Limit of the auto tranny
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leforte
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your car should be having a ZF 5hp19 gearbox which is also known as a A5S325Z in the bmw model code.
from the A5S325Z code, the transmission should be rated at 325Nm or 260ft/lbs.
have a search at the e46fanatic.com, quite a number of them have been boosted safely to at least 300hp and around 360Nm of torque. if you drive like a drag racer with a heavy right foot, spinning your rear wheels at every stop light, revving the engine to 5000rpm in N and drop it to D, the tranny will surely go in no time. but if you have a smooth launch and only step on it while moving, it shouldnt be a problem even if its at a higher output. with a centrifugal Sc in your car, the sc only produce positive boost at around 2500rpm and the full power will only come in at a high 6500rpm, by that time you should be moving and only a small amount of stress is put onto the drivetrain.
i know of a e39 with a 3.4l hiop stroker in it which produces a tremendous 380nm of torque from 2000-5000rpm and his 5hp18 / a5s300z tranny is still holding on fine after many years. in other words, they are underrated or overengineered from factory most of the time.
the key to a healthy tranny is maintenance and cooling. make sure you have the lifetime fluid changed and make sure the atf cooler is not clogged with leaves and rubbish that will obstruct the airflow and affects the cooling of the atf.
want a manual conversion kit?
from the A5S325Z code, the transmission should be rated at 325Nm or 260ft/lbs.
have a search at the e46fanatic.com, quite a number of them have been boosted safely to at least 300hp and around 360Nm of torque. if you drive like a drag racer with a heavy right foot, spinning your rear wheels at every stop light, revving the engine to 5000rpm in N and drop it to D, the tranny will surely go in no time. but if you have a smooth launch and only step on it while moving, it shouldnt be a problem even if its at a higher output. with a centrifugal Sc in your car, the sc only produce positive boost at around 2500rpm and the full power will only come in at a high 6500rpm, by that time you should be moving and only a small amount of stress is put onto the drivetrain.
i know of a e39 with a 3.4l hiop stroker in it which produces a tremendous 380nm of torque from 2000-5000rpm and his 5hp18 / a5s300z tranny is still holding on fine after many years. in other words, they are underrated or overengineered from factory most of the time.
the key to a healthy tranny is maintenance and cooling. make sure you have the lifetime fluid changed and make sure the atf cooler is not clogged with leaves and rubbish that will obstruct the airflow and affects the cooling of the atf.
want a manual conversion kit?
aramis
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ALBundy;254844 said:This is very subjective. From an engineering point of view, any object or machine that is operating closer to its limit will ALWAYS have a shorter lifespan.
That's pretty much common sense.
lol...how true. :burnout:
