From knowing nothing to having a Thunderbird supercharger on an m20b27i

[The Dark Side of Will]

At the risk of being accused of belaboring the point, because I most certainly am, that is only a crankshaft for $425, not

Yes, you are.
Just because you can't find a smoking deal *right now*, two blocks from where you live with 3 minutes of looking doesn't mean they don't come up.

Good, quick, cheap; pick any 2, etc. You get a good product on a limited budget by taking your time to find the right deals. I've gotten plenty just by checking back a little later.

That's a crank for $325 + $100 shipping. Depending on what part of TN you're in, the shipping might not be a thing.

[agent]

OK, TN has surprisingly slim pickin's.

There's always ebay:
http://www.ebay.com/itm/BMW-E46-3-Se...6a5b1f&vxp=mtr

At the risk of being accused of belaboring the point, because I most certainly am, that is only a crankshaft for $425, not

a whole M54B30 for $500

[Ether-D]

I've got a new plan brewing in the darkest corner of my mind right now. It may involve even more displacement...

[The Dark Side of Will]

Maybe for only the short block. Here is the first page of M54B30s on car-part.com sorted by distance:

OK, TN has surprisingly slim pickin's.

There's always ebay:

http://www.ebay.com/itm/BMW-E46-3-Series-E36-M3-S52-M54-3-0L-3-2L-Crankshaft-1996-2006-USED-OEM-/201115458335?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ed36a5b1f&vxp=mtr

[Ether-D]

Lower compression raises the threshold (in terms of temperature and boost pressre) for detonation at a given fuel octane.

Preignition and detonation are very different things.

Lots of info on detonation and pre-ignition and their differences

And Taco, I was referring to a used m20b27 (not a 2.7i) bottom that would be likely to have less revolutions on it because of lower rev limit (from the factory). I was a bit unclear in my wording.

[TheTacoMan]

2.7:
no machining
easy to source
cheaper
lower compression
lower revolutions per lower r3v limit so lower wear

Wut? I have my 2.7 spinning up to 7100 right now, 2.7i doesnt have a limiting factor to revving, same as a 2.5i as far as Im concerned.
The lower compression means that it will be less prone to detonate with bad gas generally speaking, this doesnt mean you can run lesser gas than 91. The 2.7i really isnt far off of a 2.5i when they are both boosted, sure it will spool the turbo quicker but the lesser compression also hinders spool time.
I would try to find a supereta if you go 2.7i as they have better compression than just the e.

[agent]

Where?

www.car-parts.com

Maybe for only the short block. Here is the first page of M54B30s on car-part.com sorted by distance:

[The Dark Side of Will]

Where?

https://www.car-parts.com

I know bigger will be better for the m90, but I think I want to also have lower compression. What's the theory about lower compression and FI? Is it about lessening the likelihood of pre-ignition and/or detonation? If so, is that the only thing it does for you?

Lower compression raises the threshold (in terms of temperature and boost pressre) for detonation at a given fuel octane.

Preignition and detonation are very different things.

[agent]

You can get a whole M54B30 for $500

Where?

[Ether-D]

I know bigger will be better for the m90, but I think I want to also have lower compression. What's the theory about lower compression and FI? Is it about lessening the likelihood of pre-ignition and/or detonation? If so, is that the only thing it does for you?

[The Dark Side of Will]

You can get a whole M54B30 for $500 and probably sell the cylinder head for $250 when you're done.

Nando's done a M20B30... ask him what it took.
Remember what we said soooo many pages ago about the blower working better with bigger engines...

[Ether-D]

Sooo much more money… Am I on the right track here though?

[The Dark Side of Will]

3.0 stroker ;)

[Ether-D]

Ok, so I'm reading about strokers to replace my rattly bottom with (while i'm in there…). There's the 2.7 and the 2.8 budget strokers. I'm getting the feeling that the 2.7i (b27 bottom b25 top) is the way to go (for me) because of lower compression for forced induction. Is this the correct idea? What would I gain from the 2.8 besides higher compression and .1L more displacement? And would the higher compression actually hurt me? I'm also thinking a m20b27 bottom would be easy to source and likely very cheap. I'll probably do a full rebuild on whatever bottom I go with so as to start with a "new" bottom, wear-wise.

2.7:
no machining
easy to source
cheaper
lower compression
lower revolutions per lower r3v limit so lower wear

2.8:
.1L more displacement

Seems pretty cut and dried, unless any of yous can tell me why I should go 2.8 instead.

[Ether-D]

P.S.
Not being a smartass (maybe a little…), but you can search individual threads with the "search this thread" button.