max power for 325 gearbox

[russellwrx]

Hi
Im contemplating fitting my 325 gearbox to another engine. What sort of power can these boxes handle?

[Kos]

I've seen then take 350 boho with out any aggro

[ross_jsy]

I have seen turbo m20's with 500ish on standard box. Would guess like a few things, it's not the power but how you launch that lunches them

[Morat]

And the level of grip you're getting at the back....

[maggspower]

Its torque, and emergency starts that kill gear boxes.

The first 3 numbers on the cast part number relate to the amount of torque the box can take. a box with a part number 260, that is the torque in NM that the box is rated for.

The rating is known to be rather conservative.

[russellwrx]

Ok cheers Im toying with the idea of making my 560sec a manual, its got 300hp so sounds like the bm box could handle it.

[jmc330i]

Its torque, and emergency starts that kill gear boxes.

The first 3 numbers on the cast part number relate to the amount of torque the box can take. a box with a part number 260, that is the torque in NM that the box is rated for.

The rating is known to be rather conservative.

Is that what those numbers mean? But do you mean NM or ft/lb?

I only ask as the E34 535i uses a '260' box, but dont they produce over 300 NM (221ft/lb)?? And the E34 M5 uses a '280' box but they are around 390 NM (288ft/lb).

[ross2009]

im putting near on 400 bhp thro mine and theres no sign of it spitting anything yet still feels strong

[jmc330i]

im putting near on 400 bhp thro mine and theres no sign of it spitting anything yet still feels strong

Do you know what sort of torque figures you're getting?

[ross2009]

no not accuratly as its not been dynod its a calculated estimate that my mapping guy has done
but as a rule of thumb with these it can be about 400 bhp 400 ft lbs so at a guess id say some where between 300 -400 ft lbs so pick the middle about 430 - 450 nm at a guess

[jmc330i]

And that's a non fiddled with ( ) M20 box?
Sounds good to me. The engine I'm looking at seems to vary for power/torque, but an average seems to be 300bhp and 350ft/lb - 475 NM.

I was told the M20 '260' box would be no good for that torque figure and the 535i box was the one to go for, but I'm not sure now as that's a '260' box

[ross2009]

no not been fiddled with at all its compeatly standard mate got a big ol 6 puc paddle clutch but apart from that it handles it very well
if you workit out to the full 400 ft lbs its 542 nm

[jmc330i]

Cheers dude
That settles that then, M20 box it is then.

[e301988325i]

The 325 got the 260 box from the 535. . . as for some unknown reason the 240 wasnn't deemed man enough, maybe they had stock of 260's?