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View Full Version : Gears installed. What do I need to change? Also temps for fans



atlantadan
06-19-2017, 05:31 PM
I finally got my 3.42's installed and now I need to adjust the speedo, OD engagement RPM, and maybe tinker with the shift points. Anything else y'all suggest?

Also, I installed some 265w fans to keep the engine cool since the OEM fans were not up to the task. The t-stat in the car is a 160, and both fans running keep the car around 176-185. What should the turn off temps be and what should the MPH turn off speed be?
Thanks

MAC
06-19-2017, 11:26 PM
Hey Dan, what part of ATL are you in? I am in Decatur.

Not sure about the cars but they probably use the VSSB. Here is a thread with more info http://www.gearhead-efi.com/Fuel-Injection/showthread.php?6111-DRAC-VSSB-Questions&highlight=vssb

MAC

atlantadan
06-21-2017, 04:17 AM
Hey Mac - I'm in Tucker and drive through Decatur every day. LOL!

Thanks for the info on the VSSB. I was / am also wondering if things like shift-points, OD engagement, and anything else needs to be changed.

dzidaV8
06-21-2017, 07:15 PM
Thanks for the info on the VSSB. I was / am also wondering if things like shift-points, OD engagement, and anything else needs to be changed.

Yes you should. After you adjust VSSB divider the MPH shift points would be off in PCM. All the shiftpoints are defined by MPH, not RPM so you'd have to multiply them by (old axle ratio)/(new axle ratio).

LeMarky Dissod
07-01-2017, 08:50 PM
Use the speedo scalars from a V4P .bin file.
Lowering the fan enable coolant temps under 85°C / 185°F (roughly under a 160°F thermostat's fully open point) is pointless.
Raising them over 100°C / 212°F for winter heating is also unnecessary.

Stokes1114
07-01-2017, 10:03 PM
So as far as adjusting for gear change, I already re soldered the pins on my drac to the recommended positions, but it did throw off shift points. Is this conversion correct- old 4.10/new 4.88=.84 roughly. What exactly do I need to do with that amount? I assume multiply it by the vss ratio scalar in my bin? Thanks for the help

billygraves
07-02-2017, 01:00 AM
.......

Stokes1114
07-02-2017, 03:41 AM
Without knowledge of what engine/trans and ECM/PCM and year I would suggest you find and alter the N/V Ratio. This cal sets the MPH on the Trans side of the PCM in Most cases. N/V is Engine RPM over Vehcile Speed. I would find the cal or bin for the year PCM and trans/engine along with the axle ratio and begin there. Most cals had up to a 3.73 and another for over 4.10 axles. This is a general over view w/o knowing what you are working with.

I have a 93 k1500, 5.7, 4L60e, 16197427 currently. I realized the RPM/VSS ratio is only for the 80e that runs directly to the TOS pin. I am using the factory DRAC module. The pins in the DRAC are swapped over for the new ratio but shift points are off. I guess I just need to alter the MPH/TPS shift table? Or is there a simpler table to modify?