Hi guys, does anybody know whether performance is affected by using resistor plugs?. NGK people say no, but I ask since my daddy's 1993 Legacy 2.0 Wagon uses NGK BK5E (5 is the heat rating at our altitude, as opposed to 6, for around sea level), and I use BKR5E plugs in my 1991 Legacy 2.2. I can't tell much of a difference, but I feel my daddy's Wagon has more pulling power... any comments? I ask since I am about to replace the plugs on my rig... On the other hand, do any of those fancy Bosch plugs work fine on subies?, the Subaru people here say no (maybe because of warranty purposes..). Thanks:rolleyes:

 

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1991 Legacy 2.2 sedan M/T AWD all stock

I don't know about "resistor" plugs, but I've always heard not to change between resistance/non-resistance wires in a vehicle.

 

An article that supports this: http://www.inct.net/~autotips/plugwire.htm

 

I'm on the third set of spark plugs (still original wires) on my 96' OBW with 217K. The second set I had was the Bosch Platinum +4, 1st and 3rd are NGK OEMs. Seem to run fine on the Bosch for me (no noticable difference), but both professional mechanics and and other board members here have stated consistantly to stay with the plugs the ignition system was designed for, especially on Subarus. I'd at least stay with the same brand plugs (i.e. NGK). If the NGK people say no difference on performance with resistor plugs, well they should know.

 

Any difference in performance between your vehicle and your Dad's could be attributed to many factors; minor engineering changes between the MYs, type brand fuel, condition of other components of the engine management system; wires, sensors, filters, vacuum hoses, etc.

get the stock OEM spark plugs for your subaru. aftermarket just isn't worth it, there's no reason to. a performance difference is not becuase of the spark plugs, i can promise you that. your car is going on 17 years old. that's 17 year old sensors, wires, grease, bearings, O2 sensors, dirt, build up, not perfectly seated valves...etc. way too many possibilities to assume the spark plug is causing anything noticeable. unless, because you put in different plugs you start mashing the gas pedal harder to "see" the performance difference, then you might trick yourself into thinking it's plugs making the difference. or your old plugs were so out of whack, that just having new plugs helped...but again that's just old plugs, not brand. spark plugs aren't the "magic power makers" that advertisers want you to think they are.

get the stock OEM spark plugs for your subaru. aftermarket just isn't worth it, there's no reason to. a performance difference is not becuase of the spark plugs, i can promise you that. your car is going on 17 years old. that's 17 year old sensors, wires, grease, bearings, O2 sensors, dirt, build up, not perfectly seated valves...etc. way too many possibilities to assume the spark plug is causing anything noticeable. unless, because you put in different plugs you start mashing the gas pedal harder to "see" the performance difference, then you might trick yourself into thinking it's plugs making the difference. or your old plugs were so out of whack, that just having new plugs helped...but again that's just old plugs, not brand. spark plugs aren't the "magic power makers" that advertisers want you to think they are.

 

Nice summation, grossgary. There's a lot of wisdom in your statement. Thanks.

resistors in the plugs won't change performance, they're there (one reason, at least) to suppress RFI, Radio Frequency Interferance. Switching to non-resistor plugs will make your radio emit a crazy whistling noise that goes up and down with engine RPM, and may even mess up signals being sent to and from the computer. so no...don't switch on a street car.

~Erik~