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m46 or m47

Hello

The m46 is not nice.
If u drive it hard the od will start to spin internaly.
The m47 is better, there it depends how u change gears how long it will last.
m47 is a true 5 speed.
I have changhed 3 m46 gearboxes in my car in a month.

Now I have a m47 "temporarly", and it is much better.

If you fill the m47 whit more oil than recomended it will last better.

Robert the swede
 
There are diffrent versions of M47. First ones were weaker. In 300-series there's M47R MKII and people are pushing over 250hp through and some over 300 so I guess with proper use it will take some power.
 
Snorko said:
B234FT...??? Pure fantasy, faulty non OEM supplier lists. That silly list has the 16 v 940 under "6-cyl". Even the 960 Turbo had a B204 engine. The 2,3L Turbo engines where all 8 valve.
M47+Turbo??? The M47 breaks easilly with a n/a engine. Turbo cars have either M46 or M90.
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Volvo made 16v B21/B23 motors also. With R-Sport head though and it was an aftermarket engine. But still a Volvo-made. ;) Mainly in rally cross use though...

16V_RSport_carb.jpg


228hp@7200rpm, twin Solex, N/A. (Turbo versions were also made but haven't seen anywhere else than in rallycross 343/360)
 
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Fuse said:
Volvo made 16v B21/B23 motors also. With R-Sport head though and it was an aftermarket engine. But still a Volvo-made. ;) Mainly in rally cross use though...
Come on! We are talking about real production runs here right? Like all manufacturers they try a lot for motorcross-markets and pre-production experiments.
Volvo made 740/240's with the 5 cyl for test purposes before producing the 850.
That does not mean you can buy it at the nearest dealer... unless you have an astronomic budget to spend on a Volvo. The 16v R-sport engine probably costed as much as a 240 Turbo. I guess you could have had the dealer install whatever transmission in a car as long as you pay for it. Just take a look at the "Evolve" projects in California now. Similar stuff as the R-sport department did when it existed.
Anyways a m47 on a HPT would be asking for trouble. You can get them for free and it doesent hurt anything but your pride when you bust one by flooring the pedal in 3rd.
I first had a M45, then a M47, alloy M46, now a iron M46.
The transmissions all broke the same way, full power (0.95Bar boost) in third gear. No rough shifting.
A Getrag 262 is now on the livingroom floor getting prepped for installation. I would like a M90 but the price is just ridiculous compared to the Getrag. $1000 v.s. $50
Save some time and effort and get a T5, getrag or something that can take a little torque.
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Snorko said:
Anyways a m47 on a HPT would be asking for trouble.
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If you mean stock HPT (ie: a B230ET / FT)...they were supplied like that from the factory, and are well documented as making it well into 6 figure mileages...can't be that troublesome!

I'm prepared to concede that if you abuse the shifts on an M4x box they don't last long. They obviously can't take high torque either. Having said that, there are several people in the UK developing the kind of torque necessary to see above 300bhp, without breaking M4xs. One guy gets above 300bhp through pretty high RPM (ie: less torque than achieving 300bhp at 6000rpm), but another makes it at 6k. He said M4xs are fine to 330bhp, but start breaking at 350. Of course there are a lot of other variables here - its not just engine torque.

Of course there are people who are breaking them because they can't take the power. However, I think there are also people who break them because they need lessons in driving a manual car :-P

cheers

James
 
maybe i missed it or over looked it, but what are the final drives on the m46 and m47? comparing the OD on the m46 and the 5th gear on the m47
 
My M47 is a (edit: 0.83...what was I thinking?!). I think that's shorter (higher RPM for a given speed) than the OD on the 46.

cheers

James
 
A question for the M46 folks. I have a '78 M46 (10 spline input shaft) and I'm considering getting an '80 M46 (22 spline input shaft). Is it possible to put the input shaft off of the '78 into the '80 M46? Are there any noticeable shifting difference between the two trannies? Thanks
 
You sure as hell better be using the clutch to shift to OD if you're pushing 250 through an M46. It's recommened to use the clutch anyway, even on stock motors.
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what :???: that was the thing that made the old 944TD sooo cool get to a high speed in 4th gear and hit the button to get the huge kick in the pants (when i was younger i thought that was a turbo :oops: )


and on the M46/7 topic my 240GLT its 4 speed OD dont know what gearbox it has but its got 192K on the original one and ive given it a heck of alot of thrashing 3rd gear clutch kiiling burnouts but still all works super fine
 
Get the clutch disc for the fine splines and be happy........Fine splines when lubricated will slide more easily making it less likely that you will crunch in to reverse or first.

JL.
 
rick3612 said:
A question for the M46 folks. I have a '78 M46 (10 spline input shaft) and I'm considering getting an '80 M46 (22 spline input shaft). Is it possible to put the input shaft off of the '78 into the '80 M46? Are there any noticeable shifting difference between the two trannies? Thanks
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Why would you want to tear apart transmissions to swap the input shafts?
It would be much easier to match the correct clutch to the correct transmission...
There should be no difference in shift quality when comparing an '80 to a '78.
The only difference will be in the overall amount of wear that either tranny has incurred.
JD
 
There were factory M47 turbos here in the UK. Most were M46s, but there were a few M47s. Most were 940s, but there was even the odd 740. It seems pretty random...I certainly know of two 1989 740 TIs, one M46, one M47.

cheers

James
 
High boost/torque will kill both.....Personally I HATE the M46/overdrive solution , it reminds me of old days -lets-forget-british built crap ....but thats just me !
Maybe the M46 is a tad stronger , IDK , but the M47 will live forever behind a modest turbo setup or for rather serious NA use.
 
hi guys just found this place, i think im in heaven, any way i want to convert my bog standard 90 740Gle to a manual. i might turbo it at some point but with university on the horizon that's probably a long way off yet. i have a M47 box but would still need to source all the other parts. is it worth it with a m47 or should i wait for a m90 to come up (the are mentally rear and expensive in New Zealand)
 
SEslayer said:
hi guys just found this place, i think im in heaven, any way i want to convert my bog standard 90 740Gle to a manual.
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Welcome!

I'll be the first to tell you to search for your answer. There are plenty of threads on manual swaps. Using google to search the site often yields the best results...

As far as turboing your m47, don't worry about what you read about the m47 being weak. Turbo first, then worry about trannies.
 
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