Mazda factory did a test many many years ago on CDI v's inductive on NA at ~300bhp level, very good test showing even kV increased on inductive to match CDI and it could not match the power, it was less 12bhp from memory, I'll try to scan the report and the graphs and tests.

Mazda only recommend and have used CDI on all factory race NA's cars since about 1978, there is good reason for this.

For CDI to work as good as inductive at idle rpm it needs multi strike of the right frequency and number (also right amount of current and voltage, not all systems are the same in this regard if you measure them). FYI Even modern OEM inductive systems are multi striking at rpm's below 1500rpm, we have one in our workshop which I train my students on :117:

CDI done badly will give you a bad experience, CDI done properly and you will never ever use inductive again, especially on a rotary engine :biggthumpup:

Tried the multi-strike, mucked around with it, as did a MoTeC engineer and a few other people, the CDI just wouldn't idle the car nicely.... It idled, but it floated around alot and just sucked. When I swapped back to the Bosch inductive, I forgot to put the dwell table back in. Set for 0ms across the board for the CDI. THe car started and idled perfected and reved to almost 3k before it started stuttering....

I admit, I'm really surprised that the CDI gained that much over the inductive even in n/a form. If this test was done way back when I was starting my drinking carrer at the ripe old age of 6 mo's with a shot of vodka back in the late 70's.... I'm sure inductive coils have come a long way and may have closed the gap. In a 400hp turbo rotary... at least the M&W cdi system just didn't make up that much grn. Paying $500/hp for that last little .75% hp increase doesn't really seem worth it.... now a 12-15hp increase and better L's, lower EGT's... yeah, I can see that, but I haven't seen it... if that makes sense :rofl:

Just did a car this morning, swapped out Inductive for full CDI system, and better idle.......... so go figure :leaving:

I think the point is with all of this (and I have seen it before across many times repeated tests) you cant take a one off "bad experience" as a case for all, as I said not all are equal.

I do know that I personally have never seen a CDI make the same power as an inductive, its always been a big + increase to the CDI system :coolgleamA: FWI to the original poster.

TTT I too had a bad experience with CDI's a few times over the years, but then I learned myself about electrics and bought my own equipment to test it, and sorted the shit from clay :9898: when you do that and quantify the spark current, and secondary voltage, burn time, and number of restrikes, you can see that there is no substitute for ignition power :auto: I don't go off brand names or people titles or who they work for, I just look at the raw honest testing data, take a look at it, understand what is going on and you will see the merits of CDI on all applications.

I'll take some pics of the Mazda test and post them for you mate.

Thanks Peter, I'd love to see it!

Yeah, can't take one bad experience and spread it across all of them, but I do know of a few others who have had the same type of results that I have had, so I just wrote it off to, that's what it is.

I agree, with big torque comes big cylinder pressures and the need for big spark current, enter the CDI. I dunno, I just can't see it making that big of a difference in the 400whp range. I would pay for a 15whp increase, lower EGT's etc.... I really would, but I haven't found a system that will do it.

What are you running pal?

Cheers

-Brian

Will get on it tonight hopefully, if not by weekend.

I currently run Dynatek CDI's, Dynatek CDI 0.5 ohm coils, RR designed Coil on plug system. I'll dig out the Current and electrical info on a typical idle setting. Its pulls as much current as some top magneto stuff :) second restrike is right up there in "power too".

When I compare this CDI system to inductive in off boost settings the engine is just much more crisp and alive, it will fire leaner air fuel ratio's (and richer too) it wont foul very cold plugs and the EGT is lower, and power is higher. Cost of my bespoke system is prohibitive for most people off the street.

The MSD Dis2HO (high output version) with MSD small coils, and leads is a very high powered system, not as powerful as the Dynatek's 200+mj constant rating but its up there. Some of the old systems I used based on the Crane Hi-6 were quite good and idled very well (see my web site of a street port and bridge running these systems under the water injection page). 2 x Hi-6's on both leading plugs and LX-92 CDI coils.

Cool shit man.... I'll have to look into that system that you're running.

Sooooo is Rice Racing hiring?
What are the gun laws in AU?
How do they deal with sex offenders?







:rofl:




But seriously.

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.

MSD is not know as MY SPARK DISAPPEARED in our game without good reason :smilielol5:

The right products even in that brand can work ;)

You will see Rod Millen Toyota Tacoma fitted with a MSD dis2 HO, it only makes 1000bhp from 2lt though :gnorsi: it will be part of the stuff I will copy and post up.

I need to go play some Elvis songs now "In the Ghetto" :smilielol5:

Another type of ign I have been trialing from Japan is ULTRA CDI's, Mazda factory use them on most PP set up's they are working well.

CDI really is the best, though I suppose some type of inductive could be made to work, but I doubt it will ever be on par.

If you have access to a scope I'd like to see how much current, secondary kV, and burn time, you get on your system.

mr rice.. what cdi setup would you recommend for someone running a dizzy

Many years ago I ran this set up on a 13BT (12AT dizzy set up).

2 x MSD6A's
2 x MSD round coils

Worked well, did leading and trailing, idle was sweet, ran 20psi boost with water injection not a problem. Was cheap as fuck cause you could buy the combo from Summit or JEGS.

These older heaps of turd work well, there is a nice video around of V8KILLA (36psi) 13B-REW with PT T76 turbo (680rwhp set up) uses 3 x MSD6A's.

Crane Hi6 is a real good unit, better electronics than the MSD6A and when combined with LX-92 CDI coils these work sweet too. Idle, power high revs the whole box n dice. You will love it.

i have been using msd stuff for 15 years. i want some thing more powerful... more like m&w pro10.. what do you think

M&W has a bad wrap here (burn out quicker than Lidsay Lohan), Dynatek have the highest rating and moderate cost. I don't like anything with the word "pro" in it :rofl:

Dynatek ARC-2.
Dynatek 0.5 ohm coils.

You can weld with it. and its constant duty rated at high power.

Autronic 500R is an excellent CDI, used them many times. The MSD Dis2 HO is proven and been used on mega powerful turbo cars, I personally know of people running it and have done for years trouble free.

What ever you buy DONT BUY AEM!!! They are the biggest heap of shit known to man kind.

I can't find a price on the Autronic systems, but within a few minutes I found the Dynateck setup for $300 and the coils run $160 for the pair, so for $620 you can have a CDI system. That equates to about $200-$300 more than a top of the line inductive setup. I'd rock that if someone can prove a VERY stable, stock like idle and a few more ponies up top :suspect:

I guess Autronic doesn't need to sell any systems becuase I couldn't find anything online... I will admit I gave up easy :rofl: