PDA

View Full Version : Mph +5



rickbtbird
05-16-2009, 01:24 AM
I got an iPhone the other day and I've been using the GPS. The GPS says the speedo is 5 MPH faster. It's a 95 5speed, stock tires and rear gears.

BuRHan90SC
05-16-2009, 03:36 AM
which app r u using for GPS? cuz if u r using ''aSmHUDCam'' then i would say that app have some bugs in it and doesnt feel rite to me...but if u r using app ''iHUD'' then i would say u have got a problem:D cuz iHUD is very accurate for showing the correct speed way faster and accurately than any app i have used on iPHONE

old_coot
05-16-2009, 09:48 AM
Pretty much SOP for a speedometer to indicate slightly fast in my experience.....borrow all your friends car and take them for a spin and check me out on that.....odometers are usually close though...........Dan

RedSC93
05-16-2009, 09:56 AM
MY tom tom says im going 5mph faster aswell. Stock tires and all... Hmm

SCarSC
05-16-2009, 10:22 AM
Makes sense that the factory sets it wrong, i always clock about 3-4 faster than the police speed detector says im going....not the laser, just the highway setup they put out...

the-big-e
05-16-2009, 10:40 AM
I was going to post something related to this.....:rolleyes:

Last week, I was testing a box of speedometers that I have.....

Most of them registered the same MPH at a designated RPM....

However, 4 of them registered 5 MPH over and a 145 speedo registered 10 MPH over.....

For a stock SC with automatic transmission in OD, I am traveling at 67 MPH at 2000 RPM......

Would this be a correct assumption.....:confused:

rickbtbird
05-16-2009, 10:42 AM
which app r u using for GPS? cuz if u r using ''aSmHUDCam'' then i would say that app have some bugs in it and doesnt feel rite to me...but if u r using app ''iHUD'' then i would say u have got a problem:D cuz iHUD is very accurate for showing the correct speed way faster and accurately than any app i have used on iPHONE

It's a fee app called Speed-O-Meter but I also have MotionX GPSlite. They both say the car Speedo is 5mph faster.

Jimmy 2Coupes
05-16-2009, 11:34 AM
One of the functions I can moniter with me Actron scan tool is vehicle mph and when both of my SC's still had stock gears and tires they both showed right about three mph fast as in the speedometers read about three mph faster than the readout on the scantool. My question is where does the diagnostic test port get it's mph data from? The vss would seem to be the logical signal output but maybe not.

TinManSC92
05-16-2009, 11:32 PM
yep! it's true. exactly 5 mph over while @ 60 mph. don't know the rpm's. is yours a 5 gear as well?

BuRHan90SC
05-17-2009, 05:15 AM
It's a fee app called Speed-O-Meter but I also have MotionX GPSlite. They both say the car Speedo is 5mph faster.

oh ok i didnt know about Speedo-O-Meter...plus i duno about iHUD if its free or not and i don remember where i downloaded it from...offical app store or installous lol....search on app store u will find out if its free or not otherwise u gotta JAIL***** ur IPHONE lol......i duno i dont have any problem with my speedo showing wrong speed its matches exactly wit GPS...i will make a video of it...

1owner89
05-17-2009, 09:37 AM
Mine has always been about 5 over compared to those speed indicator signs they put along the highway. Started to notice it in about 95 so I assume it had been like that since day one but those speed signs and GPS was hard to come by back in 89.

frdlvr30
05-17-2009, 10:32 AM
All Factory Speedo's are like this. 2-5mph high that is. It is intentional. If you are not going as fast as you think you are, you are safer. Not to mention the liability of it being the other way around.

KMT
05-17-2009, 10:39 AM
GPS was saying my '90 speedo was reading +/- 3mph fast (1~2 @30; 3~4 @60, etc.). Local police said it was reading +/- 10 mph slow, but didn't feel strongly enough to write it up (opted for window tint violation instead...).

Swapped in a '93 speedo head and the indicated speed now agrees exactly with GPS at all speeds.

90blkbrd
05-17-2009, 10:48 AM
For a stock SC with automatic transmission in OD, I am traveling at 67 MPH at 2000 RPM......

Would this be a correct assumption.....:confused:

Only if your tach reads right and if your AOD is still direct drive. I've read that almost every is off 200-400 rpms.