S13DUG

hi guys,when accelerating through gears i seem to be going faster than my speedo suggests,if i then ease off the speedo seems to play catch up,is this common with imported cars,my93 wrx,?or is it the way its been re-caliberated from klm to mph?cheers for any help.Dug

lumby

i have 98 import sti and i reckon my speedos overreading by 10% at least -tempted to take in to a garage maybe the converters knackered ?

Sounds similar symptons how much is a speedo recalibration wondering whether its worth it

Lumby

mikey f

my sti v5 overreads by 10% also. Very anoying.

Andy McCord

yes mikey i agree, i have a STi V and it deffo over reads, im sat on the M6 doing an indicated 100mph & im just about passing people, the worrying thing is the affect it has on the mileage, you would off thought that it could be calibrated correctly, dont know if anyone can tell me were to get it calibrated correctly, i wouldnt mind +/- 2% but i reckon its more like 10-15% overread

marty_t3

Dug,

I have a 94 WRX wagon with the clock converted from kph to mph. I'm sure mine is under-reading. The clock face on mine is the 180kph one stickered to read in mph. What does your car read just before it hits the rev limit in 2nd? Mine is just over 55. On the motorway id say the speedo seemed more accurate.. on a reasonably quiet motorway cruising with the traffic usually reads about 80.
My odometer reading is spot on though for miles travelled.

marty_t3

Dug,

Took my car out at lunch time and noticed that it does the same as yours. Accelerate and the speedo starts to climb. Lift off and the speedo continues to climb for a few more seconds before leveling off and starting to fall. Never noticed it before... thanks for pointing it out

redwrx

A while ago, i remember trying to work this lot out ..... what happens if you change wheel and tyre..etc?

I was going from 195/60/14 to 205/40/17 ...

inshort i think if you increase the rolling diameter, you will travel further per revolution...but at the same time recording less distance, on a downside you will lose some acceleration.

On the other hand reducing the tyre wall height increases stabilty and therefore handling.

All a matter of choice


I've stuck with the standard 16's

Frank

redwrx

wrong thread .....oops

lumby

Does anyone have any experience of the kmh to mph converters failing and causing the differences on the speedo that have been posted - could it be something as simple as this ??

If so it would be easier to get the converter changed - presumably there are different makes available ?

lumby

Does anyone have any experience of the kmh to mph converters failing and causing the differences on the speedo that have been posted - could it be something as simple as this ??

If so it would be easier to get the converter changed - presumably there are different makes available ?

S13DUG

Marty,mine does about 57 58 in 2nd before rev limiter,thats just down to gearing on early models.also when cruising at say 80 my speedo seems accurate.it just seems to underead on acceleration.on the plus side about short gearing,pick up in 2nd -3rd -4th -5th is very quick as the turbos well spooled up.even having to change to 3rd to get to 60 is still quick,at trax the other week i ran a 4.48 sec,before turning the boost up and burning my clutch.
i am off to powerstation tomorrow to get my unichip mapped ,so i will queary them about the speedos.
Dug

marty_t3

Dug,

4.48... thats bloody quick ... i'd be well happy with that... what mods you got? Just bought my car a few weeks ago so haven't touched it yet.

oh.. and is the S13 cuz you used to drive one by any chance?

Flyboy-F33

Just bought a 98MY STI and was trying to clock it today. deffo over-reading both odometer and speedo. according to the gearing it should be doing about 87mph in 5th at 4000 rpm. It indicates 95mph @4000 rpm, Time to get the GPS out I think.

S13DUG

Marty,my93,ful de-cat concept type r exhaust hks downpipe,blitz induction,dawes mbc,unichip,today at powerstation 274bhp afw,193 bhp atw,245 lbf-ft at4420rpm.at 16psi boost.just had it re-mapped today due to a blowing up-pipe,now replaced.
S13 DUG used to be my reg on previous st 200,
Dug.

marty_t3

Dug,

Thats a pretty decent spec. I'd always thought the older scoobs didn't show as good power increases from the usual mods like exhausts, chips, boost and induction Apparently not the case (which cheers me up no end since i have a 94 WRX)

Reason i asked about the S13 bit was Cuz i used to drive a S13 200sx.

cheers.