EaZy DuZ iT

Hey guys i have a question, many epople say make sure you click your O/D and it says "off" if your ever going to WOT, is that true? Also some people say to turn it off on launch but dnt click it on roll. Im not familiar with O/D much but everytime i have raced i made sure "O/D off" light was on. Can someone help me out. Thanks guys!!

gxszone

Okay this I can tell you for a fact: I had two dyno runs this past weekend and the first runwith overdrive ON the car yielded 217 rwhp (stock except weld in flowmasters) but then on the second run with overdrive OFFit was 226 rwhp.

gxszone

Overdrive just enables 4th gear in an automatic. By doing this you reduce your motors RPM's and increase gas mileage.

Brute03

i'm not entirely sure what all the pcm does when you turn o/d off but i don't think a boost in power is one of them

2002GTAUTOVERT

thats cause 3rd gear isnt a 1:1 or less ratio.... so you made 217 rwhp

gxszone

On the run that I made 226 hp (O/D OFF) my tq was 247 but on the 217 hp (O/D ON)run, the tq was 258. I'm just throwing out the numbers I made as something tangible for the OP to know what a dyno run with O/D on and off would produce.

2002GTAUTOVERT

a dyno run with O/D off isnt reliable as the faster acceleration you get from 3rd gear will show higher numbers. So why pay for an incorrect dyno run?? and your torque was higher with O/D on cause you were lower in the powerband.. meaning you had more torque longer.. as opposed to being in 3rd gear and having more power faster.

gxszone

It will only show higher numbers? The faster acceleration itself doesn't produce the higher numbers?

2002GTAUTOVERT

it isnt an equal 1:1 ratio so it will read the car as having more power than it does. a dyno applies force to the tires that the operator runs through the O/D gear to get an accurate reading of power throughout the powerband.. if you run it in 3rd gear the dyno doesnt know any better. it fudges the numbers..

next time youre on the dyno.. tell them to run it in 1st gear, then 2nd gear, then 3rd and O/D. Youll see what i mean if you dont understand now.

EaZy DuZ iT

so i duno every1s sayign sumthign different, so if i race off roll shud it say "OD OFF", and same for launch?