4.2L FSI => 2.0L FSI HPFP.

[xola3que]

A two parts question.
Did anyone try fitting a 4.2L HPFP into a GTI and does the 4.2L flows any more than a stock 2.0L FSI? They look similar enough to one another w/ all the mounting points. 4.2L uses two L&R pumps and we using one, they are both made by Hitachi. Would be great if we can make it work w/ OEM reliability and not having to pay thousands for APR pumps.

4.2L FSI HPFP
vs
2.0L FSI HPFP


4.2L HPFP

-----------------------------------------------------------------------------
2.0L HPFP

 

[TheEnforcer98]

Are they the same part numbers?

Another question is do the Audi's with the 4.2 have a campaign for replacing the pressure sensor like ours do? Cuz if they use the same model sensor then odds are better that they'd be backwards compatible, yet still slightly different to flow more for the 4.2.

AND, if you think about it, the 4.2L V8, is two BPY FSI's put into a V, however if the one half of the 4.2 was completely identical then it'd be a 4.0L V8, so the displacement of each cylinder was bumped up very slightly, thus making the fuel system need to flow more for each side.

(Above statements are just off the top of my head due to shear boredom at work, lol)

EDIT: The 4.2L is 24.375 ccm larger per cylinder than our cars

 

[The Fed]

That would be a hell of a catch if it's true. I'm thinking they wouldn't be the same part number, even if they were identical.

I'm also thinking the fueling requirements for the 4.2 MUST be more than the 2.0T.

 

[xola3que]

I'll see if I can dig up some part numbers for both L&R of the 4.2 FSI.

 

[The Fed]

Think APR or HPFPUPGRADE would tell us?

 

[The Fed]

I'll see if I can dig up some part numbers for both L&R of the 4.2 FSI.

There's a pump on each head?

 

[The Fed]

S4 4.2, don't know what year, was rated at only 339 HP, 302 torque, so one pump could be smaller.

 

[TheEnforcer98]

There's a pump on each head?

Yup, like I said above, the 4.2L V8 is two BPY's mashed together, with 2 HPFP's mounted right on top one on each head.

 

[xola3que]

yeah, 4.2L FSI using two pumps, one for each cam. The housing could be mirror (from my own speculation) for mounting but whatever the case we only need the internals if they actually similar but better than our 2.0L FSI.

Are those R8s FSI 4.2L turbo'd? I heard the 4.2L was highly reworked/retuned. what's their fuel pumps like?

 

[TheEnforcer98]

Are those R8s FSI 4.2L turbo'd? I heard the 4.2L was highly reworked/retuned. what's their fuel pumps like?

That's my thoughts exactly. The 4.2 FSI is used in such a wide range of Audis from the "mild" S4/S5, to the RS4/RS6, and up to the R8. So logically, if we have problems pushing enough fuel for 250hp, you'd think those HPFP's would be better to accomodate the needs of those engines.

I'm looking pretty hard and cant find a part number for any audi car with the 4.2. My dad has an S5 so if nobody can find it, I'll take a look when i get home.

 

[AndoN]

Is this what you guys are looking for 079127026C?

 

[AndoN]

the updated version on the S5 is 079127026F

 

[utahvwman]

the updated version on the S5 is 079127026F

Looks like 079127026F has been superceded by 079127026J.

 

[xola3que]

yeah exactly
4.2L FSI HPFP
vs
2.0L FSI HPFP

Looks like they are about an exact fit...the million question is DO THEY FLOW MORE? or ARE THE INTERNALS THE SAME?

 

[TheEnforcer98]

Only differences I can see from the pictures is the direction that the sensor is mounted, and the direction that the fitting is facing for the PRV. And of course that the Audi version has 2 threaded brass fittings rather than 1 threaded and 1 barbed.

But there is still a possibility of mechanical differences to flow more fuel.

We'd need ECS to answer that, or better yet a tech/parts guy at a VW and Audi dealer to get both versions and measure the internals and inspect them closely for internal differences.