M50 conversion

[gbauer]

Just a heads up for anyone with an e36 considering doing an M50 conversion: DDOOO IIITTTT!!! It was the best $330 + 6 hours of labor (2 spent BS'ing) that I've spent on the car so far. I did lose some torque, but the gains on the top half of the RPM range really made up for it. I have an S52 M roadster. From about 3,500 RPM's up to 7k, the power really comes alive now. I used to be a torque monster (just Dinan tune and fan delete) but after about 5,000 rpms, the car would fall flat. Now, on the other hand, I can really pull through the gears and drive it like it should be driven. Why didn't BMW do this in the first place?


Some observations:

1) Take your time with this one. There's a lot of hoses and it gets confusing. If you want to do it, PM me first and I can give you a hand for the price of a few beers. I think having experience on this job will make it go drastically faster. Instead of 6 hours, I bet I can do it in 2 now if I rush or 3 if I do it nice and slow.
2) I have a slight stutter as I accelerate. It started off with two separate stutters: one at 3k and one at 6k. As the ECU has been learning, however, I'm now down to one stutter at 5,500 and that seems to be going away. I expect the power to be smooth after about 500 or so miles.
3) The car is actually more drivable now. A little less torque and a little more high end power can really make a difference. Now I don't feel like I'm going to run into the guy in front of me in town and on the highway I can zip right around any slow-moving left-lane bandits without downshifting.
4) It's slightly more loud. I especially notice this when the engine is under light load at 2,500 rpms. The drone at that rpm is far more significant than before but most other times it's the same as before the swap.


All in all, I hope to dyno soon. When I do, I'll post up the numbers for you guys to drool over.

[martinj]

Good feedback man, I talked to you a little during your install at last Saturday's DIY. When I get my kit together, it will be good to have someone to go to for help.

[Jenson Button]

Do I understand this conversion? Do you replace the intake plenum, ECU, and fuel rail of a S52 motor to the M50 components? This is to make more horsepower at the cost of some torque?

[martinj]

only the intake plenum/manifold and the needed hoses are replaced not the fuel rail or ecu. the m50 manifold has bigger air passages which will generate more top end power.

[gbauer]

only the intake plenum/manifold and the needed hoses are replaced not the fuel rail or ecu. the m50 manifold has bigger air passages which will generate more top end power.

exactly.

The hoses are added because the M50 manifold is OBDI and I'm putting it on an OBDII car. There's more vacuum lines in the OBDII car that need to be connected to the manifold.

We didn't even have to disconnect the fuel rail much less touch the ECU!