Stroking a 95 M3 S50B30 engine and other mods - BMW Forum

BMWjesterFAN · 10-01-2005, 10:23 PM

Ok, so I already posted thie to the M3 forum, but it applies here as well. So... Anyone know where I can find info on stroking a 3.0 S50 engine? I'm looking to make some decent power NA, and then possibly go with a supercharger, but I don't want to be like everyone else and just throw a Vortech on it and call it a day. I am tearing the motor down now, and will have the head ported, polished, and decked, and a valve job done, along with the block being acid dipped and both being inspected. Where should I go from there? Keep in mind that I am not rich, and will do as much of the work as I can myself. I rebuild internal combustion engines on aircraft in the Air Force, so I think I can handle the assembly stuff, and some minor engine work. Thanks,
-Tim

Furious · 10-02-2005, 03:17 PM

why not save up and do both the same time, instead of stroking it, why not just rebuild the engine for the supercharger, low compression pistons, sleeve the walls (if thats possible on our engines), etc etc, just get the engine ready for the supercharger than slap it on, they your going to be able to push the supercharger harder. if your not going to supercharge the car than id suggest talking to some of the big companies in the engine buisness and a few in the parts business ... see what they might have for you to use or what your best bet is.........i have yet to look at my options yet so i really dont have any ground work research on this.

BMWjesterFAN · 10-02-2005, 11:09 PM

Well, I know a few options, and one of them is looking really good right now. I can use my S50 head on a 3.2 block, which I can get used for $1k from a reputable place. Then, I am almost assuredly going to get the head work done, possibly bore the 3.2 block, and start deciding whether or not to FI it. I just found out that I have an assignment to Korea for a year, with a reporting date in February, so the car will definitely not be done, and I can't take it with. That gives me a good year to get some serious machine work done. Do I hear any ideas? I am not afraid of going all motor with a ton of HP if it's possible, but I also don't have tons of cash to throw around.

BMWjesterFAN · 10-03-2005, 08:04 PM

Anyone?

Furious · 10-03-2005, 08:47 PM

sorry getting out of my league but ill see if i can chime in a friend who may know a thing or two...

thinair · 10-03-2005, 09:18 PM

You have the option of talking to the guys at HIOP, they make 3.4L stroker kits for the M50/2 engines.

The problem with the 3.2L block is that there really isn't a whole lot of room to bore, especially if you're considering FI later on.

It's sort of a toss up, you can build a strong high compression NA engine now, then be limited to a lower PSI FI setup, or commit to FI and build a low compression motor.

Regardless, if you have the time, resources, and money, you can pretty much do anything you want. I'm a huge NA fan, but I have come to the realization you can only make so much reliable power with NA. Again you're faced with the dilema, a very responsive engine with possible high revs, and a peaky power band, or a heavier and less responsive engine, but with gobs of power and the ablility to tune your powerband somewhat.

BMWjesterFAN · 10-04-2005, 02:54 AM

Hmmm... I was thinking about getting the 3.2 short block, doing some minor block work, knife edging the crank, etc. And bolting on my worked 3.0 head. That would leave me with the 3.0 block to have fun with. Which one would respond better to FI though? Which block should I prep for FI, and which for NA? Then I can drive it using one and play with the other untill I get it the way I want it, then swap it. And yes, I do most of my own work. Not gonna machine my own engine though.