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

By way of a follow up on my previous idle quality and idle speed comments below ........


Now I've fully refined and polished Monty's stage 3 ECU calibration the results on this one are in, the optimal idle speed where Stage 3 Monty holds a nice smooth and consistent drum roll idle is 1,175rpm.

No lope, no hunting, and no choppiness whatsoever!

This is achieved with Monty's idle ignition timing set surprisingly advanced at 25 degrees BTDC, and running an AFR of 13.8:1. Lighting a slightly richer mixture very early is how we've achieved a complete burn of an air/fuel charge that's affected by reversion, which is the inevitable consequence of the additional valve overlap produced by the Newman Phase 3 cams.

The smooth and consistent drum roll idle at 1,175rpm also comes with a deeper more purposeful tone, it's not antisocial, but Stage 3 Monty's new rumbling note leaves you in no doubt he has naughtier intentions in his mind compared with a regular Duratec Plus 4.

I have to say I absolutely love it

Whatever happened to that that lightweight flywheel? Maybe there’s scope to trade off a little idle quality for even more engine response

In which an entire Morgan community lives out their tuning fantasies at the expense of a single member.

Hi Rog

TBH it made sense to hold off fitting a lighter flywheel until I'd fitted the Phase 3 cams, and appraised the idle quality they give with the increased overlap.

Having done so, I'm now confident fitting a lighter flywheel would have been a bad idea

And now for a confession!

The one thing I really feared with this latest tuning project was the Newman Phase 3 cams would be a step too far, and idle quality would end up not being to my standard. However, I'm pleased to confirm after three weeks of idle tuning I've achieved a way better result than I ever thought would be possible given all the valve overlap Monty's new proper fast road/rally cams introduce at idle.

To help give you something to messure Stage 3 Monty's idle quality against, I've created the following video with a similarly cammed up Fiesta ST150, hopefully the video will give you an idea of what I've been able to achieve?



Apparently the Fiesta's Duratec is idling at 1,000 rpm, admitedly I am idling Monty fractionally higher at 1,175 rpm, but trust me there's a lot more than the additional 175 rpm going on here to get Stage 3 Monty to idle so much smoother than that grumpy ST150. Back in the day when fitting fast road cams we could only ever dream of achieving such results on carbs and a distributor, so the real prize here goes to my excellent EMU Black ECU

NB: The anoying dog is my Oliver, he's demaning his walk on Chorleywoon Common. TBH I don't think he appreciates idle quality testing quite as much as his father does

Sounds good!

Thanks, here's Stage 3 Monty's idle stability presented in a live screen recording taken from my ECUs bluetooth Android phone app.

https://youtube.com/shorts/LwVY30gfRgE?si=GjgwFKwS-nFh_oi1

The video demontrates how close he's holding his idle against the 1,175 rpm target. This is achieved at a super low and stable MaP signal of 50 kPa while feeding Monty a 13.8:1 AFR and lighting the fire surprisingly early at 25° of crankshaft rotation before top dead centre. The small timing fluctuations you see around the 25° BTDC ignition idle target are the ECU's dynamic timing based idle management doing its thing perfectly.

Freeze frame this video anywhere and you'll see typically Stage 3 Monty is only ever roughly 20 rpm either side of the 1,175 rpm target. This all took a lot of work to get right, but I feel I've nailed it now

And finally, here's Stage 3 Monty's idle quaility at the rev counter, I threw in a few throttle blips to demonstrate that my soft landing stratergy is working as intended.

https://youtube.com/shorts/Xn4dazy0As0?si=qgwlfSKg1ZRBa6r1

You may be able to hear that the rad fan chimes in early on in the clip, this is intentional as I wanted to demonstrate idle stability under electrical load, watch the needle as the fan cycles on, and then off.


NB: My apologies again for my rather vocal hound 'Oliver Dog'.

Notable difference in the idle there ... the fiesta sounds more like my MG racer, whereas Monty sounds positively smooth ... though it does have a bit of a bark! 🙂

You've done a great job ..... proper thoroughly thought through project


K

OK chaps, with the important but dull idle quality tuning and fuel economy testing complete, let's get back to the fun stuff.


To properly understand the Stage 3 gains we must first study the torque and horsepower Monty produced (and where) when he was in Stage 2 tune, at this point I should stress Monty already produced excellent torque in this tune. First let's look at the 4,000rpm - 6,000rpm window as this is where you're typically asking the engine to really deliver on the road.

Specifically let's look at what we've really added in that all important 4,000rpm - 6,000rpm window by changing the Newman Phase 2 cams for Newman Phase 3 cams, and adding the A.L Developments ported big valve head with its exhaust ports brought out from 38mm to 40mm?


Stage 2 Horsepower

In this 4,000rpm - 6,000rpm window Stage 2 Monty went from 112hp - 170hp


Stage 3 Horsepower

Over the same 4,000rpm - 6,000rpm window Stage 3 Monty goes from 145hp - 175hp


Stage 2 Torque

While the peak of figure 158 lb/ft at 5,250rpm is impressive in itself, what stood out was the way Stage 2 Monty made 150 lbs/ft at 4,000rpm, and held onto that number all the way out to 6,000rpm where Monty's Duratec was still making 150 lbs/ft! That wide 4,000rpm - 6,000rpm window where the engine consistently served up around 150 lbs/ft is what made the estimated 930kg Stage 2 Monty fast in the real world.


Stage 3 Torque

This is where it gets interesting, in Stage 3 tune Monty replaces the Stage 2 158 lb/ft at 5,250rpm with 170 lb/ft at 6,400rpm. In the 4,000rpm - 6,000rpm window Stage 3 Monty starts out with the same excellent Stage 2 figure of 150 lbs/ft, but now the torque is a rising line! This means at 6,000rpm rather than just holding on to the 150 lbs/ft as before, Stage 3 Monty is now producing a full 18 lbs/ft more torque to give 168 lbs/ft. Better still Monty holds onto that advantage all the way out to 6,400rpm where he's still making a very healthy 170 lb/ft .

If you look at the Stage 2 torque line you'll see Monty's 150 lbs/ft torque falls off steeply after 5,250rpm, at this point Stage 3 Monty is now already making 10 lbs/ft more (160 lbs/ft). However, he doesn't give up there, Stage 3 Monty then goes on to pile in another 10 lbs/ft all the way out to 6,400rpm which is 1,150rpm more revs than where Stage 2 Monty gave up making torque. Stage 3 Monty not only adds 10 lbs/ft at the same 5,250rpm where Stage 2 Monty's torque peaked, he now keeps piling on more and more torque all the way out to 6,400rpm where the new peak figure of 170 lb/ft arrives.

Back in the real world, what all this means is under hard acceleration I can now hold onto each gear for a lot longer, a full 1,150rpm longer! You really do notice this because while I'm staying in gear longer Monty is not only holding peak torque as before, he's actually pilling on more and more which is really what pushes you back in the seat.


Final Analysis of the 4,000rpm - 6,000rpm Acceleration Window

At 4,000rpm Stage 3 Monty is actually making a whopping 33 horsepower more than Stage 2, at the same time he's also delivering the same excellent 150 lbs/ft of torque as Stage 2. From there on Stage 3 Monty piles in another 20 lbs/ft all the way out to 6,400rpm, at which point there's also a small 5hp advantage over Stage 2 Monty.

Hopefully this further illustrates why I have never been too fussed about outright peak horsepower comparisons, as we can now clearly see such a short sighted evaluation and measurement of the success of Stage 3 would be to completely ignore all the meat in the sandwich!

Although I must admit, Stage 3 Monty's new party piece of spinning rapidly towards 8,000rpm, and then all the way to 8,250rpm is an absolute riot too!