M20 B3x Naturally Aspirated Stroker build past, present and future

[digger]

Ireland Engineering, mate. As I said earlier, only asking you because they have a stroker kit and it seems pretty legit, so I was wondering if you've had any experiences with them at all. Thanks in advance.

Generally speaking I would steer clear of stroker kits from any store as you can piece parts yourself for cheaper. Also I'd steer clear of generic piston. the IE 2.9 ultimate street ones are good as they aren't generic

[Reichart12]

Love the information and work you have put into understanding the m20 to the max. Wish I could find the spec sheet from when I got my pistons. CP from VAC, made to be 11:1 to be used with 135mm rods and 84mm crank for about a 2.9L. Always thought it was weird/different that my pistons were almost flat on the top when it seems like most others were rounded.

[digger]

The 885 is one of the few heads that doesn't have a flat squish pad. Those pistons look like they have a raised rounded section on the edge. They may actually use a small portion of the squish band around the circumference, but it's hard to tell

[nando]

Those pistons look badass. Can you share the cost?

I've been working on my N52 build and I'm sure the pistons I have (with like 280k miles) are well worn, but most aftermarket stuff is far inferior to stock Mahle (people like to say things like 'forged' without having any idea what they're talking about). Also I think it could use a bit more compression, but basically there's no OTS pistons for the N52 other than bone stock. A member here had some custom pistons from an old Turner race N52 engine but he gave them away before I could get to them. :(

Also I've known this for years, but basically all of the stuff on the MM M20 pistons is basically bullshit. The only thing I will say is they never made any noise and they have never broken. Also Jim at MM is really nice. But if you want to make actual power, you can do a lot better..

[digger]

Those pistons look badass. Can you share the cost?

I've been working on my N52 build and I'm sure the pistons I have (with like 280k miles) are well worn, but most aftermarket stuff is far inferior to stock Mahle (people like to say things like 'forged' without having any idea what they're talking about). Also I think it could use a bit more compression, but basically there's no OTS pistons for the N52 other than bone stock. A member here had some custom pistons from an old Turner race N52 engine but he gave them away before I could get to them. :(

Also I've known this for years, but basically all of the stuff on the MM M20 pistons is basically bullshit. The only thing I will say is they never made any noise and they have never broken. Also Jim at MM is really nice. But if you want to make actual power, you can do a lot better..

if i could get a modern cast piston for mine i would probably use that.

yeah some of the stuff with MM's pistons is a bit questionable.

[digger]

As for price they were cheaper than what MM now charge for a set of theirs

[SLEEPYDUB]

Hey Digger, It probably feels like im stalking you by now but I promise im not. Just have a question regarding your clutch and pressure plate setup that was mentioned on your first post, the HD 240mm m5 setup. I am using the same type setup on my m20. Its the RHD flywheel with the Sachs 765 pressure plate, and the organic full faced m5 clutch disc. I've been using this setup for about a year now and its been ok, but the issue im having is the clutch engagement feels abrupt and short. Meaning it only takes a little bit of travel off the floor and once its starts to engage its very quick. I used a stock throw out bearing, not sure if that will hinder its performance, and also used my stock slave cylinder. Can you share any insight to how yours feels?

I have been drifting on this clutch and after 3 events i think the disc needs replaced, because its starting to slip in 3rd on high boost. Will likely upgrade to a 6puck, or do you have another recommendation that uses the 240mm?

[digger]

Mine feels much like a stock clutch to be honest it's not abrupt. There a slightly higher rated organic you can get rather than stock m5 but I don't know details

[digger]

Baby steps….

Painted the manifold and finalised the nipples for
- Idle control valve elbows strategtically angled to suit vacuum rail
- Single Brake Booster nipple
- Seperate Vacuum nipples for synchronisation

the metal plate is an alignment tool so that when i bolt the manifolds to the head the relationship between the the 3 castings is maintained.

i have a seperate plate for mounting the throttles so the shaft remains concentric to ensure that at WOT they each open the same amount







Remade the vacuum rail





A bit overkill but a nice beefy but compact set of aftermarket I-Beam rods. Stock length 135mm but bushed to 20mm. The usual details 3/8" ARP 2000 bolts, forged and heat treated 4340 steel, shot peened…..





Everything in CAD, mostly cause why not....oh and also need to design a crank scraper and windage tray setup. Still work in progress got to get all the holes in the right spot on the block. Some stuff is just representative

[zoran]

i beam rods

hi,do you mind to share rod manufacturer and on camshaft 288/288 shrick do you have expirience regarding e100-etanol what cr can I go because at this moment is cr13-1 and I am having nock from 2600-3600rpm on 100ron fuel,after 3600rpm it is gone and car puls like it is on 1bar of boost.I hope you make that 3.3 just to see that is possible,:devil::devil::devil::devil::devil:
regards.

[digger]

They are ZRP rods though these are not on their website which last time I checked still shows the older version with the beefier cap.

No experience with ethanol but I would have though pure ethanol would be fine at 13:1. What pistons are you using and what ignition timing? Has it been properly tuned ?

[zoran]

thank you for post,Iam using ross pistons,dome top is -9cc,stock ignition,no tuning at all as i just test it and realise that is going to be very hard on pump fuel to achieve anything on that cr,yesterday I ordered vems so we will se how it works.Top of piston is not as oem at all but it is not posible at all to achive that level of cr with oem shape,i wish to be as oem but at this moment it is impossible.

[digger]

What fuel ? E100 is ethanol? You have that as pump fuel near you ?

That's too much for pump fuel petrol/gasoline i.e.98ron for sure

You can make OE style with that CR but it won't be exactly the same and needs to be modified but uses the similar philosophy. need to be careful though big dome starts going backwards if you block flame travel

Proper ecu and tune are required before you throw in the towel.

[zoran]

do you know who can make it maybe Steve from Top End performance,before i change them I will try batlle with these because if knock is gone after 3600rpm on 98ron than e100 with 114ron may help a lot,what alu spec to choose because it is event engine once a month for show that is.

[digger]

Yeah I wouldn't contemplate changing pistons at this stage if you have the option for ethanol.
It sounds like you are still running motronic and not tuned so you need to finish install the standalone and get it tuned.