Speedo correction for free!!

**Stav** · 12-01-2007, 03:12 PM

After about a year of not having the correct speedo reading and 2 jaycar non working kits I have found the way!! My speedo was exactly 10kmph too high.Speedo cogs just did not have the correction factor.

Today I decided to pull the cluster window off and at 20 kays pushed the needle down to the proper speed using my gps.It was fine all the way until I stopped.The speedo then went back to the wrong spot.

When I got home I then proceeded to remove the speedo pointer/dial and placed it in the position which I believed was correct. I got my gps and went for a drive.60 kays on the gps..now am doing 59 kays!1.I stopped and started the car and guess what? It stayed fixed.The only difference now is the needle does not point at 0 kmph when the car is off but .5mm below.It works well..lol.

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Casper · 12-01-2007, 03:21 PM

Why was your speedo out 10kph the whole way round?

I know with mine being out its not a fixed amount of kph but a fixed % due to the diff.

Effectively mine is out 15% which means at 60kph I need to do 69kph (9kph difference) but at say 80kph I need to do 92kph (12kph difference) or at 110kph I need to do 126kph (16kph difference)

Are you sure its only a 10kph difference at all speeds?

**Stav** · 12-01-2007, 03:26 PM

Dont know why? The dial used to sit on 60 and gps said 50..at 60 on gps it read 70..or maybe a bees knee off like 69 ? At 90 on the gps showed 100 on the dial.Maybe because of all the gizmos im running?

Casper · 12-01-2007, 03:29 PM

Maybe try it on the freeway at 100k where the % variance may make a bigger difference. If your's is similar to mine at about 15% then 60 is about 50, 70 is about 60 and 80 is about 70 give or take a few kph. However, once I get up to 100kph then its closer to 15kph out of wack.

sfr rob · 12-01-2007, 03:51 PM

oh...... i would need a calculator on board if i were you Casper, way too much equations going on just to sit on the right speed! Would a simple speedo corrector thing from jay car actually work?

Casper · 12-01-2007, 03:56 PM

Quote:

Originally Posted by sfr rob

oh...... i would need a calculator on board if i were you Casper, way too much equations going on just to sit on the right speed! Would a simple speedo corrector thing from jay car actually work?

Calculating 15% is pretty simple really.. takes me from the time I see a speed limit time to the time I pass the sign to calculate it usually.. a few seconds.

Yes, a Jaycar corrector will work as this is what it does.. but I'm waiting for their new model corrector to come out (and to stop being lazy and go get one)

**Stav** · 12-01-2007, 05:17 PM

It is out Capser.I have it and cant get it to work .

FS5 · 12-01-2007, 05:33 PM

i thought the edit could correct your speedo reading when you change your diff gears?

Casper · 12-01-2007, 05:47 PM

Quote:

Originally Posted by FS5

i thought the edit could correct your speedo reading when you change your diff gears?

unfortunatly not

cArSiK · 12-01-2007, 06:56 PM

Quote:

Originally Posted by FS5

i thought the edit could correct your speedo reading when you change your diff gears?

With BAs you dont need to make any adjustments as the ABS sensors record the speed, not the gearbox.

GlennBA · 12-01-2007, 05:51 PM

I go faster than what my speedo says because the 19's are a smaller profile than the 16's. I probably should get it fixed.. but meh

Sledgehammer · 12-01-2007, 05:58 PM

I remember hearing a story once that the speedos could be recalibrated up or down by a specific amount? (oh and I dont mean turning on and off 37 times whilst having you finger in your ear and toe in the lighter socket) Their was a way to adjust...Rob Herrod may have mentioned it.

Of course you can also buy another speedo drive gear as well

congo3sr · 12-01-2007, 07:41 PM

Quote:

Originally Posted by Sledgehammer

I remember hearing a story once that the speedos could be recalibrated up or down by a specific amount? (oh and I dont mean turning on and off 37 times whilst having you finger in your ear and toe in the lighter socket) Their was a way to adjust...Rob Herrod may have mentioned it.

Of course you can also buy another speedo drive gear as well

what a ****er,nearly choked on my beer,laughing

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**Stav** · 12-01-2007, 09:22 PM

Quote:

Originally Posted by Sledgehammer

I remember hearing a story once that the speedos could be recalibrated up or down by a specific amount? (oh and I dont mean turning on and off 37 times whilst having you finger in your ear and toe in the lighter socket) Their was a way to adjust...Rob Herrod may have mentioned it.

Of course you can also buy another speedo drive gear as well

Hey I am multitalented . You cannot get the correct speedo gear for every diff ratio change for my gearbox.

TwistedEL · 12-01-2007, 09:50 PM

Quote:

Originally Posted by Sledgehammer

I remember hearing a story once that the speedos could be recalibrated up or down by a specific amount? (oh and I dont mean turning on and off 37 times whilst having you finger in your ear and toe in the lighter socket) Their was a way to adjust...

I think it only applies to ex-police vehicles

FS5 · 12-01-2007, 10:17 PM

spewin about the edit i thought it could ajust your speedo .chiptorque do a chip or someting that will corect it for 300 odd bucks ,i was talkin to them after i fitted the 3.9's it also fixes the speed limmiter to.i couldn't justify the dough though.
my speedo is still out 10% , wich makes it pretty easy to calculate what speed i'm doin.my concern was the speed limiter shutting me down before the end of the qter.(i wish)

xr8ute · 12-01-2007, 11:50 PM

The problem is, the vehicle speed signal (aka VSS) goes first to your dash, and then to your EEC.

You need to change the VSS so that the dash reads correctly, this then throws out the calculations in the EEC. To fix the EEC, you use the edit to change the value in there for diff ratio.

LOWAU · 13-01-2007, 12:56 AM

Quote:

Originally Posted by xr8ute

The problem is, the vehicle speed signal (aka VSS) goes first to your cluster, and then to your EEC.

You need to change the VSS so that the cluster reads correctly, this then throws out the calculations in the EEC. To fix the EEC, you use the edit to change the value in there for diff ratio.

Does it really matter what signal goes to the ECU after the dash?

I wanted to know if I could alter the needle in the dash to make the car think its traveling at a lower speed so that I can go past the 180kph limit, I don't want to top out on the 1/4 mile after doing some new planned mods. I have gone from 3.08 to 3.73 so top speed is limited now.

au2sw · 13-01-2007, 07:34 AM

Quote:

Originally Posted by LOWAU

Does it really matter what signal goes to the ECU after the dash?

I wanted to know if I could alter the needle in the dash to make the car think its traveling at a lower speed so that I can go past the 180kph limit, I don't want to top out on the 1/4 mile after doing some new planned mods. I have gone from 3.08 to 3.73 so top speed is limited now.

your govener is stoping u from reaching over the 180k mark, remove that or adjust it to a high (unreachable) speed, and that should fix your prob there. unsure of how to do it, perhaps an ecu thing?

xr8ute · 13-01-2007, 12:28 PM

Quote:

Originally Posted by LOWAU

Does it really matter what signal goes to the ECU after the dash?

Absolutely. Vehicle speed is used in more than a few functions in the ECU...speed limiter, and auto transmission shift and lockup points being the most obvious.

There are a few things here that are very important to understand.

1. the auto is programmed to change gears, and lockup the converter at certain engine speeds...not rpm.

2. the dash does not talk to the ECU, and the ECU does not talk to the dash.

3. the signal from the VSS goes to the dash first and then the ECU, using the same wire. i.e. if you make a change the the signal from the VSS to correct the speedo, this "correction" will also be passed onto the ECU....you must consider the impact that will have on ECU calculations.

In an auto, when you change the diff ratio and nothing else...the auto shiftpoints will be at a lower vehicle speed (although the same rpm), and your speed limiter will be lower. This is because the ECU thinks your car is moving faster than it actually is.

You can fix the speedo by changing the drive gear on the VSS for one with a different number of teeth (these gears are not available for all ratios). OR you can use an electrical signal modifier like the Jaycar speedo corrector.

So now your speedo is displaying the correct speed, how have we affected the ECU?

....you'll have to wait, ive got to duck out for a few minutes. Will update this bit when I get back ;)

JC · 13-01-2007, 12:37 PM

Quote:

Originally Posted by xr8ute

....you'll have to wait, ive got to duck out for a few minutes. Will update this bit when I get back ;)

I know; it drops a cylinder right? Making engine speed match diff speed? ROFL!!!

:

: :Reverend: :eclipsee_

xr8ute · 13-01-2007, 01:19 PM

Quote:

Originally Posted by JC

I know; it drops a cylinder right? Making engine speed match diff speed? ROFL!!!

:

: :Reverend: :eclipsee_

LOL, something like that....if nothing else, it hurts my brain.

This coffee has almost kicked in, wont be long.

Walkinshaw · 14-01-2007, 01:35 AM

you are taking the **** arent you Stav?

**Stav** · 14-01-2007, 08:38 AM

Quote:

Originally Posted by Walkinshaw

you are taking the **** arent you Stav?

Sometimes I do but not this time. I fair dinkum did remove the speedo needle and placed the pointer a little bit lower than the 0 mark and it works really well. The only potential problem I faced was that at that position I could not push the needle all the way back onto the spindle. Despite this fear the needle stays on very tight and gives excellent speedo accuracy.

It all started when I received a tickford dash recently and stored it on a shelf next to my car. The thing slid off the shelf and under my tyres path overnight.When I moved the car out that morning I heard a terrible crunch! I had run over it!! What part of it survived had decided to pull the dials off and realised that you can change the angle of the speedo needle. I know that after the countless threads on speedo correction and correctors this is a bit hard to swallow but it is true..lol

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StealthAu · 14-01-2007, 08:46 AM

http://www.jaycar.com.au/productView...Max=&SUBCATID=

LOWAU · 14-01-2007, 03:32 PM

Quote:

Originally Posted by stockoau

http://www.jaycar.com.au/productView...Max=&SUBCATID=

Will this jaycar kit bring my top speed limit back to 180Kph(true speed)? my top speed now is about 155kph or something cause of the diff ratio.

**Stav** · 15-01-2007, 12:33 PM

I dont know mate..This is the first electronic thingamabob I havent been able to work ever?

chief · 14-01-2007, 08:59 AM

Stav, what did you do? You broke the cluster????

**Stav** · 14-01-2007, 09:11 AM

I had it stored on the shelf mate..slipped off at night and crunch unforuantely went under my tyres as I moved the car out in the morning. I was attached to it and was not happy when it happened.

chief · 14-01-2007, 09:15 AM

Lets just hope you are more careful with that head and cam you have in your garage :P