Hi All,

At what stage (if any) on boosted falcons do you need to improve the ignition/spark with something stronger?

I've been recommended getting a CDI for my powerdyne supercharged AUIII (VCT). I run water injection, around 10psi boost, and it will be intercooled in a few weeks. A CDI for my car is pretty expensive (had motec or msd recommended.....I have motec engine management), so I'd want to know it was absolutely necessary to get one before I forked out cash.

I don't know the ins and outs of this area, so any of your own findings and tips would be appreciated.

Cheers,
Joe

This is a wierd one Joe as the BA guys myself included have to run a tight plug gap to make boosted HP,but on the other hand some BA/F guys with their own shops are up near the 1000hp mark with the stock ignition and built motors so fooked if i know..These guys and myself all reckon if they could open the plug gap a bit there'd be more HP in it as well.So i don't know.
I think the AU's have a better ignition than the BA/F's so if they can do it you can too.
This post is probably no help but there ya go.
What do you think of the water/meth?
I have a stage 2 system sitting around ready to go on,i've just got to get interested enough to fit it.

I dont get how a AU coil pack could be better than a BA on coil on plug?

Last edited by MadMatt on Sun Apr 05, 2009 5:25 pm, edited 1 time in total.

Raising the voltage to each coil and multipe spark helps in low rpm..
Which is what MSD A6 does on dissy engines..
With wasted sprk a Dis-4 ignition box is required..
Motec use M&W ignition system.. With their name on it..

Raising the voltage to each coil and multipe spark helps in low rpm..
Which is what MSD A6 does on dissy engines..
With wasted sprk a Dis-4 ignition box is required..
Motec use M&W ignition system.. With their name on it..
http://www.mwignitions.com/cdi2.htm

If anything I felt my car ran better after fitting an MSD CDI on my el, it was N/A (stock system had done 160000km when I fitted it though).

You can get away with running stock ignition, but if I was boosting a car I would spend the money regardless as a bigger spark goes a long way to reducing any pinging, plus also generally should give a bit more power.

Thanks for those pointers.

I had a look through the M&W site EBXR8.....there are different CDI's with different amounts of channels. Your link sent me to the CDI with 8 channels (I think) and a motec input....is this what I would need, and why? I was under the impression a 4 channel (MSD Dis-4?) would do?

Skidder, what was the purpose of fitting the MSD to your car? Sounds like it was helpful. How does more powerful spark aid in reducing detonation (a current problem on my car....hence the intercooler being installed!)?

Badcooky, the water/meth injection works well. I've heard ppl say that it doesn't really cool the intake air temp but my findings are otherwise. My intake air temp at the throttle body is around 50 degrees on cruise. As I accelerate and the charger begins to make boost, intake temps at TB rise toward around 60+ degrees. As soon as water spray kicks in, intake temps reduce to around 45 degrees. I inject the water pre-supercharger. Hope that helps to motivate you.

I guess my main question still remains....from your experience do I actually need a CDI for my setup? It seems so far that it could be helpful for better power and driving characteristics, but not necessary?

Joe

The boys up here had a Jap thing on the dyno and with a plug gap of 1.1 they got 600+ out of the rear with NOS.
I told/asked Pete to close the gap up and she went over 700,it's off it's head powerwise but it couldn't hold the bigger gap.

Cooky, I'll try a smaller plug gap. I used to have my plugs gapped at o.7mm, but I think the last time it was tuned, the tuner put in standard plugs (1.1mm). I'll see if this makes a difference. Reading through the NGK website, it seems pretty important to get the torque setting exactly correct too.

Has anyone found that by running a cdi or similar, that there's been a reduction in the tendency of the engine to ping or detonate? Or more just improved the general driving characteristics?

yes, i found that once i installed the hi-6 i could run more advance on boost.

my plugs are gapped to 0.71mm

I installed a HI-6 on my EL (n/a fair bit of work, yadda yadda). The capacitive discharge and multispark added to low end torque (better burn because of multispark), and high load (e.g. WOT, low RPM because of the stronger spark).

The B series makes use of multi spark at lower RPMs. and the coil on plug gives better spark than an AU/E series, plus it's sequential (not wasted spark, like AU and EF). It is overall a better system, and most BA turbo owners get away with the stock ignition system. There's high output coil packs available (for both the 6's and 8's), but they're not used all that often.

There you go,so it's just us BA/F guys b**ch that we have to close up the gap to go forced,i just followed the band wagon and had a moan as well.
The high energy coil packs are available?I just got sick of waiting for them and never followed up.
Data mine who is making them and where do i get them?

Sorry, I can't remember (did see them on FFAU), I don't need them.

Direct ignition doesn't necessary make a stronger ignition over wasted spark or COP..
It is a better system though in theory...
A dizzy and ONE coil can make good power.. It's the stronger spark required on boosted engines..
Smaller bores as in 6's and mod V8's have lease issues than 4" bore of a Windsor..
I have been to many dyno comps, there have been many supercharged Commodore Genell's have ignition issues around 370 rwkw.. Even though they have separate coils doesn't make a strong enough spark..Btw the bore of the Gen Lll is still smaller than the 5.0 Windsor..
Keep in mind there are some high powered cars still running a dizzy.. They have high voltage system to run coil at much higher volts...
Using crank, cam angle sensors gives MUCH more acurate spark.. Which is VERY important on a blown engine "if you want it to stay together"...
Wasted spark helps big time with launch control and cleans plugs which can cause issues when running colder plugs on short trips etc..
How to Choose

To decide which products to use for your ignition system consider the following factors:

Trigger System

The ignition timing is triggered by the engine position. A Ref signal indicating crank shaft position and a Sync signal indicating camshaft position (optional) provide this information to the ECU. Many different types of trigger sensors may be used. These signals can be derived from the OEM system or by using MoTeC's trigger wheels and crank and cam sensors.

ECU
The ECU calculates the engine position from these Ref/Sync signals, and applies the appropriate ignition timing. The number of ignition output signals needed in a particular application depends on the engine (number of cylinders) and the ignition mode. If the number of ignition outputs available on the ECU is not sufficient, this can be increased by using a MoTeC IEX.

Inductive Ignition versus CDI Systems
In an inductive ignition system, the coil is charged at battery voltage for a period of time—known as 'dwell time'—prior to firing. The dwell or charge time is controlled by the ECU and should match the coil being used in order to not over or under charge. Undercharging reduces available spark energy, while overcharging can cause overheating of the coil and/or ignition module. Inductive ignition systems produce a spark, at a lower voltage with a longer duration compared to capacitor discharge ignition systems.

A CDI, Capacitor Discharge Ignition system is charging constantly and sends a large voltage charge (380–450 V) to the coil. The spark produced is extremely short in duration and at a much higher voltage than an inductive setup. Note that inductive coils should not be used with a CDI system; CDI compatible coils are required.

There are three main engine running characteristics to consider:

•High cylinder pressures
Generally, higher cylinder pressures require more voltage to initiate a spark. Boosted or nitrous injected engines create tremendous cylinder pressures that increase resistance to lighting the ignition spark. CDI systems are most often used on these engines.
•High RPM
The time available to charge the coil in an inductive system reduces at higher RPM. If the time available is shorter than the time required for a full charge, coil power and, as a result, performance will be reduced. A CDI system might be required.

•Lean mixtures
The shorter spark duration in CDI systems might not be sufficient to ignite enough of the mixture to propagate the flame front through the cylinder. Inductive ignition will perform better in this setup.
Most vehicles, including high performance road and race applications use an inductive ignition system. Generally, if your engine can run correctly on an inductive setup, it is better to leave it that way and install a CDI system only when your engine, due to high RPM or cylinder pressure, requires that you do so.


Charging the Coils
The ignition signal is provided to the ignition module that controls the coil. Choose either inductive or capacitive discharge ignition modules with the correct number of channels.

Distributor
Depending on the ignition mode your application might need a distributor to deliver the spark to the relevant cylinder.

Ignition Coils
Depending on your system, choose either inductive or capacitive discharge ignition coils

EBXR....wow that is some seriously detailed info! This detail is what makes this forum so useful. Extremely educational, some of it went over my head though.

I assume from going through this info that the standard AU system is an 'inductive ignition'. You wrote that "Generally, if your engine can run correctly on an inductive setup, it is better to leave it that way and install a CDI system only when your engine, due to high RPM or cylinder pressure, requires that you do so".

On my vehicle for the sake of saving money, I'd be very keen to keep the standard inductive ignition, if its up to the task. What are the symptoms or signs that its not? Ie, how do I know that the standard ignition is not handling the boost pressure, and needs upgrading to the higher voltage spark of a CDI?

Surely is must be in reference to the amount of boost...? Eg. an engine running 18psi would be more likely to require a higher voltage spark (CDI), than the same engine running 10psi?