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M10 Gearbox Strength - 4 or 5 Speed????
Posted: Sun Jul 15, 2012 4:15 pm
by sleeperviva
Greetings chaps!
Currently building up a turbo'd M10 1.8 for my current E21 but might be obtaining an earlier vehicle for parts which happens to have a 4-speed box
My question is.....which is stronger? standard M10 4-speed or overdrive 5-speed?
Dont fancy blowing up my 5-speed as it might take awhile to find another
Cheers
Steve
Re: M10 Gearbox Strength - 4 or 5 Speed????
Posted: Sun Jul 15, 2012 4:44 pm
by e21-Mark
I've always been led to believe 4 speed is stronger but have never blown either as the diffs gave way first.
Re: M10 Gearbox Strength - 4 or 5 Speed????
Posted: Thu Jul 26, 2012 4:38 pm
by Danny043
I believe a 5 speed overdrive box is nothing but a 4 speed box with an overdrive housing bolted to it. So I reckon there's no difference in strenght.
Re: M10 Gearbox Strength - 4 or 5 Speed????
Posted: Tue Jul 31, 2012 8:44 pm
by sleeperviva
Thanks for your replys gents!
Looks like I will just go with the 5speed for now
Re: M10 Gearbox Strength - 4 or 5 Speed????
Posted: Sun Aug 14, 2022 1:52 pm
by Sav
Has anyone had any more experience of M10 Turbos and the 245 overdrive? A place near me said the limit is 200ft-lb torque, but I'm sure I've heard of them standing more.
Did the 5 speed hold up well for you? and at what Bhp/torque level?
Re: M10 Gearbox Strength - 4 or 5 Speed????
Posted: Sun Aug 14, 2022 2:35 pm
by Wilmo
Probably the clutch is the weakest link. If you do not beef up that too much, it will protect the gearbox.
I have a NOS clutch with an E30 five speed overdrive gearbox. With my M10 I put about 160hp through it.
Re: M10 Gearbox Strength - 4 or 5 Speed????
Posted: Sun Aug 14, 2022 2:46 pm
by sleeperviva
10yrs ago
Car never received its lovely, well assembled M10 turbo engine as I got bored with the car and flogged the lot!
Sorry guys I have nothing else to add
