M50 vs. M20 for track car?

[TiSiBeast]

I have a dedicated, stripped 325is track car. The engine is tired with 200k+ on it. I am taking it down for a while before my next event in it and am going to do either a 2.7i M20 or move to an M50. That said, for the experts out there, aside from classing issues, which is better for the track? The qualities of the M50 with the 4 valve are apparent, more mod potential, etc., but which is better for track use in the E30? Weight is a potential issue. Anything else? Anyone with expertise on both sides of it that can weigh in?

[Danny]

Turbo M42 is the correct answer...

:giggle:

Reliability is for suckers.

[Charlie]

Classing issues aside, M50, no question. It's not a *ton* more top end, but it's noticeable, the big difference is in the low and mid range. Car is a lot more tractable and loses some of the "momentum car" negative side effects the M20 leaves you with. Really wakes the car up.

In terms of the weight on the nose? You notice it, it's not huge, but turn in is a little different. Bigger issue is that you're just carrying more speed into the turns now, so you gotta drive accordingly. I'm still running 205s on the car, and it's "fun" to have to feather the throttle with an M50 vanos motor and a 3.73.

-Charlie

[mazur]

The M50 will most definately be more reliable.

[TiSiBeast]

Kind of the way I was leaning on this one - M50 in a mod class. Looks like I have an M50 in my future.

[Massive Lee]

M50 is bulletproof. It requires basically no maintenance and there's no rocker arms to break. That engine is so smooth and torquier that it is a no-brainer when comes the time to remove an old and tired M20. The M50B28 is great. Or get the all mighty 3.2 M3 motor...

[jlevie]

The M50 has the advantage in terms of power and torque band, and an M52TU would be even better in that regard. But an M20 is a simpler engine that is far easier to work on without needing expensive special tools. But the real deciding factor is probably the end use. If you want to road race the car, an M20B25 is probably the way to go.

[Charlie]

The M50 has the advantage in terms of power and torque band, and an M52TU would be even better in that regard. But an M20 is a simpler engine that is far easier to work on without needing expensive special tools. But the real deciding factor is probably the end use. If you want to road race the car, an M20B25 is probably the way to go.

What "expensive, special tools" do you need for an M50?

As for being simple, coil on plug ignition, hydraulic valves, no timing belt. It's basically maintenence free.

-Charlie

[asubimmer]

The M50 has the advantage in terms of power and torque band, and an M52TU would be even better in that regard. But an M20 is a simpler engine that is far easier to work on without needing expensive special tools. But the real deciding factor is probably the end use. If you want to road race the car, an M20B25 is probably the way to go.

you've never been to the track have you

[Massive Lee]

For a race engine, the best option is the M50 motor as the M20 is 1976 technology. As far as costly tool to buy, the only one is the Vanos locking tool. Not a biggie. Cheaper than a broken rocker arm...

[1990m3]

I have an s50 -- basically the same as an m50 for the purpose of your question.

do the swap, swapped cars kick ass on the track when setup somewhat well. My car is a blast and it really has been dead on reliable. No issues with it running ever, and I rev it all the way in pretty much every gear. I think having a car with a great running motor ALL THE TIME makes tracking your car and keeping it work well much easier.

[kishg]

you've never been to the track have you

i believe he races spec e30

i would agree with jim.

[Emre]

aside from classing issues, which is better for the track?

Classing issues are pretty much the only reason to leave an M20 in a dedicated track car. You need a stock M20B25 for NASA SpecE30 or a cammed M20B25 for BMW CCA CR K-Prepared.

The M50B25 is better in every way...except for weight. It's around 70 lbs. heavier, which is hardly the end of the world.

[TiSiBeast]

Im planning on ripping out the stock tank and installing a fuel cell with foam as far back as I can. That should largely balance out the extra weight up front from the M50.

[Jon325i]

Classing issues are pretty much the only reason to leave an M20 in a dedicated track car. You need a stock M20B25 for NASA SpecE30 or a cammed M20B25 for BMW CCA CR K-Prepared.

The M50B25 is better in every way...except for weight. It's around 70 lbs. heavier, which is hardly the end of the world.

Good point, but since we're talking track car, just rip out all the AC system. That should be enough to make up the added weight.


Jon