s50 vs GPS 3.0 stroker?

[Emre]

When considering building up an M20 stroker vs. doing an S50/52 swap, you need to specify whether you plan to rebuild the S50 or just stick in a used one. Most people do the latter.

Remember that even the newest S50/52 is now 12 years old. These are high-strung engines that have lived hard lives. Personally, I wouldn't go through all the trouble (and expense) of swapping any engine without rebuilding it first. It doesn't make much sense to me to pull out a perfectly good M20 just to drop in a 15-year-old engine with 150,000+ hard-driven miles on it that I found in a wrecking yard after it's 16-year-old 4th owner spun it into a tree.

In other words, you're comparing a brand new engine (i.e., a professionally built M20 stroker) to a potentially trashed engine (i.e., an S50 from the junkyard).

Sure, an M20 stroker will never give you the smooth power delivery and low-maintenance of a good S50 ... but at least you know the engine was built carefully to your specs. Just as important, you'll have the opportunity to break it in properly and maintain it from Day 1. That's worth a LOT to me in terms of peace of mind alone.

[Roysneon]

MM M20 cost vs. M50tu cost?

[dude8383]

2,000 and you're asking about either an s50 or GPS 3.0?

Haha, not gonna happen buddy. Unless you've got some sweet connect on motors...or have them growing on trees in your backyard.

[Wh33lhop]

Doing all the work for an x50 isn't really worth it. If you were to swap go for M52 or S52. I have seen a few M52s with a tune and M50 manifold make similar or more power than an S50.

Naw. With cams and OBD1 manifold, M52 will make similar peak power to an S50, but it will be missing some area under the curve. Then it's a matter of tuning the S50...

I have done all the work of swapping in my M50NV and I'd do it again, especially if it were an S50 next time.

3.0L M20's make as much power as an M50... probably not as much as an S50 though.

You can't just slap together a bottom end and assume it will work well. I'd assume extensive head work will be included with the M20B30, and in that case I can see it producing similar numbers to an S50. Plus, you are getting a new motor.

[TexasTerp]

M50 will make about 160-70whp
m20 3.0 can make 200whp
s50 makes about 240whp.

Only the m50 will fit a 2k budget and that's on the cheap. My 2.8 m20 with a complete rebuild and custom pistons will easily cost me more than 2k. MM's 3000 Sport/Rally stroker costs $8700 - I can't possibly see Levent selling a rebuilt 3.0 for anything less than $4k.

MM M20 cost vs. M50tu cost?

Haha, you're kidding right? MM m20 2900 starts at $7000. I can easily find running m50's for $150!!

[Wh33lhop]

s50 makes about 240whp.

With full bolt-ons, maybe.

[ZM Blue Devil]

I can't possibly see Levent selling a rebuilt 3.0 for anything less than $7k.

Fixed:D

[dude8383]

Fixed:D

hehe, bet you Joel is screaming right now... THREEEEE OOOOOOOOOOOOO

[Roysneon]

Haha, you're kidding right? MM m20 2900 starts at $7000. I can easily find running m50's for $150!!

Exactly my point. My M50 swap is happening slowly for a few reasons but I've got almost everything I need except headers for $500. Oil pan, wiring, trans, brake booster and mounts. That does not include a rebuild of the engine but for the price of a Metric Mechanic M20 I can have the same amount of power with a more modern engine that has more available from modern sources and more interchangeability with other engines.

That's not to say that a Metric Mechanic built M20 isn't a good option if you can't or don't want to build your own motor, they're different means to the same end, I just think that for the OP, a 24v would be better. I believe it would cost less to reseal an M52 and buy S52 cams and from everything I've ever seen online (which could be all wrong), would make similar power to a built, stroked M20.

[der affe]

you could also do a "budget" 2.8 m20

M52 crank, eta rods, i pistons and a crank spacer (i sell those btw, shameless plug)

more torque and hp than a 2.7i swap and you have a fresh rebuilt motor.

collect all the parts and have gps build you the motor or do it yourself.
the m20 does not put down huge hp numbers without boost, but in na form it does make good torque and that is what makes a car fun to drive.

with that motor you have a chance of comming in around your budget depending on how you scrounge for parts.

i have a set of eta pistons and rods that you can have for free if you pay the shipping. the pistons are of no use to you, but you will need the rods for the motor.

a used eta motor can be found for nearly free if not free, there is a set of rods and a block, pan etc. sell the eta head for something along with the manifolds, crank, etc and recoupe some money.

a used m52 crank can be had for $200 or less.

crank spacer $55

depending if you have an i motor now, you can reuse the head and pistons.

misc machine work, balancing and bearings etc

[kcoelhoe30]

Fixed:D

ididnt mean exactly a gps 3.0 even though i said that but that was just to attract Levent to the thread:P but rebiulding my m20 to 3.0

[TexasTerp]

Despite everything OP, 1 agree with der affe on this one. Look into a "2.8 budget stroker", it'll come out to a bit above your budget to truly rebuild it but it will be worth it in the long run.

With full bolt-ons, maybe.

My bad, I forgot that the last time my buddy dyno'd he had headers, mild cams and a tune. Didn't really think about it as he just put a VAC Stage 2 head on it and VAC cams...waiting to get it retuned....

Fixed:D

hahaha, I was being pretty liberal with that one.

[Wanganstyle]

one other issue of note:

weight/balance.

M20 is lighter and better positioned for the chassis than any DOHC 24v.
24v engines shift the center of weight forwards as the head itself is heavier than the SOHC 12v head.
engine is also taller, and if you choose the long stroke versions the deck itself is taller (s50b32, s54b32). Weight bias goes forward and shifts vertically up, spring rate needs re-juggling in the front; this weight can be felt in corner entry and exit.


also the engine seems longer as the various cooling fan fit threads will attest to; This leads down a complex path for weight shifting towards the rear of car..... if one cares about these things.

I enjoy running mechanical cooling fans; seems difficult with 24v engines + e30 chassis.

I am on the M20 side of the fence as far as chassis balance is concerned, I do have a dohc 24v engine also slotted for the e30, but am worried the extra 80 lbs or so will throw the chassis off too much. I'm guessing my high comp slightly worked M20 should be close to 180-190 rwhp when happy and will be a breeze to drive.

I enjoy late braking. front weight and bias is importante.

BMW pedestrian 24v engines from 92-99 era are usually worn; they have HLA's and the S50/52's usually have dead/dying/worn units from extra stress.... IF I was going to sheer gamble on throwing in a used motor, I'd pick a M52 coupled to an automatic. OBD2 engines have less power @ top end from intake tuning, M52 cams are also mild and possibly combine to less valvetrain and HLA wear.

most secondhand s50/52 usa spec engines are garbage quality, require a full build.

I have only come across good S50/52 US engines from buying the entire running car and removing it myself;


Mystery engines require a full tear down before use; why remove a perfectly good M20 to replace with a garbage pile of S50/52 us?