1998 MGT Programmer

N8Dogg98

15 Year Member

Apr 4, 2005

3,872

238

184

MN

Aug 10, 2006

#1

• Aug 10, 2006

• #1

I have a 1998 Mustang GT 5-speed and would like to know which programmer is the best. Also, is it possible to make speedometer corrections for gear changes on my car with a programmer. It seems like every programmer says that the adjustments for gear/tire changes can only be made on 1999 and newer cars, is this true? I appreciate your comments.

 

D

DarrinB

New Member

Jul 2, 2003

40

0

0

Carmel. IN

Aug 10, 2006

#2

• Aug 10, 2006

• #2

On the pre-99 cars you have to change the speedometer gear on the VSS to correct the speedometer.

Darrin

 

Built98GT

New Member

Oct 17, 2005

211

0

0

OKC

Aug 10, 2006

#3

• Aug 10, 2006

• #3

DarrinB said:

On the pre-99 cars you have to change the speedometer gear on the VSS to correct the speedometer.

Darrin

Click to expand...

You can use a speed-cal to correct it.

 

R

Riocobravert

New Member

Jul 6, 2008

13

0

0

Granite Falls, Wa

Jul 6, 2008

#4

• Jul 6, 2008

• #4

I've read comments about flashing a chip, would this be possible on a 97 Cobra?

 

nyuk98gt

15 Year Member

Oct 10, 2000

1,427

6

79

Chesterfield, MO

Jul 6, 2008

#5

• Jul 6, 2008

• #5

Chaps:

FWIW, I have been using SCT's flasher (XCal2 [9400] and the ancient 9100) with their Advantage software for many years and I think it is an excellent product. A 4-position chip is pretty good if you don't plan on changing the tune often because the chip can just sit there (on the PCM) and you can switch between tunes without shutting off the engine. A chip requires you to pull out the PCM and there is a small risk that the chip will get bumped off the connector, usually frying the PCM. I prefer the flasher because it is very convenient since I tweak my tune frequently. Diablo also makes a flasher unit, Sniper makes one, and there's TwEECer but there is a big learning curve with it.

I have been running a SpeedCal for many years, too. As stated, the pre-99's need a speedo gear change or a SpeedCal to correct the speedo/odo.

HTH,

Chris

 

R

Riocobravert

New Member

Jul 6, 2008

13

0

0

Granite Falls, Wa

Jul 7, 2008

#6

• Jul 7, 2008

• #6

I've seen the comment that you need a speedcal or speedo gear change on the pre-99's before. I have the stock 19 tooth in my Cobra with no speedcal, yet when I put the rearend back to near stock(3:31) from 4:10's my speedometer is off by 20-25%. Any thoughts on how this can be? It seemed correct before the change.

 

nyuk98gt

15 Year Member

Oct 10, 2000

1,427

6

79

Chesterfield, MO

Jul 9, 2008

#7

• Jul 9, 2008

• #7

Riocobravert:

According to my well worn 2000 FRPP catalog, the '97 Cobra with a T-45 transmission came with a 7T drive gear and 19T VSS gear for 3.27:1 gears.

For 4.10 gears, the VSS gear should have 23.4 teeth so a white 23-tooth gear "should" be in there if there is no SpeedCal installed. If you have a SpeedCal installed, then it has to be set for the 3.31 gears. You need a "reduction" of about 24%:

4.10 / 3.31 = 1.23867 so 23.9% change due to 4.10's to 3.31's

Mark your driveshaft and mark your rear tire. Rotate the tire 1.000 (exactly one) revolution and count the driveshaft revolutions. For 3.31:1, you will get 10 driveshaft revs for 3 tire revs.

HTH,

Chris

 

R

Riocobravert

New Member

Jul 6, 2008

13

0

0

Granite Falls, Wa

Jul 13, 2008

#8

• Jul 13, 2008

• #8

Hey thanks for the reply Chris, You definitly know what should be in there. I expected to find the 23 tooth gear in there, but it was the 19 tooth. I can't see where a speedcal is installed, you'd have to tap into the wires coming out of the vss right? I estimated I was off by 22%, I drove past ten mile markers and the odometer went 7.8 miles. So I stopped by the ford dealer and got their 16 tooth gear, that got me within about 6%. still bugs me though. I think that either this thing was flashed/programmed for the 4:10's, there is a speedcal installed here somewhere that I havent found, or some other trany/instrument cluster change has happened (although I don't think so). I do appreciate your spending time thinking about this, Ken

It looks like the previous owner must have changed out the drive speedo gear to a 6 tooth, calculates out to exactly how far off I am. http://www.5speedtransmissions.com/calculators.html Anyone know what it takes to change the drive speedometer gear, going to the 7 tooth would get me to a little over 1% off.

 

nyuk98gt

15 Year Member

Oct 10, 2000

1,427

6

79

Chesterfield, MO

Jul 14, 2008

#9

• Jul 14, 2008

• #9

Riocobravert:

Thank you! The SpeedCal goes in series in the wiring from the VSS. It can be installed (like the Abbott ERA) right at the PCM but I have no experience with this method. I don't know if the alternate method is for the +99's only (since our speedo/odos have to have the modified signal right from the VSS).

That's interesting that the drive gear was changed. Does the tail shaft come off separately on the transmission? Looking at my auto, I think I would need to drop the transmission to change the drive gear (yikes).

GL & please post back with an update.

Chris

 

R

Riocobravert

New Member

Jul 6, 2008

13

0

0

Granite Falls, Wa

Jul 14, 2008

#10

• Jul 14, 2008

• #10

Not sure about the auto, I heard the gear was machined into the tailshaft on automatics. The back section drops right out on a t45 I'm told, not too bad of a job. I probably won't get too excited about changing it right away. I drove past one of those cop signs today it said I was right on the money at 25mph. The odometer is going to be reading low, but I guess that won't hurt a bunch. The main thing for me was figuring out what had been changed. Thanks for your help.