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you are also wrong ..... Posted by Kevin K [Email] (#374) [Profile/Gallery] (more from Kevin K) on Wed, 4 Oct 2000 16:52:04 In Reply to: no, you are wrong..., Bond, Wed, 4 Oct 2000 15:02:13 Members do not see ads below this line. - Help Keep This Site Online - Signup |
....... regarding same boost, same engine, diff turbos. You are right in that a ported engine will produce more hp then stock, for a given turbo and boost.
A proper turbo upgrade will give more cfm and hp than the smaller, for a given high boost, and engine, and high rpm. It is for these reasons.
1) the larger turbo will have less back pressure, esp if one is pushing for 30% more hp than stock. This backpressure is due to basic restricions of the smaller turbine, and also the fact that the small turbo creates more heat energy in addition to the pressurised flow, so it works harder. This means the VE of the engine increases, since less exh gas is left in the chambers when the intake opens, so more cfm is possible. The reduced back pressure also means less pumping losses, so more hp goes to the wheels.
2) the bigger turbo will be compressing the air more efficiently. So the boosted air will be more dense, providing more engine hp (and less chance of detonation) at the same boost.
So for the same boost, you get more cfm of cooler air, with less hp losses related to pumping out the exhaust and compressing the intake charge.
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