useing accelerometers in my cars since 1976, so I've got 30 years of experience with that particular approach. I almost get the impression that you are trying to sell the idea that they produce more accurate data than a dyno, but I assure you, that's not the case. They are no more, or no less accurate than a dyno, and their accuracy is totally dependent on proper setup and calibration. Most amateurs use accelerometers, and most amateurs are less adept at setup and calibration than most professionals. How could it be otherwise?

But the same thing is true with accelerometers, so there is no REAL difference. The FACT is that they're equivalent. The SPECULATION is that the accelerometers are not equally vulnerable to error, and the speculation is wrong.

You do realize that all the budget performance meters use either one or two accelerometers, and that the lack of three axis measurement makes it very easy for the operator to introduce errors, right? So why would you think some clown with an accelerometer, who wants to see good numbers, would do a better job than a professional dyno operator, who is paid to produce the most accurate numbers possible.

The only way to be sure your data is accurate is to either collect it yourself, or witness the process. Even then it won't be consistent, so you have to average multiple tests if you need accuracy. This is true whether you're looking at dyno plots or arrays of accelerometer output.

Now you have data you belive to be more accurate, so use it.
If you want greater accuracy, collect at least a dozen MX5 plots, and average the data. Discard the outliars. I will speculate here, and say that I believe the average you come up with will be close to the plot I originally posted.

How can you expect people to believe that you have to use VTEC in first gear in normal driving? That's total BS, and you know it.

You can't have it both ways. Either you are talking about normal street driving, where VTEC in first gear is a crime, and not at all normal, or you are talking about trying to race people away from a red light or stop sign. Be honest man, you know you can blast away from traffic without ever reaching 6k. If you can't, your S2000 isn't running properly, and that's a fact.

So, make up your mind. Are you talking about street racing, where you use VTEC, or are you talking about normal street driving, where using VTEC in first gear is a crime? Or are you driving a car that really needs VTEC to keep up with traffic? If it's the latter, your car is seriously broken.

Well, using the dyno plot you posted, it looks like the S2000 is going to be much quicker, because the MX5 has less torque and taller gearing, but if you want accuracy, you need data from a known source, and/or you need to do some averages. This is the case whether you're using unreliable accelerometer data or unreliable dyno data, and none of it is any more reliable than the operator.

IN SUMMARY: Your understanding of the source of measurement error is misguided, and your concept of normal street driving is unreasonable. The data you seek won't tell you anything you can't get from dyno pulls, but for some reason you don't seem to be able to understand why that's the case. I've explained it to you, but you still don't get it, so I give up on getting you to see things as they are. There is no way to have a reasonable discussion with someone who makes unreasonable claims, such as needing VTEC in first gear in normal street driving. If the S2000 would not blast away from traffic, without ever engaging VTEC, neither would an E320, RX300, Miata, 626, Fiat 128, YUGO, or most anything else, but almost any car will run away from normal traffic easily, so the speculation that an S2000 (or MX5) somehow can't, is just BS.

FACTS:

1) You cannot legally use VTEC in first gear in "normal street driving."

2) If you are using VTEC in first gear, it is not normal street driving, it is street racing.

3) If you are racing, and can't get into VTEC instantly, you simply don't know how to drive the car.

TwinTurbo540

I have a friend with an MX5 and i do notice it being a star at low reves we run close till vtec with out a launch but then DEATH TO THE MAZDA.

GrandMasterKhan

You know after reading all that if this guy still isnt convinced then gosh. I dont know what could ever convince him.

My ap2 is plenty quick below vtec. Wheres the Miatas at? I'll do a nice non-vtec 'race' with one hehe.

RED MX5

Normally I wouldn't even consider comparing my car to a stock S2000, because I have 4.30:1 gears and modest FI, but below 4k I have no boost to speak of, and the supercharger is still turning and using up power, so when I shift at 4.5k, my car isn't any quicker than a stock S2000 that's being shifted at 4.5k. Well, it may be a *little* quicker, or a *little* slower, but the difference is tiny. So tonight, I took the car out and tried driving around in traffic, without exceeding 4.5k. In point of fact, that is MORE THAN ENOUGH for normal driving, and even shifting at 4,500 RPM, I was able to scoot away from the traffic around me. Flooring the car, in first, just off idle, is too much for normal street driving, and you have to get off the gas if there is a car ahead, or you'll run into him, because you're accelerating a lot harder. Anyone who does't believe this needs to try it.
Anyone who tries it and can't keep up with traffic while short shifting needs driving lessons or engine work.

What kills me about this kind of stupidity is that I know full well that I can blast away from traffic in a 948cc Bugeyed Sprite, which has just enough power to reach 60 MPH in about 22 seconds, and if a Sprite can do it, and an S2000 can't, then it's clearly not the cars fault.

Of course ALL of the CCR Miata's, except mine, will blow any stock S2000 into the weeds, but that's to be expected considering that all the CCR Miata's, except mine, are running FI with high boost, along with a long list of other mods. For the cost of a used AP1 it is possible to buy a second generation Miata and built it into a much quicker car.

RED MX5

Forget the Sprite. I can scoot away from traffic in a 1200cc Beatle that only makes 36 HP, at the CRANK. If you can't do the same thing in your S2000, then I can outrun you, in a friggin' bone stock, 1960 VW Beatle.