If you're just tuning in, we're installing a Trick Flow GenX top-end engine kit, which features 225cc CNC-ported cylinder heads, a camshaft with 228/230-degrees duration at 0.050 and 0.585/0.585 lift on a 112-degree LSA, and the parts and hardware required for the swap. In addition to these parts, we went ahead and got an adjustable double-roller timing set from Trick Flow, and three new gaskets from a local GM dealer.
In the last installment, we discussed the attributes of the new parts and why we chose them. Then we began the disassembly to remove the stock parts from the engine. After we took the driver's-side cylinder head off, our hearts sank, as we stared at four piston tops that seemed to have been damaged by detonation. At that moment, the potential power gain from the swap didn't seem that important, as our nearly 80,000-mile Goat appeared to be wounded.
We pick up where we left off...
We pick up where we left off in Part I, where we were about to take the cylinder heads off. This is not what you want to see when you remove a cylinder head. There was some indication of detonation and the pistons were very rough to the touch, but looks can be deceiving.
There was an eerie silence throughout the HPP Tech Center, as we started to scrape off a large accumulation of carbon on the pistons. Happily, beautifully clean piston tops were revealed underneath. Though it took the three of us-Johnny Ramirez and Joe DeRosa of D Revolution Motorsports, and myself-a few hours of tedious work, it was incredible to see that they looked brand-new, even after all those miles and hours of track time.
Carbon looks like a thin layer of soot over the piston tops and is a natural byproduct of the combustion process. Many car manufacturers clean the carbon out of engines during routine maintenance, as indicated by the warranty. Excessive buildup can hurt engine performance and fuel economy, and have negative effects on the combustion process. To prevent this, Johnny and Joe were quick to offer their new billet catch can system for LS-series engines.
Internal combustion engines build crankcase pressure that must be properly ventilated. On newer engines such as our LS2, this crankcase pressure is bled off in small amounts into the intake manifold or, as in our case, the atmosphere, because of a previous modification to the PCV system. Off our passenger side head, there was an atmospheric vent and we still had the traditional vent into the intake manifold. It was clear that the engine was beginning to favor the intake manifold for relieving the crankcase pressure, as indicated by oil deposits in the intake runners. The catch can will retain the OEM intake recirculation, but filter out the oil that is in the pressurized air before it's added into the intake. The oil accumulates into a small canister where it can be poured back into the crankcase or properly disposed of.
The pistons were simply covered...
The pistons were simply covered in a thick layer of carbon-some of the thickest we had ever seen. Underneath it were shiny, perfect condition hypereutectic aluminum LS2 pistons. What a relief! It took several hours to get it all off, but the results were worth the effort.
Does it increase performance? Not really, but it absolutely doesn't hurt performance when installed correctly and is used more as a prevention plan than anything else. What it will do for us is hopefully avoid excessive carbon buildup after another 40,000- or 50,000 miles and keep the GTO running clean.
With a clear road ahead of us, the crew from D Revolution Motorsports was ready to put the pieces back together and get the LS2 running again. Our shiny Trick Flow 225cc GenX LS2 heads and Track Max LSX cam were ready to go and we contacted Ryan Krummick at SCT about getting the GTO tuned for optimal performance and engine safety. Following the install, we saw substantial gains on the dyno (see chart). The power level we have reached with our 364ci LS2 thanks to the Trick Flow GenX top-end engine kit is right where we want to be. Mid-400 rwhp is very controllable around a road course and is enough to give us some respectable speed on the straights. What's the most impressive to us about this LS2 is that we're running a mildly ported LS2 intake and not an aftermarket FAST 102mm or a Fasterproms Stage II ported intake. So there is more power left on the table. Maybe for another day but, for now we plan to enjoy what Pontiac gave us and embarrass some Corvettes around the twisties and down the straights!
Look for more coverage and videos online at www.highperformancepontiac.com.
We would like to extend special thanks to everyone who contributed to this article by putting in long hours and/or providing their technical expertise: Johnny and Joe, Ryan Krummick from SCT, SCSS, SpeedHut, and Trick Flow Specialties.