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Discussion Starter #1 (Edited)
hey I just recently traded for a 99 gt... it's been somewhat cloned to a cobra with the emblems & cobra front bumper cover (also a 99) ... first question
I am going to buy the foglight's & bezels for the cobra cover... what I noticed is I only see a foglight plug on the drivers side... is the other side gone or is there a pigtail that runs from one side to another??
second question...my speedo it 10 mph to fast... tires are right size..apeers to have not had a gear change ( taching 2500 @75) but I know it's had a trans change ( it's a 5 speed) could that be the speedo problem?? any help would be greatly appreciated
Thank you

edit...I found the other light plug...it was shoved back into the fenderwell... had ta fish it out
 

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um you might have gears but i could be wrong. what are the stock gears in the new edges? 3.27 or something like that. If that is right then your speedo is probably right. I have stock gears in my 98 which are lower than yours and i run 2200 at 80
 

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3.27s in new edge 99-04 gt's

that speedo sounds about right. Just try to do this one time. get one of your buddies to go 45 on a highway. pull up beside him to see if your about the same. if not your got different gears
 

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yup. and if your speedo is off yo ucan go to brother performace and get their speed adj kit. or you ca just order a tuner and be done with it
 

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Discussion Starter #7
I know it's off by 10 (shows faster than I'm going) tag on rear shows 3.27 gears
what do most people with 3.27's tach at 75 (which is 85 by my speedo) mine tachs at 2500 .... it could be gears but I really don't think thats it
 

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I've heard that bigger tires on the rear can also change the speedo. so check to see if they are 245s out back.
 

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^yeah........but if his wheels are bigger then he would be going faster than what he speedo says. His is opposite so i dont think that is the problem, because why would anyone put smaller tires on?!?
 

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Discussion Starter #10 (Edited)
front tires 245-45-17 rear tires 275-40-17 .. if you check tire dimensions both are 25.64" same as stock height tire...

Edit: not sure, may have figured this out... my speedo goes to 150 ... is that correct or do gt's usually only go to 140???
like I've said I traded for this car & it's had many mods done...I'm not sure if the speedo has been changed.. it's not white face gauges so they looked factory to me
 

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front tires 245-45-17 rear tires 275-40-17 .. if you check tire dimensions both are 25.64" same as stock height tire...

I'm not sure if the speedo has been changed.. it's not white face gauges so they looked factory to me
i have 275s out back also and i know my speedo is off. so im sure that is it.

also if the guy took the needles off when he installed the gauges that might be it as well.
 

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you could have 185s or 325s...those will not change speedo. speedo does not care how wide a tire is. overall height of tire is what changes the calibration of the speedo. a 15 inch total height spins twice as fast as a 30 inch total tire height (impractical numbers for a mustang, but you get the point).

lets say we a have a 275/40/17
the 275 is an actual measurement of tire width in millimeters
the 17 is the rim size
the 40 is a ratio between sidewall and tire width.
I cant remember the real size of this tire, but i believe its 26.5"....dont quote me on that though, i'm lazy right now and dont feel like looking it up.
 

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i know nothing about the final gear ratio of the manuals...but on my auto i tach right around 2500 at 75 with 3.73s in the rear.
 

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Discussion Starter #15
ok.. I was just guessing on the 150 speedo... if you go to tire specs a 275-40-17 is the same height as a 245-45-17 which is the factory tire size ...as far as tire width I agree but the aspect ratio in comparison with width determines height... I guess I'll just deal with it... I guess my main thought would be in a trans change which I know it's had but I don't know what trans it has... is there any way I can tell by crawling under the car?? is there any way a trans change would make my speedo off??
 

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you could have 185s or 325s...those will not change speedo. speedo does not care how wide a tire is. overall height of tire is what changes the calibration of the speedo. a 15 inch total height spins twice as fast as a 30 inch total tire height (impractical numbers for a mustang, but you get the point).

let.
i see what your saying and understand.

I think the problem is in the gauges since the other guy changed them he might have removed the needles, like i did, and didnt put them on right, also like i did. lol.

but im sure you can fix this easily.
 

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well if its a problem with the gauge, you can easily check that by having the needles sweep through its full rotation. disconnect the battery for a half hour then hook back up, this will reset the pcm...when you go to turn the key forward, the needle will sweep through its full rotation.

I believe there were some gear ratio changes done between the t-45 and t-3650...here take a look at this calculator...
PaladinMicro
 

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when i had my 97 gt with 4.10s thats about where i would be going 75-80. i dont know what it could be but theres you some info
 

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Discussion Starter #19
i see what your saying and understand.

I think the problem is in the gauges since the other guy changed them he might have removed the needles, like i did, and didnt put them on right, also like i did. lol.

but im sure you can fix this easily.
actually I'm not sure if the gauges have been messed with.... I guess I'll jack it up & do the getto gear ratio check... I figure if I mark the tire & mark the driveshaft...rotate the tire one full turn & count rotations on the driveshaft it'll give me an idea if it's had a gear change.. also on the trans can I visually tell weather I have a t-45 or a t-3650 by looking under it? (what would I look for)
and thanx guys for all your input it's helped me cross some things off my list that I thought it could be
 

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Discussion Starter #20
it's got 3.73 gears...now i know.... but it still has the 3.27 tag .. I got in touch with the guy I bought it from who called the guy that built it & he said it has 3.73's...
thanx again all for your input

so now I know it's a 99 gt with a 99 cobra front bumper cover..all the cobra badges.. cobra style black center wheels .. K&N cold air... professional products upper intake.. aluminum lower intake (stock maybe but I see no writing on it anywhere so I dunno) professional products throttle body( not sure the size).. under drive pulleys ...x-pipe without cats...3.73 gears ... b&m short shifter ... thats all I know for now I may find more add-ons later .. I'm still not sure which trans I have.. I'll have to do some research but thats about it...I've owned it a week now
 
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