Talk Morgan Forums Morgan Sports Cars Classic Morgans (pre-CX) Duratec Super Sports Exhaust Manifold

Hi all,

To help my fabricator build Monty's new exhaust system, I'd be grateful for your help in building an image library of the Duratec Plus 4 Super Sports exhaust manifold.

I'm no expert but it looks like for the Super Sports model Morgan started out with the 2.0 MZR variable valve timing version of the Duratec/Mazda L engine as used in a Mk3 MX5 (NC), maybe even the Mk3.5 vetsion that introduced a new forged steel crankshaft, forged steel connecting rods with floating wrist pins, revised pistons with stronger gudgeon pin bosses and stiffer valve springs?

A bit of research reveals the Mazda LF-DE and LF-VE versions have sequential multi-point port injection, while the LF-VD version has DISI direct injection which I believe came in on the Plus 4 around 2013/14 when it also recieved coil on plug ignition (COP)? Confusingly all Mazda versions were equipped with COP electronic ignition, but as we can clearly see from the images below the Super Sports engine is running wasted spark just like Monty who got a bog standard port injected Ford Focus/Mondeo lump with static valve timing.

Of course none of this really matters when talking exhaust manifolds as all variants of the Duratec and Mazda L are basically the same engine, the Plus 4 Duratec Super Sports manifold is by far the best design I've seen squeezed into a Morgan engine bay, so I'd like to replicate it.

I've collected these images so far but would welcome some more, if someone also has any images of the manifold off the car that would be great too

The engine used in the Supersport was the MY2010 onwards MX5 Mk3.5. It used the standard Ford, not Mazda, coil and HT leads as at that time the Mazda coils were very expensive. The later 'cooking' TiVCT engine was Ford based, not MazdaThe exhaust manifold was pretty good for power but wasn't too great on emissions, the catalyst was too small really. The genuine Supersport manifold hasn't been available from the factory for many years but there are various aftermarket copies that have been available such as the one by Williams Morgan. The Babydoll manifold was actually slightly better for both power and emsissions, not sure if anyone makes a copy still?

is the prototype engine in my Plus 4 (excuse the horrible noises, it's the back axle trying to escape!)

is it at Prescott.


You'll see just how ridiculous the standard gearing is, I believe the production Supersport had a 4.1 diff instead as standard or maybe it was a cost option, my memory fails me.

She sings well this Morgan

The horrible noises are much more noticeable in the hill climb video.

Very nice car and a good time up the hill climb plus a lot of overtaking on the track. Do you still own it?

Very nice car and a good time up the hill climb plus a lot of overtaking on the track. Do you still own it?[/quote]

Well when you only have 204bhp you tend not too slow down too much tbh! It was actually much better on the faster longer tracks where the gearing wasn't such an issue. Interestingly it had really good torque from even below idle speed, someone put a post recently saying that TBs have less torque than the standard inlet, but that is utter nonsence. Having developed and supplied both the Supersport, the Babydoll and the factory Duratec/Sigma/Zetec TB conversions they all made more torque everywhere than standard.

That car was the development vehicle for the Supersport (not the Prototype, that was owned and raced by the factory although I did do many thousands of miles in both during development). I bought it off the factory after we finished the Supersport, kept it for a couple of years and then I sold it many years back now (and regretted it but the wife wanted a new kitchen or something) to a very nice chap in Scotland. I think he improved it quite a bit, no idea if he still has it. if it is still known it would be nice to know what happened to it.

The P4SS actually had the too long 3.7 differential. The 4.1 was extra money. But the sound was a beautiful thing. To be honest, after three years I sold the car because it was damn loud, especially because I had my P4SS changed to be a LHD. With that I was sitting on the same side as those STBs, which is much louder as a driver in a RHD car. I know because I was a passenger in my car sometimes. The bonnet acts as an intermediate acoustic damping device for RHD cars. Here is a video from 2012 near Bozen.

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Thanks to everyone who responded to this one, here's what we came up with in the end, I hope you agree it's somewhat of an improvement over Morgan's adapted Mondeo exhaust manifold on the left?



And I'd argue substantially better even than the below offering from Librands, which by the way also worked out significantly more expensive than the above beauty created for Monty by Matt at Fusion Fabrications.




Reading the above, it does seem my comments elsewhere about ITBs and torque may have been taken out of context, so I'd like to qualify my point,

Firstly, a Supersports may well produce a higher peak torque figure than a standard Duratec Plus 4, but that's hardly surprising as a Duratec in the Supersports is tuned to produce more power overall, the SS exhaust manifold alone is a massive improvement over the standard Morgan exhaust manifold.

The questions we should be asking ourselves are:

1. Where in the rev range does the Supersports make its peak torque figure?

Sadly, I've yet to see a dyno graph for an SS

2. How does the Supersports torque curve compare when you lay it over the standard torque curve, and the torque curves of other tuned Duratecs, like one fitted with the Ford indorsed Mountune MR200 kit for instance ?

And finally, the question actually relates to my misquoted point...

3. Would the exact same Duratec engine make a lot more torque if you ran it on a well designed plenum with nice long runners and a single throttle, rather than a set of ITBs on a stubby ITB inlet?

i.e this.....





Vs this.....



Before jumping in to answer the third and final question, it's worth considering that inlet manifold design and the effect runner length has on the production of torque has been well understood for over 70 years

Thanks again for all the comments, if anyone does have a nice clear dyno graph showing horsepower and torque for a Supersports, I'd love to see it

Dave.

Pity you had to sell it, hopefully the new kitchen is very nice. Coincidentally I am currently making a new drawer for the kitchen. She wanted a new oven and the drawer below was the wrong size, so far three new ovens and I will have four drawers made to fit under it. Maybe if I am lucky the next time she gets a new oven it will the same size as a previous oven and I can reuse a drawer. However she assures me she loves this new oven so will not be replacing it.


Now you have me worried. My MGB has STB's on the passenger side, meaning it will be louder for the passenger, great when I take my son or most guys for a drive but I expect my wife will be very grumpy if it is what she considers a loud car. Hopefully I can short shift and drive it gently when she is in the car and not get in trouble.



Yes your new one for Monty looks the best, very similar look to what they have fitted to my MGB with the 4 pipes merging into two and the one about halfway down the gearbox..


I remember reading an article on the new XJ12 engine being developed, they found longer intake manifolds helped the engine produce smoother power. If I understand correctly you have basically built what is one throttle body into a chamber with very long runners equal length as a long intake runner length is not possible under the bonnet of a Morgan (or most cars) when using STB's. The idea being that the long runner gives more benefit that you get from STB's. From my understanding the benefits of STB's is that you get better throttle response especially at partial throttle due to them being at atmospheric pressure rather than a partial vacuum in the intake manifold, I assume your chamber will have a partial vacuum? If that is correct then a chart is not going to necessarily show throttle response going on and off the throttle which is more of a driver feel than total power being created.

Looking at old OMEX brochures they sell different length throttle bodies and different length air horns. When you are saying there is a benefit to having a longer runner length which I have heard before and I am sure is correct I am wondering whether the length from the throttle to the inlet or the length of the horn make the most difference.

The reality is there's no such thing as the perfect fixed runner length, much like fixed valve timing all you're ever going to do when you change the length of the inlet manifold runners is move peak torque up or down the rev range, and to some degree alter how long that torque is sustained.

As general rule a shorter runner inlet manifold such as you typically find on an ITB set up will help the engine make it's peak torque higher up the rev range, but this will often also come at the cost of the peak torque existing in quite a narrow engine speed window. Conversely a longer runner inlet manifold will help the engine make it's peak torque lower down the rev range, often you'll find such long runner inlet manifolds also helps the engine to sustain a high percentage of it's peak torque for longer too.

This is why car makers typically choose long runner inlet manifolds, if you're building a car for the road you want its engine to produce good low down torque and for that torque to be available over the widest possible engine speed window, unfortunately such long runner inlets can limit the production of power higher up the rev range. However, if you're building a race car so just interested in producing the highest possible peak power from an engine that will be operating in a small window higher up the rev range, then it makes sense to fit a shorter runner inlet such are typically found on an ITB setup.

It's all a state of compromise which is why designers came up with variable length inlet manifolds such as Porsche's patented VarioRam system, the idea being these technologies help you get closer to achieving the best of all worlds, ie the widest possible spread of torque over the engine's rev range. At this point it's also useful to understand horsepower is just a function of torque and engine speed, Horsepower = Torque x Engine RPM / 5252.

The other way engine designers widen the window peak torque is produced is to deploy variable valve timing, when Morgan came up with the Plus 4 Supersports they fitted it with individual throttle bodies (ITBs), because you have four individual throttle butterflies you can get more air in the engine faster, the shorter runner inlet also helps further to get that air into to engine faster so the net result is significantly better throttle response. However, as covered above the shorter runner ITB inlet isn't going to give you the best low/mid range torque characteristics so the car may well end up being a pain to drive on the road.

To regain an element of that lost low/mid range Morgan wisely gave the Supersports the superior version of the Duratec produced by Mazda as fitted the their Mk3 MX5 (NC variant), this version of the Duratec benefited from variable valve timing (VVT). Anyone who's messed about with fitting fast road cams and suffered the compromises they come with, will immediately understand just how game changing VVT technology is. So what the Supersports lost in torque by virtue of using ITBs on a short runner inlet, it largely regained by virtue of VVT, but brilliantly Morgan still retained the throttle response improvements of having four individual chokes with four individual throttle butterflies.

In my case, and because I've been tuning a standard Plus 4 that does not have the benefit of VVT, I decided ITBs were not the way to go as invariably Monty would have become less enjoyable, ess flexible on the road and so less enjoyable under all situations except aggressive driving. This is why I went with a long runner inlet, the Fusion Fabrications inlet is actually just a copy of the Mountune MR200 inlet, this inlet was supplied with their MR200 kit and was designed for the Fiesta ST150 that also ran a 2.0 Duratec with no VVT.



Mountune combined the above inlet with a set of mild fast road cams, a good exhaust and an ECU reflash to extract 200 horsepower from an ST150 at 7,250rpm, hence the name 'MR200'. However, this recipe is also proven to deliver fantastic low/mid range torque which is just what you want if you're building a fast car for the road. When tuning Monty and knowing fitting VVT was not really a practical proposition, I just copied the Mountune MR 200 kit which sadly they have not supplied for years. Unfortunately MR200 inlets are so coveted and rare these days you can expect to pay £2,500 to £3,000 for one, if you can find a used MR200 inlet that is!

Fortunately Matt at Fusion Fabrications made me his copy for a lot less, this also allowed him to custom design it for my Morgan Plus 4 which was ideal as there was actually no guarantee the Fiesta ST150 MR200 inlet would fit Monty without some modification. I went with Newman Phase two cams which are also very similar to what Mountune used with their MR200 kit, I then had Matt at Fusion build me a Supersports replica manifold and exhaust system. Actually, my exhaust setup is quite a bit better than the system used by Mountune, this is because they were restricted in what they could achieve due to the space constraints imposed by the Fiesta ST150 transverse engine layout.

In the Fiesta the exhaust manifold has to be squeezed down the back of the engine in the tight space between the block and the bulkhead, luckily there are no such space constraints in a Morgan so you can build the manifold with far longer header tubes without tight bends which is all good for promoting high gas velocity. However, it's interesting to note that whenever Fiesta ST150s fitted with Mountune ST150 kit go on the rollers they always make more than 200hp, typically anything from 203 - 208hp so the MR200 kit is both proven and consistent. This is on the Ford factory ST150 ECU that Mountune reflash with their own calibration, I am running Monty on an Ecumater EMU Black, in theory, this combined with the better exhaust manifold and a set of 440cc Green Giant injectors should help me deliver a better result than Montune achieved?

However, the peak horsepower figure Monty now makes is actually largely irrelevant to me, because my primary objective was to tune my Duratec for refined drivability and excellent low/mid range torque. Of course I also want to make 200 horsepower, but that would be a hollow victory if Monty was a pain to drive through town and he only came alive at higher engine speeds so I'm pleased to report despite the more progressive cams and all the other changes, Monty is actually even nicer to drive than a standard Plus 4.

The new tuned Monty really is super smooth and torque rich low down, for example I can easily modulate road speed through town between idle to 1,800rpm on just the throttle alone. The EMU Black engine management system combined with some careful calibration work has certainly helped, but choosing the FF copy of the MR200 inlet over ITBs was defindefinitely the right choice for what I wanted to achieve, and given I do not have the benefit of VVT. However, while as good as all this low/mid range torque is for nice street friendly manners, monty is still a sports car afterall, so he needs to rev out too, it would be disappointing to find he runs out of puff around 6,000rpm like a standard Plus 4 does.

Fortunately, I'm pleased to confirm Monty actually loves to rev and with electrifying throttle response too, here's a snapshot of a log we recorded yesterday that shows we hit 7,378rpm, and if I wasn't running the ignition based engine protection strategy by retarding the ignition timing from 26 to 22.5 degrees BTDC I feel sure Monty's Duratec would happily scream to 8,000rpm.



So, it all worked better than I ever could have hoped, the FF inlet gives a lovely usable spread of torque but the engine is still happy to rev out and give the throttle response of ITBs, the bellmouth velocity stacks buried inside the FF plenum certainly help here.



However, I think the 'best of all worlds' results are really down to just how well the long runner inlet manifold, camshafts and exhaust manifold all work so well together, tuning an internal combustion engine is a lot about carefully selecting components that interact well with each other, it's a recipe thing where the ingredients need very careful consideration to ensure you achieve your personal objectives for the final dish

For fear of repeating myself Monty doesn't have the game changing benefit of variable valve timing technology, so in that respect he starts on the back foot when compared with the Mazda Duratec engine equipped Plus 4 Supersports, but I'd wager I've leveled the playing field with my long runner inlet so I'd really love to have a back to back shootout with a Plus 4 Supersports as it'll be really interesting to compare the graphs, especially the two torque curves

Interesting if somewhat complex.
Only slightly connected but wondered - Is there any noticeable gain in torque (low/mid range) to be had on a carburettor engine by adding longer trumpets to an existing manifold setup - i.e. longer before the carb? My car has a 'rally' cam and is lumpy low down. Any thoughts appreciated.
Peter H