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

While the ported big valve head and Newman Phase 3 cams combination has the capacity to make over 240hp, and Monty's 43mm ID inlet runners and 41.6mm ID exhaust primaries should support 10hp less, I believe it's the hot air and especially the bends on the inlet side that'll be what holds him back from delivering his true 230hp potential.

Bends are not good for airflow, but they are an essential function of packaging those torque producing long runners.



The bends start here:



And continue here:



Actually there are bends everywhere on Monty's inlet side.



Turning the air creates boundary layers of stagnant air that become the new internal walls of the intake, these boundary layers effectively create a significantly narrower passage for the usable air to pass through. I believe these bends, and the boundary layers of stagnant air they create, are likely to generate a significant restriction and will be what stops Monty's Duratec from delivering his 230hp potential.

If you study the full setup from air filter to cylinder head inlet ports, it's definitely full of bends, it's probably fine up to 200hp and at lower engine speeds, but I suspect it'll start to become a restriction above that. The boundary layers around the edges of all those bends effectively create a progressively smaller and smaller bore inlet that gets worse as the air speed increases, and at higher engine speeds this is precisely the time the engine will be demanding more air!

The current air filter position is also subject to quite a lot of radiant heat from the exhaust, and the radiator too which is less than ideal. I've carefully logged my inlet air temps and I estimate a cold air intake could be worth as much as 4hp, but it's really the multiple bends throughout the full inlet path that will have more of a negative impact! The solution to it all would be individual throttle bodies, a straight shot of cooler air fired through a set of 43mm Jenvey Heritage ITBs would sound great, look retro cool, and and in theory would deliver Monty's full 230hp potential.

Here's a Caterham on Jenvey Heritage ITBs, OK so it's a Sigma engined Super Seven and those K&N filters do need a small bonnet cut out which I'd want avoid on Monty.





However, I think those K&Ns would just fit under Monty's bonnet without butchering it, as there is more width on a Morgan compared to the super narrow bonnet on a 7.





Maybe the above will end up being the final tuning step for Monty? But for now, I'll be more than happy if I can get to 213hp on the current Fusion Fabrications inlet, and his slightly warmer than ideal air feed.