M42 Turbo - Scandinavian style

[word is bond]

A 400+ hp M42 Touring!? Sub'd. You Scandinavians are wild. Looking forward to seeing where this goes.

[23732]

Do you have the exhaust manifold set up yet? Any pics?

Not yet, as I need twin-scroll, my brother has to custom weld one for me.

Maybe I am wrong about the intake but just from others builds and experience I'm pretty positive the intake can't flow that much air. Sure you can cram as much boost into as you want but it won't flow freely like you want. The biggest limitation for sure is the M42 throttle body. It has a dual throttle plate that's also very restrictive. IIRC there was someone who made a M42 to M50 throttle body adapter.

Also a word of caution make sure you check your bearing clearances and crank before putting the M50 crank bearings in. My crank was worn out when I rebuilt my M42 and I developed some bad crank walk not too long after getting it running.

I'll definitely keep my eye out on this, I'm curious to see what sorta numbers you end up with this setup. I would be thrilled to hit 200-250 whp on the stock M42 I have now and wouldn't be disappointed in 300-350 whp on a built M42.

I will check the clearances with Plastgauge. Might have to buy myself a Bently manual to have controll over the tourques and clearances.

We'll see what the poweroutput is, there is always an oppertunity to exchange it later and get it tuned accordingly. But I didn't know the E30 intake had a dual throttlebody? If so, I might change it out to a single, large one.

Also, M54B30 pistons looks like the best choice for low-compression builds.

[elcoy]

Man I cant wait to see where this goes... Looks like there is a potential for a wealth of information in turbo M42 building! Sub'd

[ccsdo5]

200whp on a stock M42 is not difficult to achieve...the turbo kit sold by jake at classic daily achieves that at 9psi.

Sent from my Samsung Note 4

I'm aware of that, but I will be abusing the car and it'll live most of its life up at the limiter on track... I also have probably like 150,000+ miles on it (I'm not exactly sure) it has never gotten a head gasket, the timing chain is pretty loud, and I don't plan to do anything to the engine until it sorta goes bye bye. I also have a slightly larger turbo than what Jake uses on his kit I believe. I have no doubt the car would be above 220 whp on a bar of boost I'm just a little scared the head gasket won't hold. that's why I said "on the stock m42 I have now" lol

[CorvallisBMW]

sub'd for turbo fun

[fresh_TD]

Maybe I am wrong about the intake but just from others builds and experience I'm pretty positive the intake can't flow that much air. Sure you can cram as much boost into as you want but it won't flow freely like you want. The biggest limitation for sure is the M42 throttle body. It has a dual throttle plate that's also very restrictive. IIRC there was someone who made a M42 to M50 throttle body adapter.

Also a word of caution make sure you check your bearing clearances and crank before putting the M50 crank bearings in. My crank was worn out when I rebuilt my M42 and I developed some bad crank walk not too long after getting it running.

I'll definitely keep my eye out on this, I'm curious to see what sorta numbers you end up with this setup. I would be thrilled to hit 200-250 whp on the stock M42 I have now and wouldn't be disappointed in 300-350 whp on a built M42.

200whp on a stock M42 is not difficult to achieve...the turbo kit sold by jake at classic daily achieves that at 9psi.

Sent from my Samsung Note 4

[ccsdo5]

Maybe I am wrong about the intake but just from others builds and experience I'm pretty positive the intake can't flow that much air. Sure you can cram as much boost into as you want but it won't flow freely like you want. The biggest limitation for sure is the M42 throttle body. It has a dual throttle plate that's also very restrictive. IIRC there was someone who made a M42 to M50 throttle body adapter.

Also a word of caution make sure you check your bearing clearances and crank before putting the M50 crank bearings in. My crank was worn out when I rebuilt my M42 and I developed some bad crank walk not too long after getting it running.

I'll definitely keep my eye out on this, I'm curious to see what sorta numbers you end up with this setup. I would be thrilled to hit 200-250 whp on the stock M42 I have now and wouldn't be disappointed in 300-350 whp on a built M42.

[varg]

Do you have the exhaust manifold set up yet? Any pics?

[23732]

definately, the m42 is a way better engine than the m40.

how did the m40 of your brother died?

It blew the headgasjet out because of one of the o-rings did not shut properly. It happened in a pretty steep hill where he was driving past his buddy on full boost ;)

[MVincken]

I would like it to last as long as possible, but with so much boost, it probably won't. On the plus side, my brothers M40 turbo lasted two summer and one winter season. 298whp on roadtune and 313whp finetune on a dyno, so the M42 probably will also.

definately, the m42 is a way better engine than the m40.

how did the m40 of your brother died?

[23732]

maybe it gets a little faster revving, but less eating out the crank? i don´t know for sure.
But no worries, like OP says: it doesn´t have to last long, and MM probably uses them for a reason indeed.

I would like it to last as long as possible, but with so much boost, it probably won't. On the plus side, my brothers M40 turbo lasted two summer and one winter season. 298whp on roadtune and 313whp finetune on a dyno, so the M42 probably will also.

Interested in seeing the m50 valve springs and VAG lifters for more r3vs! Might be interested in doing that myself in the future.

As the M42 is basicly an M50 with two cylinders less, it should work just fine. I am buying a set of little stiffer, double springs from M50.

[MVincken]

maybe it gets a little faster revving, but less eating out the crank? i don´t know for sure.
But no worries, like OP says: it doesn´t have to last long, and MM probably uses them for a reason indeed.

[econti]

I don´t really see that as a plus.
2 jears ago i worked on calibration of Alfa Romeo engines and they all broke down because of these bearings
(i work at FEV GmbH, a big engine building/calibration company)

replacing your bottom bearing scale with one with a oil groove, also decreases (by +-20%!) the gliding surface of your bearing.
this increases the average surface pressure on your bearing what leads to bearing wear (due to a thinner oil film between bearing and crankshaft)

and because the load is the biggest on the bottom bearing, it´s best to not have a oil groove here.

The plus side is you can rev the piss out of it without it eating the crank

[DER E30]

Interested in seeing the m50 valve springs and VAG lifters for more r3vs! Might be interested in doing that myself in the future.

[23732]

I don´t really see that as a plus.
2 jears ago i worked on calibration of Alfa Romeo engines and they all broke down because of these bearings
(i work at FEV GmbH, a big engine building/calibration company)

replacing your bottom bearing scale with one with a oil groove, also decreases (by +-20%!) the gliding surface of your bearing.
this increases the average surface pressure on your bearing what leads to bearing wear (due to a thinner oil film between bearing and crankshaft)

and because the load is the biggest on the bottom bearing, it´s best to not have a oil groove here.

I kind of see that. But because this engine is probably going to last one summer and one winter I am not too worried about that. Also, Metric Mechanic recommends bearings with 360degree oilgroove.

Interested to see this. I'm trying for ~300whp on a stock bottom end, don't know if it will end well. Why will you be machining pistons instead of just getting good custom pistons and doing a stroker build? 500bhp is no joke from a little 1.8!



I have been told, by people who have made much more power than I do, that the stock M42 intake is a restriction above 300hp or so.

Because this is kind of a budget build to see how much we can do on stock internals. With the Norwegian Krone going south, a set of custom pistons will be crazy expensive. And to build a proper 2l, you have to bore the block and as the walls are thin enough as they are, I am not compromising the strength of the block to do that.

As for the intake. The M40 has somewhat of a similar intake design as the M42. My brother dynoed his M40 to 313whp, so it shouldn't be a problem. If so, I'll buy one and get the car tuned for it :D

UPDATE on the thread:

M54 pistons and turbo is ordered. As the original post states, I bought a Garret T3/T4e, with 0.78A/R and twin-scroll exhaust housing and 4" antisurge compressorhousing. Also, some pictures of the block, the car it is going into, the head (all intake valves are grinded, only exhaust left), new sparkplugs and the headparts with new lifters on the top and old lifter at the bottom.