How fast was I going in a 1987 Mustang GT at 4500rpm?

robs87fox · 09-26-2007

I have a stock speedo and it max's out at 85.

Today i ended up racing a newer mercedes suv. By the time I put 7-10 cars i looked at the rpm and it read 4500rpm.

I have 2:73 gears(i was in 4th gear)
245 50 16 tire size

I was curious how fast i was going. I'm sure I haven't had this car that fast yet by the feel of it at that rpm

thanks guys

rob

85MUSTANGGT · 09-26-2007

According to the calculator I used, approx. 125 MPH.

robs87fox · 09-26-2007

Quote:

Originally Posted by 85MUSTANGGT

According to the calculator I used, approx. 125 MPH.

dang and i still felt some torque left, i wonder how much she had left?

do you have a link to a chart of the calculator for my future reference? thanks

rob

85MUSTANGGT · 09-26-2007

See if this works.

http://www.allfordmustangs.com/Detailed/635.shtml

http://www.allfordmustangs.com/Detailed/608.shtml

The MPH calculator will only give you your speed in overdrive. I had to use the RPM calculator to figure your speed since you said you were in 4th. These are under the tech tab at the top of the page in the calculators and decoders section.

robs87fox · 09-27-2007

thanks guys for your help on this, i know i need a 140 mph speedo

Snake1 · 09-28-2007

Try this site,click on the rear end you have and it'll tell you what speed your doing in all gears and at what RPM your doing it at.
5oh has an 89 GT but there shouldn't be any difference.

Mr5ohs Mustang Page

Lots of good stuff in this site.

Snake Pliskin · 09-28-2007

Years ago when I had my 90 Gt I topped her out. Mine at that time was outfitted with 2.73 gears. Top speed was attained in 4th gear. I was able to kiss the 140mph reading on my speedo but it took a while. Whenever I shifted to 5th the car didn't have enough horses to overcome the wind resistance so she would slow down. It seems to me that specs at that time put mustang top speed at 142-143 depending on who you read. I had about a 5 mile plus straight a way to do this in and that last 15 mph seemed to take a while.

Schreiber · 10-02-2007

Im not sure if those caculators are accurate because at redline my 95 GT is going any where from 40-45 in first gear... and yes it is a manual with 2.73

Snake1 · 10-04-2007

5oh's calculator is for later Foxes