stock M20 internals power levels.

[CrazyB]

I am trying to decide if I want to build a new M20 for my autocross car and keep it in dsp or if I want to go the s50 route and jump to higher class.
So was curious what sort of Whp numbers have people achieved on a rebuilt m20 with stock internals with a cat and bolt ons.

[acolella76]

Most SpecE30 guys can get 155whp out of freshly rebuilt and blueprinted M20s. And that's totally stock... so hopefully that helps you guess what kind of power you could be putting down. With bolt ons you can probably squeeze out a little more.

IMO S50 is overrated, if I were going to 24v swap I would swap an M52 with cams. They usually put down about the same power as S5x motors with a proper tune, but for 1/4th the cost. Hell you could probably even buy an M50 and use S52 internals for cheaper than an S50. Just throwing that out there.

Good luck!

[jlevie]

Most SpecE30 guys can get 155whp out of freshly rebuilt and blueprinted M20s. And that's totally stock... so hopefully that helps you guess what kind of power you could be putting down. With bolt ons you can probably squeeze out a little more.

155hp at the rear wheels on a DynoJet is pretty average for an M20B25 in good condition and tune. A blueprinted Spec E30 M20B25 and good tune (within the limits of the rules) should make closer to 165hp on a DynoJet.

The Spec E30 rules limit what we can do w/respect to tuning. I suspect that there is another 5-10hp available that could be realized with a WAR chip, or better yet, with a MegaSquirt. The best bolt-ons for an otherwise stock engine would be a free flow exhaust, but that would mean elimination of the front resonators and catalytic converters and significant increase in noise. If the car has to pass emissions testing that won't be an option.

Blue printing an engine isn't magic, though it is a bit tedious. That process is all about control of tolerances and balance. With the most important part being attention to the cylinder head.

An engine swap to an M50/52 or S50/52 is certainly going to make more power. And using an VANOS engine is going to be better (more area under the torque curve) than a non-VANOS engine. But then that is going to change the class of the car and that has to be considered.

[nando]

how much autox have you done? if you've been doing it for a while and are just getting bored, an engine swap may make sense. But if you're just starting out - leave your car stock and spend money on maintenance and tuning up the stock motor. the M20 has the advantage of being light, which will make a difference in autox. you could spend that money on some sticky rubber (Hoosier slicks) which will make the car a lot faster than +40whp.

In SM you will be swimming with sharks, and those sharks usually have more money..

[CrazyB]

I have been Autocrossing and developing this car for last 3 years.
After I fit the 17x9 wheels later this month i will be close to the limits of what can be done in my class.
My m20 is a real tired engine and i was leaving the engine as a last thing on the car as I could not make up my mind between a good m20 rebuild and stay in DSp or making the jump into SM

I do not plan to compete at national level and mainly do this for fun. And with about 200 to 220 whp the e30 should be fairly competitiveness in the local SM class.

[nando]

yeah, for fun an S50 swap would work fine. It sounds like you might be at that point.

[CrazyB]

Yeah i just dont see myself getting this car to national competitive level in dsp, not with the cougar 4xti running circles around me with 250 whp and only 300 pounds heavier.

[nando]

I know, you really need a lot of money, or a lot of skill, to be really competetive. I don't have either, so I just have fun and do things to my car that I like. SCCA classing is pretty stupid for the most part, anyway. But it is what it is, so I just have fun with it. :)