M42 turbo pt 1- it blew up!

[jwal]

That's incredible! How did a stock M42 survive that?! I'm working on a much more modest build, but I'm also dropping the CR to around 9:1. What's your cooling system setup?

[ccsdo5]

Holy crap two years running 17 psi on that GT3071R?!?! That's a pretty big turbo and a decent amount of air in that engine. I'm impressed it has lasted so long. I personally had detonation issues on my stock M42 with a small T25 turbo on track probably due to intake temperatures and too much ignition timing. But all that seemed to happen to my engine is probably a cracked piston ring, small detonation marks on the pistons, and lots of engine blow by.

If I were you I would be trying to drop the compression a bit on the engine maybe even down to 9:1 I find it hard to believe you weren't having detonation problems with such high boost on a decently sized turbo on pump gas with 10:1 compression.

I think you should toss another stock engine in and run lower boost this year. Then start to build a forged bottom end rods, low compression pistons, ect. build a nice head with those valve springs and cams then shoot for a 400whp M42 I think that'll be super rad.

[ak-]

When you say you revised the intake, are you talking about your pre-turbo inlet? Were you always recirculating the crank case breather to your turbo inlet like that in your previous setup too?

I think it's rad that you're tracking a turbo m42. Props!
You have more courage making power on an m42 than I have on my m20 turbo since I'll be tracking it soon lol.

[Dissembler]

Full throttle, heading up the hill to turn 4, just shy of 7000 rpm and there is a huge noise. Car loses power, debris is flying everywhere, smoke... all that good stuff when an engine blows. It happened without warning too, no misfires, knocking, loss of power, nothing.

The engine was still running after it all blew! Actually had to flip the ignition to shut it down lol. So engine is now out of the car, pulled the head off and this what I've found. Cyl 4 decided it no longer want to be part of the engine. the block has holes on both sides, the coolant jackets around the cyl was hit and the oil pan was destroyed.











Crazy part is, the cyl head is completely intact, the cylinder bore is completey intact (no scratches or anything), the crank and connecting rod bearings showed zero sign of damage and an inspection of the plug shows no issues or signs of being lean. Connecting rod looks almost like it had a clean break, edges just got smooshed a little from hitting the block. What do you guys think?

So for now the plan is this: A set of schrick cams (256/256) and valve springs just arrived from VAC. going to swap those into my currently stock spare m42 (plus mls gasket and studs), boost will be turned down to 14psi, then hit the dyno for some proper tuning and enjoy the rest of the year. Got some plans to travel to a few different tracks and don't want to have engine blow away from home. Bought 1000cc injectors and a big fuel pump already, pistons and connecting rods will come next year and then I'll shoot for that 450hp and see what happens!

[Dissembler]

So wasn't planning a thread until I'd done a few more things, but times change and in addition to looking for some insight, I thought everyone would enjoy the carnage!

So first up is the car. I've had this particular E30 in ever evolving configurations for 7 or so years.



Had an S52 in it for a long time and long story short I got the idea to go BMWCCA club racing, then decided specifically on D-mod with a turbo M42. Out went S52, in went M42. I haven't actually done a club race yet, as we all know life can get in the way so development of the car to get it to a point where I can go racing and be competitive has been slow. But it worked well and I do a lot of HPDEs with it (am instructor with Trillium chapter of BMW CC).

My goal for the engine was 400-450 hp, ideally using pump gas for the convenience, but ethanol would also be acceptable (and more realistic). Race gas is out of the question (and a big factor in why I chose d-mod and not s54/cmod).

So for some current specs

-M42, complete stock internals.
-Garrett GT3071r 86ar .90 trim
-MLS gasket (oem thickness), ARP head studs.
-eBay m44 bottom mount turbo manifold flipped around, modified and pedestal built for fitment.
-42lbs injectors
-eBay intercooler, BOV
-VEMS ecu

I'm aware that I will not reach my power or reliability goals with what I listed. More on that later.

So now for the bit that leads this thread. I've been running with setup I listed above for about 2 years. Overall engine has been extremely reliable and very fun. I've never been to a dyno, just "tuned" on the fly with logs and AFRs. Pushing 17lbs of boost, my butt dyno and drag races up the Andretti straight at Mosport tells me I have somewhere between 250 and 300hp.

Among my many winter projects, I picked a few more upgrades that would inch me ever closer to my goal. I always felt like the intake was a bit restrictive and that stock throttle body was crap so those are what I addressed. Did some maths, decided on a 3" throttle body, and upgraded my intercooler.

My old intercooler vs the upgrade. Mishimoto says this size is good for up to 350-500hp.





So this past weekend had the car out at Mosport for the first time this year. I didn't make any changes to the tuning from last year, but holy crap the car felt amazing, completely different from last year. The throttle response was unbelievable and the lag I used to have at 3500rpm was gone. How much of that was from the less restrictive intake and how much of that was from the getrag 260 to ZF swap I don't know, but man was the car alive!

As the saying goes, engines always run best before they blow and about 5 minutes into the very first session of the day... KABOOM!