Rx-8 iridium plugs in 13B's?
05-09-08, 05:11 PM
#27
Senior Member
Thread Starter
Join Date: Feb 2008
Location: South Florida
Posts: 309
Likes: 0
Received 0 Likes
on
0 Posts
CDI systems usually do not multi-spark at mid to high RPM, but rather only at sub 3000 rpm conditions.
At above 4000, almost all of them only provide a slightly "hotter" more intense single event spark. On a FC the only advantage at all of using a CDI system is if you spend a major amount of time above 6000 RPM (as the stock amplifier system starts breaking up around 6500 RPM) or have a ton of boost (that tends to blow out the spark at high boost).
But don't expect any low end increases or mileage increases... that won't happen. The minor high end (6500-7000 RPM) HP increases are only from a slightly more stable spark.
At above 4000, almost all of them only provide a slightly "hotter" more intense single event spark. On a FC the only advantage at all of using a CDI system is if you spend a major amount of time above 6000 RPM (as the stock amplifier system starts breaking up around 6500 RPM) or have a ton of boost (that tends to blow out the spark at high boost).
But don't expect any low end increases or mileage increases... that won't happen. The minor high end (6500-7000 RPM) HP increases are only from a slightly more stable spark.
I think the CDI systems are designed for regualar recipricating engines and thus do not provide a multiple spark beyond 3K rpm because the combustion event is to quick to benegit from that point onward in those type of engines.
05-09-08, 06:04 PM
#28
Former Moderator. RIP Icemark.
So are you saying the multiple spark at below 3K rpm does not give any type of advantage in a rotory engine? whether it be increased power, better gas milage, or decreased emmissions?
I think the CDI systems are designed for regualar recipricating engines and thus do not provide a multiple spark beyond 3K rpm because the combustion event is to quick to benegit from that point onward in those type of engines.
I think the CDI systems are designed for regualar recipricating engines and thus do not provide a multiple spark beyond 3K rpm because the combustion event is to quick to benegit from that point onward in those type of engines.
You will not get better power at any RPM under 6000.
You will not get better/fewer emissions.
You will not get better gas mileage.
You will get reduced spark plug life.
The few benefits of using a CDI on a stock engine:
You may get easier starting if you have voltage issues...but fixing the voltage issues will solve this too and make the whole car run better.
You may get a slight increase in lower end HP (but at a loss for MPG) if you re-gap the plugs... but this is very very minor and plug life suffers even more.
The ignition system on a FC is very strong and better than many aftermarket coil set ups. Some FD owners, even upgrade to the FC coils since they are so strong. And on the FC system, the leading plugs already work on a wasted spark.
Now again on modified engines (particularly ones using high boost or high RPM capability) then the CDI system is a benefit because it is helping the high RPM spark break up or quench from the intake charge in high boost situations.
as far as compared to piston engines, it would be more a comparison of ignition system design than of piston to rotary. A piston engine does not run any faster than a Rotary engine (in fact runs considerably slower if you look at the number of ignition events).
But if you have a poorly designed ignition system (such as what is found on many Honda and Nissan and Ford products), then a CDI system will provide a night and day increase. Hell I remember putting on a Jacobs CDI onto my old RA64 Celica, and that was worth almost 10HP across the whole RPM range. Why? because the design of the early to late 80's 22R ignition system was crap... not because it ran different than a rotary engine. Jacobs (BTW) makes a CDI system specific for the rotary...it is only minorly different than the standard system they make- but they get more because they call it rotary specific.
05-10-08, 04:18 PM
#31
Senior Member
Thread Starter
Join Date: Feb 2008
Location: South Florida
Posts: 309
Likes: 0
Received 0 Likes
on
0 Posts
It wasn't running any leaner(in that the same amount of fuel was being injected) ... its just that less oxygen was getting to the sensor... probly the result of more complete combustion... and less unburt fuel getting passed thru.
05-10-08, 04:26 PM
#32
Former Moderator. RIP Icemark.
You may have gotten the same change by delaying or increasing your timing slightly.
Thread
Thread Starter
Forum
Replies
Last Post
trickster
2nd Generation Specific (1986-1992)
25
07-01-23 04:40 PM
