M20 B3x Naturally Aspirated Stroker build past, present and future

[JinormusJ]

Rest assured I will be watching sub'd and supporting like a hawk

[digger]

Can I hire you as my personal engine builder? Lol

290hp dailyable m20 is no joke
That's like overshooting my dream m20 by like 90hp lol

honestly it is just correctly matching parts using techniques know for decades.

i am always happy to give an opinion. 200whp is easy

[JinormusJ]

Can I hire you as my personal engine builder? Lol

290hp dailyable m20 is no joke
That's like overshooting my dream m20 by like 90hp lol

[digger]

Finish this thing already

If 220bhp from your previous m20 wasn't satisfactory, I can't wait to see the figures you're getting on the new one!

My current 3.1L engine at one point made 164 rwkw / 295 rwNm (220 whp / 218 wtq) on a dyno dynamics shootout 6. It made 217 rwhp / 213 rwtq on a second dyno also dyno dynamics so not a fluke run and so a reasonable point of comparison.

i'm hoping for 210-220 rwkw (280-295 whp) of streetable power peaking at ~6700 rpm cutout at 7500 rpm on the same dyno dynamics machine.

Midrange torque should be huge hopefully around 250 wtq. EAPro and Pipemax both suggest this is realistic (flywheel 320-340 bhp / 270-290 tq).

Also the 25% more time-area from improved headflow and cam lift profile agree that the potential is there with intake and exhaust tuned accordingly of course.

164 rwkw x 1.25 = 218rwkw

For reference on same dyno I’ve seen

- 2 x stock M54B30 do ~130rwkw (170kw fly).
- E90 335i do ~175rwkw (220kw fly).

I’m not chasing peak numbers the cylinder heads don’t flow well enough to support a lot of hp with a very broad power band and nice low rpm manners the S54 is king there no question. I’ll leave that for guys that purely race competitively and can actually use the topend power regularly.

For those with that in mind more compression, more work on the head, 25 degrees more duration and E85 would easily add 30rwkw had i chosen that path.

[JinormusJ]

Finish this thing already

If 220bhp from your previous m20 wasn't satisfactory, I can't wait to see the figures you're getting on the new one!

[digger]

more on intake plenum design and molding pls op!

the idea is to run open trumpets but seal off the hot air and provide a means to filter the air, that is all its doing sealing off the trumpets. so i made it as big as i can within confines of hood, booster etc. .

mould is just foam shaped with a saw, files, rasps and sanded smooth. apply a thick coat of epoxy let it dry. sand it roughly so subsequent layers will bond effectively and apply coat of epoxy and sheets of glass or CF cloth then a thin layer ontop to make sure its fully wetted. trick is to cut pieces to size that drapes well and conforms to the mould. i did each layer in 4 pieces with overlap. radii can tricky same with corners to avoid pockets. then get a roller to squeeze out excess and remove air bubbles of each layer. it takes alot of time

[Bimmerman325i]

Wow. Subscribed for more!

I always wanted to do an all-out build on an M20.

[JinormusJ]

[Bimmer_man]

one of the greatest M20 builds ive ever seen

[Dj Buttchug]

more on intake plenum design and molding pls op!

[digger]

Holy crap! What a price tag I'd just turbo it if i wanted more power.

S38 crank is a cheaper alternative and will net about 3.7-3.8L tbh properly sorting the rest of engine will make a huge difference.

IMO the two piston design is poor with PPM stroker kit. i would buy the crank alone and get my own shorter rods and pistons.....when you target fictitious rod ratios and subsequently compromise the piston its a big no no. design the best piston you can, choose the engine size and fill the gap with a rod.

Everyone loves strokers these days, VAC now sell a 97mm crank for M5x engines. wont fit in an M20 unless you were talking about a short life drag motor ;) youd need a 2 ring piston, ultra small piston pin size and a custom aux shaft from quality steel. you could extend the block deck height with a spacer and sleeve it to run a longer rod and normal piston though but the timing belt and other issues would arise

[digger]

Nice build. I have a Dbilas setup at the moment but it really kills the mid range of the engine, if you build a enclosed plenum and intake system I would be interested. Cheers Leigh

i wont be building more than 1 it is too time consuming and it wont fit a dbilas setup anyway. RHD may offer something though. ive seen a prototype but not sure if it will be available or just a one off

[ThatOneEuroE30]

Cant really take the m30 bore much past 95mm, the rest of the capacity gains are in the crank (obviously).


http://www.pureperformancemotorsport...roker-kit.html

Holy crap! What a price tag I'd just turbo it if i wanted more power.

[LJ851]

Incredible work. I too am interested in maxxed out m30 motors but question the feasibility of anything over 3.7L or so due to the bore spacing. How important is longevity?

Cant really take the m30 bore much past 95mm, the rest of the capacity gains are in the crank (obviously).

http://www.pureperformancemotorsport.com/bmw-e12-e24-e28-e32-e34-m30-4-2l-stroker-kit.html

[ThatOneEuroE30]

Incredible work I like seeing work put into m20's. One day i'll do the m30 one day.....