3.0L or M3 engine?
- Thread starter piggyboyz
- Start date
shaaz said:
If you have a auto tranny, you can forget about TC your car. Even if you're running on relatively low boost for TURBO, your car will lag when you floor it and your tranny will go to limp mode. Guess the sudden gush of torque is too much for the tranny as compared to Sc where its constant. As the experts will say," This is the inherent problem with turbocharging an auto BMW. There really is no way around this. The Tranny DME is sensing too much torque and restricting your throttle. Superchargers can get away with this by running nominal amounts of boost, but turbochargers [due to their boost/torque spikes] will not mesh well with an auto. I would simply swap out the tranny for a manual...this is the only solution." enuff said.
Racebred
Core Group Members
for auto tranny solutions, there are a few, but some are not easy to find. for power up to 300~320bhp, 330i tranny will suffice. for higher power than that, you can try to use the ZF tranny, 5HP24 (i think) from the Alpina B3 3.3, since there should be a 20-50% safety margin over and above the B3's specs.
i'm not sure if the E39 540i's auto tranny can be modified to fit but it's worth a little research if you're keen on retaining an auto. TC on a BMW is quite tasty. Check out ATP.
i'm not sure if the E39 540i's auto tranny can be modified to fit but it's worth a little research if you're keen on retaining an auto. TC on a BMW is quite tasty. Check out ATP.
RB, I thought that for any tranny, its not the hp that matters but rather how much torque that your car is producing, so in that case, one would need to see the torque curve of the car rather than the peak power output right. But that being said and done, the 330 tranny should suffice. if not then just order an upgraded torque converter.
I suppose but to follow the hp number can be misleading as certain engines have high peak hp but very little low end torque... you get my meaning lah... torque figures for conversions should be available quite easily, as a rule of thumb it should be close to the torque figure of the engine you are switching too right? Since most torque figures online are published at the flywheel, there is no additional complication with drive train loss what. Am i wrong?
Racebred
Core Group Members
what i'm saying is that since rpm for bmws are usually at 6500-7000 there shouldnt be any case of high hp low torque figures, thus bhp should be numerically about the same as torque in lbft, so layman wise can be interchangable since hp and torque is essentially the same thing with rpm factored in. but you're right, tolerances should be strictly compared in torque. anyways in dynos torque is directly measured and bhp is back-calculated by the computer.
