New Motor Build

[chocolame]

I am currently set on buying my second E30. I owned one a while back as my first car and I'm looking to get another. This go around, I want to build a turbo setup. Keep in mind Im not looking to go much above 300 for the time being. One day I might want to step it way on up but for now, its my DD (even though I work from home) and I want it to not be unreliable. Im looking at building something to have some fun, reliable, and reasonable.

My budget is not the highest but Im thinking I can make it happen. Im working with around 8,000. All of this halfway relevant information aside, my big questions are:

1. How much power can an M20 make reliably via FI

2. Is it worth swapping an M50 into my car? Are they any better for a FI setup? Obviously the 24v part helps lol.

3. Regardless of which motor I get, what am I going to need to rebuild/buy that is forged to make this reliably make 250-300whp?

4. How much power are the stock transmissions and rear ends good for? It seems more likely that the wheels spin in such a light car, but none the less, in the event that it does hook up, how much can I make, and be fairly sure Im not going to break something?

Any information is greatly appreciated. I will be doing all the work myself, so thats mostly how I will be getting away with the budget I have. I'm open to all ideas, except for the idea of a turbo. I've been pretty set on that for quite some time. Thanks for reading!

[ak-]

1. Depends on your fuel and tuning ability
2. 24v with the intent of boost? 400whp+ all day stock reliably with stock ECU tuning.
3. Nothing, literally.
4. With your goals, no worries. Shorter diffs + hooking up = break stuff after 500whp I'd say.

[chocolame]

Thanks for the quick reply ak-!

Reading this makes me very optimistic. It seems like the 24v is the way to go with a turbo setup right?

I've read in to what I need for the M50 swap and all of that but the guides and walkthroughs I have read, dont say much about FI.

My next question might tie in to number 1 and 2 again. What kind of injectors/fuel pump do I need to be making 300-400hp. 250-300 being my goal; but I would like the option of upgrading down the road so why not get the good stuff up front?

[ak-]

Skip the m50 and go m52 or s50/2.

R3v will tell you how to swap the motor, and Bimmerforum's forced induction section will tell you what to use to turbo it and all the in-betweens. That section is literally 90% e36 M3 turbo cars.

If you're using pump gas, a sloppy rule of thumb is to add a 0 to the injector size to know the injector limit. 36lbs = 360hp, 42lbs = 420. Most people, especially with 24v motors, get 60lbs'ers and call it a day. Lots of tuning solutions also use this size and include them in their package deals.

The Walbro 255lph pump is popular. A bosch 044 is also another option that is rated for 300lph, I think $30 or something more and something to consider if you plan on using e85.


Getting the good stuff up front is ALWAYS the best method of practice, 100% of the time.
Countless others, including me, have paid the price for not doing this the first time around when going turbocharged.

For some inspiration ,
my best friend is making 490whp on a stock s50 (MLS headgasket / ARP headstuds) on 12psi GTK Turbonetics BB turbo 91 octane reliably.
KAMotors is making somewhere near 400whp or so on 17psi(?) with water/methanol on a stock cam'd m20 (ARP headstuds) on a 20g turbo.
I made near 300whp or so on a stock m20 (ARP headstuds / OEM bottom end rebuild) on 12psi with a medium sized t3/t4 Garrett 91 octane.

[TheTacoMan]

One of the key things to me for the debate between s5x versus m20B2x is the cost of boosting. The four valve engine is going to make more power all day long that said if I wanted some thing I was going to track alot I would go m20 for the simplicity and how cheap they are to buy and maintain. I could blow up my engine right now and not care due to the fact I can go pick one up and boost on for 200-400$. If I blew my s50 or s52 up it would cost a bit more to be back in boost.
Boosting is expensive but m20s are less expensive to do so.

[chocolame]

Well after reading all of this, I am still very optimistic! I appreciate all the input so far.

My next question would be, skipping the M50 and going to M52 or S50; I do understand, however looking at how much power I want to make, is it necessary to motor swap right off the bat to get the power I want? It seems to me that the M20's are making the power I want to make with just a turbo slapped on there?

I would love to S50 swap the car, but that seems like it will use up most of my budget right off the bat (besides buying the car itself). If I swapped that motor it seems my turbo kit will suffer in quality, so based solely upon my budget at this time, would you recommend building a nice turbo setup and taking care of the stock motor to achieve what I want?