M20 B3x Naturally Aspirated Stroker build past, present and future

[digger]

curved adapters 3D printed in ABS plastic and clamps from 48mm trumpets (e21 JPS aka RHD) so that i can use a thicker wall without crushing them. they are to get everything inside the airbox and clear the hood without using a excessively short runner and provide additional clearance to the booster and not shroud the trumpet. you can rotate the whole trumpet to point them forwards slightly to but you need to rotate them all because the centre spacing is about 90-92mm and diameter is 80mm of the bell mouth



trial assembly, trumpet length is 30mm shortened to have same centreline runner length as previous. i chose 30mm so that i can shorten them a further 30mm if needed more fasts. the new engine will require about 25mm shorter length according to calculations and simulations. the dyno will decide so i favour the longer length in the interim



this is why they are needed. this is runner 2 (no curved adapter), runner 1 is worse and runners are angle downwards. runner 6 is angle upwards but less of an angle this is to clear the booster by additional amount



runner 1 & 2 are angle down to give about 30mm less height, runner 3 is about 20mm but is not 100% needed. this was done to centre the trumpet in the box height wise



a view inside from the inlet



did some conceptual CFD to deliberately look at shrouding (distance between the trumpet and wall opposite opening) and some basic distribution to convince my self it wont be a disaster. i modelled the trumpets longer so they get quite close to the opposite wall to exaggerated the issue



quite a bit of flow comes from around the sides rather than from straight above







alot of flow comes from bellow the bellmouth



open trumpet flowed 0.152kg/s by itself. when flowed with box it is 0.150kg/s runner 6 and 0.152kg/s runner 1 so not much difference to open trumpet provide the K&N isnt restrictive. i have room for larger filter so will search the K&N site for suitable one

[digger]

Looks great, nice work. You are tempting me into replacing my dbilas intake with trumpets and then doing my own plenum chamber as well. Have to think about it more and work out the costs.

I love love to know what power you get when done.

do it:) the difference is worth it IMO.

[eb224]

Looks great, nice work. You are tempting me into replacing my dbilas intake with trumpets and then doing my own plenum chamber as well. Have to think about it more and work out the costs.

I love love to know what power you get when done.

[325ix]

Wow, that is a fantastic looking intake!

[2mAn]

one of the greatest M20 builds ive ever seen

:bow:

[digger]

couldn't get the main section how i want with clear finish so reverted back to plan A which is flat black and a bit more OEM looking which i prefer anyway. kept the CF finish for the lid.

will get proper photos when i can take pics during daylight hours and also with it installed and trumpets inside etc.

[digger]

INDEED!!

Great to see you working with Rama!! ;D

indeed his universal TB and manifolds open the door for much easier power from the M20.

[darvo]

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

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

INDEED!!

Great to see you working with Rama!! ;D

[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.