M50 vs. M20 for track car?

[Massive Lee]

+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!!!

An M20 running continuously at 6.8KRPM is a time bomb with its weak rocker arms. A 240hp M20 will require much higher rev, and its life is most likely going to be short. So, as was mentionned, please point me too where I can see spec of a 240hp M20 that can run day-in day-out.

[Paukert11]

Thats why im saying re build the motor stronger with newer parts and put a s50 rods in it!

[etxxz]

^^ might as well put the s50 in there for that effort and money..

[nando]

An M20 running continuously at 6.8KRPM is a time bomb with its weak rocker arms. A 240hp M20 will require much higher rev, and its life is most likely going to be short. So, as was mentionned, please point me too where I can see spec of a 240hp M20 that can run day-in day-out.

nah, 6800 isn't really pushing it, maybe on a tired motor with original rockers, and maybe past 7200 with new ones. You can't really rev M50s very high, either, so it's not exactly an unfair comparison. With billet rockers the sky is the limit but again not in the cards for a typical M20.

I believe he is running a 288 (either schrick or catcams) which probably peaks somewhere around 7,000, but would still have a pretty wide torque curve from 3500-5500. the 284/272 makes it's peak from 6000-6500 and is still strong up to 7k with a broader torque curve than stock.

[z31maniac]

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!).

And I thought I remembered them having to use some "special" correction factor to show the HP that he is claiming.

To all those saying rebuild the M20, Metric Mechanic claims 240 HP from his 3.1L M20, and he only wants $8k +

[Dillinger]

My m20 is probably close to that but I can't honestly say it's reliable ;)

[nando]

And I thought I remembered them having to use some "special" correction factor to show the HP that he is claiming.

To all those saying rebuild the M20, Metric Mechanic claims 240 HP from his 3.1L M20, and he only wants $8k +

no "special" correction, it was done on a dyno dynamics (dynojet would read higher). It was 220whp/218wtq (just looked) but I can't find his dyno plot, I hate the E30zone forum. :(

[Dillinger]

no special correction, it was done on a dyno dynamics too (dynojet would read higher). It was 220whp (just looked) but I can't find his dyno plot, I hate the E30zone forum. :(

They are all Brits, what do you expect?

[cleaner32]

Got an m50 for sale ;)

http://www.r3vlimited.com/board/showthread.php?t=135944&highlight=m50

[Brian D]

I sure am glad this came up, I don't remember ever seeing a thread about M20 vs. M50.

[kishg]

I sure am glad this came up, I don't remember ever seeing a thread about M20 vs. M50.

:rofl:

[Red88]

I sure am glad this came up, I don't remember ever seeing a thread about M20 vs. M50.

Open them eyes.

Stick to the m20, save some money for cool points with women.

[Massive Lee]

nah, 6800 isn't really pushing it...

Yup. I know. But many M20s still end up breaking rocker arms at that RPM. An M50 has no rocker arms. So, less parts to worry about. And it is a more efficient motor. The engineers weren't sleeping during the 15 years between the M20 and the M50.

[Dillinger]

I sure am glad this came up, I don't remember ever seeing a thread about M20 vs. M50.

Side by side the m20 and the early m50s there wasnt that much of a jump in power and IMO not much point in the swap. But with the m50tu on now you really got something, that vanos make the powerband very wide. For what I'm into I'll stick with the m20

But I must say that I have had more than a few s14 and m42 4 bangers give me one hell of a run for the money, they just plain kill you in the corners.

Yup. I know. But many M20s still end up breaking rocker arms at that RPM. An M50 has no rocker arms. So, less parts to worry about. And it is a more efficient motor. The engineers weren't sleeping during the 15 years between the M20 and the M50.

You just need the right rockers OEM shotpeened and x-rayed for the good castings.

[asubimmer]

Open them eyes.

Stick to the m20, save some money for cool points with women.

women don't like ticking slow m20 powered cars...

And I deff agree with Charlie, reliability in a track car is invaluable. And with ppl running e92's etc, you are at huge disadvantage with the older motors like the m20. Even the m50 doesn't have the powerband that the newer motors have. To get an m20 into the power range of a x5X motor you are going to end up spending a LOT more $$$ and it won't be nearly as reliable.