The ultimate Dyno Graph thread

[james]

allows you to have 134bar max is 130.


sorry ROH, was not reading what you was saying  lol

[bacillus]

allows you to have 134bar max is 130.

Just to be pedatantic the cracking pressure of the rs4 valve is 136 bar, not 134...   

[james]

allows you to have 134bar max is 130.

Just to be pedatantic the cracking pressure of the rs4 valve is 136 bar, not 134...   

   all ways good to know the correct info

[Keith@APR]

So if you run out of fuel at 129 bar, how does have a fuel rail limit of 136 bar help anything?

Is the theory that you can run the pressure up to 136 so when it dips, it doesn't dip as far?

[56OctyVRS]

I found that i suffered with the old 5200 rpm hesitation at times. With the rs4 valve fitted that has gone away and the power seems more smoother and more eager to go. Well worth the £36 i paid for it.

[56OctyVRS]

So if you run out of fuel at 129 bar, how does have a fuel rail limit of 136 bar help anything?

Is the theory that you can run the pressure up to 136 so when it dips, it doesn't dip as far?

Reading what others have logged is that some cars dont make the actual 130 bar as the oe valve has opened causing a flat spot. So the rs4 valve doesnt open allowing the fuel rail pressure to stay at the requested pressure. Some have also shown it allows a more stable pressure from the low pressure pump.

[Keith@APR]

I found that i suffered with the old 5200 rpm hesitation at times. With the rs4 valve fitted that has gone away and the power seems more smoother and more eager to go. Well worth the £36 i paid for it.

I'm not saying I'm doubting what you experienced, but I can't quite get my head around what could mechanically could be happening that the valve corrects.

A spike in fuel pressure or continuous over pressure from the HPFP in a healthy fueling system would be created by software as fuel is injected into the rail by an ecu controlled valve in the HPFP.

The job of the FPLV is to open and dump pressure in the fuel rail if it exceeds 130 bar or whatever pressure the FPLV is designed to.

The FPLV is not electronically controlled and is just a manual pop off valve.

If you ask for 129 bar in the ECU the only ways from a parts failure I see fuel pressure going above 129 bar in the fuel rail is if the HPFP solenoid is damaged and the valve is behaving erratically, the return fails (clogged or collapsed or some such) or the injectors turn off unexpectedly or get clogged creating pressure to build as the ecu assumes they are firing and fuel is going into the cylinders, the HPLV itself or the high pressure sensor is bad.

I will see this first hand next week and hopefully I'll be able to see data that helps me understand exactly whats happening.

I'll get a RS4 LPFV and try a swap if all else fails first.  I'll report back with what I find out.  Hopefully it is a simple as 36 quid.

[Keith@APR]

So if you run out of fuel at 129 bar, how does have a fuel rail limit of 136 bar help anything?

Is the theory that you can run the pressure up to 136 so when it dips, it doesn't dip as far?

Reading what others have logged is that some cars dont make the actual 130 bar as the oe valve has opened causing a flat spot. So the rs4 valve doesnt open allowing the fuel rail pressure to stay at the requested pressure. Some have also shown it allows a more stable pressure from the low pressure pump.

Ok, that makes sense.

The HPLV is not working to spec as fitted standard.

Might as well replace it with the RS4 bit then unless its significantly more expensive than a later revision standard HPLV.

Is this isolated to SEAT's?

We've never had a problem when asking for 129 bar with the HPLV on other 2.0TFSI's.

Thank you!

[james]

i put one on my car made the mid range far smoother,  then rail was set to 134bar @ wot

[bacillus]

I will see this first hand next week and hopefully I'll be able to see data that helps me understand exactly whats happening.

I'll get a RS4 LPFV and try a swap if all else fails first.  I'll report back with what I find out.  Hopefully it is a simple as 36 quid.

This is from a previous posting (no fighting please because it's done using revo software)...   

[ROH ECHT]

So you ED 30 people do have to upgrade your hpfp as well as opting to add the RS4 valve, correct?

Sorry, I began thinking that you didn't because there wasn't any mention of it being done really or being posted in sig - mods.

[ROH ECHT]

you just need to upgrade your fuel pump mate, that is it.

i am pushing 396BHP at the fly.

What mods/remap got you there? WOW!

[ROH ECHT]

@ ROH, the cams are the same as yours regarding the hpfp lobe, if the ed30/leon Cupra/S3 were different and giving higher pressure, they wouldn't be needing the rs4 fuel pressure valve 

So then why do they have different versions for the S3, ED 30, and Cupra? I had heard that the difference was a slightly larger fuel lobe, but this is turning out to be incorrect info, yes?

S3 BHZ
Cylinder head complete 06F103063P or 06F103063PX
Piston complete 06D107066K
Camshaft exhaust 06F109102D
Camshaft intake 06F109101G

Seat Cupra BWJ
Cylinder head complete 06F103063P or 06F103063PX
Piston complete 06D107066K
Camshaft exhaust 06F109102D
Camshaft intake 06F109101G

Edition 30 BYD
Cylinder head complete 06F103063PX
Piston complete 06D107066K
Camshaft exhaust 06F109102D
Camshaft intake 06F109101G



Normal GTi BWA
Cylinder head complete 06F103063NX
Piston complete 06D107066C
Camshaft exhaust 06F109102B
Camshaft intake 06F109101B

Normal GTi AXX
Cylinder head complete 06F103063NX
Piston complete 06D107066D
Camshaft exhaust 06F109102B
Camshaft intake 06F109101B

[danishmkvgti]

RS4 Valve. One of the best mods Ive done

What difference did it actually make if you don't mind me asking? I was told is wasn't worth bothering with

there is a difference in the valves on the gti, some allow 124 psi others up to 135 psi, it's a gamble whether yours allows the extra pressure of an uprated hpfp to stay or releases it, and at the same time the low fuel pressure also drops. so a mod worth doing IMO 

[ROH ECHT]

So which RS4 valve should I get - B7?