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turboteener turboteener is offline
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Quote:
Originally Posted by copbait73 View Post
No, no I didn't suggest a T25 SINGLE on a 3.2 Porsche. Second, this GT25 may not be the compressor on the T25VNT.
Finally, I said I recall T25 singles used on 3.2L DET cars with full restrictive CATs and low power settings. Mainly torquers meant for bottom end power ending around 4000RPM. I think they were GrandAms roughly 88-90 timeframe.
But, using this map, If you look at a Porsche 3.3L with twins you look at say, 3000 RPM, 20#/min at 2.0P.R.(1 bar) and 6000, 48#/min, 2.0P.R. Taking these flow readings at half you are centered on the map.
Actually the VNT can drive you right up the surge line. In this example it's at a full 1 bar at 3000RPM. Obviously this is a problem and the reason why most modern turbos use recirculating inlets and broad range impeller designs to improve the surge line so you can use your more desirable higher flowing turbos.

Oh sorry I misunderstood your post. Yeah I could see GM doing something like that on their big sedans. I bet it did make good torque, but I am sure gas mileage suffered and the engines ran hot. The turbo would be way too restrictive for that size engine. I found some turbo Dodge websites that dissected the VNT. The compressor wheel is tiny. I am afraid it is not worth it. May be great for bottom end but will peter out up top. Don't need lots of bottom end on a 1900lb car.
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Brett
Old 03-03-2008, 08:51 PM
  Pelican Parts Technical Article Directory    Reply With Quote #39 (permalink)