200hp out of M20

[ukrbmw]

Guys,

I read a lot of info on the site about swaps and mods, etc. But, I can't seem to find any solid information. Here is the situation:

Building a time trial car. Basically, I can do cams, intake, headers, exhaust, head work, tune, and all these mods don't account for many points. On the other hand I can do an M50 swap which puts me in the same class. I've been reading up on the swaps and it seems one can be done for about $2,000 - give or take a little. By the same token it looks like Schrick 304 Cam with upgraded valves is only $500 from Turner, plus some machine work, software, etc would only add up to $1,500 or so. Basically, it's roughly the same price. How much would an M20 with 304 cam and software put down?

My goal is to get 200 hp out of the motor in the car, but based on what I'm reading this may not happen without a Stroker which is more then I want to spend.

So, I'm looking for some guidance from people on the board with a lot of experience modding M20s.

One thing, before you post keep this in mind:
I can't swap an M52 or S50/52, that would bump me up too much
No ITBs, or extravagant parts like that - I'm not spending that much money.
This is a track car, it spends very limited if any time on the track
Goal is 200 whp on decent budget or at least as close as I can get to it using M20 or M50 without braking the bank

Thanks for the help.

[Fidhle007]

You can get 200hp out of an M20 and an M50 reasonably easily if you're not afraid of headwork, but the M50 will probably be cheaper. I've seen M50s with simple bolt-ons that were putting down at least 200 and you'd have a wider powerband too but I suppose you'd have to factor in the cost of the swap too. To do it right you'll spend at LEAST $2k on a solid swap but that's about what you'd have into the headwork on the M20 too. Bottom line IMHO: Big power M20 is not that hard but it won't have much grunt down low (which should be fine on a track car.) Big power M50 is easier and will have a wider powerband but you still have to get it under the hood, first.

When I did my swap it was because I had broken a rocker. I had planned to spend $1.5 - $2k on a "hot" head but when I lucked into an S50 for not that much more then that, I knew it was the obvious choice. It was more work and more money also 100hp more then I ever would have gotten out of the M20 without boost.

[Aptyp]

what is your budget?

[jlevie]

I'd hazard a guess than an M50 is going to outperform a built M20 in this application due to the broader torque curve.

[ukrbmw]

Jim - you're everywhere buddy!

Aptyp

It's not a question of a budget, but more bang for the buck. Basically, should I do a swap and maybe software or get the M20 worked over?

I already have a money pit, it's my Spec E30 car. This is just a fun project to see if I can get the thing to be somewhat competitive for a reasonable amount of money.

[Philo]

24v all the way.

[Fidhle007]

I'm sure you could get some grunt out of an M50 with S50 cams, larger injectors, a GOOD intake and some headers. That might be your best option in terms of hp/cost.

[jlevie]

You could build a high output M20, but I suspect that would wind up costing well north of what an M50 swap would cost. There'll be a big difference in the shape of the torque curves, and that is where speed comes from, not in what peak HP a motor produces.

I'll have well more than the $2000 you've mentioned in the built motor that is going into the new car. And that is just to get (hopefully) in to the 160-166 peak HP range. To go further would mean cams, lighter pistons, serious head work, and custom tuning. It can be done but it is pricey. But even then the torque curve will be narrow as compared to a stock M50.

[Danny]

I'm building up my spare M20 in the garage with 11:1 pistons, schrick 288 and MegaSquirt.

Probably gonna spend ~3500.

[ukrbmw]

Well, things are changing on me. Just read that E30 325IS was bumped up in to TTE for next year from TTF. I just emailed our national director to find out what's going to happen to the M50 swapped car (previously it was in TTE with a 7 point penalty).

So if the swap moves me up to TTD, then I'm back at trying to figure out a way to get some decent power out of M20 without going too far.

PS - Jim, I know all about a built M20. Just ask me for the copy of the BRE bill...However, look at my recent lap times, almost 2 seconds better!

[Fidhle007]

What are your gearing allowances and is that an option without too much penalty?

[Stu]

I'm building up my spare M20 in the garage with 11:1 pistons, schrick 288 and MegaSquirt.

Probably gonna spend ~3500.

Do you guys get 93 out there? Need to be careful with 11:1. $3500 is a good budget for that motor if you're building it yourself, sounds like a fun project.


It's a waste IMO to try to get real world performance from a 75mm stroke M20, it might make some noise from 4500/5000-->7000 but will be worthless on the bottom. It'll atleast need a TD crank or better yet any of the forged M52/S50 cranks to really haul and have real world torque. From there, power and torque potential is great, with a strong area under the curves. Even a 2.8 with ~10:1 and a mild cam will really haul assuming the car is setup right (not too heavy, good rear end gear, good exhaust, etc). There are a lot of options using OEM parts to build budget strokers. One of the most fun cars I've ever driven was an '84 E car with a 10:1, 85x81, Schrick dual pattern 284/272 and 4.10 rear

[Danny]

That's true, maybe I'll go 10:1 due to the 91 California gas.

[LowR3V'in]

There's some good info in this thread.

http://www.e30tech.com/forum/showthread.php?t=52734

[Johnny Redline]

Me and my buddy are just about done with our m50 swap with s52 cams. the m50 only cost us 900 bucks, the motor mounts, trans, brake booster, electric fan, drive shaft work, e36 calipers and rotors, oil pan, new lifters and trays for the cams and probably like two other things cost us just around 1700.

but then we also we have the head port and polished, with a 3 angle valve job, and a dinan chip to open it up. so were shooting for some were around the 200 whp