Using an AT dropping resistor in place of the BCS

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Legacy777
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Using an AT dropping resistor in place of the BCS

Post by Legacy777 »

This info may be floating around in a couple threads, but Matt had asked me about it recently, and thought it deserved a thread.

The principle behind the mod is that when you go to a MBC or aftermarket EBC, if you don't leave the BCS plugged in you will get a CEL. Well in comes the dropping resistor. The resistance of the dropping resistor is very similar to that of the BCS, AND on the 90-91 MY's the electrical connector is identical. So you can unplug the BCS and plug in the dropping resistor and avoid a CEL.

The AT dropping resistor mounts to the back side of the turbo sensor bracket and is a good way to clean that area up. For me, I used the resistor when I was running a MBC and mounted it where the BCS used to mount.

http://main.experiencetherave.com/subar ... s/joepmbc/

Here are some pics of the BCS and the dropping resistor & their connectors

http://main.experiencetherave.com/subar ... gresistor/

From what Matt described the electrical connector is different on the 92-94 MY's so you'll need to find one from the 90-91 MY's.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
cj91legss
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Re: Using an AT dropping resistor in place of the BCS

Post by cj91legss »

i have 2 dropping resistors in my garage and they both have different plugs an neither of them plug into the bcs plug. i'll get pics tomorrow.
91 L-TW Wagon with a full Swap -RIP
92 SS Prefaced, GD dash swapped, 22T/205 Hybrid 20 psi - BEAST!
93 SS Bone Stock Gone!
94 TW Bone Stock Gone!
91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
Legacy777
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Re: Using an AT dropping resistor in place of the BCS

Post by Legacy777 »

What year are they from?
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
cj91legss
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Re: Using an AT dropping resistor in place of the BCS

Post by cj91legss »

Its been over a year since I grabbed them... i couldn't tell you.
91 L-TW Wagon with a full Swap -RIP
92 SS Prefaced, GD dash swapped, 22T/205 Hybrid 20 psi - BEAST!
93 SS Bone Stock Gone!
94 TW Bone Stock Gone!
91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
Mattheww044
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Re: Using an AT dropping resistor in place of the BCS

Post by Mattheww044 »

from my experience at the junkyard today, it seemed to be that the pre-facelift (90-91) had the ROUND connector which is the exact same plug as MY (91 SS) BCS plug. From what I saw, all of the 92+ resistors had a SQUARE connector. It looks to be the same device and all, but the plastic plug is different from my experience. Does the 92+ SS have a round connector for the BCS or square? Meaning that they either changed the engine harness or the BCS plug. I will try to get a pic or two of the different styles since I have a few of each.
Legacy777
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Re: Using an AT dropping resistor in place of the BCS

Post by Legacy777 »

The 92+ BCS connector should be round. The harness I got for my ej22t conversion was from a 94 turbo Legacy if my memory serves me correctly.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
Mattheww044
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Re: Using an AT dropping resistor in place of the BCS

Post by Mattheww044 »

I am selling a resistor to someone who has a 93 and said it has a "square connector".
Ill send it and if it's the wrong one send him the round one haha. Will update when I find out whats up
Legacy777
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Re: Using an AT dropping resistor in place of the BCS

Post by Legacy777 »

That's weird how there are these small discrepencies between the different model years. Silly Subaru :)
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
cj91legss
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Re: Using an AT dropping resistor in place of the BCS

Post by cj91legss »

I have a round connector one in my garage (only one i found so far)
91 L-TW Wagon with a full Swap -RIP
92 SS Prefaced, GD dash swapped, 22T/205 Hybrid 20 psi - BEAST!
93 SS Bone Stock Gone!
94 TW Bone Stock Gone!
91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
bcmaxx
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Re: Using an AT dropping resistor in place of the BCS

Post by bcmaxx »

So if i have a na car with na harness i will have to wire this along with the map sensor and solenoid to the ecu?
cj91legss
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Re: Using an AT dropping resistor in place of the BCS

Post by cj91legss »

If it has the same connector as the boost control solenoid, then you have no wiring to do, Just plug it in.
91 L-TW Wagon with a full Swap -RIP
92 SS Prefaced, GD dash swapped, 22T/205 Hybrid 20 psi - BEAST!
93 SS Bone Stock Gone!
94 TW Bone Stock Gone!
91 SS 4EAT Sold!
98 LGT 4EAT
98 LGT Wagon 4EAT
Legacy777
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Re: Using an AT dropping resistor in place of the BCS

Post by Legacy777 »

CJ,

I think he's asking if he converts his na car to turbo, does he have to run the wiring, and the answer is yes you will need to run the wiring from the BCS, MAP sensor, & pressure exchange solenoid. The MAP sensor is three shield wires, so if you can find a complete MAP sensor wiring setup that would work. For the BCS & pressure exchange solenoid, you only need to run one wire each to the ECU. The other wire is an ignition 12v source which you can add a relay & tap off of another ignition 12v source in the engine bay to trigger the relay if you want. Depending on the ignition 12v source you may be able to just tie directly into it, but I'd make sure you're not overloading anything.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
2020 Outback Limted XT

If you need to get a hold of me please email me rather then pm
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