Apexi RSM inaccurate??

Hey,
my RSM seems to be a bit off on the Revs and speed. When it reads ~2000rpm on my tacho, it's about ~1800 on the RSM... about 200 off...
which one is more accurate? I assume the stock tacho. Is there a way to make more accurate? what kinda settings?? My speed is also about 3-4Km more than stocks...

The settings i have now on the 'ETC' menu settings :
Cycl : 4
SP1 : 4P (Signal Pulse) ??
ADJ : 100% - what is this suppose to be??
Tyre: 106%

I dont know what the SP1 and ADJ settings suppose to be...


thanks.

shouldnt stress dude...thats normal...the stock tach is bout 200-300 rpm off

the RSM is more accurate...

it is not normal from what i saw in my previous rides
i dunno jazz tho...

even in the apexi manual it states a 2-300rpm difference can be expected.. i get that also... in my prelude..

lol
are u guys sure?
it rev like my meter b4

yup stock tacho have been known to be off...not all of them though

Speedometers are generally less accurate as it needs to convert electrical pulses to mechanical, thus the inaccuracy, the RSM taps straight into the electrical pulses and will give a more accurate reading...

AS for the speed, don't worry, I tested my RSM speed against a speed measuring device and it's accurate to the DOT...

As for the tyre correction value.. it should be 100% unless you are not using your stock wheels.. it's the difference in rolling diameter..

SP1 is the vehicle pulse value which u play around to correct the RPM (I Think) as near to the speedometer...

ADJ is the Speed pulse value.. Same thing, play around to get as close to the Speedometer speed as possible...

Hope this helps..

CHEERS
Nick

Hey thanks,
i played around the ADJ and got the speedo on the dot with the stock. But the RSM seem laggy; when I stop, the RSM reads at about 5Km/h for about a second or two before it goes to 0... ?? i've adjusted the ADJ to 98 now instead of 100.

yeah i have bigger wheels, i just got a rough estimate and put 106% as rsm documentation formula is (New Diameter / Old Diameter)x100.

Rev still different... but if RSM is accurate then i wont worry about it...

thanks guys.

I know this is heaps old but wanted to bump this to ask a question re: Apexi RSM.

If I install into a Civic FD which has the digital speedo, will there be a difference between what's on the RSM and what's on my speedo? I'd imagine the speedo in the Civic doesn't refresh/update that quickly (i.e. it delays a bit?), but was wondering if the RSM would also have a more accurate reading as opposed to the optimistic speedo?

Ta
jc.

the reading will be the same...but it might refresh abit faster...the defi link display refresh super fast...but not sure weather defi and rsm which one refresh faster

Dudes, its going to be off by a little bit. It doesn't really matter does it? RSM's only for the wank factor

Stock speedo in Civic is pretty off already. I was thinking if I change rims size then using the RSM would be an effective way of getting a more accurate speedo.

Dont worry because speedo in small car actually show 1 - 3 km/h different than your actual speed. Any data obtain from your ecu are more accurate than the speedo. I know jazz, echo all have speed varies from actual speed because of their wheel size.

Quote:

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Originally Posted by kelvinthai

Dont worry because speedo in small car actually show 1 - 3 km/h different than your actual speed. Any data obtain from your ecu are more accurate than the speedo. I know jazz, echo all have speed varies from actual speed because of their wheel size.

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thanks.

yes :p btw speedo always show 1 - 3 higher... my friend told me about it which i further confirm upon using my greedy informeter.

^ i noticed that also from even my Tomtom GPS.. but i was more wondering if that's because the ECU outputs the inflated figure, or if the speedometer (in my case, the electronic speedo) was applying some kind of formula/calculation to inflate it.

speedometer other than data obtain from ECU can silightly varies due to government legislation. Normally the difference is only a aspect ration of +-5 which makes around 1 or 2 km/h diff above 100. Car maker tend to set it to higher than actual reading.

The reason the speedometer will read differently is because of what is called roll-out. Roll-out is the distance the vehicle will travel for every complete revolution of the tires which is equal to the circumference of the tire. A speedometer is calibrated for a certain roll-out based on the tire size. Tires that are too big will cause you to be travelling faster than the speedometer reads because you will travel farther in the same amount of time. A smaller tire will be the opposite, you will travel less distance in the same amount of time. So if you do change the tyres or tyre wear, there is a difference.

Some question the reliability of GPS as a speedo as there is a time taken to transmit the data to and fro satellite while you are on the road. afterall you are a moving vehicle although GPS tend to have serveral satellite lock on.

I am not a expert on this tho :p

hmmm but my defi vsd speed shows the same as my speedo?? why is that?

not too sure.. but your jazz is not normal :p thats for sure.

i had it in jazz and dc5....both had the same reading in both the defi and the speedo....i think they show the same speed for all cars

just buy Greddy informeter. I still have mine for sale, brand new.

just a question, would anybody happen to have a rms installed on a jazz? having trouble locating the rpm and speed signal wires to install it. have powered it up and found it working however the apexi instructions seem a bit off. anybody out there that can help me?