found this on BDMs section on SCN. thought it might be of interest to the guys runnig stage 2+ remaps on the TFSI vRS

Logs are from REVO (FPRV = fuel pressure regulator valve)

the extra fuel pressure is what makes the uprated HPFP/2+ such a good mod on the TFSI with the torque increase and midrange gains being immense. and this £30 valve alone seems to add around 4bar on top of that as well so there must be gains to be had,

I know the guys on k04 have noticed very good gains with this valve as well as smoother power delivery.  not many guys have done it with the k03 @ stage 2+ though.  

From BDM the purpose of this valve is it allows you to hold higher fuel pressure which gives your injectors a little more headroom.  

Now with the injectors on the k03 flowing less than that on the k04 TFSI, then maybe gains could be even more noticeable on this engine.  

Anyone considering this?

Edited 22 November, 201015 yr by janner_Sy

found this on BDMs section on SCN. thought it might be of interest to the guys runnig stage 2+ remaps on the TFSI vRS

Logs are from REVO (FPRV = fuel pressure regulator valve)

I know the guys on k04 have noticed very good gains with this valve as well as smoother power delivery.  not many guys have done it with the k03 @ stage 2+ though.  

From BDM the purpose of this valve is it allows you to hold higher fuel pressure which gives your injectors a little more headroom.  

Now with the injectors on the k03 flowing less than that on the k04 TFSI, then maybe gains could be even more noticeable on this engine.  

Anyone considering this?

Yes, I am considering this.

I asked JKM if they could fit this for me when my car is in with them in a few weeks but the advice that I got was that "there is no real benefit in fitting the RS4 valve" and to leave it for now. The part seems relatively cheap but it looks like a bugger to fit

Yes, I am considering this.

I asked JKM if they could fit this for me when my car is in with them in a few weeks but the advice that I got was that "there is no real benefit in fitting the RS4 valve" and to leave it for now. The part seems relatively cheap but it looks like a bugger to fit

yet PDT, back draft motorsport and jabbasport all think there will be gains. as do revo. IMO the fact that even revo think there are gains when they wont make any money out of it, say it all.

Its definitely awkward to fit, my LPFP sensor got changed on mine couple years back after failing by skoda breakdown outside my house, took him absolutely ages, and he said he would never recommend them to do it like that again and would pass it off to a dealer ship.

to be fair id say its probably more important on the k03 when you consider the injectors flow less than the k04 varients, so it gives that little bit of extra headroom

Edited 22 November, 201015 yr by janner_Sy

Very interesting, any idea on price?

Very interesting, any idea on price?

around £30 with an hours labour for fitting.

Linky

probably not worth buying though unless your on a good stage 2+ map that is requesting near maximum fuel pressure, if not you might not reap the benefits

Edited 22 November, 201015 yr by janner_Sy

yet PDT, back draft motorsport and jabbasport all think there will be gains. as do revo. IMO the fact that even revo think there are gains when they wont make any money out of it, say it all.

Its definitely awkward to fit, my LPFP sensor got changed on mine couple years back after failing by skoda breakdown outside my house, took him absolutely ages, and he said he would never recommend them to do it like that again and would pass it off to a dealer ship.

to be fair id say its probably more important on the k03 when you consider the injectors flow less than the k04 varients, so it gives that little bit of extra headroom

Yeah, I should have said that JKM mentioned this in the context of fitting a K04 and S3 injectors. I guess the question is if getting a few bars of rail pressure above requested will translate to gains on the road or dyno to justify the RS4 valve (i.e. the hassle of fitting rather than the cost of the valve). I have heard positive comments about it but they have all been a bit subjective and talked of the car feeling better but without hard data to back it up. Similarly the spreadsheet above shows a clear 'gain' in terms of rail pressure but it would have been nice to see dyno results behind each of the 3 scenarios. Perhaps that info is out there and I just haven't spotted it.

its a relatively newly found mod, that was sourced as a result of guys trying to solve fueling issues they were experiencing when at stage 2+

around £30 with an hours labour for fitting.

Linky

probably not worth buying though unless your on a good stage 2+ map that is requesting near maximum fuel pressure, if not you might not reap the benefits

Will be soon.....

its a relatively newly found mod, that was sourced as a result of guys trying to solve fueling issues they were experiencing when at stage 2+

Tell me about it That's why I started thinking about it although my fuelling issues were probably unrelated to the stock valve

Tell me about it That's why I started thinking about it although my fuelling issues were probably unrelated to the stock valve

lol, your rail pressure isnt requesting enough to use this mate lol

lol, your rail pressure isnt requesting enough to use this mate lol

Don't rub it in! Last time I checked, it wasn't requesting enough to challenge a stock HPFP without any uprated internals

Edited 22 November, 201015 yr by muckipup

Can i rub it in Dave

These are some logs of my fuel rail at Stage 2+

Sorry couldn't resist

carls logs correlate more with the first column of logs in the original post. and thats requesting 2.5 bar less as well

Mine looked like this.....the actual rail pressure was a bit funky but the requested never made more than 102.9 until well up the revs

'230

Rail Pressure Rail Pressure Rail Pressure

(specified) (actual) Difference

bar bar bar

85.02 83.93 1.08

84.93 85.28 -0.35

85.17 85.83 -0.66

85.42 85.25 0.17

85.14 85.44 -0.3

86.13 85.24 0.88

87.54 87.33 0.21

88.81 89.56 -0.75

90.06 91.13 -1.07

91.48 93.21 -1.73

92.74 93.77 -1.03

94.22 94.9 -0.68

95.53 96.42 -0.9

96.79 97.34 -0.56

98.29 99.48 -1.19

99.4 101.75 -2.35

100.15 102.89 -2.74

100.79 102.99 -2.2

101.27 104.46 -3.19

101.62 103.32 -1.71

101.92 103.67 -1.75

102.12 103.84 -1.72

102.24 104.51 -2.27

102.29 103.24 -0.95

102.29 102.34 -0.05

102.29 103.58 -1.29

102.29 103.32 -1.03

102.29 102.63 -0.34

102.29 102.68 -0.39

102.29 102 0.29

102.29 98.85 3.44

102.29 101.43 0.86

102.29 103 -0.71

102.29 102.61 -0.32

102.29 102.54 -0.25

102.29 104.34 -2.05

102.29 102.3 -0.01

102.29 104.51 -2.22

102.29 104.75 -2.46

102.29 105.71 -3.42

102.29 106.75 -4.46

102.29 108.46 -6.17

102.29 105.46 -3.17

102.29 104.15 -1.86

102.29 111.29 -9

102.29 104 -1.71

102.29 97.96 4.33

102.29 102.34 -0.05

102.29 110.76 -8.47

102.29 97.53 4.76

102.29 102.05 0.24

102.29 101.95 0.34

102.29 100.49 1.8

102.32 103.42 -1.1

102.73 95.9 6.83

103.34 99.34 4

104.22 102.23 1.99

105.7 99.52 6.18

107.66 100.47 7.19

110.72 112.85 -2.13

113.62 111.25 2.37

117.49 119.22 -1.73

119.13 126.36 -7.23

120 125.15 -5.15

120.47 123.83 -3.37

120.71 127.67 -6.96

120.84 126.91 -6.07

120.92 128.25 -7.33

112.36 130.37 -18.01

thats the thing, with yours running how it is now requesting hardly any pressure, there is no issue of the HPFP struggling to cope, as a result you have a lot of negative differences and have a positive fuel rail pressure over the requested. essentially you would get sweet FA benefit from this mod at the moment. id be interested to see what tims rail pressure is? APR and GIAC both yield neigh on identical requests to carls above

heres my stage 1, shouldnt have more pressure than your stage 3, but it does!!! :S

Edited 22 November, 201015 yr by janner_Sy

Yup, I don't get what's going on. :wonder:

The first suspect was the map itself but there was clearly something else going on that Tim's car, with a supposedly identical map, wasn't suffering from. It got me wondering if the map had the potential to request the full 130 bar but some other problem meant that the car was limiting the requested rail pressure. That got me to thinking about MAF & MAP sensors to the in-tank fuel pump limiting what was being done on the low pressure side. I dunno. I may be better trying an in-line fuel pump before anything else.

Yup, I don't get what's going on. :wonder:

The first suspect was the map itself but there was clearly something else going on that Tim's car, with a supposedly identical map, wasn't suffering from. It got me wondering if the map had the potential to request the full 130 bar but some other problem meant that the car was limiting the requested rail pressure. That got me to thinking about MAF & MAP sensors to the in-tank fuel pump limiting what was being done on the low pressure side. I dunno. I may be better trying an in-line fuel pump before anything else.

have they sent you your new map update/fix yet

Sounds more like your HPFP is fooked.

have they sent you your new map update/fix yet

Nope. Not too bothered though given my plans :p

Sounds more like your HPFP is fooked.

what make you think that? the actual rail pressure is surpassing the requested across the entire rev range so there is no evidence of it struggling

what make you think that? the actual rail pressure is surpassing the requested across the entire rev range so there is no evidence of it struggling

No, I can't see it failing to make the requested rail pressure...just that it is requesting too low which is what got me wondering if there is some sensor that can limit the requested rail pressure (or if the map fully controls this). I've just come in from checking the low pressure side (just revving on the driveway to SWMBOs annoyance ) which looks pretty good so I've cancelled the idea about a new in-tank pump.

a guy on the GTI forum (usename:trickGTI) has just posted up his logs on a standard k03 car with the std FPRV and the uprated RS4 FPRV.

Even on the standard map it has made an additional 1-2 bar over the standard item, with 10bar increase at the top of the rev band. so thats proof it works. on a standard car gains should be more noticable :yes:

Also @ dave, his standard map requests 109.99 bar rail pressure across the entire rev range.

a guy on the GTI forum (usename:trickGTI) has just posted up his logs on a standard k03 car with the std FPRV and the uprated RS4 FPRV.

Even on the standard map it has made an additional 1-2 bar over the standard item, with 10bar increase at the top of the rev band. so thats proof it works. on a standard car gains should be more noticable :yes:

Also @ dave, his standard map requests 109.99 bar rail pressure across the entire rev range.

Interesting

As mentioned in the other thread, I am not sure how much difference this will realistically make when it's only 1 or 2 bar across the rev range except for at the very top (I guess about 6000 rpm and above) where it becomes a bigger difference. Even then, iirc VCDS logs often look a bit funky with rail pressure at the top end - he was a fair bit over requested rail pressure at high revs even before the RS4 valve. However, I think even the stock FPRVs can be a bit out of spec and vent before they hit the theoretical max. In that case, it's a no brainer.

Lets assume I'm an uneducated goomba when it comes to matters like the type discussed in this thread, in laymans terms what benefit (if any) would this addition offer on a car with only a stage 1 map?

Lets assume I'm an uneducated goomba when it comes to matters like the type discussed in this thread, in laymans terms what benefit (if any) would this addition offer on a car with only a stage 1 map?

IMO looks to me that you would be able to run much more aggressive maps (more for the revo guys who can adjust fueling ) without the likelihood of fuel cut being an issue. the main gain on stage 2+ isa result of the increased rail pressure available due to the HPFP upgrade. this small valve is also providing an additional 1-2 if not more bar of pressure on the fuel rail, which should equate to a bit more shove, and on an aggressive map it should make it easier to make the requested pressure, and maintain the performance without running lean on fuel or suffering fuel cut.

ontop of that as Backdraft motorsport/revo have said, any additional pressure takes the strain off the injectors trying to make he correct flow of fuel as well. BDM also say this will release a good few Hp as well. they seem to have fitted quite a few as well.