M20 B3x Naturally Aspirated Stroker build past, present and future

[ForcedFirebird]

Loving the skills digger. Normally don't say much on this site, but why are you LHD in up-side-down land?

[digger]

thanks guys

did the install today and everything fits and runs well.

unfortunately it is a fair bit quieter than open trumpets but still better then stock and dbilas which are too quiet.

definitely alot more power than the socks which lose about 15-20whp but i never drove this setup without socks so i dont know whether it will match the dyno run of 152kw with open trumpets no socks.

still got to find a better sized K&N filter and make a heat shield.....

[digger]

thanks guys, i like the m20 due to its simplicity and rawness

[tinkerputzer]

That's cause the guys from down under never gave up on M20's. Been following since the start, keep up the good work digger :up:

[nando]

nice, glad I saw this. it's amazing how much more information there is on M20 builds these days. Part of the reason I just decided to stop on M20s was because I knew I'd have to totally redo my entire motor from the bottom end up. If I knew back then what I knew now I wouldn't have done anything like what I have now in my 2.8.

[digger]

ideally having more room opposite the bellmouth entry and a shallower entry would probably work best. an even bigger inlet helps to. its not really possible to get much different there was only really one area the filter will fit.

i should add that i only modeled air being drawn through 2 runners at a time as this is really what happens at any instant and 1 and 6 aren't occurring simultaneous from memory. its more complicated to do a full transient flow

typical turbo manifold



m50 style


i would say having the trumpets proud of the wall rather than having a flat plate with radius might be advantageous

[LJ851]

What do you think about mixture distribution equality in the cylinders with the different angles of entry ?

[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