I've heard you can use FC and FD plugs in FB's (I have a GSL-SE) without any problem, is this true? I just went to the store and they ordered BR9EQ's for me, but they ended up getting the wrong ones, so I went to another store and picked up 2 BUR9EQ's (FC trailing) and 2 BUR7EQ's (FC leading).

I'm going to guess this isn't going to be a problem, but is the BUR7EQ going to be too hot?

btw might want to archive this once it's answered

 

I've been running BR8EQ-14 in all four holes with DLIDFIS. I've tried BUR7EQ in the leading holes in a rotary B2000 and BR8EQ-14 in trailing with DLIDFIS with great succes. I'm going to try this combo on my engines when the BR8EQ-14 plugs need replacing.

As I understand it, the FC plugs need a hotter spark to jump the gap. Apearantly, stock FB ignition (through a cap and rotor) may not be the best. That is why my trailing plugs will continue to be stock FB plugs since it's running through the cap. Leading can get away with a plug meant for direct fire, thanks to DLIDFIS.

As for the heat range of the plug at 7 in the leading holes, I'm not sure. Mileage and your driving style/porting will determine that.

Did you know that the 20B came stock with BUR6EQ in leading and BUR8EQ in trailing because the way an automatic luxury car is driven, needed a hotter plug. The BUR7EQ in leading may be ok for you. You could always order two BUR8EQ plugs if necessary. I think some people here run BUR9EQ plugs in all four holes for racing. 9 may be too cold for most normal street driving though.

 

I don't care what anybody says: the autolite plugs work great. I run them in the leading with NGK on the trailing.

Just make sure you keep an eye on the autolites. I'd change 'em with every other oil change.

 

Autolites work great....change them with every oil change....

Something doesn't seem right about that.

 

he said every other. but even then, 4,000 miles or so would seem rather short of a life for plugs, even on a rotary.

 

people (at least I heard some racers) swear a single (electrode?) is best for power. They usually convert the BR9EQ's to single though, not sure why they don't use autolite. Maybe not good, I dunno..

then again, I'm not sure of that information and if it's good or why exactly they do it.

 

i use autolites with no problem. i am going back to ngk though, just for that tiny bit of extra smooth idle. hahaha

 

factory mazda plugs are ngk. dont you think there's a reason for it?

 

I just took out a set of autolites. The car was ideling and just started to die. I could keep it running but it did not sound right. I had to bump up the idle to keep it running. pulled the plugs and they were very nasty. it is a Street port engine and runs two stroke. was told it has about 3-4 K miles on it. So I would guess that is what the plugs had on them. I went to autozone, advance and pep boys looking for stock plugs. pep boys was the only ones that had them.

 

autolites. i have used them as a back up. they sit in my storage bin as a back up only. i swear by ngk, period. i know a couple people who run nippon denso in their 7. they also have a quad tip like the ngk. pesonally, i stick with ngk. like oni-dori said, there is a reason for it.

 

I changed from Denso back to NGK a week ago. Denso plugs only lasted 6k miles, half of what my earlier NGK plugs lasted.

 

Autolites are cheap. At $2 apeice [$4 total] it's no big deal to change your leading plugs with every oil change if you want to. You'll always have fresh plugs, and they do work better on a stock-ported engine with an aftermarket ignition. I say stock ported because the autolites aren't made to go over 7,000 RPM.

I'm going to try some of those side fire NGK plugs that seem to be all the rage these days. They're cheaper ($.99) and supposed to be much more durable than the autolites. And all you have to do is cut them with a dremel and hit them with a hammer a few times!