Best way to get 02 Volts from Scanmaster???

[ReaL99]

I have heard to leave the car in 2nd and from 40 mph to 80mph that should give an accurate reading.The difference in my car is that I have 3:73 Gear's but I do have 28 Inch tall tire's in the back.I guess that would bring my Gearing down somewhere between 3.50 to3.55.Instead should I just keep in it drive to try and get the 02 Volts

 

[84BuickGNYorkPA]

I was always told at the top of 3rd gear, ideally at the local 1/4 mile track.....as you cross the finish line, with the gear selector in drive(3rd gear), not overdrive(4th gear).

Chuck

 

[ReaL99]

I was always told at the top of 3rd gear, ideally at the local 1/4 mile track.....as you cross the finish line, with the gear selector in drive(3rd gear), not overdrive(4th gear).

Chuck

I was wondering where I would be MPH wise with my 3:73's with 28 Inch tall Tire's

 

[tplett]

The equation to calculate MPH is:
(TD X Pie) X RPM in 1000's/Rear End Gear ration.
Example: Tire Diameter of 28. Pie is a3.1417. Use 3 1/7 to get close. RPM of 5000 = 5..

28X3 1/7 X 5/3.73 =
88 X 5 / 3.73 = 440/3.73=118 MPH @ 5000 rpm.
Summit offers a slide rule where you match your numbers up and simply read it off.

 

[tplett]

In drive.

Forgot to add. This is with transmission final drive of 1:1. Drivee in the 200 R4. OD you have to plug in the change of ratio also.

 

[ReaL99]

The equation to calculate MPH is:
(TD X Pie) X RPM in 1000's/Rear End Gear ration.
Example: Tire Diameter of 28. Pie is a3.1417. Use 3 1/7 to get close. RPM of 5000 = 5..

28X3 1/7 X 5/3.73 =
88 X 5 / 3.73 = 440/3.73=118 MPH @ 5000 rpm.
Summit offers a slide rule where you match your numbers up and simply read it off.

There's not that much a difference when running a 28 inch DR Radial with 3.73 Gear's compared to the Stock 3.42 with the 26 inch tall tire.The last readings I got on my scanmaster was anywhere from 65mph to 85mph at the top end.I guess that recorded the lowest 02 volts because after that nothing registered.By this equation would my 3rd gear be around 118mph and 5000RPM??? Hard to understand a little.I know my speed on the speedometr as off by a little and I don't have an RPM gauge yet.

 

[tplett]

3rd gear ratio is 1:1 which means with a 28 inch tire your speed should be 118 MPH at 5000 rpm. I'm an engineer so we get to work with formulas every day.

 

[GNVYUS 1]

The reason why everyone suggests 3rd is because of load, the car has a greater chance of going lean at the end of 3rd than 1st for example.

But like you've shown it's not always that practical to do a run into 3rd so make sure you are not seeing your ideal AF/R/Millivolts in 2nd if that's as fast as you can go while tuning. By the time you hit the end of third there is a good chance you've leaned out .2 or better on the wideband due to load etc.

 

[ReaL99]

The reason why everyone suggests 3rd is because of load, the car has a greater chance of going lean at the end of 3rd than 1st for example.

But like you've shown it's not always that practical to do a run into 3rd so make sure you are not seeing your ideal AF/R/Millivolts in 2nd if that's as fast as you can go while tuning. By the time you hit the end of third there is a good chance you've leaned out .2 or better on the wideband due to load etc.

Yeah its a little dangerous going to 118 mph on the street when there is alot of traffic where I live.I did try going from 40-80mph to get a reading.It said 808 but I didn't come close to 80mph.I don't think its the tune.I think its the 009's which require's a chip but then again why even play with the 009's.Maybe go to the 60 Mototron's and a chip.If that doesn't help with quicker spool up then the 3200 Vigilante would be next on the list.