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Re: Question: hp/turbo efficiency numbers absolute? Posted by Kevin K [Email]  (#374) [Profile/Gallery]
(more from Kevin K) on Sun, 24 Dec 2000 14:12:43
In Reply to: Question: hp/turbo efficiency numbers absolute?, Eric van Spelde, Sun, 24 Dec 2000 05:39:30 Members do not see ads below this line. - Help Keep This Site Online - Signup |
What happens at the compressor, regarding air in and out, pressure ratio, and compressor efficency, as related by the map data, is independent of eng displacement or volumetric efficency. You seem to confuse overall efficiency of a turbo system, and or engine efficency, vs the compressor only efficency which I focused on.
Your 2.0 vs 2.3L case is a perfect example: the 2.3 at 17 psi could well be more efficent overall in producing power (less boost => less total heat due to compression), but it could, in theory, be running the compressor at a less efficient point on the compressor performance map, vs the 2L at 20 psi.
The intercooler should not be used to cover-up gobs of heat produced by running a compressor inefficently. It took engineering 'work' to creat that heat in the first place, which has a corresponding amount of work at the turbine, which usually means more backpressure there .... not a good thing. The IC should have to work to reduce the unavoidable heat of compression, and not the avoidable heat due to very inefficient compressors.
Don't blame the US tuners for giving customers what they want. I'm sure most of them (tuners) would prefer to deliver balanced package of internal and external mods, but most customers just want bolt on's, and just want to crank up the boost.
Your 2.0 vs 2.3 power potential question is a bit apples and oranges, so to speak. The better comparison is identical 2.0's, except the latter T25 turbo on one vs earlier T03 on the other. As far as max power potential, the T03 would win, but not by a huge amount. As far as broad power band and response the more modern T25 wins.
I agree with the concept of fast response broad power band .... I'm on record as stating the the T3/4 is a high power race only mod for this reason. For low end on non-trionic, I came up with improved timing curves (see jeff c's site for my info) using and MSD-retard unit, that later evolded into the SPG9-AID advance/retard actuator.
If your stock T03 is a 45 trim, your 260 hp will occur at very low compressor efficiency.
, Fri, 22 Dec 2000 12:21:12, Fri, 22 Dec 2000 15:30:22, Sun, 24 Dec 2000 14:12:43 <-- Viewing This Message, Fri, 22 Dec 2000 17:32:40, Fri, 22 Dec 2000 17:42:09
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