North American Turbocoupe Organization



MPH Question
Gregg Offline
Senior Member
#1
I only have the stock Speedo, so I am wondering.....I was in 5th gear and the RPM's were about 4K...tires are 225/55/60...

About how fast was I going???

------------------
1987 TC 5 Speed
K&N Cone mounted on the VAM, soon to be front mounted, Disconnectd BCS
Gregg
Reply

tylerport Offline
Senior Member
#2
Well, according to <a href="http://www2.turboford.org/nato/ubb/Forum1/HTML/000794.html">this</a> previous posting, with 225/60R16 tires you'd be going 111mph. But your 225/55R16 tires have a smaller diameter, so you'd have been going slower than with the larger tires.

------------------
Jim Portteus
86 Turbo Coupe, 131K Miles, 140MPH Speedo, Gillis Valve, 2 1/2" Downpipe to 2" Duals w/ 18" Glasspacks, 245/50R16's and new paint.
Jim Portteus
Reply

Walsted Offline
Posting Freak
#3
I worked up some tables and posted the urls in this thread . Hopefully, this will help others with similar questions.

------------------
Mike Walsted
1986 5-speed TurboCoupe .
NATO member.
Mike Walsted - Sold my 1986 5-speed TurboCoupe
Reply

Noname
Guest
#4
Nowhere in those equations do I see a coefficient of drag. Trying to move through the air at high speeds WILL slow you down, no matter how slippery the shape of the car is.
Reply

Walsted Offline
Posting Freak
#5
I think we had this discussion in a much earlier thread . The drag induced by moving through the air WILL slow the car down, as will internal friction, but since we have a solid connection from the crankshaft to the wheels, and we assume no slippage of the clutch or tires on the pavement, that which slows the car will also slow the engine rpm. Thus, it is mathematically correct to compute the speed of the car by tach speed using the given equations, assuming that you have the same gears, tire height, and transmission, and no clutch or tire slippage is present.

------------------
Mike Walsted
1986 5-speed TurboCoupe .
NATO member.
Mike Walsted - Sold my 1986 5-speed TurboCoupe
Reply

Noname
Guest
#6
Fair enough.
Reply

Kev Offline
Posting Freak
#7
Finally, someone else sees the mechanical connection fact. Very well put.

Kev
Kev
1988 TC 5spd
Reply





Users browsing this thread:
1 Guest(s)



Theme © iAndrew 2018 - Software MyBB