Impedance Adaptor value???
12-13-2002, 07:09 AM
#1
Race Director
Thread Starter
Impedance Adaptor value???
So there's this Impedance Adaptor #944.612.421.00 on non-USA cars that is used to select some alternate maps on the chips (similar to Region Coding plug in USA cars). Does anyone have one of these in their cars and could you measure the resistance for me? Thanks! <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />
12-13-2002, 08:30 AM
#2
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Join Date: Dec 2002
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Yes Danno I have one of those impedence adapters installed in my car. It seems to run better with it installed along with the jumper wire inplace of the lambda sensor.
I haven't measured the resistance of the adapter but the wiring schematic shows it to be 1.8k Ohms.
I paid $12 for it from the local Porsche emporium here in Phoenix, but the local Radio Shack has the same resistors for about 4 for a dollar.
F R Wilk posted this over on Pelican a few months ago. Thats where I learned of it.
Steve Frew
I haven't measured the resistance of the adapter but the wiring schematic shows it to be 1.8k Ohms.
I paid $12 for it from the local Porsche emporium here in Phoenix, but the local Radio Shack has the same resistors for about 4 for a dollar.
F R Wilk posted this over on Pelican a few months ago. Thats where I learned of it.
Steve Frew
12-13-2002, 06:03 PM
#5
Race Director
Thread Starter
"I haven't measured the resistance of the adapter but the wiring schematic shows it to be 1.8k Ohms."
Thanks Steve, I can't find this value shown anywhere in the manual, what page are you looking at?
Keith, when you make these, do you hard-wire them into the harness, or do you add a plug?
"i think i have that "region coding plug" in my car... would it run better without it?"
The region-coding plug is different than the impedance-adaptor. They look similar, but the region-coding plug is simply a wire short. The input-line that is used for the impedance-adaptor is connected to the altitude-sensor on USA cars and the plug isn't even available.
Since there are two binary triggers here, we have 4 possible combination of states. These states correspond to the fuel and ignition maps inside the chips.
So to answer the question of whether the car runs better with or without the region-coding plug installed depends upon the chips you have in the car. For the stock chips, it won't matter. Most aftermarket chips that are based upon the stock Porsche chip only have modified maps in one of the maps, the rest are stock. So you have to juggle the region-coding plug & impedance adaptor to guarantee that you're selecting the upgraded map instead of the stock one.
This was the case with the TurboCup chips. They only modified one map and the rest were stock. Some people who installed the TurboCup chips didn't noticed any improvements because they were still selecting the stock maps within those chips. The TurboCup maps were actually used in the later TurboS street cars (except for 2 minor changes in the ignition map, the other 142 zones are still the same).
Thanks Steve, I can't find this value shown anywhere in the manual, what page are you looking at?
Keith, when you make these, do you hard-wire them into the harness, or do you add a plug?
"i think i have that "region coding plug" in my car... would it run better without it?"
The region-coding plug is different than the impedance-adaptor. They look similar, but the region-coding plug is simply a wire short. The input-line that is used for the impedance-adaptor is connected to the altitude-sensor on USA cars and the plug isn't even available.
Since there are two binary triggers here, we have 4 possible combination of states. These states correspond to the fuel and ignition maps inside the chips.
So to answer the question of whether the car runs better with or without the region-coding plug installed depends upon the chips you have in the car. For the stock chips, it won't matter. Most aftermarket chips that are based upon the stock Porsche chip only have modified maps in one of the maps, the rest are stock. So you have to juggle the region-coding plug & impedance adaptor to guarantee that you're selecting the upgraded map instead of the stock one.
This was the case with the TurboCup chips. They only modified one map and the rest were stock. Some people who installed the TurboCup chips didn't noticed any improvements because they were still selecting the stock maps within those chips. The TurboCup maps were actually used in the later TurboS street cars (except for 2 minor changes in the ignition map, the other 142 zones are still the same).
