Aerodynamics

[Protoss]

WTF is the 8.5 comming from? did i miss something in a previous post?

is that a correction factor? and if it is a correction error, wouldn't it be calibrated for error?

[bivery]

WTF is the 8.5 comming from? did i miss something in a previous post?

is that a correction factor? and if it is a correction error, wouldn't it be calibrated for error?

yeah you most have missed one of bizbo's previous post.
he said that he could verify at least 8.5 mph over Car and Drivers 122, i did my 5% margin of error from the 130.5 mph, which would have a lower limit higher than C&Ds max speed.

But on another note my 92' dx could do 117 mph and i know my lx has a much better top end.

[JesseSays]

Bizob also has a totally differen transmission...

[Davard]

Car and Driver takes the cars to a 7.5 mile oval to test top speed, using a calibrated radar gun. They test in both directions to cancel the affect of wind. But, they are also testing new cars with new engines, so it is possible that with a more mileage (or a less abused engine) that the cars could go faster. Some of their long-term test cars do go faster after 40k miles (although some go slower).

In a preview test in Japan at Mazda's test track, Road & Track saw 130+mph on their high speed oval...on the speedometer.

Mazda speedos are more accurate than Honda speedos, but are still optimistic. With new 205/50-15 Azenis (which are oversized), my speedo is accurate at 70mph, based on using mileage markers and a stopwatch over 10-15 miles. With the stock tires, it was slightly optimistic.

The Hondas that I have tested were really far off. My wife's old '86 CRX Si was actually doing 68mph at 75mph indicated (verified with the AAA speedo check program), and my mother's 94 is off 5mph at 75mph. When I had my '98 Accord tested by the AAA, it was 3mph off at 75mph...the guy testing said it was the most accurate Honda he had tested (and he'd been doing it a long time). The odometer was dead on (off less than 0.1 in 100 miles) when new.

Most odometers are more accurate than speedos. Honda got into big trouble in the 80's from leasees who were getting overcharged for mileage, with odos that were off by as much as 8-10% (which also helps with gas mileage numbers ).

[Protoss]

see the problem with that 8.5 is I dont know in which direction. is it a + or - 8.5?? and if they measured it as being 8.5 off, then that is the error.

therefor 8.5/122 is the relitive error of the speedo. doee that not make sense? i still am not getting at why you have this 8.5 + error?? was bizob recording a 130mph?? and bizob has a longer 5th gear so he will be able to achieve a higher top speed.

also we need to compare measured with actual, not theory with ajusted extrapolated values.

a high drag coefficent or not the protege is a lightweight car respectivly(sp) thus the higher speed.

[JesseSays]

see the problem with that 8.5 is I dont know in which direction. is it a + or - 8.5?? and if they measured it as being 8.5 off, then that is the error.

therefor 8.5/122 is the relitive error of the speedo. doee that not make sense? i still am not getting at why you have this 8.5 + error?? was bizob recording a 130mph?? and bizob has a longer 5th gear so he will be able to achieve a higher top speed.

also we need to compare measured with actual, not theory with ajusted extrapolated values.

a high drag coefficent or not the protege is a lightweight car respectivly(sp) thus the higher speed.

weight doesn't really matter in top speed. Infact, most top speed cars use MASSIVE amounts of ballast to keep the car on the ground, because using most sorts of downforce cause too much drag.

F = ma

at top speed, you barely have to accelerate, so mass becomes fairly useless, but it'll just take you longer to get there.

[Bizob]

Just to clear it up, I said that Car and Driver was off by at least 8.5mph because what I read on my speedometer was 210 km/h. I used the http://www.convert-me.com/en/convert/speed converter to get a value of 130.5mph. Also, 210 is the speed I was going when I let off.... I watched it climb at least 3 or 4 km/h before letting off the throttle... It probably would have kept accelerating had I not let off. The thing is, this all happenned a long time ago and it happenned very fast, so I can'T be sure. I'm just saying that 122 is definately and underestimation for my car.

[bivery]

see the problem with that 8.5 is I dont know in which direction. is it a + or - 8.5?? and if they measured it as being 8.5 off, then that is the error.

therefor 8.5/122 is the relitive error of the speedo. doee that not make sense? i still am not getting at why you have this 8.5 + error?? was bizob recording a 130mph?? and bizob has a longer 5th gear so he will be able to achieve a higher top speed.

also we need to compare measured with actual, not theory with ajusted extrapolated values.

a high drag coefficent or not the protege is a lightweight car respectivly(sp) thus the higher speed.

they reading between the lines if bizbo is talking about C&D being wrong about the top speed (saying its too slow), the 8.5mph the C&D is off by would not be 8.5 in the negative.
yes bizbo obviously recorded 130.5
and even though bibzo has the dx tranny the longer gear would not play the biggest part in his top speed, the tranny would come into effect when he gears out (meaning he has the power to go faster but the tranny wont let him) and i seriously doubt he has geared out.

[JesseSays]

umm, the longer gearing will hurt him as up around where he'll hit top speed, it won't have the rpm to be in the power range needed to keep accelerating.

It *could* hurt him...but I don't have a dyno by speed handy.

[Boston]

vortexs, and pressure variations forms on the trunk.

Vortices

[bivery]

Vortices

Captain Grammar strikes again.

[Protoss]

read the sig...

so if you read 210, and was really going 130, that would make an error of 1-(130.5/120)

[Bizob]

Who gives a sh!t what the scientific notation for the margin of error is? lol

I was just saying I think they were off, or that I guess my car performs differently that the car they tested.

[bivery]

IMO, even the stock speedo/odo are guesses probably within 5%

Protoss, i am working with a FIVE percent margin of error.
At least your good with fluid mechanics (i think it is), but leave the math to me.
bivery=math

[Protoss]

lol, ok i'll go off and intergrate stuff. lol. this tread just confuesed me.