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

Being on holiday sat bored on the beach has finally given me the time to properly study the torque and horsepower differences between Stage 2 Monty & Sage 3 Monty. Before I start, I'd like to point out Stage 2 Monty went really well and was already a vast improvement over a standard Duratec Plus 4, but power and torque did drop off dramatically from 5,700rpm as shown by the white arrow below.



After our more recent tuning efforts I was pleased to discover that from idle to 5,700rpm, Stage 3 Monty has basically the exact same torque rich Duratec we created for Stage 2 Monty, and this means he's retained all that lovely flexible drivability I value so much.

But that all changes now when I wind out Stage 3 Monty beyond 5,700rpm and on to 7,300rpm, at which point he is serving up an additional 44 lbs/ft of torque & an even more impressive 50 more horsepower than Stage 2 Monty achieved at the same engine speed. That's a mighty 40% uplift in both torque and horsepower at 7,300rpm, now push on further to 7,700rpm and you're 2,000rpm above where Stage 2 Monty previously fell over.

This additional 2,000rpm gives so much more time in each gear, which ultimately translates to a lot more fun

On the road, I've actually found it's the first additional 1,000rpm of increased power delivery from 5,700rpm - 6,700rpm where Stage 3 Monty's bigger lungs are proving most useful for overtaking, but once you've completed the manoeuvre he will also happily go on to give you another 1,000rpm on top of that. Finally, if do I choose to wind Monty's Stage 3 Duratec out even further to 7,900rpm, he's now delivering a whopping 63 more horsepower than Stage 2 Monty achieved at that same heady engine speed.

While Stage 3 Monty's power currently stays flat from 5,700rpm - 8,000rpm, I have to say staying flat is a huge improvement over Stage 2 Monty's 'fall off a cliff' at 5,700rpm power delivery. OK, so Stage 3 Monty isn't making the headline grabbing 213hp we predicted (yet!), but while we're fixing that I hope you'll all agree what we've already been able to achieve is pretty impressive?

The way I'd summarise Stage 3 Monty is he's way more than a 182 hp Plus 4. From 5,700 rpm onwards, his Duratec now behaves like an entirely different engine producing around 40% more torque and over 60 hp more than Stage 2 at the top end, and importantly he does this while giving away virtually nothing in low and mid-range drivability.

For me, that's a far more significant improvement than the modest 9 hp increase in peak power alone would suggest

I always find these postings of interest, and tend to notice that the empthasis is mainly on generating bhp and less so torque, I've always basically understood it as while torque measures the turning force produced by a vehicle's engine and the engine's ability to perform work, horsepower measures how fast the engine can perform the work. Therefore, basically high torque makes an engine accelerate faster from a stop, and high horsepower makes for higher top speed.

WIth higher revs introducing greater stress and wear on an engine, I've always thought it was important to keep an engine in its highest torgue band at the lowest revs possible, in fact even short shifting to keep it there, and therefore with an eye to engine longevity.the pursuit of acceleration was having the greatest torque band at the lowest possible revs,.Having very high top speeds is potentially academic on public road use.

My CX PLus Four has 20% more torque than the manual, it has the same bhp and final drive ratio and therefore same top speed, but mine has a quicker 0 to 60 speed, and in gear acceleration, I know helped by an auto but it also has 2 more gears to change compared to the manual. You can feel the difference in the power and its delivery when compared to the manual.

In theory, with the suspected exhaust restriction removed, Monty should do this

To explore the blocked sports cat theory I've removed and inspected it.



I appreciate the photos are poor, but TBH the core looks fine to me, so maybe it's just my sports cat was always too small, here's what it looks like next to the standard Mk3 Mondeo cat Morgan fitted to Duratec Plus 4s making 145hp tops.



Given the above, I've been measuring and evaluating the original Ford oval cat's estimated internal envelope wich gives a massive 76% larger frontal area facing the yet to be converted exhaust gasses, it also has 15% more volume! I've also studied the cat Caterham use on their 420R and then compared the lot.


The Caterham cat is interesting as a 420R is known to make a genuine 210hp plus, moreover, Northampton Motorsport reports a 420R making 224.8 bhp with its original catalyst still fitted, but then 227.1 bhp with a de-cat, so what they're saying is the factory cat tops out at 225 bhp before it starts to become a restriction.

The evidence does seem to confirm Monty needs a cat that's at least 30% larger, or better still no cat at all, and it's now looking highly likey the sports cat was too small all along. However, I'm holding off gutting it as the only real proof it is genuinely a restriction will come when I run the back pressure test.

This kit should arrive from Temu Land soon, so before long we'll know for sure

Interesting timing for me. My cat, 2013 Duratec, needs replacing and I am looking at the Librands manifold, still have the horrible stock item, and cat as a safe option. I have had Librands replacement manifold and cats on my last two Morgans and was happy with the outcome but if there is an alternative option would be interested in knowing what is out there. I have the Williams cold air intake and engine remap but they only offer Librands products at the moment. Would need to be a bolt on replacement as whilst I am fascinated by the developments on your car my skill set is nowhere near your level.

Interesting. Two or three years back, my cat developed a leak around the annular weld on the entry pipe. I managed to get it welded up and so far it’s holding. I have the Librands in mind.I didn’t realise though that the original is a standard Mondeo fitment, as Dave has suggested.
Turning attention to Monte, Dave has made no mention of what this might do to emission levels. When Dave W was playing around with alternative cats some time ago, I seem to recall he ran into emission problems. Bearing in mind too, the current Gov study into tightening up on emissions, will this make Monte an off roader only? ( or a bit of spannering each year, prior and post MOT?