Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Monty Takes A Deep Breath

Using my ECU Masters EMU Black ECU.



I can accurately log my true IATs in real time, while I primarily use the data to build my IAT correction settings that influence my base VE table, it's quite clear when reviewing the data that there are significant benefits to come from relocating the primary induction point. As always, it's a battle between the ideal vs packaging, however, I'm confident we can move to a forward facing TB that not only allows for a proper cold air intake, it also eliminates a series of bends which is always a good thing.

From this:



To this:



To relate intake air temperature to air mass (density or mass flow), the core equation comes from the Ideal Gas Law. For engine/airflow purposes, this is usually rearranged into air density form as follows:



Obviously the horsepower curve mirrors density almost exactly (because power ∝ oxygen mass), which using the numbers below allows us to plot our data clearly on a graph and using 0°C as our baseline:

20°C ≈ −7% power
40°C ≈ −13% power
60°C ≈ −17% power

Our graph it ends up looking like this:



In reality designing a good cold air intake is all about minimising to difference between ambient temperature and intake air temperature, but taking an average of UK climatic conditions and average elevation above sea level the true potential percentage horsepower gain calculates as 6%.

If we then include the cross sectional area improvements calculated as a function of removing all the existing bends in the current induction pipe, and the one sharp turn at the throttle body (all of which generate boundary layers of air), we end up with a carefully estimated air flow improvement that should deliver a 4% improvement in horsepower.

Add the temperature based air mass hp percentage improvement of 6% to the 4% flow based hp improvement, and my 'Straight Shot' cold air intake design has the very real potential to deliver a 10% improvement in horsepower over whatever we make at Surrey Rolling Road on the 20th June when Monty will still be running his current 'Hot Air' setup. Let's say we make 204hp on the day, adding my 'Straight Shot' cold air intake and forward-facing throttle body over the winter, should see Monty making 224.4hp when I return one last time to SSR in the spring of 2027.

TBH, if I can eventually get Monty to make 220hp at 7,380rpm and 185 lb/ft at 5,250rpm on the long runner Fusion Fabrications inlet manifold, I'll be over the moon! However, as I've said all along, we just don't know where the Mountune MR200 copy inlet manifold is going to start becoming such a restriction in airflow that making any more power becomes impossible?

All will be revealed in the fullness of time