km/h meters

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'89civicSI

Junior Member
I wanted to know if my km/h meter is giving the good speed. I replaced my ED7 for an ED9 engine whit the ED9 gearbox. The crx ED9 has on the meter an topspeed off 220 and my ED7 has an topspeed of 200 on the meter. So what is true? Must i Replace the hole meter concole, just the meter pleats or what?
 
i guess the easiest way to figure out if its close to acurate would be to have a friend drive behind or along side of you and when you get to specific speeds ask him how fast hes going (on a cellphone or a 2 way radio)... this wont be exacy but it will be close enough for you to know if your speedometer is way off or not
 
Originally posted by 92b16vx@Dec 30 2002, 01:46 AM
I don't see it effecting the speed displayed,just how high it will read.

exactly-
and stock speedometers are not very accurate the faster you go. they are meant to be MOST accurate between 0-60 mph (or about 0-100 km/h)
 
on my parents honda odyessy (cant sp) and my sol they are both about 5mph off. Those signs that say what speed you are going always say i am about 5-8 mph slower than what my speedo says. One way to judge about what way is good or not, find a place that is a known 1 kilometer long, drive 60km/h through that and either have a freind with a stop watch time you or something like that and if your speedo is correct, it should take you exactly 1 minute. If it takes you longer, your speedo is giving a fast reading and if you do it faster than 1 min. then your speedo is giving a slow reading.

In some countrys car companys have to do that. In germany, alot of the new cars have bell shaped speedos curves so when you are going 60 mph, you are really going 55 mph but when your speedo says 120 mph you really are going 120mph (diffrance between says and actuall matches as you go faster)
 
If you know you are travelling precisely 1 mile between markers, you can use a simple division trick to get your actual speed.

v = 3600/t

where t is the time it took you to travel one mile, measured in seconds, and v is the velocity in miles per hour. If you have a stopwatch, that would be the most accurate. I would say try a few different speeds between markers, to see the "bell curve" that your speedo has. Also, before doing this you want to make sure your tires are properly inflated, as this will (barely) screw up the stat.

hope this helps.
 
All these complicated solutions when there is no problem.It is going to be the same because your still traveling the same distance at the same speed the transmission doesn't know there is a different speedometer so it is sending the same signal.If the signal was different than when I swapped a German motor into a American car with a completely different speedo in it,I would be like 40mph off.Not to mention everyone that has put a Japanese motor in and not switched speedos.

v = 3600/t???? What is that.What is 3600 supposed to be a variable for the distance he may travel,converted to what meters(1610),feet(5280)?It would be V=D/T.Lets not forget gear ratio,tire size and inflation,weather,air density and grade traveled upon,also the fact that he his measuring in kph,etc....so to make a complicated story short your factory speedo is probably not right anyway.But the fact that if you speed sensor from your tranny was that different then it probably wouldn't work anyway.
 
oh its just the electronics??so if i swap the km/h plates+console off the crx into my civic the speed is accurate. The redline of the crx console is a litle bit higher
 
That's what I am thinking the engine,revs higher and there for would have a higher reading on the cluster.Just out of curiosity where are you and what model are you swapping?
 
its just a display dude. the dash does NOT effect the motors redline or top speed
lol
 
Originally posted by pissedoffsol@Jan 1 2003, 02:50 PM
its just a display dude. the dash does NOT effect the motors redline or top speed
lol

That's what I am saying,the face is going to read higher on the original car(donor),because the motor has a higher redline and they added more space to it,but it isn't going to change the information sent. :)
 
Originally posted by 92b16vx@Dec 31 2002, 01:15 PM
v = 3600/t???? What is that.What is 3600 supposed to be a variable for the distance he may travel,converted to what meters(1610),feet(5280)?It would be V=D/T.

Well, as my original post said "v is the velocity in miles per hour".

Let me show you how to use my "complicated" algorithm. Say you travel a mile in 58.2 seconds.
v = 3600 / t
v = 3600 / (58.2)
v = 61.86 mph

You can use this speed and determine how badly your speedometer lies at any speed.

cheers
 
So you still have enlightened me as to what 3600 represtents.According to your formula you can't know V only T and D,since your trying to find V.If he had V then he wouldn't need to post this thread.
 
Originally posted by 92b16vx@Jan 4 2003, 08:22 AM
So you still have enlightened me as to what 3600 represtents.According to your formula you can't know V only T and D,since your trying to find V.If he had V then he wouldn't need to post this thread.

in physics you measure everything in seconds and stuff like that 3600 seconds = 1 hour but the top thing should be a length not a time like 5xxx (how ever long a mile is)
 
Originally posted by 92b16vx@Jan 4 2003, 08:22 AM
So you still have enlightened me as to what 3600 represtents.According to your formula you can't know V only T and D,since your trying to find V.If he had V then he wouldn't need to post this thread.

D is the distance = 1 mile, which I specified in my earlier post, but I'll expound --->

Say you travel 1 mile in t seconds, so

1 mile
v = ------------
t seconds

but you want to know mph (not miles/second), so you convert to hours from seconds

1 mile * 3600 seconds 3600 miles * seconds
v = ---------------------------- = ---------------------------
t seconds * 1 hour t hours * seconds

which, then you can cancel the seconds/seconds, and you get

v = 3600/t miles per hour, where t is the time it takes to travel one mile, measured in seconds. B)
 
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