adjustable fuel pressure regulator

[87 GT MUSTANG]

ok i just wanna no what the deal is with this adjustable regulator, i see everybody switching there fuel pumps from stock to around 155gph-190gph, what exactly does this regulator do to help this change in gph, does it give more hp or trq at all or is it just a simple upgrade from stock, also what would a 155gph fuel pump and regulator set me back canadian. Thanx

[chris91LX]

Switching to an Adjustable FPR can give you up to 10hp according to all the articles and stuff I've seen. It lets you set the fuel pressure to an optimum rate when mixed with the air coming into the chamber. Adj. FPR are good to have even if your car is mostly stock, and a good AFPR like the Kirban is about $75 U.S. Bigger fuel pumps are needed with modifications, the more HP your motor has the more fuel it needs, the regulator then lets you set the pressure to the most efficient Air/Fuel ratio.

[jimberg]

The air/fuel ratio is set by the computer and can only be changed with a modification to the computer. AFPRs are only truly useful if you are at the upper limit of the amount of fuel your injectors can supply at stock fuel pressures.

[chris91LX]

My bad. I didn't mean you can set the Air/Fuel ratio, but you can definitely adjust the amount of fuel being injected by adjusting the pressure to lean it out or richen it up.

[Hethj7]

The first time I was on the dyno I saw a 12 horsepower increase at the rear wheels by just playing with the fuel pressure using the adj. regulator. I don't know that I would have ever got an optimal tune using it on the street, but the dyno made it easy.

[mysweetlx]

Is that true about the AFPR not regulating the a/f ratio? I've always been told that the only way to really "tune" the car is to adjust the fpr. So, a computer chip would be better to tune your motor?

[Dark_5.0]

Yes it would if you get a custom burned chip. The FPR is only useful if you are outgrowing your injectors basicly.

Like I am my 19# injectors are reaching there limit on my 5.0 so I uped the fuel pressure to 45psi.

If your stang is speed density then the FPR is a very usefull tool even with only light mods. The computer wont boost the amount of fuel delivered in a speed density system so you have to manualy do it with the regulator.

[jimberg]

Hethj7, yes, if you are doing a dyno tune you will see results. The problem is that our computers adapt to the lack or addition of fuel. The change you made will be erased by the computer's adaptive strategy.

[mysweetlx]

Thanks Dark 5.0 and jimberg. I've got a JMS chip and plan on installing a AFPR w/ in the next 2 weeks. After it's in, w/ a few other mods, I plan on getting a dyno tune. Once it's dyno tuned, if I get the JMS reburnt, will I see good improvements?

[Dark_5.0]

If nothing else you will optimize your set-up....You should see at least some improvement. At least you will know you are getting the most out of what you have.

Later,