This is on a GSR, but generally in IT trim is it neccessary to have a fuel pressure regulator? If so why and what brand/s are best? Thanks in advance!

Trying to finish this darn car up so I can race it!

 

I would assume that a modern FI car can regulate its own pressure adequately, unless you monkey with the pump or ECU controls of the system. Traditionally, an FPR drops pressure from a pump to the really low numbers preferred by some carbs (e.g., 3-5 pounds for a Weber).

K

 

What he said.

The Spec RX-7s (and ITA RX-7s) like really low fuel pressure (3-4psi). Most aftermarket pumps supply 7psi or so, so a fpr is needed to bring the pressure down.

For fuel injected cars, you'd have to do some dyno runs with a wideband o2 sensor. If you're ecu and stock fuel system can't keep up, you might need the fpr to bring the pressure up a bit.

 

The factory FPR on fuel injected cars runs at a "set" pressure. It uses a combination of a spring and intake vacuum to regulate the fuel pressure. Fuel injected cars run higher pressure (roughly 35-55psi depending on the car) than carburated cars. Depending on how you want to run the car, the factory FPR may or may not be fine. It may be set to be optimal for normal driving conditions. But may not be for WOT high RPM track driving.

If the motor is stock, you might be fine with the factory FPR. If there are any mods and especially if the motor is a full IT build, you may benefit from an adjustable FPR. This will allow you to get the exact AFR and the most power out of the engine. The computer can only compensate so much for the changes made. As far as I understand it the computer tuning and FPR tuning go hand in hand.

I am not an expert on fuel management, but I think that this gives the jist of what is going on. There are probably some experienced engine tuners here that can offer more details at greater depth.

 

I have a adjustalbe FPR on my ITA civic. I put it on there and set it to stock.....

I will be making a trip to the dyno to see if we can pull a few HP, playing with timing and fuel pressure. I would be happy if we could pick up 2 HP up top with it.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jisu009 &raquo;</TD></TR><TR><TD CLASS="quote"> I put it on there and set it to stock.....

I will be making a trip to the dyno to see if we can pull a few HP, playing with timing and fuel pressure. I would be happy if we could pick up 2 HP up top with it.....</TD></TR></TABLE>

That is what I did...you should be able to find a couple of ponies in there. It will only take a couple of psi to make the difference.