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

I've been studying runner length today, and the results are quite revealing. I've crunched some numbers via a few runner length calcuators, and assuming we're keeping Monty under 8,000rpm, which we are, the optimal runner lenth that keeps coming up, is... 300mm.

However, there's under-bonnet packaging to consider too, for example there's no way on God's earth we're fitting 300mm long ITBs under Monty's bonnet, even with a bonnet scoop! Having measured up today, the maximum runner length of a set of Jenvey individual throttle bodies fitted with a low profile foam air cleaner, that would fit and still allow me to close Monty's bonnet, are 160mm, so a long way off 300mm!

I've also just measured the long curved runners on my Fusion Fabrications inlet, they're 370mm, all the evidence suggest they're perfect if you want to stay under 5,800rpm, but they're 70mm too long for an engine we want to keep making power out to 7,800 rpm.

To make the evaluation of all the induction options more clear, I've created the following table.



And assuming we can make it fit and still close Monty's bonnet, it does seem like the Fab9 Elite Manifold would be the ultimate compromise.



It theory, it should give us this.





Monty should retain his excellent mid-range punch, but at that same time now keep piling on the horsepower from 5,500 rpm out to 7,800 rpm tops where he'll be making somewhere between 210hp - 220hp. I now think the Fab9 Elite intake is the way forward, but fitting it without a bonnet scoop is looking like it'll be very touch and go!