Transmission tuning (The hinge of equal angular speeds)

[Dexter]

Good afternoon!
Excuse for my English, I slightly know it.
I have such question: At tuning the car, in especially the engine, it is necessary to think and about transmission, and so that you do with the hinge of equal angular speeds, whether you change them on sports or there are alternatives from other cars?


With greetings from Russia!
Yours faithfully, Vladimir

[jtbo]

I think only way to change gearing with any reasonable cost is to change differential, there is few different ratios used in 300-serie.

For example 360GL has 3,36:1 ratio when 360GLT has 3,64:1 ratio, however certain years had bit different ratios too.

But transmission gearing is bit more difficult, it is possible to have proper gears made in companies that make gearwheels but it is not so cheap.

[Dexter]

I have 3,27:1 the ratio. What maximal twisting moment (Nm) of the engine can stand the transmisson?

What are you doing with standard hinges of equal angular speeds at tuning a engine.

[Fuse]

If gearbox and it's parts are in good condition M47R will handle something like 350-4xxNm with gentle use. It will handle about same as M46 used in other Turbo Volvos except the fifth gear in M47 is weaker than the overdrive unit in M46. But usually parts are worn and it is easy to brake it with less too. And if you abuse it might broke with less torque too.. It all depends of the usage and the condition of the gearbox.

But it seems that above 400Nm you start braking pinions with just pushing the gas pedal.

[Dexter]

With it, is OK, but what you tell about hinges of equal angular speeds?
Whether they will break by sudden pressing a pedal with engine B23?

[Fuse]

I'm not quite sure what you mean with "hinges of equal angular speeds" but if your engine is going to be naturally aspirated B23 you are fine. Whole drivetrain in 360 will handle the power.

In rally use it is different thing though but if it is going to be a street car then stock drivetrain in 360 will handle B23 fine.

[Dexter]

I wanted to tell, that the hinge of equal angular speeds it the hinge of a driving shafts.(from 3,27:1 to wheels)
What maximal twisting moment hinges will be stand?
Are you understand me?

[Fuse]

Aaaa the driveshafts and the joints? Well I guess that the differential it self would broke first before the drive shaft or the joints. Driveshafts it self will handle the same power as the differential.

Differential is the weakest link in the driveline I would say and usually it breaks down before the gearbox does. I don't know how much is the maximum torque handling for differential. Again it all depends on the usage and how worn the differential is. Some people have broken the differential pinions with stock engine too with too abusing use, so with wrong use you can broke things with less power.. But if you're engine is going to be a naturally aspirated B23, I would say that the differential and driveshafts will hold fine in normal street use if the differential parts are in good shape.

In turboed 360s it seems that the first one to go in the driveline is the diff, though this one guy, Kevin Strong, has a stock gearbox and differential and he's got a 2.5l 8V Turbo in it, over 300hp and he's doing fine. http://mysite.wanadoo-members.co.uk/360s/kevin.html Though what I've heard he only gets rolling starts with it so no strain on driveline parts in launches.

[jtbo]

I have heard numbers around 250nm for differential/driveshafts, but never nothing confirmed.

Quick starts of course are stressing these parts a lot and they can fail with less power if abusing a lot. Differential seems to be not liking from rubber burning from what I have heard.

I can't confirm but from my memory some VW transporter van's driveshafts may fit , but still there is differential problem left.

You can make 240 Volvo differential to fit of course, it requires quite lot of work, but of course it is much stronger.