OK, a lot of time has passed since our last update on the LSX project and I apologize for that. Please let me explain.
To make a long story short and get to the good stuff I will tell you what happened as briefly as I can. We finished the naturally aspirated version of the engine and it ran good. But truthfully not as good as I had hoped. It made about 500 RWHP and I expected more. I did the math on HP per CID and it was about the same as a cammed LS7. I said to myself, "self, with all of your engine building knowledge and experience, how can this be." (Remember, it’s been more than a few years since our last update and everyone’s knowledge of all types of LS engines wasn’t as great as it is now.) Well, I’ll tell ya.
It was only a few months after this that a customer wanted us to build him a twin turbo LS7 for his Z06. (Which we did and it turned out awesome. But that’s another story for another time.) It was only when I disassembled the LS7 that I realized why the LSX made only about the same HP per CI as the LS7.
I was amazed at what I saw. The LS7 had coated, short skirt pistons, a tiny ring package, CNC ported heads, dry sump oiling, titanium intake valves, 1.8:1 rocker ratio, titanium connecting rods, forged crank and lots more. GM had built a race engine for the street, with all of the HP tricks I used (and even some more) on the LSX!!! Bravo GM!!! Now most of the things that were incorporated into the LS7 I had known about, but I guess I had to see it laid out in front of me to really appreciate it.
Anyway, I drove around the WS6 for a couple of weeks and it ran pretty good. I’m sure it would have been more than enough HP for 99% of the people with a license, but remember, I drove 200 MPH NASCAR stock cars for 10 years of my life and 500 RWHP believe it or not can get a little boring after a while. I’m sure anyone who has ran faster than 11’s at the track would agree. (Right guys) So, I decided to hit it with a little go juice until I could finish the project with the twin turbos it was designed for.
I installed a 200 HP wet plate kit and it really woke it up. I’m sure it would have taken me more than a few days to get bored, but we never made it that long. Here’s where the story starts to come together and you’ll understand why it’s been many years since an update.
One night we were all out having fun and beating on our toys when the engine started knocking. We towed it home and did the post mortem tear down. What I found was a broken rod. It was broke right in half about half an inch above the big end. Naturally I needed to find out what exactly happened so every part was scrutinized very carefully. Bearings and caps all looked good. The bearings showed a perfect wear pattern. Combustion and headers showed good color meaning the air fuel mixture was right. There were no signs of detonation so what happened? After examining the breakage area of the rod under a microscope, it was apparent what caused the failure. There was porosity in the rod that could not be seen on the outer service. The porosity was on the inside of the rod as if the forging was a blem. You would never see this with a visual inspection. This is the kind of thing that takes x-ray or ultrasound to detect. You’re not going to get this type of quality control from a set of $600.00 rods. It goes back to, you get what you pay for and that’s why the best rods are in the $2000.00 range.
So there you have it. The engine sat disassembled for about five years and the WS6 got put back to it’s original state. Not to worry though. We started another project for the LSX to go into and this time we finished it the way we originally planned. That’s right, with twins.