Misfires under boost... - CH Crasy Ideas

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Till now I was running a number 3 nozzle with my water meth kit. This nozzle size is meant for a K03 turbo car. Till now I was only using the kit to help with the prevention of carbon buildup. There was a cooling effect on the boost but not as it should. The Snow performance water-meth kit I got had 2 nozzles in the kit a number 3 and a number 4. The number 4 nozzle was meant for K04 setups.

Usually, when you use a water-meth kit on a car it is for performance gains. The higher the horsepower the bigger nozzle you want to run as the airflow and intake temps will be more. I got to the stage now that I was trying to get as much power out of the K04 turbo while keeping it reliable. I also didn’t want to change over to race fuel or octane booster. Max power with pump fuel (95 Octane) and with water-meth.

I did the nozzle change, and the car ran really nice. Running some log pulls with the laptop in the car and there was no sign of any knock. I was really surprised. Usually, you will see some knock events low down in the RPM range. This would be a norm on a hot day like this day. I set up the boost level with one set point with my REVO SPS. Ran some more log runs with a higher boost setting and got some small knock events. It was still within the factory limits.

The knock events were only at low RPM so I set the water-meth controller that the water-meth started spraying at a lower boost level. This took the knock events away. The car pulled like a train.

Cooler ambients

Winter was here and the early morning temps were dropping. Our temps do not go as low as some other countries but we do see the 0 Deg C and some time -1 Deg C. I was on my way to work one morning. It was the first morning I saw the temp at 0 Deg C. There was a vehicle in front of me that was driving really slow so I decided to overtake. I accelerated hard and as I hit higher boost levels the car started misfiring. When I tap off the misfire goes away and as I accelerate again the misfire returns.

This was a funny scenario. The car has never done this before. Later that day when I was on my way home again I tried to replicate the misfire. Nothing, the car was running like it usually does. I wondered what could have made the car misfire the morning.

The next morning we had another cold day. On my way to work, I tried to replicate the misfire again and surely it was back. I could not get onto boost properly without the car popping and banging. This was really annoying. That afternoon the misfire was gone again. This went on for a week and was driving me nuts.

So what did I find out

I spend some time on the internet to see if someone had similar issues, I could not find anything. I had to put on my thinking cap. The only thing I could think of is that it was temperature related. The afternoons ambient temps were between 17 and 20 deg C and the mornings were between -1 and 2 deg C. I started looking at my logs I have done on the car. With the new intercooler, I was seeing intake temps of 25 to 30 deg see on a day with an ambient temp of 30 deg C. So if the Ambient is 0 deg C the intake temps can be below the 10 deg C mark. With the water-meth, if you get a 10 to 15 deg C drop in temp(It could be more) that will give you sub 0 intake temps.

Engines like cool air so why would it matter if the intake temps go sub 0 deg C. The issue is if air temps go that low the density of the air gets too thick and the spark plus may battle to fire. I started looking for upgraded coil packs.

VW\Audi did do upgraded coil packs for some of there engine variants. The most common was the Audi R8. The coil packs looked exactly like the standard coils even with the same plugs. The only difference was the coil packs were red. So what makes them so special? The coil windings on the secondary coil in the coil pack is different from the standard coil. This means the voltage of the output of the coil is higher. So this means that there will be a greater spark.

Finding R8 Coilpacks

I thought to myself that “Audi R8” coil packs, that is going to be very expensive. I started searching the net and found them everywhere. This was a common mod on the higher horsepower TFSI engines. The people even did conversions to fit them on the older 20 valve engines. I found a local company VAGCAFE that sold a kit for the Golf 5 GTI. This was a set of coil packs with NGK BKR8EIX spark plugs. The spark plugs were full iridium plugs. The Price was also fairly reasonable for what you got.

Audi R8 Coil packs and NGK BKR8EIX Spark Plugs

The outcome and my opinion.

I bought a set of coil packs and spark plugs from VAGCAFE. It took about a day to get to me via courier. I installed the plugs and coil packs the same day they arrived. Took the car for a spin, the car drives that same, feels the same. Going from standard plugs and coil packs to the R8 goodies do not give you a power gain. The next morning it was super cold again and I dried the new coils and plugs out again. The car pulled smoothly without a hiccup. The coil pack and spark plug setup fixed the misfire issue.

I would recommend fitting the R8 Coil pack and NGK BKR8EIX plugs to and stage 2 and above Golf 5 GTI. This will make certain that you always have the perfect spark to make the engine run smoothly in all conditions.

Here are some links that you can check out:

R8 Ignition Coil – Priced Each

BKR8EIX Iridium Spark Plugs – Set Of Four