What boost should my 1z TDI be making?? - TDI Engine -General Info - VWDiesel.net The IDI, TDI, and mTDI source.

• What boost should my 1z TDI be making?? by rixy on 10 Aug, 2009 15:29
• hi peeps, i've just fitted a 1z tdi 1.9 engine in my 1996 T4 transporter van, along with a large Front mount intercooler, just wondered what boost the engine should make under load?? Im getting about 12 - 13psi tops?? is this normal??
  
  Also, what options are available for tuning them etc??
  
  Would the pump timing affect boost??
• #1 by blackdogvan on 11 Aug, 2009 09:29
• Where did you mount the intercooler?
• #2 by rixy on 12 Aug, 2009 01:35
• the intercooler is a large T5 transporter front mount item, and is located in front of the radiator,behind the grille, in the best place 
  
  it certainly doesnt drive like its losing boost, but i've never driven on before, so i wouldnt really know??
  
  i was told they produce 15, and should do it even with new intercooler, due to ecu controlling actuator on turbo etc....??
• #3 by rixy on 12 Aug, 2009 12:16
• its a t4, not a t3?? lol boost pressure is measured at the inlet elbow on the inlet manifold, so after intercooler,and right before it gets crammed into the head!
• #4 by rabbid79 on 15 Aug, 2009 03:28
• Quote

  boost pressure is measured at the inlet elbow on the inlet manifold, so after intercooler,and right before it gets crammed into the head!

  Where specifically does the ECU measure boost?  I assume you're using a mechanical gauge to read the pressure yourself.  And where specifically is that attached?  You could easily be losing a couple lbs. of boost through the intercooler all of that plumbing.  In one scenario, it's possible that the ECU is "seeing" 15 lbs. of boost right after it comes out of the turbo, but you are only "seeing" 13 lbs. at the manifold.  Whether or not this is the case depends on where the ECU and mechanical boost gauge are attached, and how accurate they are.  You should also consider that there can be +/- a couple lbs. error either way.
  
  I really wouldn't worry about it.  It sounds like your engine is healthy.  Now, if you were to "chip" it to intentionally increase the boost, and you don't see an appreciable increase, then I'd be concerned.
• #5 by rixy on 15 Aug, 2009 16:44
• cheers for the reply bud...the ecu measures the boost at the inlet manifold, at the same point as the mech boost guage....
  
  however, i did find earlier that the vaules that my MAF should be reading, are a long way from ACTUAL values,so i think my maf is playing up, which will lead to boost problems, and limp mode..
  
  only noticed earlier as i found a fault code summit to do with difference in manifold pressure or summit?? also got a temp sender fault...... so might need a new one of them!!
  
  cleared fault codes, and it seems to go better, but only for a mile or so.....so imguessing they are back!!!
• #6 by G60ING on 28 Aug, 2009 10:13
• My AHU (Same basic generation of TDI as the 1Z) requests 13psi but it often over boosts to 18+ PSI when I'm WOT. I think my over  boosting has more to do with my Intake manifold being a PD unit and my IC plumbing being 2" with no EGR. My N75 valve is new, my vacume hoses are all new and my wastegate is fully functional.
  
  But yes the map sensor in the ecu should be getting its boost level from the IC plumbing. Mine is tapped into the intake manifold. The temp sensor should be located before the intake manifold but after the IC.
  
  Good Luck
• #7 by rixy on 28 Aug, 2009 15:56
• wicked mate, yeah, im getting 16psi now, prob as u say, due to a larger intake manifold,and huge fmic, with pipe work.
  
  I get 16psi at first touch of full throttle, then it back off after a few seconds to about 11 psi? is this normal??
• #8 by G60ING on 28 Aug, 2009 16:11
• sounds about right. The ECU is requesting roughly 13PSI so that sounds about right. Do you have Vag-Com? you can see the millibars that its requesting and seeing.
• #9 by rixy on 28 Aug, 2009 16:19
• i do have vag com yes, but the laptop doesnt have a battery, so i cant try it whilst driving the van, so i can only see it static, and diesels dont make boost until under load!!
  
  when i manage to get vag com working on my other laptop, i can test it whilst going up the road, then i'll be cool :-)
• #10 by G60ING on 29 Aug, 2009 18:36
• buy an invertor so you can plug the lap top into the 12V power plug.
  
  Cheers to another norfolkian
• #11 by rixy on 30 Aug, 2009 14:30
• i tried this...but its not powerful enough to start the laptop up :-(
  
  might have another go tomorrow