how inaccurate is the EK speed reading at high speed?!

[Kit]

Hey guys,
I was looking through some old pictures and managed to dig up the following.

it was a picture taken of my RSM after a dyno run in 4th gear.
Now.... I know 4th gear can't reach 205km/h at redline.

http://www.users.on.net/cho/rsm.jpg

CHris

[McChook]

Hmm, that is interesting

How do RSM's plug in - I didn't think they used the standard plugs....

[VTEC16]

Shouldnt this topic be called

"how inaccurate is the Apexi RSM speed reading at high speed?!"

jk :P

[Civic Type R]

hahahahahahahaha

dudes, dyno runs are very different to on the road situations.
You eliminate drag coefficient factors.

off course u will go faster on a dyno because there is no drag generated on the car. duh.

[Kit]

hahahahahahahaha

dudes, dyno runs are very different to on the road situations.
You eliminate drag coefficient factors.

off course u will go faster on a dyno because there is no drag generated on the car. duh.

Civic Type R: hehehe sorry dude, dont wanna bust ur bubble, but....
top speed in each gear isnt dependant on drag. its gearing, its mechanical, it cant be changed. 4th gear top speed will be the same whether on the dyno or on the road.

if you factor in drag coefficient of on the road, then all it will effect is how long it takes for you to accelerate to that speed, not the actual top speed figure itself. :)

VTEC16: hehehe well thats true, but i wasnt sure if its the RSM being inaccurate or the signals from the ECU. But i figured the RSM is just interpreting what the ECU is feeding it eh?

I tapped in all the wires to the ECU correctly, triple checked them all :)

Chris

[vuvu]

hey it could be right yknow?
i've done 195 ish in 4th at redline in my civic si (eg model)
and no not on a dyno :roll:
would size of wheels affect it as well? :shock:

peace

[ginganggooly]

hmmm, my integra has taller gearing than the civic vti-r and my 4th is kissing the rev limiter at around the 180km/h region.


does the rsm get a reading from the vss or the ecu? sorry, i gots no idea how this thing works :)

[McChook]

hahahahahahahaha

dudes, dyno runs are very different to on the road situations.
You eliminate drag coefficient factors.

off course u will go faster on a dyno because there is no drag generated on the car. duh.

EDIT - Like kit said.....

Anwyays, just compare the RSM speed to the speed on the dyno printout

[Kit]

hey it could be right yknow?
i've done 195 ish in 4th at redline in my civic si (eg model)
and no not on a dyno :roll:
would size of wheels affect it as well? :shock:

peace

vuvu,
the EG civic has a taller 4th gear than the EK4.
The EK4 gearbox topped out at about 180km/h in 4th gear.
speed measurements can be affected by different wheel sizes, but not by over 20km/h out.
I had 205-16-45 tyres on my car, which were slightly bigger than stock. so, if anything, the speed on the car should have been reading slightly lower than actual speed.

I just had a look at the Dyno sheet. the chart has the power curve ending at 176km/h. so it was out by 29km/h.

Gingan: the RSM gets its signals from the ECU. I tapped in the wires in the footwell on the passenger side.

Chris