Since the motto of this site is fast on a budget, can I get some input on a cheap 1:1 FPR? Normally I'm not one to skimp on things, but since I am trying to get my car track ready on a very strict budget, everything helps.

Anyone running a Megan Racing or similar ebay FPR? If so, have you blown your engine yet? Or is the FPR still working as it's supposed to.

 

1:1 is the same as a factory fpr.
for best results, you're going to need either and adjustable rising rate fpr or one that uses discs. you'll also need a wideband to dial it in

 

I bought the cheapest, highest quality "looking" FPR I could find

 

Are you sure the factory is 1:1?. I was under the impression it held at 38PSI through the whole RPM band. I have an aeromotive on my RX7 which works very well, however I don't feel like paying $200 for one for the Miata.

1:1 means one PSI of fuel pressure up per PSI of boost. And anyways, I want one to bump up the static pressure and for a more stable pressure under boost. I know I need to tune for it... that's all taken care of.

 

brain... that's a 1:1? How is it working out for you? Did you disassemble it to inspect the diaphragm and castings at all?

 

yeah 1:1 used it for a few months worked as it should, raise the idle pressure slightly to get more headroom. didn't take it apart, it was riveted iirc.

 

Try and find a used Greddy FPR or a used BEGI wastegate if you can.

 

wastegate?

 

FM has some BEGI RRFPR listed for $125 on their past deals of the day page at the bottom

 

I got mint condition greddy FPR for sale. Pm me.

 

ive run an ebay fpr before to try and stabalize my fp at idle with a walboro 255 hp and the one i bought was garbage no matter how much i adjusted it i had 60+ psi fp, and i know my clycerin filled gauges where accurate. In my initial setup i ran a obx 12-1 fpr with much succes wes has it now. Why are you looking for another fpr man? The stock one isnt an issue unless you just put a realy big pump on there like me. fwiw my diy dual feed mod smoothed the pressure down alot and put me back into the stock range i dunno how but it did.

 

Just doing what I've done on the past 5 cars I've built. Larger injectors, dual feed, fuel pump and AFPR. So what you're saying is if I run a 190 walbro I should be fine with 460cc injectors? I'll still never use the injectors to their full potential...

I just want a solid pressure with no fluctuations. Makes tuning a lot easier.

 

FWIW I have Brain's old FPR and it works fine.

 

yeah stock fpr will be just fine.

 

oh, so you don't want a simply 1:1 FPR you want a silly AFPR with bandaids.

Your formula doesnt make sense. The stock ECU cannot handle larger injector so it's flawed there, there's no need/benefit/gain for a dual feed, and with an AFPR you'll have too much fuel especially over 5K. You aren't even touching timing.

To run 200rwhp with the stock ecu you'll need 265-305cc injectors, an AFPR, a fuel pump, and a timing device. You'll fueling will be less than ideal and go rich as **** above 4.5-5K. What sort of tuning do you actually expect to do, honestly?

I urge you to compare the cost/benefit of simply a standalone MS unit + 460-550cc injectors vs. slightly larger injectors, an AFPR, a Bipes/MSD, and a fuel pump.

With the affordability of the MS unit, there's no reason for anyone to ever put together an inefficient band-aid setup ever again, unless they were building a Lemon or GRM Challenge car.

 

Sorry, no... I mis wrote that. I thought AFPR stands for adjustable fuel pressure regulator. I guess it means something different on this website.

I want to raise the stock fuel pressure with an adjustable 1:1 and potentially run my RC 360cc injectors or just keep stock pressure with my 460's and just have nice solid pressure all the way to redline. A quality aftermarket FPR will hold solid pressure better than the stock one.

I will be getting one of your megasquirts eventually. I've never even had the slight inclination to go with bandaids. I don't half *** things.

I've built more than a few +500whp cars, and know the proper way to get things done... reliably.

That's why I made this thread. Typically I would go with an HKS which I used on my GTR, or an Aeromotive which is currently on my FD RX7, but I'm trying to cut costs where I can. The FD takes most of my cash flow for cars and I need to get teh Miata running well on the cheap.

 

GOOD for you, skippy. Good for you.

 

I would raise pressure and run the 360s before I ran the 460s on stock pressure...especially if you've never had the RX7 injectors clean. This route also nets you the more stable pressure benefit, in addition to a better spray pattern and flow matched injectors.


Of course all of this is pissing in the wind with bandaids. The crap in the rest of your post about doing things right, and then saying you'll "eventually" get a real ECU just don't mesh. Not trying to be rude, I just know how much it sucks to swap motors.

 

The factory FPR on '90-'97 cars is 1:1, with a calibration of around 40-45 PSI or so above reference.

As a result of this, it maintains a relative pressure of 40-45 PSI throughout the engine's whole operating range, as measured against manifold pressure.

On the '99 and later cars, the FPR is configured to maintain a fixed pressure of around 55-60 PSI relative to atmo, without regard for manifold vacuum.

 

nah man brain mistook your post your fuel pressure will good and stable as joe posted a few mins ago. And you can run up to 550's realistically on the stock rail with the stock fpr, pressure etc. Its just people like me who went way oversize on the fuel pump who need another fpr for more flow sometimes.