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<x-charset iso-8859-1>Hello- (long, technical response follows... read on only if ya care :-) > http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1866906388 > > Would a T3 benefit from this? Very costly, for sure... Not one damn bit. Take a look: the fancy rails have 5/16" ins and outs. The stock rails have 5/16" ins and outs. What the heck are ya gainin'? :-) And, even if they were bigger, what are you accomplishing? The answer, for the most part, is NOT more flow. Fuel is mostly an incompressible fluid, so it doesn't matter much, especially at this scale. At high flow rates, the smaller the orifice, the larger the pressure drop. So, small lines with high flow (i.e. high power car) make for a steep pressure drop, which means _uneven_ fuel delivery, i.e. the injectors on bank 1 may see a different pressure than on bank 2. Make sense? Those aftermarket ones have another strike against them: they go from 5/16" barb to a big, open chamber (likely 9/16" since that's what 3/8" NPT is), back to a 5/16" barb. Those sudden changes in diameter make for MORE of a pressure drop. Again, whether or not the scale of this pressure difference matters at all is another argument. However, even if one thought there was something to gain, think again... Bottom line: the most important thing for a pulsed injection system to have in the fuel system is DEAD EVEN pressure to all injectors. Now, if you take a look at 1500hp blown alcohol dragsters and note the huge fuel lines going everywhere, remember that this is a mechanical fuel injection system. And, to keep the same goal of even pressure with a high flow rate and a very different fuel-routing system (nothing like a typical EFI), they need this. But, if you apply this big-is-good idea to a little T3, it won't do very much. For example, I built my own fuel rail system for my T4 engine in my T3, as I use modern injectors and a "rising-rate" pressure regulator (i.e. instead of holding a constant fuel rail pressure like stock T3, it maintains a constant differential pressure between the rail and the manifold... this is better for a few reasons). I used common fuel rail stock, which has a 9/16" ID. I then drilled two 17/32" holes to slide in modern Bosch injectors (they don't use anything like the old barb-and-flex-hose setup of the T3). And, I tapped the ends of each for 3/8" NPT. The inlet to bank 1 is 5/16" (same as what was in the body of the car). The line between the two banks is 3/8" line, just to knock down any potential pressure drop a 'lil bit (note: this is the line to make huge-sized if you want an even better pressure distribution). The aftermarket pressure regulator is mounted directly to bank 2 using an AN10 setup (5/8" ID) giving it a nil pressure drop, and has a 5/16" return line (again, same size as what was in the body of the car). The pressure regulator and all four injectors see a VERY even pressure. Perfect? Probably not. Does it matter and do I care? No. It's good enough. :-) If I did care, I'd build the system like we're building Charles's engine. The inlet line is teed to each bank. Then, the exit lines from the banks go to a two-inlet aftermarket pressure regulator, with a single return to the tank. This is even more accurate than what I have. Actually, my pressure regulator has two inlets too, but I'm too busy with other stuff to care to set it up that way - it really doesn't make much of a difference compared to what I have now for my application, nor does it Charles's, but the method we're using for his is prettier :-). Take care, Shad Laws LN Engineering - Aircooled Precision Performance http://www.LNengineering.com ------------------------------------------------ To unsubscribe, E-mail to: <type3-off@vwtype3.org> For more help, see http://vwtype3.org/list/ </x-charset>