M50 or Turbo M42?

[Stu]

toss an E36 low mileage M42 in that bitch and slap a DASC on. Now that would be crazy. Basically S50 power...

Not nearly, more like 325 (M50) peak power, and a lot less area under the power and torque curves.

[Ziggens96]

shit me sideways. if i hear one more person say that lack of knock sensors is the reason behind not boosting an m42 i will cry. and high comp isnt that big of a deal, so long as you keep the boost sensible.

the other flywheel option is the m40 fly. however, you need to use the smaller clutch with it ... im not sure this would be the optimum setup in a turbo application. try and lose some weight off the oem fly.

there are two things i see as vital in regards to turboing the m42 1) keeping boost to a safe level, and 2) running some nice management.

So what is the reason then? The high compression is a big deal, keeping the standard CR would require such low boost that it wouldn't even be worth the turbo fitting. Cracked heads are a big enough problem as it is.

[asubimmer]

welp i just bought a garrett t3/t4 for the m42. I'll let you guys know what happens :)

[Streetspec_iS]

So what is the reason then? The high compression is a big deal, keeping the standard CR would require such low boost that it wouldn't even be worth the turbo fitting. Cracked heads are a big enough problem as it is.

i never said you could boost it to high levels with std CR, sure it is a limiting factor, but it isnt a reason not to do it. running like 8psi will give you enough to have a healthy, nimble street car. its all in tuning.

lots of motors run boost with a lack of knock sensors, this is all that i mean by that. people talk of it as if the m42 is the only motor in the world with out a knock sens that anyone has contemplated turboing.

i wasnt having a go at you dude, its just something that bugs me.

[asubimmer]

are the intercoolers on ebay crap like the turbos? what intercooler do you people w/ turboed m20's use?

[Brew]

IMO, it comes down to this:
If you're looking for a reliable, quick, daily driver type car, go with the M50. You can always mod that later if you get the bug.

A custom turbo set-up will never be "daily driver reliable" unless you spend some serious cash and are willing to go through a lot of R&D.

BTW, not sure how your chapter/group classes engine swap cars, but in the Boston chapter they just classed my car as an E36 w/ LSD plus all my mods. Puts me in the same class as E36/E46 M3s, Z4s, 330's- all pretty close on a tight course.

[Ziggens96]

i never said you could boost it to high levels with std CR, sure it is a limiting factor, but it isnt a reason not to do it. running like 8psi will give you enough to have a healthy, nimble street car. its all in tuning.

lots of motors run boost with a lack of knock sensors, this is all that i mean by that. people talk of it as if the m42 is the only motor in the world with out a knock sens that anyone has contemplated turboing.

i wasnt having a go at you dude, its just something that bugs me.

gotcha. 8 psi sounds about right, but if I were to go through the trouble of turboing my car, I would go all out. If you want to run higher than 8 psi, 8:1 forged pistons would be proper, right? I know that it is indeed possible to turbo an M42, but I have literally NEVER seen it so I assumed it must be quite difficult.

[asubimmer]

gotcha. 8 psi sounds about right, but if I were to go through the trouble of turboing my car, I would go all out. If you want to run higher than 8 psi, 8:1 forged pistons would be proper, right? I know that it is indeed possible to turbo an M42, but I have literally NEVER seen it so I assumed it must be quite difficult.

well i'll let you guys know later this winter when i get it all together. I have my turbo an bov and still collecting other parts for the setup. i will prob run about 8psi till i rebuild my engine. I have over 220,000 miles right now.

[asubimmer]

guys i have a video of a turbo m42 but don't know where to host either the zip of wmv. where can i do that?

[TANK]

I'd say M42 TURBO. I'm intrested in how that will work out and How many ponies do you think 8psi will add to the M42?

[asubimmer]

i got my bov today and the turbo should be here tommorrow or mon. What would be good injectors for a turbo m42. the stock ones are barely sufficient for the n/a m42. I'm still thinkin about where to put the intercooler and what size I need. Also I'm still researching my best bet for engine management. I'll try to keep you guys posted.

[Streetspec_iS]

How many ponies do you think 8psi will add to the M42?

a lot of ppl work on 8-12 hp (av 10 for rough guide) per psi ... others say 8% per psi. either way, on an m42 with 7-8psi should see you up around 200hp, depending on setup, fueling, tuning, cooling etc etc

[B2ThaZiZza]

HERE YOU GO http://www.tdi-plc.com/bmwE30318iS.htm

[Rob]

I voted turbo M42 because I want to see it done.

The secret to boosting cars with compression is tuning. Megasquirt+spark or SMT6, on a dyno, with a tuner who knows his ass from his elbow will go long long ways towards a reliable, safe, and powerful boosted motor.

No one has mentioned weight yet, I dont think a turbo setup will add as much weight as an M50, big tranny, and big diff. You might need a diff upgrade though.

For the flywheel, look closely at the 325i swap, which will lose many lbs of rotating weight, and get you more capacity for HP (http://blackforestindustries.com/m20flywheel.htm) It doesnt seem like a huge deal.