so my aftermarkter fuel pressure reglutor went out, it would raise the pressure so high the the fuel line would inflate like a ballon causing leaks. it was tuned on it making 610 to the wheels at 27 psi, i only usually run 15 pounds on this weekend driver maybe 20 max if there is some slight competition, the fpr went out this past weekend, had noticed the afr were going lean around 12-13, it was tuned at 11.5:1 on e85. if i swap out the aftermarket with a stock one will it cause the afr to go really lean, and the tune to be off. how much hp are the stock fpr rated for?

 

its not a matter of HP... You need to get another adjustable regulator and set t back to however much fuel pressure you were tuned for. If you put a stock one back on, the car will likely not even run due to the change in fuel press.

 

if u dont mind what regulator u had

 

it was a b and m

 

I have made 675 on a stock one either get a stock one and retune it or get a new aftermarket one and set it to the same static pressure as your old one

 

Well the b&m is jut a modified stock regulator. You shouldn't be running one of those on a 600 whp car there only good for the 400hp-500 range because hy don't add enough fuel when the boost starts getting up in psi. Pick up an aeromotive for a Honda

 

Lol you dont need it to add fuel just regulate it thats why they call it a regulator

 

should i put on a stock one and retune? i have other upgrades like valvsprings and top manifold coming to i am going to have to retune anyways.

 

the one thing you haven't mentioned is...at what fuel pressure was the car tuned? just because it had an aftermarket regulator doesnt neccesarily mean it was being used to increase the fuel pressure.

if you put a stock fpr on you will get stock fuel pressure. if the aftermarket fpr was also set to stock fuel psi then you shouldnt really see any change in the tune. just keep an eye on afr and you should be fine.

now if the aftermarket fpr had the base pressure increased or decreased then you may have tuning/driveability issues like Gunmetal was refering to

 

+1 on that



Also I made over 400hp on stock reg

 

Apparently you dot know how a fuel system works. Stock regulator is a 1:1 pressure regulator. It increases and dereases fuel pressure in vacuum and boost. So if you base is 50 psi and in 14 psi vacuum your effective fuel pressure would be 36 psi and with 15 psi boost your effective pressure would be 65 psi.

Fuel pressure needs to increase with power production so NO it's not just regulated at one pressure genius it's regulated throughout the vacuum and positive pressures the engine sees

 

The stock diaphragm and regulator usually can't go past a peak of 65 PSI of fuel pressure... Even if it does, you will notice that injector pulse widths are much higher than normal due to pressure oscillations. It's just like getting a B&M FFM (the hat that goes onto the stock unit) and completely bottoming out the screw + a shim, and it can't go much higher because that's the max. Having 30+ PSI on top of that won't change the maximum travel of the diaphragm of the stock FPR.

Having boost reference port hooked up is one thing, but chances are that your peak fuel pressure never went beyond 65 PSI if you had a stock FPR, or a B&M unit from the beginning.

An aftermarket unit like an Aeromotive, or a Weldon, etc.. those can maintain 1:1, so for those high boost setups (25+ PSI), it will achieve full matching rising rate and get 70+ PSI (eg: base of 50, + 25 = 75 PSI).

So to the OP, if your car was originally running a B&M -- and indeed running 20 PSI of boost -- then you can probably get away with putting a stock FPR in there for the weekend. You might run lean in the midrange boost levels because you could have had a higher static fuel pressure with the B&M. However, I don't think your peak fuel pressure would change between the stock FPR or the B&M under full boost.