Blown Motor - Advice Greatly Appreciated

[M.Hagen]

OP - Glad to see you are getting a competent shop to put everything back together. I'm sure the piece-of-mind with all new components will make the car much more enjoyable than your first 2,000 miles. Good luck on the rebuild.

One item that caught my attention is this:

Originally Posted by scaryharry19

Well, we found out what happened. I over-boosted, lifted a head and blew a head gasket. The culprit was a tiny, out of spec vacuum line (blue line in the pics) that Shop #2 installed to run to the BOV. It should have been about a 1/4" gauge but was about not even close.

BOV's do not control boost - the only possible outcome the BOV can have on the manifold pressure in your system is a loss of pressure if it leaks. Even if the reference line on the top of the BOV was undersized, it would not affect the function of the BOV where it could cause a system pressure increase. The function of that line is to apply resistance to the diaphragm during positive-pressure (in boost) operation so that it does not open; as you let off the throttle the reference line is now under vacuum, allowing the diaphragm to open and let out the positive pressure remaining in the charged inlet system. Even if the BOV was stuck closed, the boost in the system is already at its maximum, and will surge past the supercharger impeller and out of the airbox - this is the function of the BOV is to prevent that excess pressure from damaging the supercharger. It is not a safety device for your engine.

The shop technician who told you that information may have BOV and turbocharger Wastegate confused. The wastegate looks like a BOV (in fact they are mechanically very similar devices), and does control the boost pressure in a turbocharged system. An incorrectly plumbed, or wrong sized reference line on a wastegate can affect the system pressure, and can cause an engine to go boom.

Since a supercharger creates its pressure from engine load + RPM (fixed volume air pump), a BOV cannot be a method of increasing boost.

Here is a simple diagram of how a BOV works:

[scaryharry19]

M.Hagen Thanks, I believe I didn't interpret what Alex was originally telling me. We talked about a lot of things in one conversation, it's all unfamiliar to me.


We decided to spice up the engine bay with colored valve covers. I'm excited to see how it turns out! I think the orange will complement the light blue supercharger & plenum color well.

[pbonsalb]

A slow acting BOV can allow boost spikes that can cause damage. Active Autowerks broke an S65 while developing its supercharger kit. It addressed the issue by adding more bypass valves. I think it’s S65 kit uses 2 or 3. Maybe the valve it originally used was undersized. Other kit makers like ESS and VFE use only one valve and they have not had issues.

[scaryharry19]

A few updates... what do you guys think about the orange valve covers? I'm digging it. Should look awesome contrasting the s/c color (also pictured). Also, v-bands for the exhaust . Can't wait to get back in it!

[scaryharry19]

Motor pics

[scaryharry19]

S/c color

[scaryharry19]

V-band pics

[Assimilator1]

What are V bands when they are at home?

Like the cam covers colour btw

I assume you have it running now, what power is it pushing?

[scaryharry19]

Originally Posted by Assimilator1

What are V bands when they are at home?

Like the cam covers colour btw

I assume you have it running now, what power is it pushing?

Hmmmm... I got nothin'..

I wish she was running.. we had some set backs. Firstly, had to source another motor after finding damage. The damage wasn't internal but Alex didn't want to sell it to me. Good thing is the newly sourced motor has even less mileage (28k if I remember correctly). I got to see it apart when bearings, head studs and gaskets were done, it looked super clean in the bottom end. It also took us a lot of time waiting for a few parts. Alex has been very thorough which I'm happy about. We'll be on the dyno sometime in the coming week or two, haven't scheduled yet. Will keep you posted!

If/when Alex tears down the blown motor I'll let you guys know. I got to see the carnage from the bottom view in person, it was gnarly. definitely doesn't appear to be bearing failure. We haven't found any obvious hole(s) in the block and there was no obvious heat discoloration around the rod or crankshaft. I broke piston 1 in half and bent the rod and filled the bottom end with coolant. We're pretty set on gasket failure at this point.

Thinking about doing an LCI upgrade and extended fox red interior swap.. what do you guys think? Waste? Value add? Engine bay colors will clash?

[SYT_Shadow]

I think LCI tail lights are a must have

[scaryharry19]

Originally Posted by SYT_Shadow

I think LCI tail lights are a must have

I installed LCI tail lights as soon as I first got the car haha. Previous owner had blacked out pre-LCI's

I was thinking about updating the iDrive and/or installing an apply carplay, but don't know if it really make much of a difference. It definitely updates the car but really, I'd prefer having the stripper package with no infotainment.

[SYT_Shadow]

Originally Posted by scaryharry19

I installed LCI tail lights as soon as I first got the car haha. Previous owner had blacked out pre-LCI's

I was thinking about updating the iDrive and/or installing an apply carplay, but don't know if it really make much of a deference. It definitely updates the car but really, I'd prefer having the stripper package with no infotainment.

I much prefer the no nav interiors of my E90 and E92.

Even the LCI nav is stone age

[Assimilator1]

Originally Posted by scaryharry19

Hmmmm... I got nothin'..

I wish she was running.. we had some set backs. Firstly, had to source another motor after finding damage. The damage wasn't internal but Alex didn't want to sell it to me. Good thing is the newly sourced motor has even less mileage (28k if I remember correctly). I got to see it apart when bearings, head studs and gaskets were done, it looked super clean in the bottom end. It also took us a lot of time waiting for a few parts. Alex has been very thorough which I'm happy about. We'll be on the dyno sometime in the coming week or two, haven't scheduled yet. Will keep you posted!

If/when Alex tears down the blown motor I'll let you guys know. I got to see the carnage from the bottom view in person, it was gnarly. definitely doesn't appear to be bearing failure. We haven't found any obvious hole(s) in the block and there was no obvious heat discoloration around the rod or crankshaft. I broke piston 1 in half and bent the rod and filled the bottom end with coolant. We're pretty set on gasket failure at this point.

Thinking about doing an LCI upgrade and extended fox red interior swap.. what do you guys think? Waste? Value add? Engine bay colors will clash?

Sorry to read that you totalled your M3 a couple of years ago , but I wondered if you'd had it dyno'd beforehand like you planned?

[Honda]

Originally Posted by Assimilator1

Sorry to read that you totalled your M3 a couple of years ago , but I wondered if you'd had it dyno'd beforehand like you planned?

Why bring an old thread from the dead? lol ... He replaced motor and moved on ..

[egebhardt]

Why?
Because it's a good story. A more common story than people admit.

A supercharged BMW V8. That's asking for trouble. 9 times outta 10, those guys would do it again. It's that much fun.

[Assimilator1]

Originally Posted by Honda

Why bring an old thread from the dead? lol ... He replaced motor and moved on ..

Because I wanted to know what power it was putting out! Is that alright with you??

[Honda]

Originally Posted by Assimilator1

Because I wanted to know what power it was putting out! Is that alright with you??

Did he answer you?? No ... so your post was useless

[kolosy]

Originally Posted by Honda

Did he answer you?? No ... so your post was useless

never understood why people get so worked up about posts they don't find useful. just ... don't engage with it? seems like a lot of effort for something you think is useless.

[Assimilator1]

Originally Posted by Honda

Did he answer you?? No ... so your post was useless

Not yet, but then it hasn't been long!

Your post is pointless and rude, go act a dick elsewhere!