Ignition Thoughts/Ideas/Recommendations

[NoDOHC]

Ok, so I have an unfortunate update:

I made 185 WHP at 5,400 rpm.

Peak torque was 182 W Lb-Ft at 5,300 rpm.

The reason that I list the peak WHp at 5,400 rpm is that I lost compression on the front rotor at 5,400 rpm.

The failure is a classic spark plug boss growth failure (chips off apex seals).

There was almost no marking on the rotor at all (all grooves are still in spec) but the housing is damaged.

I will post pictures later.

The reason that I posted this here is because it appears that the housing growth issue is much worse with higher spark energy (I ran for 4 hours, about 20 runs with the factory ignition with no issues).

I think that I should try turning the pulse width down and run cooler Iridium Spark plugs as dudemaaan suggested.

I never got a chance to see what the plug would do for very high rev testing. I only got to 9,000 rpm once, blew the front rotor on the second run of the day. (first run was with 11.2:1 AFR and netted 176 WHP @ 8,800 RPM, second run was with 13.2:1 AFR).

[ROT8WA]

Erm, I'm not sure how you a running LS2 coils with a CDI box as the Ls2 coils have there own built in Ignitors. I thought that this type of coil would be a total miss match on a CDI system?

Originally Posted by NoDOHC

I would give 200% of my budget for this project for a fancy CDI system like you have Peter... (can I get one for $400?)

Other than that, I have personally replaced a MSD CDI system (6AL) with LS2 coils with a significant reduction in misfires and power increase of about 15 Hp (400ish horsepower N/A V8).

Strangely, I too found the CDI to misfire significantly more at idle (as TTT found).

All I want is enough ignition energy to light the air/fuel charge in my Naturally Aspirated Rotary until the VE decreases to the point that I might as well stop. I am expecting this to be between 9,000 and 10,000 RPM. I am reasonably confident that 120mJ of ignition energy will get the job done.

If every car was a Ferrari, I would be walking to work.

I just want something that is functional and inexpensive.

The LS2 coils appear to fit the bill.

I hope they do, because I have installed them on the car and will hopefully be starting it this weekend.

[ROT8WA]

Sorry Guys, scratch that last post, I misread what was written.

I didn't realize that the MSD was "replaced" with LS2 coils..

[NoDOHC]

Short update:

I finally came to what appears to be a logical conclusion on the engine failure.

My first problem was that I was running an experimental 15 degree negative split on the ignition timing, second was that I had never calibrated the CAS. Unfortunately, this required the death of yet another set of apex seals to discover.

It turns out that the rattling noise that I was always hearing in second and third gear on the highway (which was really loud on the Dyno, in 4th gear) was not the transmission, but was actually preignition. I am surprised that the engine held together for 6,500 miles like that. I thought that I was running 32 degrees BTDC timing, but I was actually running 42 degrees timing leading (not really too bad) and 57 degrees BTDC timing trailing (which caused the preignition).

Other information for his thread:
F
Iridium Plugs really help, they lowered EGT, improved idle quality, and significantly improved preignition resistance.

Clean spark plugs are a must for an hard acceleration or dunno runs.

I made 1 dyno run in second gear (warmup) with the Defined Autoworks headers (which are really awesome, by the way) and put down over 230 WHp at 8,800 RPM (which reads very low, as the test was done in 2nd gear). My first 3rd gear run made 218 WHp at 6,800 RPM (which was max rpm where all faces of both rotors were operational). I was hoping to do an actual 4th gear run, which usually read about 5% higher, but chipped an apex seal on the front rotor.

I wish I could post the graphs, but the printer was down at the Dyno and I really just wanted to get home after breaking the engine again. This allowed me to catch the CAS stabbing mistake (which accounted for 10 degrees of the unintended advance), but unfortunately did not allow me to catch the negative split issue. I caught the negative split issue later when I heard the engine rattling again after the seals were replaced on the front rotor. A later tear down to replace oil seals revealed that three of 6 apex Seals were broken, but remained in the groove, allowing the engine to make compression.

Returning the trailing timing to 0 degree split and setting the leading spark advance to 34 degrees eliminated preignition for about 2,000 miles. Unfortunately, after everything got broken in and carboned up, even this configuration rattled, requiring new spark plugs (which are not cheap). NGK iridium plugs resolved this issue for about 6,000 miles so far.

When I can afford the engine blowing up, (which will probably be spring) I will try again on the dyno. (Getting dyno plots this time).

[RICE RACING]

Good job, thanks for updates
you will like my thread in the tech section on 13B power at one bar absolute pressure, its all turbo but in terms you understand... N/A.

[RETed]

I don't understand why you're having so much trouble with a non-turbo set-up...?

The "mistakes" you mention are all basically rookie mistakes that could've been easily prevented if you have made diligent checks.
Blaming stuff like "spark plug boss growth" is almost - I'm sorry to say - BDC-esque, where you're grasping at straws looking for something to blame...

Tuning the NA should be pretty quick and efficient.
Messing around with spark plug heat ranges shouldn't be that big of a deal unless you're tuning on the ragged edge of reliability?
(I thought this was a daily driver?)
The fact that you're fighting "dirty" spark plugs implies that you're still running too rich, or your spark plug heat ranges are wrong - i.e. too cold.
What's going on?


-Ted

[RICE RACING]

eons ago when I fucked around with N/A Peripheral Ports, inductive ignitions were the way to solve all the hassels with firing plugs, it was straight out of the Mazda factory racing hand book, however I was a broke ass like BDC and could not afford shit so inductive it was, and had similar nightmares like this bloke. < (well boxes of spark plugs changes anyway)

Inductive is garbage, always has been on rotaries always will be.

Man Up and get a CDI system, you will long forget needing to change plugs (hot warm up) cold racing lol! one plug does ALL! and you never ever need to worry about fouling, CDI gets through ground shunts with ease, does not care about fouled plugs so it is made for very low air speed poor fuel mixing Peripheral Ports are natorious for.

Leave inductive ignitions for the rookies and ass hat tuners.

[RETed]

Okay, I had to go back and reread this whole thread...

I can understand if we're dealing with some "exotic" ported engine, like a PP, but the OP is using a regular side-port engine?
The .sig just says "4-port NA"...
So we're not dealing with some kinda massive port with air / fuel homogeneous mixture problems, right?


-Ted

[88turboii]

im havingn trouble with the LS2 truck coils, thinking about upgrading to IGN-1A's

[C. Ludwig]

Take a trip over to yellowbullet.com and do some reading on the truck coils. The domestic guys will hardly touch them.