Engine Overspeed

[Icecream]

What's the logic for removing this?

I dont know, tbh I'm confused what happened exactly. Hopefully slim3 can clarify after recuperating if this was still smg or a swap or if/why the logic was changed.

[mrgizmo04]

Yeah I'm not exactly understanding what happened either. Even with stock gearing 2nd gear runs out north of 60, so not sure what caused this, downshifting to 3rd at
Agree, maybe op can clarify after some recovery time.

Sent from my SM-G950U using Tapatalk

[paulclaude]

Sorry to hear Brian - i'm sure you'll get it all rebuilt and back up and running soon, hope the head/pistons are ok. Failure does seem strange unless you are running an abnormally high RPM limit? Judging on the amount of high rpm mine has seen on track over the years (8250 limit), they can put up with quite a lot.

[digger]

damn, that sucks must have been a pretty decent over rev

[eacmen]

The smg will not downshift into an over-rev.

The stock ECU tune also has a rev limiter.

Do you really think this was an over-rev?


Sent from my iPhone using Tapatalk

[SliM3]

Alright guys a little more clarification:

I was cruising in 4th gear, downshifted to 3rd and punched it. My rev limiter is set to 8600, the shift lights will begin to light-up as it approached the limiter, and that's where I would shift.

I was paying more attention to the AFR gauge, missed that point when I would shift gears and that's where I overran the limiter. I'm pretty positive that by the time fuel cut was enabled it was too late at that point. My AFR's were right around 12.3 on E85 and ignition timing was @ 31° + fuel cut hysteresis at stock 400 rpm.

[Mspir3d]

I’d expect it to bend the rod before sucking the end cap off. Sorry for your loss, that’s painful.

[newton22]

You set the limiter at 8600? That sounds awfully high for a stock internals engine.

[SliM3]

You set the limiter at 8600? That sounds awfully high for a stock internals engine.

Not stock internals.

Integrated Engineering rods, CARR bolts, JE Pistons, REM polished crankshaft, Ferrea Valves, Supertech Springs, 288/280 cams, REM polished VANOS, 440cc injectors @ 3.5 bar, E85.

I had dialed in WOT fueling and had been pounding on it the whole ride, but shifting well before limiter until this run.

[SliM3]

I’d expect it to bend the rod before sucking the end cap off. Sorry for your loss, that’s painful.

Yeah, I had CARR bolts in there too!.. You can see the rod in the picture (it's teflon coated black), and right by the harness is big end without a cap.

[digger]

shouldn't fail from 1 excursion to 9,000 IMO i'd say something else at play id strip it down meticulously to look for signs of other problems

[Apex_80]

Still a little confused, if the limiter is set to 8600 it shouldn't exceed that. But are you saying the limiter did not catch it and it ran to 9k and boom? Or did it blow up @8600 and below.

[Sharocks]

Wait how the hell does SMG overrev? Maybe a slipping clutch?

Makes no sense but still sorry to see, that's awful.

[maupineda]

Still a little confused, if the limiter is set to 8600 it shouldn't exceed that. But are you saying the limiter did not catch it and it ran to 9k and boom? Or did it blow up @8600 and below.

If you read carefully, he said he was doing pulls, he downshifted to 3rd at 60mph, which is fine, and climbed up and not paid attention to shift around the 8600 limiter and the engine blew, that said, it seems it was going to blow anyways, as said above, one visit to 8600 won't destroy an engine, it was either a constant over-reving that wore the engine down up to the point it couldn't take anymore or a mapping issue that caused severe detonation blowing it out. Regardless, sad about your engine OP

[Will]

Damn, bummer about the blown engine. I remember reading your posts about the motor build on m3f. Glad you were able to safely pull over on the side of freeway, though. Keep us posted with what you're planning.