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Old 09-24-2011, 01:40 AM
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KhanTyranitar
KhanTyranitar is offline
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Ok, before your start, need to ask you some questions.

Is your engine turbo ready? In order to take boost and still be able to run reliably on pump gasoline, you need to run forged internals. You need forged pistons as a minimum. The stock pistons are too high a compression ratio. You might be able to push them a little bit, maybe as much as 7 lbs boost, which is a lot of extra power, but at that level, if anything goes even slightly wrong, like a fuel pump failure, vacuum leak, overheating, injector failure, etc, the engine will ping under boost and your pistons with either melt or shatter. In order to reliably prevent that, forged pistons that are slightly dished or have a lower height will lower the compression, which reduced the tendency to knock and reduces the dependence on high octane fuel. Plus the Forged pistons will withstand more heat and stress, so if something goes wrong they won't fail.

I'm not sure how much the stock rods and crank will take, but I'm sure if you stay under 15 lbs boost you are probably ok. Mostly the pistons are the critical upgrade. It is also probably a good idea to run better valves too, try to find performance valves made from stainless steel or that specifically say they are designed for forced induction. Ferrea is a well known brand, they should make something that will work. Stock valves will be ok for mild boost.

Once you have better internals, you need fuel delivery that can keep up. You can either raise the pressure under boost with a fuel management unit (FMU), with a 10:1 ratio. This will force the injectors to flow more than normal to prevent the engine from leaning out. Or you will need to get larger injectors and a custom tune. I personally vote the second route, FMUs are usually just a band aid for not having a proper tune anyway, they do work, but not perfectly.

From there, you need an intercooler too. Even under just mild boost, the performance increase of running an intercooler far outweighs the cost. Plus it adds extra protection against detonation and helps you keep the octane requirements down.

You will probably need a custom made exhaust system too.

Not impossible to do, just expensive. But if you cut corners, it will toast your engine sooner or later. What I have listed here is pretty much the bare minimum, the more boost you run, the more you need to beef up other parts to handle it.

Its ok to run cheaper turbos, especially if you are doing twin turbos and you need to get the tuning right. The cheaper chinese ones last long enough, and are actually pretty descent for the money. Under mild boost and with the right care they should hold up fine and will help keep your initial costs down. No point in sinking $2000 in just turbos when you haven't gotten everything else working properly yet. Get a running setup, then look at more boost and better quality turbos. Just make sure your engine and drivetrain can handle it first.