Adjustable Fuel Pressure regulator

[95talontsi]

My friend bought a adjustable fuel pressure regulator for his gsx because and he's putting on a big 16g, I told him that that wouldn't solve anything, considering we already have a boost reference fuel pressure regulator. Isn't it like putting a band aid on the problem won't really fix it, because of the turbo is not like a roots supercharger that has a linear boost, boost depends of load and can be erratic. correct me if I'm wronge or tell me a reason that I can tell him why he is stupid for refusing to get an afc or a pyrometer.

 

[Enigma_Man]

Well, an adjustable fuel pressure regulator is useful, but I don't think in quite the way your friend is using it.

I have a 16G on my car with no other fuel mods, but I also have the boost turned down real far, and it works fine. I'm guessing your friend wants to run the 16G at a high-ish boost level.

If your friend is thinking of turning up the fuel pressure, to provide more fuel, he's going to run into a lot of problems:

1) If he doesn't have an upgraded fuel pump, the pump will run out of steam anyway, so the fpr will do nothing.

2) Making the fpr provide more pressure will make the car run richer across the board, so your idle, and part-throttle cruising will be rich as well, less gas mileage, spluttering, poorer performance, etc.

3) This still doesn't fix the fact that the ECU is going to see more air coming into the car than before. This will possibly lead to the stock injectors being run dangerously close to, or at their maximum level. The ECU doesn't know about the fuel pressure increase, so the injector duty cycle will remain the same, and the injectors will still be the bottleneck.

4) Just because the car is running richer across the board doesn't really increase by much the maximum amount of fuel flow that the car can see (if you increase the fuel pressure by 5%, you'll only increase max fuel delivery by 5% as well) So, he's only giving himself a tiny bit of extra leeway.

However, don't think that the FPR is useless:

1) The stock fpr can be "overrun" with an upgraded fuel pump, and not be able to correctly regulate the fuel pressure. The aftermarket ones can handle higher volume of flow.

2) It does provide adjustment down the road, when he really knows wtf he's doing with the car, and possibly has to adjust fuel pressure.

BTW, sorry if I keep using the word "you" instead of "him", you know what I mean And also, all of this isn't from personal experience either. So don't take my word as gold. If he really wants to make good use of his 16G, he'll need to get bigger injectors, some method of fooling the ECU into controling them properly (AFC, or VPC, both, or some other system, but those are the most common), and a better fuel-delivery system (upgraded pump)

-Jesse