Awesome. That was my interpretation. I read it after a rough night.
She's hurt, engine making real bad noises.
The logs don't show "a reason"; but, it definitely happened.
MONTE CARLO "COPO" Monte Carlo SS - Turbosaurus Build (Swinging Dick Racing's c*ck got bent... she bounced a little too high & hard, & came down awkwardly)
- Thread starter motorheadmike
- Start date
- Status
Awesome. That was my interpretation. I read it after a rough night.
She's hurt, engine making real bad noises.
The logs don't show "a reason"; but, it definitely happened.
Maybe, might have a line on a 6.0. It's good to be friendly with peeps at the track while they pour over your hurt junk.
So here's a quick run down on what I do know. For reference the white log is LogWorks for the SCG-1 and has a 4 bar MAP so we can see what happens above 2 bar in HPTuners and it is referenced against RPM and EQ. Note: The WG was turned off for all of this, maybe that was a contributing factor, but I don't believe so because the boost spiked at 18psi and settled in around 15psi - so the turbo wasn't running away (creeping).
Pass 1
A short knock event (that was tuned out for the next pass), conservative timing 11* (with almost 3* pulled for high IATs), a rich EQ. The only major difference between this pass and the next one is I wasn't full throttle for most of the pass and the Dyn AF was notably higher despite no changed to the turbo's settings (boost).
Pass 2
Was aborted because some rookie left his hood pins out and watched the hood come up at a speed, thank goodness for the factory catch.
Pass 3
The only changes here were some timing adjustments for KR and leaning out of the EQ. Nothing special, just baby steps. The boost curve stayed the same throughout most of 3rd gear as it had before, but there is a bit of an indication of when things went wrong. And it wasn't just the cloud of smoke coming out of the exhaust around the 3/4 track point (which cleared up when I let off, perplexing in the moment).
For reference I hot lapped the car, since I'd only made it to half track and had the advantage of cooling the air off (to street heat levels) before getting back in the staging lanes. Again, in 3rd gear there was a slight tickle of KR which cleared up quickly, and the EQ is cleaning up. It's almost like I know how to tune a car... but, it doesn't mean that the car has to like it. I was WOT through the whole of 3rd gear, but curiously the Dyn AF was down. Curious because the IATs weren't that far out of line from the first pass. It is important to note that the engine isn't being over spun either (I honestly thought the noise I heard was me floating the valves (because of the used LS6 springs).
From what I can see, and logs only tell so much, is there is an event about half way through 3rd where the B1S1 O2 sensor does something weird, as does the MAP (boost does dip), Cylinder Airmass, etc - almost like air is escaping. It looks like this is the moment I went full Dominic Toretto, stayed in it, and was running down the TRX that go way out on me. I got praise from a dude with a sweet '57 Chev for never lifting.
All we can see externally is it blew the PCV line off the PS valve cover and hosed the brand new alternator down with oil which suggests I holed a piston (over reliance on water/meth not enough base fuel - perhaps?) and pressurized the crankcase something fierce, and its smoking out the exhaust which indicates it's burning something it shouldn't be. It didn't window the block (it still has all of the oil it should in the pan)... however, the engine is rattling rather badly, doesn't seem to happy to be alive...
And to answer the question that everyone wants to know: WHAT DID IT RUN, MIKE?
For comparison: left to right are the one pass I made two weeks ago, and Pass 1 and Pass 3 above. Pass 1 had the car picking up nearly 30mph in the back half is huge with the same 1/8 mile trap speed as a few weeks back, so clearly it was making more power despite my part-throttle test pass. Now, notice how on Pass 3 the car was at 92mph in the 1/8? That is the same as my Hellcat but with the Monte being traction limited and with my executing horrible 1-2 and 2-3 shifts to compensate. This thing was making some serious steam and I don't doubt had it stayed together would have matched the Kitty for MPH.
But, hey... its as fast/quick now as it used to be with the nitrous 355 I had in it 20 years ago. All this work really seems worth it, eh?
FML. Back to the drawing board.
I have a tough time reading those logs. I don’t see an 18psi spike in the HPT log? Am I looking at the correct thing?
FWIW, the tear apart is going to tell you what happened. It does sound like you broke a piston. If the other 7 look good and the plugs don’t show sign of detonation, then there is a excellent chance that your tune had nothing to do with this. 7 good pistons and one bad - throw out that injector and coil pack. Time will tell.
Sorry for the crack a couple of post backs. I need to stop that.
Thinking a little more, don’t throw this motor out yet. A bent rod is a cheap fix if you have some spares. And DSPbuilt ’s comment is a great choice for what you’re doing here- a 4.8 is much more resistant to tune issues than a 6.0, and damn it’s fun listening to them spin between 7-8k.
FWIW, the tear apart is going to tell you what happened. It does sound like you broke a piston. If the other 7 look good and the plugs don’t show sign of detonation, then there is a excellent chance that your tune had nothing to do with this. 7 good pistons and one bad - throw out that injector and coil pack. Time will tell.
Sorry for the crack a couple of post backs. I need to stop that.
Thinking a little more, don’t throw this motor out yet. A bent rod is a cheap fix if you have some spares. And DSPbuilt ’s comment is a great choice for what you’re doing here- a 4.8 is much more resistant to tune issues than a 6.0, and damn it’s fun listening to them spin between 7-8k.
HPT only reads up to 16psi, the other log shows the 18psi spike.
Autopsy will reveal a bunch, I am pretty systematic so I will play close attention. I just hope I didn't hurt the heads.
I really want a Gen IV 4.8L. 😉
If I can get the 6.0L for $500 I'll run it for now, it'll make a nice addition to Natasha's Z28 if I don't nuke it too.
Agree. Don’t overlook the Gen 3 4.8’s. They aren’t the same as a Gen 3 5.3 and 6.0..
Last edited:
- Status
