NZEFI has been involved with the tuning of the car for several years now. The car has enjoyed great success in the past, but reliability issues last season meant that the car wasn’t able to reach it’s full potential.

Many people have spent a lot of time in the off season working to rectify the issues they were having and NZEFI have been part of that solution. Several months ago we undertook an extensive rewiring project and created a new engine loom while fitting a new Link G4 Xtreme ECU.  The new ECU is setup to monitor many parameters that are critical for good reliability – including engine temperature, oil pressure, oil temperature and fuel pressure. If any of these parameters go outside pre-programmed limits then the ECU can take immediate action in conjunction with warning the driver. It appears that if the car has had these features in the past, they could have saved a lot of headaches.

With everyone’s work done, the boys headed up to Auckland for the 2012 Pukekohe 6 hour Endurance Race. The race wasn’t without hiccups, but in the end the car finished in a very respectable second place. Our automatic warning and limiting features did show up some mechanical issues still in the car, but they allowed the car to finish the  race in one piece.

Here is Craig McDermids summary of the weekend:

Hi Everyone

Well this year has started off with a pretty solid 1^st race, I must say!! Even more impressive was NO RAIN in Auckland during the 6 hours at all……………………just about a first for us to experience!!!

The entries were pretty good with 30 cars a number of Porsche’s a Ferrari F430, Dean Perkin’s big block Falcon, a Dodge Viper a heap of late model BMW’s and of course ourselves in the old Corolla………..

Friday’s test session had us pinged on noise, over 100 db against a 95 limit so some work to be done in a hurry but the night’s compulsory test session had us at 93-94 so it was all good.

Saturday morning was fine with even some sun. Qualifying went well, using this time to scrub in some new wets should they be needed, and in the end P4 on the second row of the grid which we were more than happy with.

Scott and I were driving.  Planning a bit of a strategy, Scott had proved he is both fast and comfortable racing in the dark so we worked back from there, trying to estimate fuel stops etc. This had me in the seat at race start.

Race start at 2 o’clock, the Ferrari in P1, Dean Perkins Falcon P2, ‘racing Ray Williams’ in a Porsche P3 and us in 4^th, but at the exit of turn 2 Ray was behind me and it was all go ripping down the back straight at over 250kph………….beats cutting the lawns!!!!

After just about 4-5laps Ray Williams had to pull into the pits and wasn’t to be seen again, but the race was on to stay in touch with the Ferrari and Falcon, but as usual it didn’t take long. Just about 40 minutes before the first safety car came out and closing up the gap again.

Pit strategy plays a huge part in the long distance races and the Ferrari guy’s had all the cards and stars aligned over the race and this gave them the opportunity to grab some fuel but lifted us to P2……not a bad place to be at this stage.

After about 1 hour 40 we made the call to do a driver and fuel change. We got Scott in the car and he went out flying with a series of 1.03 laps which was rapidly closing on the other 2. However, in pushing the extra few rev’s the noise officer recorded us back up over the 95 limited so we were given the opportunity to make so alterations. Scott had only been in the car for about 40 minutes much less than we had planned but enough to be in a position to throw me back in to get in a position to have Scott good to run to the end……………that was the plan.        

 Fortunately we had had a ‘turn down exhaust’ in our gear (a pipe turning down the exhaust by close to 90 degrees) so this the guy’s quickly fitted, then fuelled the car and strapped me in again.

More safety car interruptions with a big hit coming on the front straight, had a 996 Porsche in bits scattered right across the track and a 3 series limping back to the pits with the left corner in tatters. At this stage I think we may have got to P1 and about 2 ½-3 hours run. The Falcon of Perkins had by this time run off the track and damaged its left front and was out of the running so the battle was going to be with a very fast Ferrari………………..and of course stay out  of trouble.

A wee loss of concentration on my part had me doing 360’s off the end of the front straight but with some very good luck, and bugger all skill I manage to get back on the track not hitting a thing…..but a big moment I can tell you!!

With about 1hr 50 to go, Scott went back in the car.

2^nd was looking pretty safe with a big gap some 8-10 laps ahead of 3^rd but just a couple behind the Ferrari and he again started to push on and making some in roads but with all the mods done in the off session some of our electronic fail-safe protections kicked in causing a engine cut coming out of most corners, we thought we knew what it was but elected to push on as 2^nd was safe and 1^st………well anything can happen and just maybe the Ferrari would need more fuel and possibly tyres. They did, but managed to do this again under a safety car so didn’t lose a lap.

Fuel was to an issue for us when the low level light came on with just 3-4 laps to go, Scott ripped into the pits only to run out in pit lane!!!!! A sprint by the team members had him pushed back to the garage for a splash and away to the finish.

 2^nd was to be ours, and the team very please to be back with a solid run in one of the country’s longest races running its 16^th year.  Taupo in July is our next event, so we will see what that brings.

 Thanks to all our supporters both sponsors and team members who give us so much time to get the car ready.

 Cheers

 Craig McDermid

NZEFI wishes Craig and his team the best of luck for the rest of the season.

The big advantage of CDI is that the capacitor can be fully charged in a very short time (typically 1ms). This means that CDI is well suited to application where insufficient dwell time is available (i.e high-revving V8 engine using a single distributor).

Although the energy of a good inductive system can be equal to that of a CDI, there is one other consideration. The CDI may release the same amount of energy, but it does so over a much shorter duration. This means that the CDI has a more intense spark, but it does not last as long. This has both advantages and disadvantages.

The short spark duration is not good for lighting relatively lean mixtures as used at low power level. As a result misfire may occur. To help this problem many CDI ignitions release multiple sparks at low engine speeds. This multiple spark discharge method is where the company MSD got its name. The idea is that if the engine misfires on the first spark then one of the subsequent sparks should ignite. Another approach is to use an inductive ignition at low rpm and switch to a capacitive ignition at high rpm (as claimed by the HKS TwinPower).

The intense spark of a CDI is very good at igniting mixtures under high loads. This makes CDI well suited to firing a plug under very high levels of boost pressure, or with water injection or overly rich air/fuel ratios.

CDIs do generate very high levels of electromagnetic noise and this is the main reason why CDIs are rarely used by automobile manufacturers. However if good wiring loom layout and other suppression techniques are observed then CDIs may be used with any engine management system with very good results.

CDI coils
As mentioned earlier, CDI coils do not use the inductance of the coil to store energy. Therefore a good CDI coil has very different properties when compared to a good inductive ignition coil. Very low inductance coils may be used to produce the most intense (but shortest duration) spark. Using a conventional inductive coil with CDI releases the spark energy over a longer duration which can be a good or bad thing depending on the application.

The Ultimate CDI System
As with inductive systems, the ultimate CDI systems use a single coil per cylinder. These coils can be driven quite hard has they only have to fire once per 720 degree engine cycle and have time in-between to cool. Unfortunately, this requires a multiple channel CDI which doesn’t come cheap. Typically it is this added cost which sways many of our customers towards a well-setup inductive system.

When the igniter supplies a ground the coil charges. When the igniter removes the ground the spark is generated. The length of time that the coil charges for is called the dwell time and is measured in thousands of a second or milliseconds (ms).

The igniter also limits the coil current to a predetermined value. This limiting feature provides protection of the coils if the dwell time is set too high. It is possible to get igniters with different current limits. Different types exist which limit anywhere between 6-10A. There are also some igniters with no current limiting and particular care must be taken when using these.

An ignition channel is required for each coil. So on multiple coil ignition setups a multi-channel igniter is required. Never run more than one coil off a single igniter channel.

Coil Requirements for Inductive Ignition Systems

For maximum spark energy coils designed for high-energy transistor/inductive ignition systems must be used. These have a primary winding resistance of between 0.4 and 1.0 Ohms. The coil must also have sufficient inductance (although this is much harder to measure) as it is the inductance of the ignition coil that is used to store the energy. The amount of energy stored in the coil is given by the following equation:

E is the energy stored in the coil (measured in Joules), L is the inductance (measured in Henries) of the coil’s primary winding, while I (measured in Amps) is the current flowing in the primary winding before the coil is fired. This equation shows that to get more spark energy you can either choose a coil with a higher inductance or pump the coil up to a higher current.

Although a coil with more inductance will store more energy than one with low inductance, it will also take longer to charge assuming the resistances are the same. As a result it needs more dwell time to be available. In an application where the coil must fire very often (i.e a V8 using a single distributor) it may be impossible to achieve this dwell time at high rpm. In this case choosing the coil with more inductance will result in less spark energy at high rpm. This is because the coil will not reach maximum current and the current is more important than the inductance (because of the squared term in the equation).

The current may be increased by increasing the dwell time provided the igniter has not reached its current limit. This means that there is no point using 5ms of dwell on a coil that charges to 9A in 5ms if the igniter in question limits at 7A. All this will do is make the igniter run hotter – no extra ignition energy will be produced. So you can see that the ideal dwell time is not just a function of the coil but the igniter too! Even if the igniter is not limiting the current, the extra ignition energy comes at a price. The heat dissipated by the coil goes up with the square of the current too! This means that there is much higher risk of burning the coil out, especially in distributor applications which must fire very often.

Also remember that the available dwell time will drop of at high rpm on distributor applications. This problem is much worse on engines with a high number of cylinders. As a general rule a distributor fed 4 cylinder will start to drop dwell at 7000rpm, while the dwell on a single distributor 8 cylinder engine will start to drop off at 3500rpm! This is the reason why any high performance V8 needs either a dual-distributor setup, multiple coils or a capacitor discharge ignition (CDI) system.

The Ultimate Inductive Ignition System

The ultimate inductive ignition system uses direct spark with one high-inductance coil per spark plug. Each coil only needs to fire once during each 720 degree engine cycle so there is plenty of time to charge the coils even at ultra-high rpm. Each coil may be charged to a higher current than in a distributor application because the coil is firing less often and has time between firings to cool. Such a system is capable of storing and delivering as much energy as a good capacitive (CDI) setup.

Although “coil-on-plug” types do not need an HT lead, these are not ideal because the space constraints make it difficult to design a high inductance coil. As a result these typically these have low-inductance (they charge very quickly). Their small size also makes them incapable of handling the increased heat that results from using high current/dwell. The result is that these typically store and release about half as much energy of a good coil being charged to higher current.

We feel that “coil-near-plug” with a much better coil more than makes up for having to use a very short HT lead. This opinion is reflected in the line-up of ignition products that we offer to our customers.