Why Bigger Is Not Better!!!!!

(By: Andy Fox)

So the truth is out, I am here to say that ‘bigger is not better’….

For sure this is quite a revelation for some of you…The proof is in the pudding.

If you have been following our journey so far, you will be up to speed with some of the development of our GQ Patrol.

Central to the whole exercise are the modifications to the engine. Over the last 18 months we have had our own version of the Myth Busters going on at the Dynomotive Headquarters in Bayswater, Victoria.

Mark is the brains there and is quite a different tuner. He is a great thinker and challenges the conventional way of doing things.

The old motor had everything huge in it, the cam was off the planet the headers were wombat holes and rest followed suit. I would call this the ‘Varmint Theory’... apparently they are attracted to shiny things.

Bigger valves, bigger headers, bigger biggers, if you get what I mean.

Based on our ‘Smaller Guy’ theory, we set about making everything match in the motor. This process led us to the Headers. Mark has been mentoring me on the build for the last 18 months and if the count is right we are up to run 111 on the run sheet… ooops.

One point to remember here is that we have max HP at 5700rpm, so why spin it to 7500 to try and make power. The idea is to make as much torque as you can as low as you can and be all over before 6000rpm.

To the Headers...

The theory was to step the headers and connect the 180 degree opposite cylinders, 1-6, 2-5, 3-4. What this means is that each cylinder is getting help every 100 degrees. The second part was the recipe Mark pulled out the ‘black book’. He delivered a spec and a bunch of stainless mandrel bends and said, “Go tig big fella”.

The idea was to step the headers and then merge 6-3-1 and make all the distances equal. Mega hours later the job was done….

HPC Coating was applied to the headers. Then the job of making a full custom mandrel bent exhaust was to follow. The new system reduced the 3 inch system to 2.5inch. mmmmm small guy stuff…

Some of the tricks are;

1. Make the headers out of stainless, it holds the heat, therefore making the header slippery and faster flowing.
2. The stainless tricks the gas into thinking that the header is longer, giving more torque.
3. The stepped primaries give you a greater port velocity, which aids scavenging.
4. The HPC coating helps the heat to stay in the pipe and to keep the under bonnet temp lower. They Quote 24%.
5. Longer Primaries develop more torque.

Enough of the theories, the results were spot on, 35nm of torque across the range and another 12 Kw both at the rear wheels, Worth every second of pain.

In summary, we are running a smaller cam, smaller headers, smaller exhaust, standard valves and standard head and we made much more power.

So maybe the small guys have the edge...