This was another salvage yard engine just like the first one. This one was probably in better condition than the first one too judging by the better compression numbers. Hard to say though. I beat on this engine all winter on the back roads messing with my boost control and stuff. I kept the boost a little lower than the first one too. It saw like 4 days of autocross with a little rev limiter here and there. It died on run 4 Saturday.

 

Rods breaking like that have usually experienced an over-rev. I log RPMs at the highest frequency possible, even a brief downshift a little early can weaken an engine. Not saying you did it, if it was out of a manual car, could've been the previous owner.

 

Not sure I ever did but possible. It was out of an automatic. I have never found one out of a manual yet. Which is an interesting point. Auto cars are probably less abused because it's not really possible to. I log at 5ms rate. Here is a screenshot.


My plan is to get this engine in, put it on a dyno to see what it is actually doing, lower the rev limiter a little, building a new bottom end, swap it when I can.

 

New engine is in. It doesn't know about those that have fallen before it. I set the hard limit 7000. Turned off progressive cylinder shutoff. So spark retard and then spark/fuel cut at limit.
I need to investigate flat shift. It seems like the engine overshoots quite a bit when the clutch is pressed. I need to log this and see what's going on.

 

It is crazy how the rpm jumps 700 rpm with flat shift. The clutch release and rpm climbs. The switch activates and 40ms the fuel shuts off. I assume the spark is cut off too. But the rpms still climb. Is boost driving the pistons to higher speed?

 

I know very little about flat shift, but does your clutch switch activate at the top or bottom of the stroke? The stock one activates at the top, when you first start to move the pedal.

 

I would double check that spark is being cut. I just checked back on a log of my flat shifting and it looks like it's doing a full ignition cut. I think I tried fuel cut but it might've been too slow like what you're seeing.

 

Top

 

With the power of datalogging and AI to scan through the code base. I can say that spark cut will randomly and progressively drop sparks in the soft limit zone. So unburned fuel is happening. Could that building up and hydro lock a cylinder? I doubt it but who knows. I'll stick with standard fuel cut moving forward. It will hard cut at the limiter and turn on below the soft limit zone. I'll do soft zone timing retard as well.

 

• 414.8 / 1.16 ≈ 357 whp
• 365.8 / 1.16 ≈ 315 wtq
  So, this is a little more boost that normal but it is making power. This is on e85 and stock internals. I fiddled with timing here and there but pretty much pulled 4 degrees across the board because it was only making 10 more numbers, not worth it. So ya, the tune was on the ragged edge but not detonating. E85 is forgiving like that.

 

I agree with dropping the SAE J1349 correction given turbocharged, intercooled. Not many folk do that.

 

Rods don't care about correction

 

Hold my beer.
Building an engine.

 

This thread is ramping up hard in the most nonchalant way.

Specs?!

 

Hopefully not because of another failure? In for built glory

 

No engine failure yet. I hope to keep it that way.
Nippon Racing pistons
Eagle rods
Head studs
valves, guides, springs
Just trying to make a reliable engine that can survive a money shift to 8K and handle 500hp without worry.