how much boost with stock manifold? (CAD pics inside) - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• how much boost with stock manifold? (CAD pics inside) by gldgti on 04 Nov, 2010 23:33
• Hi All,
  I am currently running my aaz up to 25psi with the stock manifold (using merc t3). If anyone saw, it made 110hp at the wheels on the dyno the other day. Anyway, I'm in the process of designing/making a new manifold to squeeze in front of the turbo with some runners and duel plenum (see pics) but just thought - is anyone else running this much boost (and since its a merc t3, its actually quite a lot of air flow) through the stock manifold?
  
  I still have stock headbolts.... just worries me a little the thought of all the preferential feeding to cyls 2 and 3
  
  pics of my new manifold design for your interest:
  
  
  
  
  
  
  
  I plan on using the flange->90 deg turn from a 1z manifold I have cut up for the inlets, and fabbing up the rest. Desinging it in cad gives me the convenience of getting the flat panels laser cut from sheet to the right shape so all i have to do is tack and weld them together.
• #1 by theman53 on 05 Nov, 2010 06:05
• Just an idea. My mani that I can't use is shaped similar, see my build thread for pics if you want. You will have to take the intake off to get to the valves if it is like that. If you are designing then building it is something to consider.
• #2 by gldgti on 05 Nov, 2010 13:46
• Libby, see my post in the other thread re my design.
  
  In australia, mk2's are rare and mk2 diesels non-existent altogether, so not sure what this manifold your talking about looks like, but i'm interested to see a pic...
  
  theman53 - i thought about valve cover access, and i have dimensioned it appropriately so I can still remove the valve cover. I saw the pic of your manifold in the other thread, it looks a bit 'lower' on the underside. good point to consider though. I think I will measure up the head and put that in the 3d model as well, so that i can be 100% sure of the design.
• #3 by bugnut on 05 Nov, 2010 17:47
• Here is my try at the dual plenum design.  To say the least it bent my rods.  That was at 30 psi. I think the water injection didn't help any.  All the rods were bent just a little bit more the the other starting at number 1 as the most and working it way down to #4 being not bent at all.  My slit from on chamber to the other is 110% the intake opening.  That is a number I found somewhere and went with it.  I might try and make another one with 85% opening and open up the second plenum to the same volume of the engine or a little bigger.  Maybe 2 liters. 
  
  
  
• #4 by carrizog60 on 06 Nov, 2010 04:47
• why not a 1Y manifold?
  i have one on my passat 1.9td and is less work involved...
• #5 by gldgti on 06 Nov, 2010 21:04
• 1y manifold would be nice, but none in australia - want to find one ofr me and post it to me?