Hey guys. After reading just about every thread in this section on the matter I have come to the question(s):

Background

According to Ted's webpage, MSD can grant you an extra 5 horses. That's a pretty good deal, I say to myself. You see my goal is to use every cost efficient method to gain power vs weight w/o creating more lag with a larger turbo (keeping away from 20b and ls1's), keeping my response time. I guess you could say I'll be right around Ted's Stage 4+ when I finish my project, roughly around 330 I'm guessing.

Question

So , what's it worth putting in one MSD 6A box after the ignitor, Using 3 MSD 6A boxes, or using a Motec CDI box? Is it worth paying 1800 for the CDI box, what kind of advantage can paying an extra 1500ish do for you (That's a lot of money :O).

Anyway, happy to hear what the experts say and if I sound like a DIY'er who's about to get himself in to a mess of problems, thats probably because It's true. So, any help is greatly appreciated.

 

I would go with an M&W Pro14 Rotary, this will be a great CDI to use, and best to pair it with a set of M&W CDI coils.

However, I will stress the following, the stock 2nd Gen coils and igniters are capable of giving you over 450hp with no problems if they are in good condition, AND! the LS1 coils are capable of over 500HP on a rotary which i mentioned in a thread around here just a few days ago.

So, technically, you really do not need to purchase any kind of CDI for your power goals.

 

Okay, so what about this crisper more powerful spark I'm hearing about, that could save some gas and give horsepower, that a little too good to be true?

 

Okay, update in my knowledge base i think. Using a MSD, you can add a bit more fuel to your ratio and the stronger spark burns it up, thus keeping you closer to stoich which in turn gives you a slight increase in combustion. Am I right so far and may I reiterate my original question?

Which is worth more for the dollar in your opinion, the MSD or M&W CDI (By the way, thats a much more affordable price of 1200 rather than 1800 for the 500r or Motec).

*Edit* Or am I getting ahead of myself?

 

At the power level you are looking at the stock coils usually are quite adequate. You're not going to pick up much in the way of power or economy with a hotter spark. Once you start to try to run higher boost pressures the combustion chamber becomes less spark friendly. The higher the combustion pressure the harder it is for the spark to jump the plug gap. That means more electrical energy is required to jump the gap and properly light the mixture.

If you were looking at making over 400 whp then it might time to start looking at a hotter ignition. At 330 whp I'd throw the money elsewhere. If you must have the M&W drop me a PM. I know where you can get the Pro14 Rotary for a lot less than $1200.

 

Alright, thanks Ludwig. Guess i'll save the money for the rebuild, thanks again guys =)

 

I just want to comment on this thread since it specifically mentions me...

I like CDI boxes cause they do a number of things which are advantageous (for the rotary engine).
One of the less obvious answers is that it keep flooding problems minimized by being able to fire through "bad" spark plugs.
The drawback is that you can run your fuel maps slightly richer and not know it by your butt dyno.
This is connected to being able to fire through difficult conditions - i.e. high boost, "exotic" fuels, etc.

Higher boost should not be a problem...

Supplemental injection - i.e. water and / or methanol - is not a problem.
These types of additional injection systems are popular nowdays.

Running a single (channel) CDI box on the leadings is always recommended in my book.
Running additional CDI channels on the trailings is usually overkill until you start pushing over the limits of pump gas (~15psi) and / or 400+ hp.

Yes, the stock FC coils are fine (just by raising the charge time), but purchasing a single CDI box for the leadings should not break anyone's budget at this stage of the game.


-Ted

 

Okay, that sparked my interest again. Would you also recommend a M&W CDI just for the leadings RETed?

 

You need to ask yourself what your goal really is? What HP are you looking for?

Then you can choose which way to go..

 

I'm basicly looking to get as much hp from tunning and modding with my 13bt and stock turbo housing while keeping it street legal as possible
.

 

You won't need more then stock turbo 2 coils..

 

I second that. Best case scenario you can use LS1 coils which are cheap and really good, and proven on 550+ HP 13B motor with no problems.

 

Lol alright, guess its back to the rebuild =D