1.9 Head Gasket How much Boost is Too much? - IDI Engine - VWDiesel.net The IDI, TDI, and mTDI source.

• 1.9 Head Gasket How much Boost is Too much? by Kantdrive55 on 31 Jan, 2007 09:55
• Just wondering how much boost is too much for the stock head gasket.  Had my pump rebuilt and they turned the fuel up about 20% over stock spec.  I make about 28-30psi now.  Should I be worried?  I know what the cummins/ford/and dmax can take, just not my own car.
• #1 by jtanguay on 31 Jan, 2007 10:12
• really depends i guess... at those boost numbers your stock stretch bolts, assuming you haven't upgraded to head studs, might give under the stress.
  
  others on the forum have experienced leakage at 28 psi... and others report no leakage...
  
  i've taken a stock 1.6TD (with an IC) without the 1.9 HG upgrade to 20 psi before... no issues.  depends on your luck i guess  :wink:
• #2 by andy2 on 31 Jan, 2007 15:21
• 28 psi with 20% over stock fueling will probably be ok.I'm running somthing like 120% over stock on 29psi and my gasket and studs will not hold up.Pump timing will also factor in as well depending on how much advanced it is.Which turbo are you running?The biggest bolt on turbo (T3,k24) from a 1.6TD are both hardly adequate for that much boost on a 1.6/1.9.I hope your not running a stock turbo (ko3,t2,k14) with that much boost and no pyro.Your work for BD right?
• #3 by DVST8R on 31 Jan, 2007 17:02
• Psi is really relitive and what we need to be more concerned with is volume.
  
  First thing to address if you are running a stock ko3 / k14 / t2, the most it will do is about 18psi after that it is just hot air, and your drive pressures are through the roof! and Egt's get outta control quickly.
  
  If you are running a k24 / t3 off of a 1.6TD then you have to about 24psi after which you don't gain much either.
  
  I personally have run on a 1.6TD with the stock pump at its ragged edge borderline runaway for fueling and 35+ psi, and probably closer to 40psi, I had a boost controller malfunction going up to the tollbooth on the way from vancouver to kamloops, on the 10% grade. Anyone from the area will know what I'm talking about just after you go through the snow shed. I had my foot to the floor, and the controler failed my wastegate was fully closed and it wrapped my 35psi autometer gauge. This was on stock head bolts, stock fiber gasget, and it lived.
  
  That same car went through 3 or 4 020 transmissions and saw 28-30psi everyday for 8months without a single motor problem and was beat! Many runs in excess of 180km/h and pyro temps in the 1800F range.
  
  I personally know several other people with cars running 24+psi out of stock k24 or t3's and never having problems, intercooled or not, as the volume of air just isn't there.
  
  The headgasget problems I have seen to date are caused by three things:
  -Head or motor resurfaced and not done to spec. Ie: head not perfectly flat.
  -Overheating the motor! this is the leading cause! watch those engine temps, even closer then the pyro!
  -Too much volume with the boost
  
  Now we all know or should know that your 29psi, is not Andy's 29psi.
  Just as I will put this in Cummins terms as your are probably most familiar with that 29psi out of a HX-35 is not equal to 29psi out of a Sledpuller 66, or in duramax terms 29psi out of the stock IHI is not the same as 29psi out of an Aurora 5000.
  
  So what are the exact limits of the gasket, I don't know, but I do know this. Twin turbo's like Andy's are too much, and so is a GT20 at 30+psi, but a stock you can run as much as the turbo will let you and you should be okay.
  
  The one thing I know forsure is the next motor I build will have the head and the block O-ringed.
• #4 by andy2 on 31 Jan, 2007 18:04
• Another thing to factor into headgasket safe max is the engine condition in terms of wear.An old worn out engine(300-375 PSI compression) may handle 35 psi and loads of fuel and high EGT's when compared to a rebuilt engine running the same thing but with great compression say (475+psi).
  
  A tight engine running 28 psi with loads of fuel can have HG issues as compared to a worn engine running 35 psi and alot more of fuel to basically make the same power in the end.
• #5 by Kantdrive55 on 31 Jan, 2007 21:43
• Thanks for the replys guys.  There is a problem inside the pump that is causing some issues so I will have to take it off tomorrow. On the stand it was flowing 65cc. (which seems soo small as we built a p7100 pump for a race cummins that produced over 1100cc of fuel) I understand the whole volume boost thing, just was wondering what I should consider a safe point.  I work for a diesel performance company so I know the pyro is manditory and I do have one.  It is post turbo and I have run 1100 once.  I usually only see 950-1000 on a hard pull with 28psi.  I am going to pull the tag numbers off the turbo so I know which one it is.  The cool thing where I work is we are a Borg Warner/Air Werks engineering shop, we think it they build it.  I have an in house turbo engineer, we have a full turbo rebuild shop.  We are also a Garrett Distributor, so I have access to lots of turbos.  I want 150hp to the ground reliable.  I dont think that will be too hard to get to.  We also have the tool to oring a head so when I have to I can do that.  I should probably just look for a head to build and then just swap it on.
• #6 by DVST8R on 31 Jan, 2007 22:43
• I used to live across the street from BD, litterally, I called them when we were building Malone's Franken motor and they said at the time that there Oringing tool didn't go small enough. If it does let us know, as I know there will be a few people looking that way.
  
  A GT20 is a great turbo as far as spool up and enough flow and will support the 150whp you are looking for.
  
  I totally agree with Andy as well on the low compression of an old motor, as that is exactly what the circumstances with my old motor were. However I run ~30psi (k24 unintercooled) everyday with my current motor and it run 490psi across the board... So I actually don't know. :lol: