Holy hell is this thing off. Me in my omni and my buddy in his 3kgt were on a closed course in mexico. I passed him doing what my speedo said was 95-100. He told me he quit at 110 and I looked at him like he was an idiot. I got a speedo gps app on my phone and it said I was doing 105 when the stock speedo said 85... The stock speedometer only seems accurate to about 55mph.
Do you have the correct drive gear for the tire size?
Probably not. I have 205/50/16's. According to the tire calculator on neons.org, the difference in tire size would make it 5 mph off at 90.
According to my reckoning, those tires are short, so your speedo should read higher, not lower, so it's probably something else other than the gear... like the speedo drive has gone weak or something... Or I guess it could be your gear got worn and is skipping...
DD1: '02 T&C Ltd, 3.8 AWD. DD2: '15 Versa Note SV, replacing.. DDx: '14 Versa Note SV << freshly killded :( ....... Projects: '88 Voyager 3.0, Auto with shift kit, timing advance, walker sound FX muffler on 15" pumpers wrapped in 215/65/R15 H rated Nexens.... and a '95 phord escort wagon PnP head << Both may need to go :( ..... I like 3.0s ... so??? ... stop looking at me like I've got two heads!
How can the tires be short? Stock on a GLH is 205-50-15 (might even be 195-50's), he went to a 205-50-16. That would make the tire taller, and his speedo read slower than actual, wouldn't it?Originally Posted by RoadWarrior222
Barry
86 Shelby Lancer Prototype
90 Daytona Shelby VNT
91 Spirit R/T
For your questions about SDAC, please contact BadAssPerformance
Yah, you're right, I was going off bad info for the stock tire diameter...
Though what I'm looking at now, has the GLH size 1.3% under stock Omni, which I doubt they changed the gear for, and the 16s 2.9% over, so still seems a bit far off...
DD1: '02 T&C Ltd, 3.8 AWD. DD2: '15 Versa Note SV, replacing.. DDx: '14 Versa Note SV << freshly killded :( ....... Projects: '88 Voyager 3.0, Auto with shift kit, timing advance, walker sound FX muffler on 15" pumpers wrapped in 215/65/R15 H rated Nexens.... and a '95 phord escort wagon PnP head << Both may need to go :( ..... I like 3.0s ... so??? ... stop looking at me like I've got two heads!
I have that tire size on my Charger, and I'm running the blue gear. According to those road side speed signs, my speedometer is dead on. Unfortunately, they only seem to put those in town around here, so it's only been tested up to about 55.
Stock GLH tire is 195/50r15. Stock GLHS is 205/50R15. 205/50r16 to 195/50r15 is only 6.1 % difference. I wonder what speed a scanner would read compare to you speedo.
Last edited by tryingbe; 04-26-2012 at 12:33 AM.
Well Omni's are an economy car and they aren't known for having accurate speedometers. Both my 1981 Omni Miser and my 1985 GLH were off (both were bought new). And both of those speedo's read faster than what I was really going. I used to see so many Omni's driving slow on the freeway and always laughed and thought to myself that they probably thought they were going faster than they really are.
Barry
86 Shelby Lancer Prototype
90 Daytona Shelby VNT
91 Spirit R/T
For your questions about SDAC, please contact BadAssPerformance
My '87 Charger Shelby has an odometer that is practically dead on. But the speedo is off so much it can get you in trouble. I bought the car over 300 miles from home. When I picked it up, I was passing people like they were standing still, I had to open the speedometer app on my phone. Sure enough, when the speedometer in the car reads 65, I'm actually doing 74.
Bob Doherty..... mnsdac.com
Coon Rapids, MN
'90 Chysler TC
'87 Shelby GLHS #784
'87 Shelby GLHS #654
'87 Shelby Charger
'89 Daytona Shelby TII T-Top
'89 Lebaron Convert TII
'89 Lebaron Convert TI auto
SDAC Member.expires 05/2016.MNSDAC Vice President
Mine is as accurate as it gets.
Yep. My gps says the speedo is accurate till about 55. At 65 it says im doing about 72. At 75 im doing about 90. 85 im doing almost 105. At one point i was doing nearly 100 according to the stock gauge. I must have been going 120-130.
Oh btw, some GPS get less accurate as you go faster.... it's not really a case of "can" GPS measure speed accurately, since 1/10 of a MPH is possible with units designed to do so, but yer average made by the lowest bidder GPS may not be terribly accurate, especially if it only tracks a relative few sats at once, and is old with a slow microprocessor, or a lot of other stuff going on, like playing MP3s and recalculating a route every time you pass an exit 'coz you forgot to tell it you aren't going there any more.
DD1: '02 T&C Ltd, 3.8 AWD. DD2: '15 Versa Note SV, replacing.. DDx: '14 Versa Note SV << freshly killded :( ....... Projects: '88 Voyager 3.0, Auto with shift kit, timing advance, walker sound FX muffler on 15" pumpers wrapped in 215/65/R15 H rated Nexens.... and a '95 phord escort wagon PnP head << Both may need to go :( ..... I like 3.0s ... so??? ... stop looking at me like I've got two heads!
I used my phones gps. Htc sensation.
I own a few GPS's. I've compaired them to each other and they read virtually the same. I also have the HTC Sensation and noticed the GPS is a little slower to read, but will catch up and state the same speed as the "Nuvi" GPS's I own. That is, if I stay at that speed for a few extra seconds.
Coon Rapids, MN
'90 Chysler TC
'87 Shelby GLHS #784
'87 Shelby GLHS #654
'87 Shelby Charger
'89 Daytona Shelby TII T-Top
'89 Lebaron Convert TII
'89 Lebaron Convert TI auto
SDAC Member.expires 05/2016.MNSDAC Vice President
Hmmm. I suppose I could borrow my parents-in-law Garmin and test that. I should also note that I'm running the electronic speedometer from a '90 Omni, which tops at 100 and can't go past that.
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