Is this possible?

Just looking at the 4.111:1 final ratio... seems a little low for a big six.

Well if you go by the fact that 380 gearboxes have been fitted in Magna... I guess there's a good chance you could...

In a way, yes.
The final drive gear in the 380 manual box can be swapped over for the Magna gear.
RPW used to offer this, not sure they do any more, but if you can source the parts from a Magna box then any competent transmission specialist should be able to do it.
And yes, the 380 manual box final drive ratio is a bit short, I used to run just under 3,000 rpm at an indicated 110 km/h where the 380 auto box was only turning around 2,300 rpm.
The MMAL excuse is they needed to fit a short final drive ratio to the manual box to ensure that the manual accelerated as quickly as the auto.

It doesn't make any sense to me that the manual was geared shorter to keep up with the auto, unless the gear changes are blisteringly quick in the auto and can't be matched in a manual.

My understanding was that the manual was geared much shorter to make it feel sportier in the VRX model - because people buying a manual VRX wanted sporty.

The upshot was that the auto was actually just as fast 0-100 because it achieved it in first and second gear only (requiring one change only), where as the manual needed a shift from 1-2 and then 2-3 (hits the limiter around 90-95) over the 0-100 range.

Hence, they had identical times 0-100 and were advertised as much. The manual however would be quicker 0-90 or 0-120, or pretty much every other range. 0-100 stats just didn't suit the manual ratios.

If someone other than RPW offered the upgrade to the Magna final drive ratio for a reasonable price, I'd be throwing my money at them. The 380 drives comfortably in its longest gear (5th) at 60km hr, and as TreeAdeyMan said - revs ridiculously high at 110. It would be a great mod.

The upshot was that the auto was actually just as fast 0-100 because it achieved it in first and second gear only (requiring one change only), where as the manual needed a shift from 1-2 and then 2-3 (hits the limiter around 90-95) over the 0-100 range.

.

My experiances contradict that, in fact,the auto is a good second quicker in the 0-100 than the manual.

I have proven it with both a normally aspirated and a supercharged manual 380....and both an auto supercharged and manual supercahrged 380 side by side too.

The ratios are an absolute joke.

If you start the 380 manual in second then you can keep up with the auto...just.


.

The manual is an absolute slug compared to the auto...it's just not possible to get a decent launch....the auto flogs it.

In a way, yes.
I used to run just under 3,000 rpm at an indicated 110 km/h where the 380 auto box was only turning around 2,300 rpm.
.

The difference is bigger than that.

The auto at 110km/h runs at 2000 rpm not 2300rpm in all my cars and the manual runs at 3000rpm.

It's a huge difference and affects fuel economy significantly....(2L/100km I reckon)

Yes, the first gear ratios is an absolute joke in the manual. Nothing more than about 1/2 throttle is possible without wheel spin.

Have you driven a late third Magna Zilo? The ratios are pretty much perfect, except 3,4,5 could each be a little bit longer to keep the highway revs down.

If an auto is faster than a manual with the exact same engine, it's only ever down to gearing. The physics is that an auto box consumes significantly more drivetrain wastage. If the manual was geared the same, it would be undoubtedly quicker.

Such a shame they ruined it by moving away from the late third gens, where the higher tuned 3.5s such as the Ralliart and VRX were so well matched to their manual gearbox.

Edit: And the other thing I've noticed about the 380 is the traction control is rubbish in the manual. I discussed this with a service manager once because I wondered if mine was faulty, and he said the TCL software was written for the auto drivetrain - and the software didn't really work with the manual ratios. He said it was a known issue but because so few manuals were made, Mitsi didn't re-jig it for the manual.

Thanks for the input everybody. All great news. Confirmation of what I knew already with a dusting of speculation. I wouldn't want it any other way.

I'm buying a 380 for my "amputee vs manual gearbox" project. I don't think I'd be pulling the gearbox apart anytime soon, as I'd only do it if I had the funds to install an LSD at the same time.

If I were to just dump a Magna 5 speed in there, are the original 380 driveshafts reused? Why are people using the 380 boxes in Magnas... to climb sand dunes?

Will this affect the speedo? I think from memory if you change the final drive ratio using the Magna gear then the speedo will be out.

Will this affect the speedo? I think from memory if you change the final drive ratio using the Magna gear then the speedo will be out.

I did some calcs on this a few years ago and swapping the gear over will improve the speedo accuracy such that it would be very close to correct.
The stock set up is about 6% optimistic (over-read) such that when the speedo says 110 km/h you're really only going about 104 km/h.

TreeAdeyMan - You've done the gearbox swap, or, the ratio swap?

TreeAdeyMan - You've done the gearbox swap, or, the ratio swap?

Nup, I thought about it but never did it.