Please know I have mad respect for what you guys have accomplished power-wise on a Dyno Dynamics.

I have also had two CT9As, and I will just say I disagree on the engine strength. I don't recall seeing 4G63s chipping piston crowns off like that, no matter who tuned them. I don't want to get too much off topic, so lets try to keep this about the 4B11 failures.

 

There where threads almost exactly like this in 03' when the Evo's first came stateside and people started to tune them. I've mentioned this before, but people for some reason like to ignore how ironic this is.

- Bryan

 

I am reading this thread thinking the same thing. This is the same conversation i read about years ago on the 4g63 evos.

 

Did they revamp the internals after that? Or did people just figure them out more? My 03 had original internals and I sold it with 55k miles on it.

 

i think it was more of a learning curve on what the motors did and didn't like in terms of tuning.

 

Anyone else with pictures are welcome to step forward and we will add pics to the original post.

 

Here's mine...#4 piston, all others are clean.





Originally posted here
https://www.evolutionm.net/forums/ev...-thread-4.html

 

Here's one from the results of miss shifting and over reving to god knows what RPM:





The intake valve smacked the piston and the valve head actually broke off bouncing around in the cylinder

 

That looks just plain wrong...

 

Yours does resemble the rest however there is a distinct melting of the piston which either was caused by a lean condition or a hotspot developed after the initial breakage.

I am not going to lump yours into the group just yet.

The pic Sic provided obviously was a mechanical driver error and not what this thread is directed at.

 

^Either way I chalked this up to ring land failure or bad injector, just figured I'd share...

 

Just wanted to put are 2 cents in that we are i guess very lucky that we are making 600 wheel on stock motor with no problems on 93 octane on 27psi on a 6765 billet. Hopefully tomorrow at the track in Orlando ares is guaranteed not to do the same .

 

I think it has a lot to do with tuning i think everyone is going off previous evolutions and with the newer designed motors . As well as every car and motor is never the same one ring land or compression can be different than other car . Just say tuning is a big part.

 

was it my eyes playing tricks or is it true that the failures stats are mostly limited to the same piston # on the engine?

could it be the manifold design, that provides better VE (airflow) to it thus leaning that cylinder out? i believe most of us are using a single WBO2 post turbo, such a lean out will not be spotted unless we have 4x WBO2 and will not solved w/o the ability to tune each cylinders individually.

btw, how many wires does the stock O2 sensor has? both pre-cat and post-cat. I've noticed many modern cars come with WBO2 STOCK .. and some of them actually run close-loop under all conditions.

 

Actually I turned my motor to 8500+ at the track several times with no "known" issue. I'm sure the valvetrain was completely out of control with these little soft springs. When mine let go it was at 4000 RPM. It really can't be compared or analyzed here given the large shot of nitrous Not the same at all.

Just for fun...I wonder what happened first....chicken or egg? Logs are good, all plugs are perfect, etc.

Whoops! This cylinder had piston to valve contact. Bent 2 intake valves, split piston in half, snapped rod in half. If you look close, the same piston ring land area is broken near the intake valve, but I imagine from breaking the rod


See piston broke in same place others are having breakage. Gotta wonder about their p2v?


Ignore the carnage on the left. Notice the middle rod snapped in half and rod bolts in tact. Also, other than the wrist pin being ripped out, the top of the piston and ring land area is fine.


Bottom line, I over powered the rods and **** broke loose, in my opinion. No evidence of a tuning issue or ring land failure. If I had just had the ONE damaged cylinder with the p2v contact I'd be looking there, but the 2nd rod with the clean break says otherwise. 700wtq @ 4000 seems like too much for that little toy rod