Couple Qs about a stroker build

[nisfro98]

I know this comes up all the time but sometimes you just have to resort to asking questions. My current setup is a stock 325i (89) and I think Im gonna go stroker route. I originally wanted to do a s50/52 swap but finding one close by is fairly difficult. I've done quite a bit of reading on the webs and there seems to be almost an endless combination of ways to stroke the m20 as far as crank and pistons and head components but basically boils down to using an eta block and an I head. I have an option to get a busted engine (broken timing belt) from an '86 eta (160k).

Is there some kind of master sheet or doc that lists out all the possible build combinations with HP and TQ potential? i.e. using eta block and I head you can use these parts for X gains and for straight I stroke you can use these parts for X gains.
Is there a large advantage to using the eta block and I head over stroking the I engine itself?
will the eta drop straight in w/o modification?
Is there a larger advantage to using a super eta vs eta and is it worth holding out for one? I think I can get the eta block (with crank and pistons) for under $100 so not sure what super eta would go for.
Is it possible to proof a stroker for future FI (turbo)? Im ok with doing head work later but rather not tear the block apart.

Im not really concerned with reaching a certain displacement just the best/highest apex (cost vs performance). I've come to terms with spending a couple grand (with doing all the work myself) for the little gains you get for stroking. I'd like to get around 200-210 HP na. My father-in-law has been a BMW mechanic for over 20 years so if I need help I know I can rely on him.

[bluptgm3]

Preparing an engine for boost generally includes lowering compression. Lowering compression on a non boosted non-VaNos engine further reduces power level to a point that almost makes it undriveable.


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[95BMWIC]

I personally have never seen a master sheet - but you probably already know that due to your extensive reading. Im assuming you already know that you can set your compression with a custom piston head. All you have to do is work with the numerous aftermarket companies that will help you. http://www.iemotorsport.com/bmw/E30-...20pistonf.html is one example - tell them what compression you want - tell them what components you are using. etc. etc and they can help dial it into the ratio you want to achieve for your turbo. Im not recommending IE - just giving you an example.

I would "re-read" the epic threads to gain a deeper understanding - then reach out to some of the users on the E30tech thread - most of them are on this and R3V board and can help you. Most of your questions will be answered by reading these threads.

try here on stroker builds for the M20: http://www.e30tech.com/forum/showthread.php?t=48288

more on the eta and super eta here: http://www.strictlyeta.net/technical/328i_1.html

[digger]

for 210 bhp on a budget, you could do a few things bottom end wise that will still take some boost but nothing like a built bottom end

- m52b28 crank, eta 130mm rods, m20b25 pistons, requires mods to crankshaft counterweight and piston skirts to avoid interference. also needs upto 0.5mm off the block to get the best compression.
- m20b27 crank, eta 130mm rods, m20b25 pistons, requires decking block 2mm to give proper compression and adjustable cam gear.

forget about m20b25 on complete eta bottom end it doesn't really make more power than fresh m20b25

to make more power you are going to want a bigger cam as a minimum.