My M42 Turbo Project...

[Omi]

Don't get excited, I'm just planning this at present, but I know there's a lot of people with an M42/44 finding it hard to get information and advice. I've been doing a lot of research over the last few weeks, in conjunction with a few people I know in the industry, so I'm going to plan it out on here and use you all as a sounding board to correct any mistakes, keep me on the right track and offer advice for others considering a similar conversion.
The very basic specs will be as follows:

• Cast Log exhaust manifold.
• Forged low-compression pistons.
• Garrett T25-54R BB Turbo.
• Cosworth/Mercedes Intercooler.
• Dual-Piston Blow-off Valve.
• GM Throttle with Position Sensor.
• Manifold Air Pressure Sensor.
• Uprated Fuel Pump.
• Uprated FPR.
• Uprated Injectors.
• MegaSquirt 'n' Spark Management.
• Wideband O2 sensor.

Manifold

I'm thinking a log manifold for a few reasons... Firstly, I can get one manufactured much cheaper than a tubular one. - Secondly, Tubular manifold gives inconsistencies in temperature due to the differing metal in the weld and pipes, which can lead to cracking. Tubular would also require supporting mounts for the turbo to prevent vibrations causing cracking. Thirdly, space is a problem in the RHD M42 engine bay and a log is more compact. Lastly, a compact 4 cylinder engine such as this will keep plenty of backpressure in a log manifold, without the need to scavenge opposing-cycle cylinders.

Pistons

Given the choice between running 7-8PSI of Boost with standard compression and the risk of hotspots/pre-det etc., or 10-14PSI with lower compression... Both would result in similar power, but the latter would give huge torque gains, and probably more stable. There is a US company which can supply forged pistons to my specifications for the same cost as a new set of standard items from BMW.

Turbocharger

A friend of mine does a lot of work with Nobles and Morgans and happens to have a brand new GT25R with a scratch on the compressor housing at a bargain basement price. - The internal wastegate is fixed at 0.5 bar, but £70UKP should sort out a boost controller! The turbo can be seen in detail on the link below: "not allowed to post URLs..." Google for the GT2554R...

Intercooler

Plenty of other turbos on here for reference, and a couple in the UK... I'm looking at a Ford Sierra Sapphire Cosworth intercooler to fit behind the valance, but I'm sure I've read somewhere that there's a Mercedes CDi item that sits snugly between the front lights?

Blow-Off Valve

Vacuum fed from the inlet manifold, towards the entry point to reduce fluctuations from the inlet valves.

Throttle position sensor

Apparently there's a GM item commonly used by 'MegaSquirters' which I've been offered at a silly-low price... Senses position rather than the standard Idle/On/WOT switch.

MAP

Located in the inlet manifold, independantly of the blow-off valve vacuum pipe to prevent false readings.

Fuelling

I'm a bit stuck here... Do I leave the standard pump/sender in place in the tank, then use a second, in-line, fuel pump to raise the pressure at the engine? This would save having the whole system running pressurised. Would a swirl pot be necessary?
I'm not sure which injectors I can use, as my understanding is that the M42 uses a different type of injector to most other BMWs. I'm also unsure of fuelling requirements. Uprated FPR and injectors controlled by MS seems like the way though.

Timing and Tuning

Another grey area... Can I mate the crank pulley sensors to MegaSquirt'n'Spark? How does it do cylinder recognition? I'm looking at retro-fitting a knock sensor too, as per the M44, to help tune out pre-detonation.
Wideband O2 sensor makes a lot of sense, as I'm not going to have easy access to a rolling road to set the car up and I can make sure she's not about to blow up due to undefuelling!

So there... What are your thoughts? - I'm posting this around a couple of the BMW forums I frequent to get a wider response and I'll wait until I've got a solid plan in place before I start with the rebuild of my 2nd iS.
Thanks in advance for your support and comments!

Omi

[Gizmo330iT]

Good luck, I too have looked long and hard at the VERY little space we have to work with on our RHD models. Now if we could only get a turbo in there and still keep our air-con...that would be ideal. A custom engine mount would be needed to free up some space.

No need for retro fitting knock sensors, the M42 has two already.

I just think the turbo will be a little small, you will get bored of the power. Go for something a little bigger like a T3 or a T28 with some nicely setup wheels...

[Gizmo330iT]

Here's some pics I took at a local event of an E30 318i turbo.

[Omi]

Did you get the guy's name, number or anything? - That's an iS M42 he's got there, and it looks like a nice tubular manifold... - I NEED to know where he got it!! lol

M42 in the E30 doesn't have knock sensors... - Only the E36 version did. Should be easy to retrofit in the same locations though. (I hope)

I don't have air-con in the E30 either, don't need it in the UK! (Too hot, open a window... Too cold, put the heater on.)

[Gizmo330iT]

Well, his car was featured in a performance mag here, so I can tell you what its got. But since the feature he has changed a few things like the intake mani and the 4 fogger NOS kit.

He is using a T66 ball-bearing turbo @ 30psi, 8.5:1 comp, Pauter rods, Arias pistons, 550cc injectors. On the dyno it makes 458whp without NOS, with the single fogger he had on the stock intake manifold it made 510whp.

[Gizmo330iT]

So far, his best 1/4mile has been 11.01sec @ 136mph.

[captainkarl]

Where have you found information on integrating Megasquirt with BMWs? I have read a lot about MS, but not really much about working with bmws, mainly just hondas and the like.

[943184dr]

Well, his car was featured in a performance mag here, so I can tell you what its got. But since the feature he has changed a few things like the intake mani and the 4 fogger NOS kit.

He is using a T66 ball-bearing turbo @ 30psi, 8.5:1 comp, Pauter rods, Arias pistons, 550cc injectors. On the dyno it makes 458whp without NOS, with the single fogger he had on the stock intake manifold it made 510whp.

Interesting, those injectors seem really small for having such a large turbo. that and for having that huge turbo and boosting that much those numbers seem pretty low..... The only reason i say this is because the motor in my car has been spec'd to do ~400whp with a t3/t4 @ 25psi on 660cc injectors.

beautiful car none the less.

Tom

[BmotorMsportW]

http://www.vacmotorsports.com/cgi-bi...man=CP+Pistons , lots of pistons, rods, built heads, metal headgaskets all for the M42 on this site.

[Bigbores Bro]

omi look for a 318TD mani (yes Turbo Diesal) they were in europe only.

[clevertd]

http://store.666fabrication.com/m42-...d-e30-fit.html

[haledj]

http://store.666fabrication.com/m42-...d-e30-fit.html

+1 jon volk makes some very pretty shit

[spoolmyair]

There was talk on other forums about the log manifolds are prone to splitting. Has anyone had experience with this? Im in a debate between Turboing the m42, S/c ing it, or flat out engine swap. I need more info on turboing this motor.

[costica]

ive been searching alot over the past couple months and ive looked into making a stroker or turbo charging or swap and swap seems to be the most cost affective.

im actually in transylvania visiting my mom and family and the td e30's they have out her have some balls. i asked a family member if they could hunt me down one for me to ship back to the states