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

Hi all,

For those of you following the ongoing development of Monty, here's the new custom fabricated inlet manifold created by Fussion Fabrications:










And a couple of early videos showing the engine running on the new manifold.

https://youtu.be/QzQsjna_xCo

https://youtu.be/yiFpY3Ekzl4

I hope my Morganeering friends agree, the new inlet manifold complements the exhaust that Fusion Fabrications also created for Monty?




I collect the car tomorrow

Dave.

I hope it goes well. I understand then you have the orignal throttle body feeding four inlent trumpets. Do you think the trumpets are needed in an enclosed manifold? I've never seen that before hence my question.

I had trumpets inside the plenum on my racer .... they still help with gulping air into the relatively narrow TB throats in an expeditious way.

K

Hi John,

The Fusion Fabrications inlet manifold is a super proven piece, it's been around for years and was developed to cover a gap in the market that appeared when Mountune stopped supplying their legendary and also equally well proven MR200 manifold, but more on this later.

It's also super common practice to bury velocity stacks (trumpets) inside a plenum, we see the same 'bell mouth trumpets inside a plenum' set up literally all over the place, and in both aftermarket and OEM plenums.

Here's what you find inside the plenums used on a Porsche Boxster:



And here's a look at BMWs E90 M3 arrangement:



However, probably the easiest Morgan friendly example would be the Lucas 14CU and 14CUX equipped RV8 Plus 8s, where you'll find 8 velocity stacks (trumpets) under the plenum. Here's a little mod I made to my TVR Chimaera (same engine) to improve the trumpet mouths still further:



In the four cylinder world, again we see the same setup all over the place, here's a Honda example that actually very closely resembles my FF manifold:


And here's some interesting results of very similar long runner inlet that picked up a full 24 wheel horsepower on a K24.

https://youtu.be/438S8whO7sM

That's almost 30hp at the crank, which is on top of the existing performance manifold used on this particular K24, an extremely impressive gain!



The Fusion Fabrications manifold I've had made for Monty is actually a hand fabricated version of the fabled Mountune cast aluminum MR200 long runner inlet manifold/plenum.



As I previously eluded to, Mountune stopped supplying this manifold back in 2012, they're so sought after these days that they now change hands for £2,500 plus on the used market, but they seldom come up for sale.



As we can see from the above Fusion Fabrications manifold dyno graph, the reason people are so keen on the fabled Mountune MR200 and hand fabricated Fusion Fabrications long runner inlet manifold/plenum design is it produces excellent torque.

For a vehicle driven on the road, this makes it a way better choice than the rather short runner Caterham inlet/plenum or even the genuine Cosworth inlet/plenum whic is also a short runner design, and now rocking horse poo rare/expensive. A long runner plenum setup is also massively better than a set of individual throttle bodies (ITBs) as used on the Duratec Morgan Plus 4 Super Sports and ARP4, this is because the elephant in the room for ITBs that nobody seems to talk about is they always come with a very short runner inlet manifold, and there's simply no room on the Morgan application to extend the velocity stacks (trumpets) long enough to make the torque you really want on a street driven car.

Going with a plenum also provides the reliable vacuum signal you lose with ITBs, this means you can run the engine management system on the far superior 'Speed Density' strategy as you can retain the MAP sensor, this is how the OEM Ford engine management system is designed to work. As soon as you go down the ITB route you not only lose torque, you're also forced to run 'Alpha-N' which is simply TPS Vs RPM so a long way off the proper engine load reference you really need to build a good fuel and ignition calibration. 'Alpha-N' also forces you to invest in a stand alone mappable ECU, this is why Morgan used an Omex system on the Super Sports, there was no way the Ford ECU would support an ITB set up.

For all these reasons you tend to lose a lot of engine flexibility when you go down the fashionable, but in my opinion flawed, ITB path. While there's no denying they sound great and make good top end power, obtaining smooth OEM drivability with ITBs can become a real headache. A good long runner plenum is therefore the smarter choice for anything other than a race car, and adding bell mouth trumpets inside the plenum gives you those lovely 'Braaarp Braaarp' throttle body sounds anyway.





Jump to the 20 second point on the following video and you'll hear what the Fusion Fabrications inlet manifold sounds like on an ST150.

https://www.youtube.com/watch?v=6Y38AS8NHxQ

Monty should sound even more visceral

But look like this

I know about plenum chambers where air come generally from above direct to the inlet..
I just wonder how cylinder 4 inlet is affected by air having to flow past all the other 3 inlets. I guess it doesn't matter

Correct, it doesn't matter a jot, because the whole plenum is under a constant and consistent state of depression.

Until you're at at wide open, at which point the plenum is at atmospheric pressure.

Interesting, The car sounds great in the videos and the Fiesta also sounds nice. On the bottom of the Manifold it looks like place for two sensors. I am guessing one is the MAP sensor, what is the other one? Also I am wondering where the injectors are, I can't seem them in the photos.

I had a look at the ARP4 and it looks lovely with carbon fibre bits and Cosworth wording but there is not much room for the throttle bodies, I am hoping my car doesn't lose too much torque as the trumpets do look longer than what would fit on a Morgan.

One is the maf . The black one. The silver one is the IACV

Surely the MAF sensor would be between air cleaner and throttle body so most likely MAP as it measures manifold pressure. The other one could be for purge valve from charcoal canister since I believe IACV is closer to throttle body on cars that have them.

What you are seeing above is the MAP sensor on the left and the IACV on the right, the manifold is upside down here so the sensor and the valve are both hidden underneath the plenum when fitted.

The restrictive swirl flaps and heat producing EGR system are now deleted too.