Why did Mazda use plugs with a flat top with a sideways firing tip (almost a surface gap) instead of a regular type plugs, and why is there a metal damn outside the plug holes?

It has nothing to do with the plugs being better, which they aren't. It has to do with preventing the average
unknowing owner from inserting normal plugs and having the apex seal broken by hitting the plug tip along with braking the plug tip. It is called ACCIDENT PREVENTION and holds the owner at fault if they screw up the engine because it takes a special tool and knowledge to use the wrong plugs. It's a lawyer type requirement!

The BUR9EQ/EQP extend very far into the chamber and are very close to the surface. They had to do this also to get a decent ignition from these plugs. These side firing plugs are not the most efficient.

To use the shorter B9EQV type plugs require either of two go-arounds. Either a thin wall plug socket or have the plug hole barrier ground off.

The B9EGV/BR9EIX have improved access to the air-fuel mixture and thus fire more realiable . The center electrode is also smaller which concentrates the spark thus making it hotter.

 

Here's a pic of NGK BR10EIX (iridium) and a Denso S-31 (equivielent to the OEM copper NGK 9). Notice the NGK electrode end is slightly less then 1/4" shorter and the porcelin end is slight more then 1/4" shorter as well.

 

Actually, it has been documented in SAE papers that the NGK BUR spark plug design was for flooding fouling resistance.  I believe the term "semi surface gap" was used.

The method of "unshrouding" the conventional spark plug side electrode has been confirmed by many people who have experimented with this.  In that respect, the surface gap type spark plugs is superior to the side-electrode type spark plug.


See above about unshrounding
Spark plug "reach" is also an important point, and the "motorcycle" spark plugs have shorted reach, which can't be an advantage.


-Ted

 

Isn't it amazing that the RX-8 plugs: RE7A-L and RE9B-T
are single electrode standard shaped plugs like the R6725-105 and similar to the BnEGVs and BRnEIXs?

The high HP owners new the truth long ago!
Real world is better than paper ideas.

 

I don't think this means anything.
NGK produces the 10.5, 11, 11.5 heat range spark plugs to their design, and I think it was just not consistent with the BUR spark plugs design.

It's obvious the large spark gap on the BUR series spark plugs is significantly wider than the single side electrode design of the 10.5, 11, 11.5 heat range plugs for the rotary engine.  Maybe it has something to do with the colder spark plugs being able to fire a hotter spark by requiring the side electrode?

All this gets thrown out the door for the NGK 13 heat range spark plug, as it's a full surface gap design...

http://fc3spro.com/TECH/MODS/IGN/plugs.htm

I guess you like running stock type spark plugs for your "high HP" motor?


-Ted

 

I run NGK Iridiums B9EGV's for the street, and B19EGV's for the track.

I felt a significant improvement over the non-iridium B9's and B10's.

Idle was smoother and rock solid, as well as abolutely no breakup at any rpm at any boost.

Fouling is almost non-existant now.

I do run MSD 6 Boxes as well.

 

the flooding resistance was them cutting the cross shape into the plug so gas can drain out, theres a bulliten on that

 

It all has to due with the aftermarket single ground axis firing electrode plugs doing a better job of igniting the combustion mixure than the mutiground side firing stock BUR*** plugs. The single axis electrode design(most commom) is better at letting the fuel air mixture to get between to two electrodes where it can ignit. The stock plugs are not quite a good.

 

http://www.thecarricos.com/ACRE/
Recent-tech84-7-11.pdf

Scroll to bottom of that .PDF document...


-Ted

 

whoops

 

I installed my B9EGVs (which are working better than the BUR9EQs ever did) in my FC with a $3 lawnmower spark plug tool from Lowe's. It looks like a piece of pipe formed into a socket. I just ground it down a little.



http://www.lowes.com/lkn?action=true...e=037049911806

 

Any updates on how the BR10-EIX plugs are working out?

 

I'll have a set some time next week to test out with a GT4088 and a CLR-built motor.
Michel

 

what brand/heat range of spark plugs would be recommended for a 550-650RWHP application? (single turbo, halfbridge)

 

I would say 9 possibly lower if they make it.

My best dyno to date puts me at 453rwhp with b10egi's.

 

I'll be around 400-450whp daily driven. Should I go with 9L/10T?

Also EGV's or EIX's

Recommended gap?

Change them out every 10k?

 

???

 

ive been running the 9's and 10's.. and every once and awhile i just pull em out and clean them off.. no issues yet.. car still runs amazing. big street port and 350rwhp..

 

Hey what up I am new to this forum. I have a 93 greddy single turbo FD. It is not running yet because I need to get it tuned with my emanage. But I also need to know what kind of spark plugs I should run. I will be running around 11 to 12 psi. Your advice would be greatly appreciated.

 

I run my BREIX plugs gapped at .030

 

After running EGVs and EIxs, I prefer the EGVs as they idle better with a CD ignition and give a hotter spark as they are non-resistor.

 

I just purchased a set of BR10EIXs to try them out....going to see if the BURQEP9s can handle 16 psi first.....

 

that's what I've decided on after my research. I'll just keep checking them. 2YR warranty from Advanced iff they do foul on me