z-ya Posted July 15, 2003 Share Posted July 15, 2003 Is the 280ZX Turbo FPR the same as the 280ZX NA FPR? Pete Quote Link to comment Share on other sites More sharing options...
fl327 Posted July 15, 2003 Share Posted July 15, 2003 turbo fpr is 36psi at idle, goes 1:1 on boost i think NA is like 19psi at idle, dont know if it can reference boost. Quote Link to comment Share on other sites More sharing options...
z-ya Posted July 15, 2003 Author Share Posted July 15, 2003 All of the FPRs have manifold reference capability. The turbo and NA FPRs look identical. I have an NA one int here now, and the pressure is around 38psi (1000RPM). I'm just wondering if the turbo FPR is a rising rate, or is it the same as the NA. Pete Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 15, 2003 Share Posted July 15, 2003 They are the same. Both are manifold referenced, about 37-38 psi. Quote Link to comment Share on other sites More sharing options...
280Zen Posted July 15, 2003 Share Posted July 15, 2003 ok, maybe a stupid question, but if they are the same then why does MSA sell different Rising Rate FPR for the NA and Turbo Quote Link to comment Share on other sites More sharing options...
DAW Posted July 29, 2003 Share Posted July 29, 2003 They are calibrated differently. The max psi the na regulator delivers is calibrated to occur at zero manifold pressure, while the turbo is calibrated to a positive (zero + boost psi) manifold pressure when max fuel pressure is delivered. DAW Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted August 11, 2003 Share Posted August 11, 2003 Calibrated? If they have a vac port there's no calibration to speak of - they're 1:1 which is what you want. I've used generic "N/A" regulators on forced induction cars plenty of times - they work fine. The only time I've ever seen one specifically for forced induction is when it's being used as a "crutch" ala FMU and has a greater than 1:1 rise in fuel pressure. It works like this - 1psi (for lack of a better term) of vac lowers fuel pressure by the same amount. 1psi of pressure raises it by the same amount. However the fueling to the injector remains the SAME. Why? Well, in vac the engine is attempting to draw fuel through the injector like soda through a straw - the fuel pressure is reduced as a result of not needing the additional pressure to inject the fuel. Under boost the opposite occurs and must be counteracted - boost is attempting to push the fuel back up the injector and into the fuel tank. Make sense? You could certainly use an FPR with NO vac connection but this would make tuning the fuel a nightmare and under boost might push back enough that the injector wouldn't be able to provide enough fuel or distribute it correctly. This is one of the reasons I HATE FMUs - they make tuning a nightmare since you no longer know how much fuel the injector is oging to actually be spraying at any given time - even assuming the silly thing raises pressure correctly (not often). Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 11, 2003 Share Posted August 11, 2003 I think DAW was referring to the difference between a rising rate (like the cartech piece) FPR for turbo vs. n/a. In this case, what he said makes sense - a rising rate FPR for a turbo would do nothing on an n/a car, since you would never get to the non-linear part. I'm still not convinced that the RR FPRs actually do anything on n/a cars, though (i.e., I don't know if they actually calibrate them differently). Quote Link to comment Share on other sites More sharing options...
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