Will stock FPR do 3 bar, or close to it?

wild man · 08-22-2009, 10:08 PM

Stock fuel pressure is supposed to be 33-39psi, with mine being right in the middle @ 36. But since I am getting some knock counts @ WOT with the perf mods that I have installed, I would like to try raising it up to the 40-44psi range to see if that helps. What is the highest nominal (no vac) pressure that a stock FPR can be adjusted to?

bearone2 · 08-23-2009, 06:25 AM

it's a 2 1/2 bar reg and not adjustable. 2.5X14.7=36, where you are.
3bar x14.7=44.1, where you want to be.

if you went to bigger injectors(not listed), not enough motion lotion.
many mods require more fuel to operate correctly.

wild man · 08-28-2009, 04:44 PM

Ok, I think I do need 1 then. I thought that the nutted set screw on that diafram looking thingy that is right in front of the fuse box was for adjusting fuel pressure. Apparently that is incorrect. But then, what IS it for?

I posted a WTB for 1 in the classies, but so far no response. And on ebay, there are none currently listed that are 3 bar. Where can they be had?

mitfa911 · mitfa911's Garage

Lindsey Racing sells 3bar FPR

carlege · 08-29-2009, 03:06 AM

Quote:

Originally Posted by wild man

Ok, I think I do need 1 then. I thought that the nutted set screw on that diafram looking thingy that is right in front of the fuse box was for adjusting fuel pressure. Apparently that is incorrect. But then, what IS it for?

I posted a WTB for 1 in the classies, but so far no response. And on ebay, there are none currently listed that are 3 bar. Where can they be had?

before you start doing all that... i would get a Wide Band O2 so you can monitor your Air/ Fuel ratios why do you think you need a 3 bar? usually if you get chips you will need one if the chip requires it

wild man · 08-29-2009, 05:16 AM

Quote:

Originally Posted by carlege

before you start doing all that... i would get a Wide Band O2 so you can monitor your Air/ Fuel ratios why do you think you need a 3 bar? usually if you get chips you will need one if the chip requires it

I think I may need 1 because my fuel injectors are at (or slightly beyond) maxing out at normal pressure (2.5bar). Basically, I'm not really happy with the numbers I'm seeing on the knock counter. That is what is driving my motivation to go 3bar. But I am also looking for a pressure switch to block the non-significant counts from reaching the counter.

I have autothority mass-air chips, and don't know if they "require" 3bar, as I purchased the setup used, on ebay, without paperwork, other than a single "installation instructions" sheet, which could be done without, anyways. But with my free-flowing intake and exhaust mods, along with running 1.1bar of boost @7krpm, I have worries about going lean, especially if I get some bad fuel.

I actually don't want to go this route, because it will hurt my fuel economy, especially during warm-up, when it is at it's worst, anyways. I do have a Vortex FMU, but it is straight-up 10:1, which isn't going to work. What I would REALLY like to get my hands on, is a rising-rate FPR, that can be set to be linear (2.5bar) up to a certain amount of boost - say around 10-12psi, then go rising-rate above that. But I have yet to see such a device available for these cars. Does any1 know if they can be had, and, if so, where?

bearone2 · 08-29-2009, 06:18 AM

i guess you have to decide which is more important, sacrificing fuel economy/3 bar or going lean at 7K.

carlege · 08-29-2009, 06:29 AM

Quote:

Originally Posted by bearone2

i guess you have to decide which is more important, sacrificing fuel economy/3 bar or going lean at 7K.

either way he is going about it all wrong. You need to have in place After market boot gauge and AF wideband before you start adding stuff. Thats how You blow head gaskets and ruin engines. Being able to monitor those simple things can atleast give you an insight to how the engine is set to act

wild man · 08-30-2009, 07:46 PM

Quote:

Originally Posted by bearone2

i guess you have to decide which is more important, sacrificing fuel economy/3 bar or going lean at 7K.

Given the choice... I think I would be more inclined to sacrifice fuel economy. But does any1 make a chip tailored for autothority MAF, AND a 3bar FPR, in an S? There would be no loss of fuel economy in that case.

Quote:

Originally Posted by carlege

either way he is going about it all wrong. You need to have in place After market boot gauge and AF wideband before you start adding stuff. Thats how You blow head gaskets and ruin engines. Being able to monitor those simple things can at least give you an insight to how the engine is set to act

Knock counter is not good enough? I have no plans on additional mods beyond what is already on the car. I do plan on monitoring (narrow band) O2 voltage until
I am sure I'm not going too lean. But due to the variations in fuel quality, I kinda feel more "secure" going by knock counts, rather than stochiometric ratios. I don't see the necessity for an aftermarket boo(s)t gauge, when there is one already built into the car. I basically hate to clutter-up the clean stock look with redundant aftermarket stuff. It is never going to see track use, and, like I said, there are no additional aftermarket performance improvements going into it, so I don't feel the need to get too out-of-hand with extra stuff. I just want to increase my "fuel" safety margin a little bit, from where it is now.

carlege · 08-31-2009, 03:31 AM

Quote:

Originally Posted by wild man

Given the choice... I think I would be more inclined to sacrifice fuel economy. But does any1 make a chip tailored for autothority MAF, AND a 3bar FPR, in an S? There would be no loss of fuel economy in that case.

Knock counter is not good enough? I have no plans on additional mods beyond what is already on the car. I do plan on monitoring (narrow band) O2 voltage until
I am sure I'm not going too lean. But due to the variations in fuel quality, I kinda feel more "secure" going by knock counts, rather than stochiometric ratios. I don't see the necessity for an aftermarket boo(s)t gauge, when there is one already built into the car. I basically hate to clutter-up the clean stock look with redundant aftermarket stuff. It is never going to see track use, and, like I said, there are no additional aftermarket performance improvements going into it, so I don't feel the need to get too out-of-hand with extra stuff. I just want to increase my "fuel" safety margin a little bit, from where it is now.

Narrow band is good for a light show in your car thats about it. for 180 on ebay you can get a good Wideband with Sensor etc

wild man · 07:34 AM

Quote:

Originally Posted by carlege

Narrow band is good for a light show in your car thats about it. for 180 on ebay you can get a good Wideband with Sensor etc

I'm not big on light shows, so there isn't even going be one of THOSE gauges in the car. Just a DMM hooked up temporarily, to make sure I don't go below about 0.8 volts whenever boost is above 10psi. And I'm not really into the hassle (and expense) of going wideband, either. I just don't think that it is necessary for my setup. German products are complicated enough (do I hear, over-engineered?). I don't want to add any additional complications, unless I deem them to be an absolute requirement. I'm not trying to say that it is not a good thing to have - it sounds like you are happy with yours. But I still feel that a knock counter "trumps" it, because it displays the actual cause (detonation) of the effect (blown engine) that I am trying to "insure" against.

Also, I just found out that autothority MAF calls for the use of a 2.5 bar FPR. Time to start considering a different approach, regarding high boost, high rpm, WOT enrichment.

carlege · 08-31-2009, 07:52 AM

ok do what you will.

running_cold924 · running_cold924's Garage

[QUOTE=wild man;4867637]Given the choice... I think I would be more inclined to sacrifice fuel economy. But does any1 make a chip tailored for autothority MAF, AND a 3bar FPR, in an S? There would be no loss of fuel economy in that case.

as for chip in the S, i believe both the S and non-S are identical except for the turbo being a k26/8 vs. the 26/6. i think chip tuning is just based on mods. (exhaust, wastegate setup, intake, turbo, FPR, injectors, MAP/MAF/AFM, displacement) roughly...

wild man · 08-31-2009, 02:02 PM

Quote:

Originally Posted by running_cold924

as for chip in the S, i believe both the S and non-S are identical except for the turbo being a k26/8 vs. the 26/6. i think chip tuning is just based on mods. (exhaust, wastegate setup, intake, turbo, FPR, injectors, MAP/MAF/AFM, displacement) roughly...

I'm curious about that because I know weltmeister makes 2 different sets for the 88 turbo. One set for the standard turbo, and another set for the S, which obviously will also work in all 89 turbos.

Does anyone "have the knowledge" of what the differences in the chips would be?

running_cold924 · running_cold924's Garage

i know that some go by octane rating as well, some areas don't have 93, some have 93+...

nize · nize's Garage

the s and non-s chips are not the same.

wild man · 09-01-2009, 07:51 AM

Quote:

Originally Posted by nize

the s and non-s chips are not the same.

But what IS the difference? Is it just a matter of a different fuel map to support full boost up to a higher rpm?

carlege · 09-01-2009, 08:50 AM

Quote:

Originally Posted by wild man

But what IS the difference? Is it just a matter of a different fuel map to support full boost up to a higher rpm?

Yep i believe you got it