Adjustable fuel pressure regulator question

[Turbo Keith]

A friend has just got a low mile stock GN , He has upgraded the fuel pump and installed a hot wire kit . he then ask me what the advantages to a AFP regulator would be and I couldn't give him a good answer . I know we have one on my car , cause with a fuel pressure gauge it should read 43 lbs of pressure ? I'm I right their ? That is with the vacuum off . He has a scan master on the way also , Any help , Thanks Keith

 

[Jerryl]

Fuel delivery is a function of pressure and duty cycle in the chip. If the pressure is low, the ecm will adjust depending on the chip and settings. If wb controlled AND in closed loop, ECM will adjust the DC but not the best way to do this long term. If runnimg non closed loop, it will be lean since the chip has no way of knowing the fp.

Whatever you decide . . . . STAY AWAY FROM THE NEW ACCUFAB!! The real old units work fine. Here is o b e example of a brand new unit. I am sure Accufab and vendors don't know about this. Lmao.

 

[Turbo Keith]

Fuel delivery is a function of pressure and duty cycle in the chip. If the pressure is low, the ecm will adjust depending on the chip and settings. If wb controlled AND in closed loop, ECM will adjust the DC but not the best way to do this long term. If runnimg non closed loop, it will be lean since the chip has no way of knowing the fp.

Whatever you decide . . . . STAY AWAY FROM THE NEW ACCUFAB!! The real old units work fine. Here is o b e example of a brand new unit. I am sure Accufab and vendors don't know about this. Lmao.

Thank you Sir for the info

 

[TTA308]

Fuel delivery is a function of pressure and duty cycle in the chip. If the pressure is low, the ecm will adjust depending on the chip and settings. If wb controlled AND in closed loop, ECM will adjust the DC but not the best way to do this long term. If runnimg non closed loop, it will be lean since the chip has no way of knowing the fp.

Whatever you decide . . . . STAY AWAY FROM THE NEW ACCUFAB!! The real old units work fine. Here is o b e example of a brand new unit. I am sure Accufab and vendors don't know about this. Lmao.

Right on Jerryl... but i let them know about it loud and clear a few yrs back.. Silence speaks volumes in my mind...

 

[Jerryl]

Right on Jerryl... but i let them know about it loud and clear a few yrs back.. Silence speaks volumes in my mind...

I have seen 4 out of 4 that never sealed.
One had total fuel pressure fluctuation was measured at 7-9 psi, at WOT.

Key words for google searches:
Accufab FPR bad junk horrible leaking not holding pressure

 

[BlackonBlack]

Accufab: bad. Noted!

This may have been answered, and perhaps I just need it restated...


I'm getting ready to install a TT chip on an all stock GN, along with a new Scanmaster. I read on another thread that some are happy with a Bosch 237 FPR.

From what I can tell, most TT chips are burned for 43 psi, and this FPR is sufficient for a set it and forget it mentality.

If I'm looking for a solid and reliable street driver, would this be sufficient? Would the stock FPR need to be replaced in the first place? What is it's output?

 

[john keskes]

Yes go with the -237 . works great

 

[mikestertwo]

Accufab: bad. Noted!

This may have been answered, and perhaps I just need it restated...
I'm getting ready to install a TT chip on an all stock GN, along with a new Scanmaster. I read on another thread that some are happy with a Bosch 237 FPR.
From what I can tell, most TT chips are burned for 43 psi, and this FPR is sufficient for a set it and forget it mentality.
If I'm looking for a solid and reliable street driver, would this be sufficient? Would the stock FPR need to be replaced in the first place? What is it's output?

Yes, go with the Bosch 237. It's very reliable and will work great with your setup. I have one on a 10 sec. car and never have to worry about fuel pressure issues caused by the FPR.

 

[Turbo Keith]

I think BlackonBlack has also read about one that comes already set at 43lbs but it has no adjustments , Would that work ? I told him for tuning purposes he would need one that will adjust , I'm I right in saying that ? and Thanks gor the imput Keith

 

[whitehot1]

I have always used an adjustable fuel pressure regulator since they became available for our cars.Even though i have never had to make many adjustments with one. I do try to save money when and where i can but the fuel system is not one of them. I used to use Kenne Bell and Accufab AFPR's i believe they are or were the same. I now use the one from Kirban Performance and have for a few years now.

You may get lucky by using a stock fpr but i would recommend a performance type AFPR designed for that purpose if it was me. This is my opinion so take it for what it's worth. I will say this in all the years since 1987 when i bought my first GN I have never had a fuel system problem,i contribute this to using the best parts available,not something that might work because it's cheaper.

 

[1984 t-type]

And I was just about to sell my 237 and buy a new accufab.

 

[Jerryl]

And I was just about to sell my 237 and buy a new accufab.

Use the 237.
Thanks for rating my post "old". Not sure why but going to ass-u-me it was a fat fingered rating.

 

[1984 t-type]

Use the 237.
Thanks for rating my post "old". Not sure why but going to ass-u-me it was a fat fingered rating.

Dang my bad didn't even notice.

 

[Frederickdav]

Jerryl can you please educate the nooby and explain what I'm looking at in your picture in #2? Thanks

 

[Nick Micale]

,............. with a fuel pressure gauge it should read 43 lbs of pressure ? I'm I right their ? That is with the vacuum off . He has a scan master on the way also , Any help , Thanks Keith

The base pressure of 43 psi may be fine on most cars, but my opinion is to have more fuel pressure rather than less. Many variables can enter into what base pressure for a given car and build.

The gauge reading may be off, or fuel does not have the octane advertised, or other factors may cause a lean condition, so I prefer to start with more fuel, higher pressure by 2-3 psi, rather than less. Use the O2 values and read the spark plugs along wtth other data from a Scanmaster or Powerlogger to determine what the engine likes best.

Some GN's like base pressure at 55 or 60 psi for modified builds, and this also depends on the fuel and how the car is used/driven.

A rich condition is not good either, but it is less likely to cause damage than being too lean when tuning the car.

 

[Jerryl]

Jerryl can you please educate the nooby and explain what I'm looking at in your picture in #2? Thanks

The FPR is referred to in the API world as a PRV or Pressure Relief Valve. It is a multi billion dollar industry and heavily regulated for many good reasons.

There are many many different types of PRVs and what we are dealing with is in essence the most basic of all, and referred to as a direct spring hard seated valve, vs a soft seated valve. We are dealing with a reverse flow PRV on top of that.

Besides the obvious spring . . . a hard seated valve has a metal to metal seal. The ratio of the seat/disk diameter is a critical element in its operation and . . the disk (or poppet) and the seat (picture) have to be flat with surface finish in the 4 micron level. A well designed PRV wil start to lift or bypass about 92-94% of set pressure.

Now . . . if surface finish is not even close WITH A BURR (as in the pic), the valve will continually bypass and never seal. On a car that runs at say 50% of fuel system capacity, it may not be an issue. If the car requires 80% capacity, it will more than likely be a major issue.

I have been heavily involved with a proprietary design of a much better rail mounted FPR design, which will significantly reduce the negative impacts we are seeing today, but will also never see the market.

Probably more than you wanted to know but wanted to explain the reasoning behind the potential impact to your wallet of crap quality.

Hope this helps.

 

[69RSCLONE]

I have a Accufab AFPR and have always had an issue with bleed off. Keyed it will go to 43 psi then drop to 20 or so in 2-3 seconds. Then hold around there but drop slowly over a couple hours. I pinched off the return and pump will go to 80 and hold, so I know it's a regulator issue. I took it apart, but the seat looks perfect, no rough surface like that picture.

Sent from my SM-G935V using Tapatalk

 

[Pronto]

Fwiw, I found the 237 fp to be 44 when I tried one (while diagnosing my pos Acuflub).

 

[bison]

I've never seen a Bosch 233 or 237 regulator on any 3.8 or 3.0 fail in service. They are very good reliable pieces. Millions of miles of r&d. Millions were put into service


Sent from my iPhone using Tapatalk

 

[Pronto]

Are you running a 237 on any xfi cars?