M50 vs. M20 for track car?

[jlevie]

you've never been to the track have you

Not much. I only average 10 track events a year either racing my Spec E30 or instructing.

Classing is the prime reason the stay with an M20. That allows the car to be set up for Spec E30, KP, PRO-3, ITS, etc where there are reasonable sized fields and good competition. I don't remember where an M50 would push you to with NASA or SCCA, but I think it means DM with BMW CR. And then there's cost. A low mileage (less than 100k) M20 can be had for $800 or less, or roughly half the cost of a higher mileage M50B25TU. Head rebuild is significantly less as is just about everything else associated with an M20.

Now if the car is just going to be driven in DE's, an M50 makes more sense as classing isn't an issue.

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.

That isn't such a good plan. The stock tank is in an ideal position, low and in between the wheels. Moving that weight aft of the rear axel will increase the polar moment and adversely affect handling.

[TiSiBeast]

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

The car is already totally gutted, no AC, no CC, no door glass, interior, wipers, etc. It's a shell with a cage, buckets, 4 wheels, an engine and a tranny. It's a little nose heavy still, but mostly because of the 54 lbs of sound deadening I removed from the trunk. Moving the tank back should take care of that.

[Massive Lee]

If you feel a bit adventurous, I suggest you explore the possibilities of moving the engine (and transmission) back by an inch. This will transfer a lot of weight to the rear.

Moving the fuel tank will also help rebalance the car, but it will also increase the polar moment of the car as the fuel tank's weight will be located at the tip of the car.

[Charlie]

I don't remember where an M50 would push you to with NASA or SCCA, but I think it means DM with BMW CR.

An M50 swapped E30 makes a nice GTS-2 prepped car, and you can squeak it into TTE if you're creative and don't mind tiny tires. Judging by Adam Nitti's results, it makes for a hell of a TTD car as well.

-Charlie

[asubimmer]

Not much. I only average 10 track events a year either racing my Spec E30 or instructing.

Classing is the prime reason the stay with an M20. That allows the car to be set up for Spec E30, KP, PRO-3, ITS, etc where there are reasonable sized fields and good competition. I don't remember where an M50 would push you to with NASA or SCCA, but I think it means DM with BMW CR. And then there's cost. A low mileage (less than 100k) M20 can be had for $800 or less, or roughly half the cost of a higher mileage M50B25TU. Head rebuild is significantly less as is just about everything else associated with an M20.

Now if the car is just going to be driven in DE's, an M50 makes more sense as classing isn't an issue.


That isn't such a good plan. The stock tank is in an ideal position, low and in between the wheels. Moving that weight aft of the rear axel will increase the polar moment and adversely affect handling.

He said classing doesn't matter, he was interested in the better track motor.

I do agree though that the m20 would deff be cheaper mainly because swapping to an m50 would put you in xM in club racing. It would depend on what displacement he went with to which mod class it would be. And regardless of which Mod class he would be put into, it would cost a LOT more to build that car than a specE30.

Unless I'm reading him wrong I think he's just looking to have fun out there. It doesn't seem like he's interested in running in the front of the pack, wether it be specE30 or SM.

[Paukert11]

I would stay with an m20. because you are going to have to swap out a shit load of stuff. I would just become a better driver with that motor.Just beef up the m 20 a little and you will be good to go. Remember fast drives dont always need a fast car to beet other people.

[kishg]

i would stay with an m20. Because you are going to have to swap out a shit load of stuff. I would just become a better driver with that motor.just beef up the m 20 a little and you will be good to go. Remember fast drives dont always need a fast car to beet other people.

+100

[JGood]

I have a chipped m50b25tu 85 325e and a chipped m20b25 87 325is, I think I'd prefer the m20 for a track car. I've put a lot of miles on both, and I am aware of the powerband differences and maintenance differences.

I really like the lightweight feeling of my m20 track car (2380 lbs) and don't think the power increase of the m50 is worth all that weight up front. Of course an s50 or s52 would be a different story.

It is nice to not worry about timing belts, broken rockers, and adjusting valves with the m50. But it's also nice to know if I need to work on the m20, I don't need to find the tools required to do so on an m50 (cam lock tool, tensioner tool, etc...), and replacement parts are cheaper (and there are fewer parts.) It's just a simpler design.

For a daily driver on the other hand, I love the m50. It's so smooth and easy to drive in comparison to an m20 because of the throttle response and powerband. And the extra weight on a street car is (well, should be) irrelevant.

[mazur]

Classing is the prime reason the stay with an M20. That allows the car to be set up for Spec E30, KP, PRO-3, ITS, etc where there are reasonable sized fields and good competition.

I do not see this being an issue in AZ since Spec E30 is non-existant and most people in race group are classed based on Time Trial classing.

I believe a highly modified E30 with an M50 would land you in PTC (WTW racing). This class is capable of 1:09's at PIR, just for reference, though most will never reach that level speaking from experience.

Best thing to do would be to email Greg on the NASA forums and find out what your classing options would be with both engines with different power level goals.

[Liam]

If you feel a bit adventurous, I suggest you explore the possibilities of moving the engine (and transmission) back by an inch. This will transfer a lot of weight to the rear.

Moving the fuel tank will also help rebalance the car, but it will also increase the polar moment of the car as the fuel tank's weight will be located at the tip of the car.

Hell shove it back farther than an inch, put the back of the head just about where the radio used to be.

[Paukert11]

stick with the m20!!!!!!!!!!!!! M50 is a street car thing.just do a nice gc setup and some good race seats, beef your motor up. and you will be having a shit load of more fun. and you will be passing peps.

[Charlie]

stick with the m20!!!!!!!!!!!!! M50 is a street car thing.just do a nice gc setup and some good race seats, beef your motor up. and you will be having a shit load of more fun. and you will be passing peps.

Um, mine, and the many M50 guys I know that track their cars would beg to disagree. Swapped e30s make great track cars..

-Charlie

[Dyno4mance]

+1 Stick with the M20....Modified you can get 230 -240 hp from it IMO thats plenty of power for a track car....weight is the enemy!!!

[Charlie]

+1 Stick with the M20....Modified you can get 230 -240 hp from it IMO thats plenty of power for a track car....weight is the enemy!!!

Can you link me to a reliable 240 hp NA'd M20?

-Charlie

[nando]

Can you link me to a reliable 240 hp NA'd M20?

-Charlie

I know of at least one- guy down in NZ/Aus (posts on E30zone) but it's not something you would get from your typical $500 budget 2.7 build. it takes displacement, headwork, a good cam, well thought out exhaust and good tuning. I think he tried a couple different cams and exhausts before his final results. You can pretty much eliminate everything but displacement from the typical M20 builds here, and without all of those components combined it's going to be dissapointing to say the least (hello dave length!).