How can i figure out what my highway rpm's will be at 70 mph with my 4 speed, 3.23 gears, and a 29 to 29.5 inch tall tires would be?

 

70 mph * 63360 inches/mile / 60 seconds/minute / (29" tire dia * pi) * 3.23 * whatever overdrive ratio your transmission has.

 

sweet, thanks. i guess i should be runnin about 2600 rpm then.

 

say 60mph, with 26.5" tall tires, 3.27 rear gears, and a 700r4 (is it .67 or .70 overdrive ratio)

i got me a 1742 rpm at 60mph with .70 overdrive
and a 1667 rpm with .67 overdrive

prob is that im running 2000 at 60mph with the above. i believe my stall is alil more than stock(idk wat stock is) but i think its 1700-1800 stall

 

The factory tach is known for its inaccuracy.

 

ive tested it with a scanner as well, the tach is basically dead on... maybe 50-100 rpms off. i had the scanner connected when i did the test. also my car seemed to lose a bit of tq down low after i installed 3" mandrel bent exhaust with xpipe over my other 3" true dual compression bent dual exhaust no crossover on a basically stock 350tpi (in my sig). could that be the reason why my rpms are higher bc of the loss of tq? thats what im guessin.

i know the exhasut is overkill but i had to upgrade it bc it was too low and i was dropping the car with sportlines and its upgraded for my future 500hp 383 hsr.
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sry heres my sig

 

Are you sure your converter clutch is locking?

 

i really didnt do anything to the trans, it was working before the exhaust swap. all i did to the trans was install billet 30% larger than vette servo and 50% larger than stock overdrive billet servo, new trans filter, new raptor blood fluid, deep pan, and new mega boost valve and low reverse boost valve.

i dont think u can affect the converter with those mods... can U?
any way to tell if the converter is locking up?

 

Customblackbird the stock overdrive for a 700r4 is 0.70.