Swap.

[rpoliah]

Hey guys I want to do a auto to manual swap , before everybody on the forum starts getting at me let me explain my plans.

I plan on doing a Active Autowerke Supercharger on my car which has 95xxx miles and I feel like the auto transmission won't be able to take that power so in the mean time i want to start to buy up all the parts to do a auto to manual swap that way in the case the tranny does go I will do a Swap. Bad idea or good idea? Now would any m54 manual transmission work or Do I Need to get something Z4 specific?

[Westersund]

I know this is the boring answer. But isn't it easier to sell your car (and keep aftermarket parts) and buy a Z4 with a manual gearbox instead? The best is always a Z4 M, the drivetrains on these cars can take a proper beating (except the stock clutch).

Besides that, I think the auto would be able to handle the power unless you're going heavy on the boost. But if you're going heavy on the boost I don't think the gearbox will be your biggest concern it would be the pistons or the rods.

[rpoliah]

Originally Posted by Westersund

I know this is the boring answer. But isn't it easier to sell your car (and keep aftermarket parts) and buy a Z4 with a manual gearbox instead? The best is always a Z4 M, the drivetrains on these cars can take a proper beating (except the stock clutch).

Besides that, I think the auto would be able to handle the power unless you're going heavy on the boost. But if you're going heavy on the boost I don't think the gearbox will be your biggest concern it would be the pistons or the rods.

No I'm going with 8 psi of boost think the gearbox would handle it ? It's the stage 2 kit which active sells for the 330i

[Westersund]

Originally Posted by rpoliah

No I'm going with 8 psi of boost think the gearbox would handle it ? It's the stage 2 kit which active sells for the 330i

Depends on how you're gonna use the new found power. Red light racing? Some highway pulls? Track?

If you're gonna have the car for daily use with some spirited driving and not frequently race at red lights I see no reason why it should break, maybe the clutch will start to slip with time but that's inevitable. BMW usually have a lot of overdimension in their drivetrains. Especially on the "top of the line" engines, all the M-cars but also 328/330/335/530/540/740 etc.

Edit: I know of a guy here in Sweden that have over 400HP and 800NM in his 335D E9~ with a standard automatic gearbox (no dubbelclutch) and his gearbox is holding up depsite it being spec'd to 600 NM. BMW usually uses top notch stuff for their drivetrains.

Edit 2: Made some research, if you have a 2005 Z4 3.0iA US car it will have the a5s325z-gearbox. It will hold for 325NM according to the spec's, but it will handle a lot more than that. Depending on driving style ofc.And as with all FI cars that are NA from the begining it will wear out a lot of components faster.

[rpoliah]

Hey man its a 2003 bmw z4 3.0 automatic transmission. I love driving my little Z4 hard so yeah i guess you could say spirited driving along with some highway pulls.

[Westersund]

Originally Posted by rpoliah

Hey man its a 2003 bmw z4 3.0 automatic transmission. I love driving my little Z4 hard so yeah i guess you could say spirited driving along with some highway pulls.

It has the gearbox I mentioned in my previous post, 325NM spec. Probably holds for a lot more. You won't know until you break it.

[rpoliah]

Im aiming for about 400 to the wheels so i guess ill be fine .

Originally Posted by Westersund

It has the gearbox I mentioned in my previous post, 325NM spec. Probably holds for a lot more. You won't know until you break it.