VP44 Tuning and SOI- BMW 320d 136 hp 2001

by **juice** » Thu Sep 18, 2014 12:36 pm

Hello guys, there on internet are many articles regarding tuning of VP44 pump and most of us we know that vp44 is limited.
Any advices regarding the tuning of this PUMP?
Personally i`m running now on my bmw 320d with 2350 mbar absolute pressure and 68 mg of fuel but i`m not sure that this fuel is really present in engine and if pump supports this.
By only making logs i can see only requested ecu fuel..i can write 500 mg, will show but pump will not put this quantity.
What about SOI for rotary pumps? Its a good idea to give some additional degreees ?

by **moz78** » Thu Sep 18, 2014 10:35 pm

Hi, you could gradually lower boost until you get smoke then you would have a rough idea of whats being injected.
I left SOI standard on my audi as I got vibration with the usual 1-2 degrees advance.

by **juice** » Fri Sep 19, 2014 8:53 am

Vibration while driving ? I increased SOi only from 1250 rpm not on idle, well i dont have any vibration on idle and while running i cant feel extra vibrations..only basic tdi sound.
What about SOI in full load area ? some increases ?
What about fuel economy? What tricks did you make guys?
Lowering boost? Increase Soi in part-load ? Open turbo vanes ?

by **moz78** » Fri Sep 19, 2014 3:14 pm

Vibration was at 1500rpm part load above this was ok but no noticeable improvement so I put it back to stock. I have read somewhere that with this pump its not really worth altering SOI

by **juice** » Sat Sep 20, 2014 6:56 am

Why not altering ? Some reasons?
I`m very curious too..because this vp44 pump doesnt work like other rotary pumps..and SOI is different than PD or CR engines..
I want to ask you guys a thing. What you do with SOI after you block EGR ? Advance it or retard it ?
If you take a look at SOI maps, you can see a lot of negative values..well ATDC. IS a must to be advanced after EGR off or can be still stock ?