gears????????

85McLaren · Post by **85McLaren** » Wed Apr 08, 2009 12:25 pm

If it is, just pull out the little speedo cable gear and make sure it is a 3.27 gear with the 225/50-50 series tires. That gear should get you close....

I forgot what color the gear is, but you could always count the teeth.

Jason

tfs2121 · Post by **tfs2121** » Wed Apr 08, 2009 1:59 pm

well i have a 8.8 now but when i had the 7.5 in it was fast. now its like 10 mph fast.

85McLaren · Post by **85McLaren** » Wed Apr 08, 2009 2:14 pm

Probably different gears in the 8.8. Maybe 2.73's in. Whatever gear is in the rear end, just pick one gear size up on the little speedo gear.

Example:
If the rear end is 2.73, put a 3.08 speedo gear in with the 50 series tire.
If rear end is 3.08, put a 3.27 little speedo gear in it.
If rear end is 3.27, put a 3.55 gear in it....

That will get you close.....

Jason

Sandy · Post by **Sandy** » Wed Apr 08, 2009 8:37 pm

Mine is 3.73:1 Automatic option only (0r so it said on the order blank)

tfs2121 · Post by **tfs2121** » Thu Apr 09, 2009 11:47 am

well i know its a 3.55 out of an auto turbo coupe.

last time i looked into it i had to change the gear on the output shaft of my trans and the gear on the speedo cable.

my trans is out of a 92 gt

86capri62 · Post by **86capri62** » Thu Apr 09, 2009 12:25 pm

Just want to clear up something that SOME peoples don't understand. Never compare the difference in speedo value in mph. Always do it in percentage. A speedo is not 4 or 5 miles off at 50 mph it is 10% off. When you'll be a 100 mph the difference will be 8 to 10 mph. The cops will catch you at 110

or 90

85McLaren · Post by **85McLaren** » Thu Apr 09, 2009 1:08 pm

What is stated above is correct. All I am stating is - you can get close to the actual speed, but never exact. And - yes - the faster you go, you will be off more and more. I judge mine at 55-60 as that is what the max I normally drive without fear of speeding. I know that I will be slower the slower speed I go which is safe to me.

The comment made above was well stated.

Jason

86capriasc · Post by **86capriasc** » Thu Apr 09, 2009 10:59 pm

I used my gps to calibrate my speedo after the 3:73 swap and then again after changing to larger diameter tires. Mine is perfect now, or at least according to the gps. I haven't had any problems with getting pulled over even at 70 down the interstate. 70 is 70 and 30 is 30.

85McLaren · Post by **85McLaren** » Fri Apr 10, 2009 1:47 pm

Do the GPS's measure the Y-AXIS? I thought it only measures the X-AXIS for speed.

In other words, if you are on a flat road, the GPS should be fairly accurate for speed, but if you are going uphill or downhill, does the GPS know about the Y-AXIS (incline or decline) as far as speed?

Jason

Post by **negusm** » Fri Apr 10, 2009 1:50 pm

85McLaren wrote:Do the GPS's measure the Y-AXIS? I thought it only measures the X-AXIS for speed.

In other words, if you are on a flat road, the GPS should be fairly accurate for speed, but if you are going uphill or downhill, does the GPS know about the Y-AXIS (incline or decline) as far as speed?

Jason

Actually I think elevation is the Z-Axis. X would be front/back. Y is left/right...

I don't think it will understand an incline. It merely shows how fast you are going as it relates to the satellites. Some newer GPS systems are starting to work with elevation but I don't think the consumer grade ones do.

-Mike

85McLaren · Post by **85McLaren** » Fri Apr 10, 2009 2:03 pm

You are correct - it is Z. Forgot my depth dimension....
I just thought this is something some people should realize when using their GPS to guage speed.

Jason