M20 B3x Naturally Aspirated Stroker build past, present and future

[zwill23]

I swapped my booster and master for an E93 unit as well after looking at prices for standard E30 boosters. Even with stock brakes, massive improvement in pedal feel and considering the price point and ease of modification this is a no brainer.

Car is looking lovely as always

[skarlqvist]

It is all about the total package head. This awd dyno result is from my m20 low comp na stroker build. It pulls harder than an original s54. With a bigger cam there is a lot more to gain.

[digger]

It is all about the total package head. This awd dyno result is from my m20 low comp na stroker build. It pulls harder than an original s54. With a bigger cam there is a lot more to gain.

That is a nice curve, would be interested if you could post more details

[MrBurgundy]

That is a nice curve, would be interested if you could post more details

2nd

[skarlqvist]

ACSchnitzer S3 IXT with VW T5 Ronal wheels, Original M3 fenders with rework for read doors and handles.
E36 compact hubs in rear and E87 rear hubs in front. Aftermarket big brake kit.
CNC ported AMC head 43/37. Flows 173/134 at 10mm lift
89,6mm M54B30 crank
DP pistons 86mm/135mm Compression 9.0:1
Full RHD roller cam kit with (AGAP roller cam 296gr)
DBilas itb 45mm MaxxEcu sport
Headers with 2x2,5" stainless exhaust and dual race cats.

[hasa]

Thats better than what I'd expect for standard compression and 173CFM head! Nice packet.

[digger]

~240whp (281bhp) seems about right for that, though i would expect it to peak at higher rpm with the short runner dbilas intake but this might be a lazy dyno tech not setting up rpm correctly. Personally i would consider the RHD inlet it is far superior perhaps except for the OEM looks or lack thereof

[skarlqvist]

280 whp in an ix on a awd dyno with perhaps 15% drive train loss is a dead race against an original S54 (tested on the same dyno).
There is room for an additional horses if you go for the 302/309/316 roller cams (street-ability will suffer, this is none vanos engines).
The RHD roller setup allows for revving to 10K but the 89,6mm crank in my car translates to a pistonspeed of 25m/s at 8400 rpm.
Piston speeds of 25m/s is the upper limit in most engines.
The original m20 oil pump will start to cavitate at 8000+ so the real max rpm is actually 8000 (one must move to dry-sump for higher revs).
My engine is build for boost and >500Whp. If I was to keep it na I would have gone for RHD itbs, any day.
I have been talking to DBilas and they have pressure tested the plenum and itb construction for 2 bar.
For this car I have bought an Australian "Raptor V" supercharger and since the ix front diff is the weakest part I will limit power to 500whp on pump gas.
The engine needs a lot of air in and out. I use AEM Dry flow 76/135mm and the custom build 2x2,5" exhaust below.

[litu]

It is all about the total package head. This awd dyno result is from my m20 low comp na stroker build. It pulls harder than an original s54. With a bigger cam there is a lot more to gain.

Wow, that engine in ix. We want more, way more info...Is there any where i can follow this project

[skarlqvist]

A proposal for the ultimate screamer:
Move to dry sump, Use a 2.5l crank, Port the head, Bore the cylinders from 80 to 87mm, Use hi-comp pistons 12:1, Use RHD itb and roller kit with 316 cam.
Add a really light fly wheel and clutch pack and rev this 2,7l m20 to 10K.
This will give you more than 300whp at piston speed 25m/s and with the right exhaust a sound like a Honda CBX1000 ;-)

[litu]

Nam nam

[skarlqvist]

If you want to run classic wheels and a big brake kit. K-sport is a nice alternative. This kit has 3 piston callipers and 350mm rotors. I have tested it to work with all the 18" wheels I like.
Order a 325mm rotor and it will clear 17" also.

[leez]

Any updates for us digger

[2mAn]

A year later & we still havent gotten our update digger

[digger]

Here is the “short” update list (high level). I will try expand in due course with happy snaps where these were taken for the stuff that has been done:

1) I installed new set of wheels mid 2023 to allow bigger brakes and step up the number of quality tyre options

• 17x7.5” Maxlite 4x100 Alpina style wheels ET25
• 205/45/17 Michelin Pilot Sport 5 (front)
• 215/45/17 Michelin Pilot Sport 5 (rear)

2) I did a major update to steering/front subframe late 2023

• I purchased a reinforced front subframe from Dan Grooty (Grooty’s Race and Resto)
• I got a re-manufactured purple tag rack from LPSR and their steering linkage
• New PS lines from Dan in UK (BM Conversions)
• New OEM engine mounts
• New Lemforder e46 inner tie rods and e36 outer tie rods
• New Lemforder Control arms
• New GC 8641 1198 SPORT shocks (old ones were blown)
• Powerflex offset CAB (replaced worn OE eccentric)

3) I did a major update to brakes early 2024

• 300mm.de BBK 4 lug 312/294 E34
• New braided lines
• E90 Booster and M/C
• 2002 Remote reservoir

4) I did a major interior update late 2024/early 2025

• Replaced torn carpet (purchased a good used crapet from the UK)
• New dash
• New centre console (both)
• New under dash cover (driver side)
• Installed A/C solutions full kit
• Rebuilt the heater box
• New Evaporator
• New Heater Core and Valve
• Added a bunch of noise insulation/barrier (Resonix CLD and Lockout) also used mass loaded vinyl

5) I got a used subframe and welded the eccentric bolt adjusters

• Got multiple alignments and readings showing toe out at rear of varying magnitudes 1mm to 3mm
• Rear has about 1mm toe out per side confirmed and now getting consistent numbers and checked with stringline
• Will use either OE bushes or powerflex

6) I did a major front suspension overhaul earlier this year

• New shocks (again as started rattling)
• Rebuilt GC street top mounts (axial/thrust bearing and poly bushes)
• New Coilover Springs 250 lb/in x 9 inch 2.5" ID
• New GC bump stops properly setup

7) I got a ATI Vibration damper functioning prototype made (to be tested). Note this was my project (not in conjunction with them) and ATI didn’t produce any new parts.

• Used ATI Inertia ring and their o-rings
• Custom crank hub for light press fit to snout
• Inner and Outer shell outsourced to Xometry
• Dynamically balanced

8) I messed around with front suspension some more to try and improve comfort, tramlining and potentially bump steer.

• Tweaked camber to get LH to RH consistent
• Went back to concentric bushes (still Powerflex)
• Went back to 22 mm bar (H&R) from Whiteline 24 mm
• Happy with results on rough roads compared to before but may still look into bumpsteer correction through rack or tie rod end and may still go to OE rubber concentric CA mounts

9) I actually spoke to a engine machine shop the other week so will probably be dropping stuff off in the next month or two i am just doing a stock take of parts to make sure i have everything but at least moving forward.

10) Future Works - There are a couple of higher priorities before engine can go in

• I need to install rear sub frame and bushes first so i can align it properly and do some R&R on fuel system / brake system above tank and diff speed sensor wiring based on what i find.
• Fix cluster indicator and spurious speedo dropout
• Get the Haltech Elite installed with dual WB and tuned so that i have a good ECU up and running before swapping engine so when i start it is good tune. My current ECU is functional but archaic
• New airbox to try and incorporate strut brace and improve filtration
• I will likely be doing a 6 speed swap but will do this when swapping engine
• I will also be doing a new header and exhaust but will do after the new engine is in as any testing on current one is a moot especially since the power feels like it has fallen off since the last dyno which is like 10 years ago