DavidDeco

Got my car back and have been breaking it in.

The biggest problem I am having is I think due to the Rising Rate Fuel Pressure Reg that was installed.

At normal idle and non acceleration/boost, it reads typically between 2.5 and 3.0 and I get about 10-12 A/F on my meter (4 wire 02 unit not stock).

ANY acceleration even without going above 0 boost sends this Fuel Pressure to 5 kg/cm2 and my A/F meter zooms to 8 (the lowest reading) or at best between 8 and 9.

My idle is also really rich (the meter is not consistent on this but it is stable on whichever range it picks...go figure).

Anyone else have a Rising Rate FPR? I have a PowerFc also knew and by putting in one of the non base maps (mostly) I am now getting much better results.

I am breaking it in so boost has never exceed 7 psi and is typically none. A/F seems good crusing but that RRFPR seems to be overly boosting my FP and sending me way rich on any accleration.

Mods below. Thanks.

spigot

iTrader: (4)

First question, what type of rising rate regulator is it?

1) fixed ratio (increases linearly with boost) ex: Aeromotive

2)increasing ratio (increases in more of an exponential curve) ex: M2 rrfpr

From my understaning the first on is the type you want if you have an aftermarket ECU. This allows you to dial in the desired base fuel pressure and maintain the Flow rate even under boost by increasing the pressure to match the boost.

The second type is used when it is not possible to change the fuel maps and you need to add fuel at the top, but not as much down low.

Tuning the second type with a stand alone would be a pita, since there are so many variables to change, if you have to use one of these with an aftermarket ecu, I'd suggest setting the pressure at idle for what you want and then apply a pressure source to the fpr and set the rate as close to 1 to 1 as you can. ex: base pressure 45psi @ 0 psi boost, 59psi @14psi boost. This way you have less to worry about since the PFC will give you all the adjustability you will need.

Matt

DavidDeco

Well, I ordered it from I think Rotary Extreme. (I'll have to check receipys, I've ordered over $10k of parts in the last 2 months doing this project). It was supposed to be the SX Press Reg I believe but it said Walbro on it. Just fyi. I'm a bit new to modding my FD and this is all going on at once.

I think its exponential. There is no in between anyway. It's either around 2.5/2.75 or its at 5 kg/cm2. It's been 600 miles or so and I've never seen it in between. The transition is immediate. No flux whatsoever although I do see at times 2.25 to 2.75 at idle. The 5.0 is solid though.

At 2.75 my meter reads pretty well. That all goes way Rich on ANY accelration, independent of positive BOOST. I can go from -20 vac to 0 boost psi and it still shoots to 5. Both my Boost gauge and PFC match so its not a reading error I believe.

My mechanic mentioned something he could do to delay it so that it only goes on boost. He seems pretty competent on normal RX stuff (they are a specialty shop on Mazda's) but he admits a lot of what I threw at him is new to him so I want to be a bit cautious since he hadn't done a RRFPR or PowerFC before.

I think the problem is with the RRFPR. There's no way in my very novice opinion that fuel pressure should shoot to 5 kg/cm2 on almost any acceleration.

maxcooper

I'm running the stock regulator with a beefy fuel pump, and my pressure jumps when the fuel pump goes on high-speed, as best I can tell. If you have a kinked or otherwise restricted return line, the jump would be even greater. Try to accelerate at 0 psi and see if the pressure drops as the RPMs rise. If so, you might have a fuel return line issue.

If you have an SX regulator, you don't have an adjustable RRFPR, but rather a 1:1, which is what you want for your setup. Does the regulator have an air bleed adjustment valve on it? If so, you probably have an adjustable RRFPR.

-Max

DavidDeco

Accelration at 0 psi still increases fuel pressure. Dont think its the return line.

I'm lounging around but I'll check the air bleed adjustment valve tonight or tomorrow. SX may have just stuck in my head. I doubt it's 1:1.

David

DavidDeco

Just a little more info...

We put a delay valve in there and I drove it around to see how it would work. I noticed that now it would jimp from 2.75 to 5 and a new 4.2 or so reading.

Anyone else have a RRFPR?? Just curious what you are seeing for comparison. 5 kg/cm2 seems so high (72 psi) .

I'm new to a lot of this modding but this seems extreme and the unit is connected correctly I'm told now.

Wade

iTrader: (1)

For the mods you have, those 1300cc injectors are far big enough and you really don't want to use a RRFPR. Depending on your fuel pump, running high pressure like that with such big injectors might actually cause to the pump to be inadequate and stop dropping pressure at high boost and RPMs. If this is the case, it would be far better to run lower pressure and have steady fuel pressure while boosting.

It would be much better to use a standard 1:1 adjustable unit. Even without the help of the fuel pressure your car is probably going to run pretty rich.

After getting your fuel pressure under control, you should spend some time with a wideband lambda meter to get your fuel dialed in. Relying on your GReddy unit for tuning would likely be a mistake.

Wade

DavidDeco

Yeah, I already had plans for dyno testing this week but had to push it back because of other issues. I'm just using the Greddy as a guideline (not that I can't smell it either).

From reading the forums, it seemed like a RRFPR was a good idea and recommended by some. I was already considering taking it out for now until all else is set.

When would I want to use one then?

DavidDeco

ah screw it. From feedback on this board and 2 others via phone, I'm ditching the Rising Rate and got a 1:1 Raising Rate per all the advice. Hell what's another $200 more now

Part for sale