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Old 02-04-2016, 10:52 PM   #1 (permalink)
charnathan
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Quote:
Originally Posted by tonythetiger View Post
so whats the purpose of going to bigger liter from 3.7L to 4.5L?? bigger compression?
i want to go twin turbo but im not sure if my stock internals can hold. im at 103K miles
Yes. A bigger compression ratio will result in more power. But that's why turbo/superchargers are used, so you can gain power at a lower compression ratio.

I'd suggest going through all of the Single and Twin Turbo threads to see what others are doing. From what I gather, the stock internals hold up, but not everyone is running full boost to ≥1 Bar (≥14.5 PSI) all the time. Most of them set up to almost 1 Bar (~13 PSI) just to see how much power they can produce. They are more than likely using a lower PSI (~8-10 PSI) DD. So we can't fully know how the stock internals will handle such power increases due to fatigue.

You also have to understand that eventually, you'll want to go to better internals. Engine manufacturers will only produce fatigue results based upon their power outputs on a stock vehicle. So a much more in depth FEA study must be done for higher power outputs, which most Turbo/Supercharger companies will not conduct since their designs can go onto various amounts of vehicles.

So, I'd say, just to be on the safe side, account for cost of changing internals/ reworking the engine to a larger displacement upfront, so you know your costs. If you don't do it right away, at least save the money on the side for a later date.

Edit: Also, going with just a larger bore size is much more costly than just stronger internals because of the machining and shop time. That's why most will consider doing that, along with a twin turbo to make sure they get their money's worth.

When searching into this, you might want to also look at a different engine too. But that is for a different discussion.

Last edited by charnathan; 02-05-2016 at 12:30 AM.
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