'03 supercharger problem

[wareagle]

I recently purchased a 2003 LC with a supercharger (engine upgrade?). It had one previous owner. 3 months ago, the supercharger caused the engine to 'throw a rod' (service department's words) and break a hole in the engine block. My local dealer replaced the engine and then a test drive blew that engine up, and that was when they realized the problem was in the supercharger. They removed the supercharger and sent it to CA, and after 6 weeks we haven't heard anything about it from the people working on it.

Does anyone here have a supercharger? Since my local dealer doesn't seem to be familiar with them, I have basically no knowledge about it. Are they difficult to maintain? Any help or directions to information would be greatly appreciated!

[ej95cobra]

Since the dealer was working with you, I take it that you have a TRD twin screw supercharger. I'm not familiar with the TRD; but I have a Kenne Bell twin screw on my Cobra. They're pretty reliable but there are some caveats; you can't use regular gas and under boost, there should be a mechanism to get more gas into the cylinders in order to keep a safe air/fuel ratio. The best way to do this is with a computer tune but there are also FMU's (fuel management units) that act to increase fuel pressure under boost. The TRD is about 6 lbs of boost, a mild boost pressure and I don't see where they come with an fmu. The normal a/f ratio is around 14.7/1; under boost I look for 11.5 - 12/1. It may be possible that your engine was leaning out, meaning it wasn't getting a good air/fuel mix under boost. That would lead to excessive heat and the potential for engine failure.

If you use regular gas, you may get pre-detonation; e.g., the air/fuel mixture will explode before the piston reaches top dead center (TDC) forcing the piston back down the cylinder against the force of the connecting rod. This would cause the engine to "throw a rod". Higher octane fuels burn slower allowing the piston to reach TDC before combusting. (Did you fill it up with regular gas?)

As far as meaintenance, I change oil in the KB every 15,000 miles. I use 50w synthetic; it only takes about 1.5 pints. They also suggest that you have a posi-traction (limited slip) rear with a sc to distribute the extra torgue and power. Good luck.